WO2016011201A2 - Epha4 cyclic peptide antagonists for neuroprotection and neural repair - Google Patents

Epha4 cyclic peptide antagonists for neuroprotection and neural repair Download PDF

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Publication number
WO2016011201A2
WO2016011201A2 PCT/US2015/040649 US2015040649W WO2016011201A2 WO 2016011201 A2 WO2016011201 A2 WO 2016011201A2 US 2015040649 W US2015040649 W US 2015040649W WO 2016011201 A2 WO2016011201 A2 WO 2016011201A2
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hours
epha4
seq
apy
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WO2016011201A3 (en
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Elena B. Pasquale
Philip Dawson
Stefan J. RIEDL
Erika OLSON
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Scripps Research Institute
Sanford Burnham Prebys Medical Discovery Institute
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Scripps Research Institute
Sanford Burnham Prebys Medical Discovery Institute
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Priority to JP2017501706A priority Critical patent/JP6847824B2/ja
Priority to US15/326,442 priority patent/US10322161B2/en
Priority to EP15821503.8A priority patent/EP3169344B1/en
Publication of WO2016011201A2 publication Critical patent/WO2016011201A2/en
Publication of WO2016011201A3 publication Critical patent/WO2016011201A3/en
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    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61K—PREPARATIONS FOR MEDICAL, DENTAL OR TOILETRY PURPOSES
    • A61K38/00—Medicinal preparations containing peptides
    • A61K38/04—Peptides having up to 20 amino acids in a fully defined sequence; Derivatives thereof
    • A61K38/12—Cyclic peptides, e.g. bacitracins; Polymyxins; Gramicidins S, C; Tyrocidins A, B or C
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61P—SPECIFIC THERAPEUTIC ACTIVITY OF CHEMICAL COMPOUNDS OR MEDICINAL PREPARATIONS
    • A61P25/00—Drugs for disorders of the nervous system
    • A61P25/28—Drugs for disorders of the nervous system for treating neurodegenerative disorders of the central nervous system, e.g. nootropic agents, cognition enhancers, drugs for treating Alzheimer's disease or other forms of dementia
    • C—CHEMISTRY; METALLURGY
    • C07—ORGANIC CHEMISTRY
    • C07K—PEPTIDES
    • C07K5/00—Peptides containing up to four amino acids in a fully defined sequence; Derivatives thereof
    • C07K5/04—Peptides containing up to four amino acids in a fully defined sequence; Derivatives thereof containing only normal peptide links
    • C07K5/12—Cyclic peptides with only normal peptide bonds in the ring
    • C—CHEMISTRY; METALLURGY
    • C07—ORGANIC CHEMISTRY
    • C07K—PEPTIDES
    • C07K7/00—Peptides having 5 to 20 amino acids in a fully defined sequence; Derivatives thereof
    • C07K7/04—Linear peptides containing only normal peptide links
    • C07K7/08—Linear peptides containing only normal peptide links having 12 to 20 amino acids
    • C—CHEMISTRY; METALLURGY
    • C07—ORGANIC CHEMISTRY
    • C07K—PEPTIDES
    • C07K7/00—Peptides having 5 to 20 amino acids in a fully defined sequence; Derivatives thereof
    • C07K7/64—Cyclic peptides containing only normal peptide links
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61K—PREPARATIONS FOR MEDICAL, DENTAL OR TOILETRY PURPOSES
    • A61K38/00—Medicinal preparations containing peptides

Definitions

  • Ephrin (Eph) receptors are a large family of receptor tyrosine kinases with many functions in physiology and disease. They bind their activating ligands, the ephrins, mainly through a high-affinity binding pocket located in the N-terminal ephrin-binding domain.
  • Each of the five ephrin-A ligands can bind to most of the nine EphA receptors and each of the three ephrin-B ligands can bind to the five EphB receptors.
  • a cysteine-rich region and two fibronectin type III domains connect the ephrin-binding domain to the transmembrane segment.
  • the cytoplasmic portion of the Eph receptors includes a juxtamembrane segment, the kinase domain, a sterile-alpha-motif (SAM) domain and a C-terminal PDZ domain-binding motif.
  • Eph receptors and ephrin ligands Interaction between Eph receptors and ephrin ligands, which are attached to the cell surface through a GPI-anchor (ephrin-As) or a transmembrane domain (ephrin-Bs), typically occurs at sites of cell-cell contact. Ephrin binding promotes activation of the receptor’s kinase domain, triggering“forward” signals. Ephrin ligands engaged with Eph receptors can also affect the cells in which they are expressed by mediating“reverse” signals.
  • GPI-anchor ephrin-As
  • ephrin-Bs transmembrane domain
  • Ephrin type-A receptor 4 (EphA4) signaling can be activated by all ephrin ligands, including the five GPI-linked ephrin-As and the three transmembrane ephrin-Bs. Highly expressed in the nervous system, EphA4 tyrosine kinase activity and downstream signaling leads to inhibition of axon growth and retraction of synaptic structures known as dendritic spines. The repulsive effects of EphA4 in neurons help guide the growth of developing axons towards their synaptic targets and may contribute to inhibition of axon regeneration following injury.
  • EphA4 interaction with the ephrin-A3 ligand expressed in astrocytes stimulates "reverse" signals through the ephrin that limit the uptake of the extracellular neurotransmitter glutamate, thus modulating synaptic transmission.
  • EphA4 is also highly expressed in adult hippocampal neurons, where it controls synaptic morphology and plasticity.
  • EphA4 appears to contribute to the maintenance of brain neural stem cells in an undifferentiated state. This is in contrast to muscle, where EphA4 may contribute to myoblast differentiation.
  • EphA4 activity and/or function has been implicated in the pathophysiology of neurodegenerative disorders, the promotion of neurotoxicity, the inhibition of nerve differentiation and regeneration, and in the progression of cancer.
  • low EphA4 expression and loss-of-function mutations are linked to late onset and prolonged survival in amyotrophic lateral sclerosis (ALS), a fatal diseases that still lack any means for effective therapeutic intervention.
  • ALS amyotrophic lateral sclerosis
  • EphA4 gene inactivation has shown beneficial effects in animal models of ALS, making EphA4 inhibition an attractive strategy for counteracting neurodegeneration.
  • EphA4 was identified as a possible inhibitor of nerve regeneration after spinal cord injury. Experiments in mice suggest a role for EphA4 in the behavioral responses to cocaine administration.
  • EphA4 in the pathogenesis of spinal cord injury and other neurological diseases such as Alzheimer's disease, multiple sclerosis, stroke and traumatic brain injury.
  • These pathological roles of EphA4 in the diseased nervous system are regarded as being linked to its increased expression and activation by ephrin ligands or A ⁇ - oligomers in the Alzheimer’s brain, leading to abnormal inhibition of axon growth, synaptic function and neuronal survival.
  • EpHA4 signaling prevents the generation of cochlear sensory hair cells suggesting that inhibition of EpHA4 activity could be an effective therapy in the treatment of hearing loss.
  • EphA4 in various types of cancer, including glioblastoma, gastric cancer, pancreatic cancer, prostate cancer and breast cancer.
  • EphA4 downregulation studies have suggested a role for EphA4 in leukemia, prostate cancer, pancreatic cancer and gastric cancer cell growth and in liver cancer metastasis.
  • High EphA4 expression has also been correlated with shorter survival in breast and gastric cancer patients, although the opposite correlation was found in lung cancer patients.
  • EphA4 is also highly upregulated in Sezary syndrome, a leukemic variant of cutaneous T-cell lymphomas.
  • EphA4 can enhance the oncogenic effects of fibroblast growth factor receptor 1 in glioblastoma cells.
  • EphA4-ephrin interaction could be useful for promoting axon regeneration and neural repair, providing neuroprotection and regulating synaptic plasticity in the nervous system as well as inhibiting the progression of cancer.
  • the two main strategies to block ephrin-induced EphA4 receptor signaling are inhibition of EphA4 kinase activity using kinase inhibitors and inhibition of ephrin binding to the EphA4 ligand binding domain using antagonists.
  • Kinase inhibitors are hampered by low selectivity because they typically target multiple kinases due to the high conservation of the ATP binding pocket. As such, it is very difficult to identify kinase inhibitors selective for EphA4.
  • the ephrin-binding pocket in the extracellular EphA4 ligand binding domain has unique features that can be exploited for more selective antagonist targeting.
  • the ephrin-binding pocket is very broad (exceeding 900 ⁇ 2 ) and shallow for high affinity binding of small molecules, and small molecule EphA4 antagonists found to date are not very potent and exhibit problematic features that make them unsuitable for therapeutic applications.
  • peptide antagonists have been identified that are highly selective for the ephrin-binding pocket of EphA4.
  • the most potent peptide antagonist identified to date was the linear dodecapeptide KYLPYWPVLSSL (KYL; SEQ ID NO: 1) which was shown to specifically inhibit EphA4 signaling in culture systems and animal models.
  • the KYL peptide significantly dampened ALS pathogenesis in the classic rat SOD1 G93A ALS model.
  • recent data have shown that KYL peptide can inhibit the toxic effects of A ⁇ oligomers in in vitro and in vivo mouse models of Alzheimer’s disease.
  • the KYL peptide was also shown to promote axon sprouting and recovery of limb function in a rat model of spinal cord injury.
  • the KYL peptide clearly demonstrated the therapeutic potential of EphA4 antagonistic agents.
  • An EphA4 receptor antagonist can comprise a cyclic peptide comprising, consisting essentially of, or consisting of the sequence X 1 -X 2 -X 3 -C 4 -X 5 -X 6 -X 7 - ⁇ A 8 -X 9 -W-X 11 -C 12 (SEQ ID NO: 3), or X 2 -X 3 -C 4 -X 5 -X 6 -X 7 - ⁇ A 8 -X 9 -W-X 11 -C 12 (SEQ ID NO: 4), or X 3 -C 4 -X 5 -X 6 -X 7 - ⁇ A 8 -X 9 -W-X 11 -C 12 (SEQ ID NO: 5), wherein X 1 is independently ⁇ A, DAla (D-A), A, E, G, Q, D, L, S, F, or Y; X2 is independently P, A, G, Ahx, Ava, ⁇ Abu, ⁇ A or Sar; X3
  • the length of the cyclic peptide may be 10 to 16 amino acids in length or more.
  • a pharmaceutical composition comprising one or more EphA4 receptor antagonists disclosed herein.
  • a pharmaceutical composition disclosed can further comprises one or more pharmaceutical acceptable carriers.
  • Other aspects of the present specification disclose a method of treating an EphA4-based disease, disorder or pathology. The disclosed method can comprise administering an EphA4 receptor antagonist disclosed herein or a pharmaceutical composition disclosed herein to an individual in need thereof. Administration of an EphA4 receptor antagonist disclosed herein or a pharmaceutical composition disclosed herein reduces one or more symptoms associated with the EphA4-based disease, disorder or pathology.
  • An EphA4-based disease, disorder or pathology includes, without limitation, a neurodegenerative disease, a hearing loss, a promotion of nerve regeneration, a promotion of neuroprotection, or a cancer.
  • Other aspects of the present specification disclose a method of treating a neurodegenerative disease. The disclosed method can comprise administering an EphA4 receptor antagonist disclosed herein or a pharmaceutical composition disclosed herein to an individual in need thereof. Administration of an EphA4 receptor antagonist disclosed herein or a pharmaceutical composition disclosed herein reduces one or more symptoms associated with the neurodegenerative disease.
  • Other aspects of the present specification disclose a method of treating a hearing loss.
  • the disclosed method can comprise administering an EphA4 receptor antagonist disclosed herein or a pharmaceutical composition disclosed herein to an individual in need thereof. Administration of an EphA4 receptor antagonist disclosed herein or a pharmaceutical composition disclosed herein reduces one or more symptoms associated with the hearing loss.
  • Other aspects of the present specification disclose a method of promoting nerve regeneration. The disclosed method can comprise administering an EphA4 receptor antagonist disclosed herein or a pharmaceutical composition disclosed herein to an individual in need thereof. Administration of an EphA4 receptor antagonist disclosed herein or a pharmaceutical composition disclosed herein stimulates of facilitates neuronal differentiation and/or growth, thereby promoting nerve regeneration.
  • Other aspects of the present specification disclose a method of promoting neuroprotection.
  • the disclosed method can comprise administering an EphA4 receptor antagonist disclosed herein or a pharmaceutical composition disclosed herein to an individual in need thereof. Administration of an EphA4 receptor antagonist disclosed herein or a pharmaceutical composition disclosed herein protects neurons or nerve tissue from damage, thereby promoting neuroprotection.
  • Other aspects of the present specification disclose a method of treating a cancer. The disclosed method can comprise administering an EphA4 receptor antagonist disclosed herein or a pharmaceutical composition disclosed herein to an individual in need thereof. Administration of an EphA4 receptor antagonist disclosed herein or a pharmaceutical composition disclosed herein reduces one or more symptoms associated with the cancer.
  • aspects of the present specification disclose a use of an EphA4 receptor antagonist disclosed herein in the manufacture of a medicament for treating an EphA4-based disease, disorder or pathology.
  • Other aspects of the present specification disclose a use of an EphA4 receptor antagonist disclosed herein in the manufacture of a medicament for treating a neurodegenerative disease.
  • Other aspects of the present specification disclose a use of an EphA4 receptor antagonist disclosed herein in the manufacture of a medicament for treating a hearing loss.
  • Other aspects of the present specification disclose a use of an EphA4 receptor antagonist disclosed herein in the manufacture of a medicament for treating a cancer.
  • aspects of the present specification disclose a use of an EphA4 receptor antagonist disclosed herein or a pharmaceutical composition disclosed herein in the treatment of an EphA4-based disease, disorder or pathology.
  • Other aspects of the present specification disclose a use of an EphA4 receptor antagonist disclosed herein or a pharmaceutical composition disclosed herein in the treatment of a neurodegenerative disease.
  • Other aspects of the present specification disclose a use of an EphA4 receptor antagonist disclosed herein or a pharmaceutical composition disclosed herein in the treatment of a hearing loss.
  • Other aspects of the present specification disclose a use of an EphA4 receptor antagonist disclosed herein or a pharmaceutical composition disclosed herein in the treatment of a cancer.
  • FIG. 1A shows crystal structures of the EphA4 ligand binding domain (grey) in complex with APY (orange) shown as surface representation
  • FIG. 1B shows crystal structures of the EphA4 ligand binding domain (grey) in complex with APY (orange sticks) shown as ribbon representation
  • FIG. 1C shows crystal structures of the EphA4 ligand binding domain (grey) in complex with part of the GH loop of ephrin-A2 (green, PDB 2W03) shown as surface representation
  • FIG. 1D shows crystal structures of the EphA4 ligand binding domain (grey) in complex with the ephrin-A2 receptor-binding domain (green) shown as ribbon representation; (E) the EphA4 ligand binding domain (grey) in complex with part of the GH loop of ephrin- B2 (cyan, PDB 2W02) shown as surface representation; and FIG. 1F shows crystal structures of the EphA4 ligand binding domain (grey) in complex with the ephrin-B2 receptor-binding domain (cyan) shown as ribbon representation.
  • the DE, GH and JK loops lining the ephrin-binding pocket in the EphA4 ligand binding domain are shown in darker shades of grey.
  • FIG. 2A shows a detailed view of the structure of APY shown in stick representation in orange with oxygens in red, nitrogens in blue and disulfide bond in yellow
  • FIG. 2B shows a detailed view of the three intramolecular hydrogen bonds of APY (dotted green lines, with distance in ⁇ shown in black)
  • FIG. 2C shows a detailed view of APY within the ephrin-binding pocket of EphA4 with the hydrophobic residues interacting with EphA4 shown as spheres and EphA4 shown in surface representation in grey with the DE, GH and JK loops in darker shades of grey;
  • FIG. 2A shows a detailed view of the structure of APY shown in stick representation in orange with oxygens in red, nitrogens in blue and disulfide bond in yellow
  • FIG. 2B shows a detailed view of the three intramolecular hydrogen bonds of APY (dotted green lines, with distance in ⁇ shown in black)
  • FIG. 2C shows a detailed view of APY within the
  • FIG. 2D shows a detailed view of five hydrogen bonds (dotted green lines, with distances in ⁇ shown in black) between residues in APY (orange) and EphA4 (grey), with only EphA4 residues engaged in hydrogen bonds are shown; and
  • FIG. 2E shows a detailed view of the hydrogen bonds (dotted green lines, with distances in ⁇ shown in black) between Tyr6APY and Gln71Eph4A and between Gln71 Eph4A and Thr69 Eph4A .
  • FIG. 3A shows competitive inhibition curves showing inhibition of ephrin-A5 AP binding to immobilized EphA4 Fc by APY in ELISAs, with the 0.1 ⁇ M peptide concentration is indicated in red;
  • FIG. 3A shows competitive inhibition curves showing inhibition of ephrin-A5 AP binding to immobilized EphA4 Fc by APY in ELISAs, with the 0.1 ⁇ M peptide concentration is indicated in red;
  • FIG. 3B shows isothermal titration calorimetry profiles for peptide binding to EphA4 (upper part of each panel) and plots of the integrated values for the reaction heats [after blank subtraction and normalization to the amount of injected peptide) versus EphA4/peptide molar ratio (lower part of each panel); and
  • FIG. 3C shows Eph receptor selectivity for APY- ⁇ Ala8.am. [024]
  • FIG. 4A shows a crystal structure overlay of APY- ⁇ Ala8.am (green) and APY (orange) revealing marked differences in the ⁇ -turn region, particular in the ⁇ Ala8, Ser9 and Trp10 residues (highlighted by stick representation), with residues labeled for the APY- ⁇ Ala8.am peptide; and
  • FIG. 4B shows intramolecular hydrogen bonds of APY- ⁇ Ala8.am.
  • FIG. 5A shows inhibition of ephrin-A5-induced EphA4 tyrosine phosphorylation, with the graph on the right showing quantification of individual EphA4 tyrosine phosphorylation levels from the immunoblots of 2 experiments, normalized to the phosphorylation level in the ephrin-A5/no peptide condition in each experiment;
  • FIG. 5B shows inhibition of EphA4-dependent growth cone collapse;
  • FIG. 5C shows that the APY- ⁇ Ala8.am peptide does not have detectable cytotoxic effects as assessed using the MTT assay.
  • EphA4 is a particularly promiscuous receptor that can bind both ephrin-A and ephrin-B ligands.
  • the difficulties in obtaining submicromolar EphA4 antagonists are likely due to the nature of the ephrin- binding pocket of EphA4 to accommodate the binding of multiple ligands.
  • ephrin-binding pocket of EphA4 is very broad (exceeding an estimated 900 ⁇ 2 ), lacks sufficient hot spot regions and is highly dynamic, being able to assume multiple conformations.
  • cyclic peptides are more structured in their unbound form, which can improve binding affinity and pharmacokinetic properties. Furthermore, cyclic peptides are able to better occupy a wide cavity such as the ephrin-binding pocket of EphA4 due to their circular conformation. [027] Towards this end, the cyclic peptide APYCVYRGSWSC (APY; SEQ ID NO: 2) was optimized to identify peptide that have high potency and selectivity for EphA4 as well a good physiological stability.
  • the APY peptide was selected, in part, because it has an intramolecular disulfide bond, is only marginally less potent towards EphA4 than KYL, and selectively inhibits EphA4 but not other Eph receptors.
  • the crystal structure of APY bound to the EphA4 ligand binding domain was solved in order to reveal mechanism of APY-mediated antagonism.
  • This structural analysis enabled rational design of an improved APY cyclic peptide derivatives.
  • the crystal structure of one of these derivatives reveal features contributing to its increased potency.
  • Secondary phage display screens were also conducted to discriminate the importance of different peptide residues. Using this information further APY cyclic peptide derivatives were created that exhibited better potency and stability.
  • an EphA4 receptor antagonist disclosed herein (also referred to as an EphA4 antagonist) is a cyclic peptide that selectively reduce or inhibit EphA4 receptor signaling activity and/or reduce or inhibit any other functionality of an EphA4 receptor.
  • an EphA4 receptor antagonist comprising a cyclic peptide completely inhibits EphA4 receptor signaling activity and/or other functionality of an EphA4 receptor.
  • an EphA4 receptor antagonist comprising a cyclic peptide may selectively reduce or inhibit EphA4 receptor signaling activity and/or other functionality of an EphA4 receptor by, e.g., about 10%, about 20%, about 30%, about 40%, about 50%, about 60%, about 70%, about 80%, about 60%, or about 100%.
  • an EphA4 receptor antagonist comprising a cyclic peptide may selectively reduce or inhibit EphA4 receptor signaling activity and/or other functionality of an EphA4 receptor by, e.g., at least 10%, at least 20%, at least 30%, at least 40%, at least 50%, at least 60%, at least 70%, at least 80%, at least 60%, or at least 100%.
  • an EphA4 receptor antagonist comprising a cyclic peptide may selectively reduce or inhibit EphA4 receptor signaling activity and/or other functionality of an EphA4 receptor by, e.g., at most 10%, at most 20%, at most 30%, at most 40%, at most 50%, at most 60%, at most 70%, at most 80%, at most 60%, or at most 100%.
  • an EphA4 receptor antagonist comprising a cyclic peptide may reduce or inhibit EphA4 receptor signaling activity and/or other functionality of an EphA4 receptor by, e.g., about 10% to about 20%, about 10% to about 30%, about 10% to about 40%, about 10% to about 50%, about 10% to about 60%, about 10% to about 70%, about 10% to about 80%, about 10% to about 90%, about 10% to about 100%, about 20% to about 30%, about 20% to about 40%, about 20% to about 50%, about 20% to about 60%, about 20% to about 70%, about 20% to about 80%, about 20% to about 90%, about 20% to about 100%, about 30% to about 40%, about 30% to about 50%, about 30% to about 60%, about 30% to about 70%, about 30% to about 80%, about 30% to about 90%, about 30% to about 100%, about 40% to about 50%, about 40% to about 60%, about 40% to about 70%, about 40% to about 80%, about 40% to about 90%, about 40% to about 100%, about 50% to about 60%, about 50% to about 70%, about 50% to about 70%, about 50% to
  • Cyclic peptides disclosed herein are peptides derived from APY (SEQ ID NO: 2), a 12 amino acid peptide with a disulfide bridge between the two cysteines (Cys) at positions 4 and 12. All APY cyclic peptides disclosed herein contain a disulfide bridge, which helps impart the cyclic structure of the peptide. All APY cyclic peptides disclosed herein are useful as an EphA4 receptor antagonist. An APY cyclic peptide disclosed herein can be chemically synthesized using standard techniques such as liquid-phase synthesis or solid-phase synthesis including Fmoc and Boc.
  • an APY cyclic peptide may have an amino acid length of, e.g., about 9 residues, about 10 residues, about 11 residues, about 12 residues, about 13 residues, about 14 residues or about 15 residues.
  • an APY cyclic peptide may have an amino acid length of, e.g., at least 9 residues, at least 10 residues, at least 11 residues, at least 12 residues, at least 13 residues, at least 14 residues, at least 15 residues, at least 16 residues, at least 17 residues, at least 18 residues, at least 19 residues or at least 20 residues.
  • an APY cyclic peptide may have an amino acid length of, e.g., at most 9 residues, at most 10 residues, at most 11 residues, at most 12 residues, at most 13 residues, at most 14 residues, at most 15 residues, at most 16 residues, at most 17 residues, at most 18 residues, at most 19 residues or at most 20 residues.
  • an APY cyclic peptide may have an amino acid length of, e.g., about 9 to about 10 residues, about 9 to about 11 residues, about 9 to about 12 residues, about 9 to about 13 residues, about 9 to about 14 residues, about 9 to about 15 residues, about 9 to about 16 residues, about 9 to about 17 residues, about 9 to about 18 residues, about 9 to about 19 residues, about 9 to about 20 residues, about 10 to about 11 residues, about 10 to about 12 residues, about 10 to about 13 residues, about 10 to about 14 residues, about 10 to about 15 residues, about 10 to about 16 residues, about 10 to about 17 residues, about 10 to about 18 residues, about 10 to about 19 residues, about 10 to about 20 residues, about 11 to about 12 residues, about 11 to about 13 residues, about 11 to about 14 residues, about 11 to about 15 residues, about 11 to about 16 residues, about 11 to about 17 residues, about 11 to about 18 residues, about 10 to about 19 residue
  • an APY cyclic peptide disclosed herein that is modified by amidation (am).
  • Amidation is a chemical reaction that results in the addition of an amide functional group to the free carboxyl group of an amino acid.
  • an amide group is added to the free carboxyl group of the C-terminal residue of a peptide.
  • C-terminal amidation increases peptide stability because it eliminates a potential charge, thereby further protecting the peptide from rapid degradation by ubiquitous exopeptidases.
  • an APY cyclic peptide disclosed herein is amidated by adding an amide group to the free carboxyl group of the C-terminal amino acid.
  • an APY cyclic peptide disclosed herein is amidated at the cysteine located at position 12.
  • ac acetylation
  • Acetylation is a chemical reaction that results in the addition of an acetyl functional group to the free amino group of an amino acid.
  • an acetyl group is added to the free amino group of the N-terminal residue of a peptide.
  • N-terminal acetyl increases peptide stability because it eliminates a potential charge, thereby further protecting the peptide from rapid degradation by ubiquitous exopeptidases.
  • an APY cyclic peptide disclosed herein is acetylated by adding an acetyl group to the free amino group of the N-terminal amino acid. In another aspect of this embodiment, an APY cyclic peptide disclosed herein is acetylated at position 1. In yet another aspect of this embodiment, an APY cyclic peptide disclosed herein is not acetylated at the free amino group of the N-terminal amino acid. [033] Aspects of the present specification disclose, in part, an APY cyclic peptide disclosed herein that is optionally modified at the amino terminus.
  • an APY peptide disclosed herein may optionally be modified by other functional groups in order to increase peptide stability.
  • an APY cyclic peptide disclosed herein may be modified at the N-terminus by carboxybenzyl (Cbz).
  • an APY cyclic peptide disclosed herein is not modified at the N-terminus by carboxybenzyl (Cbz).
  • an APY cyclic peptide has the sequence X 1 -X 2 -X 3 -C 4 -X 5 -X 6 -X 7 - ⁇ A 8 -X 9 -W-X 11 - C12 (SEQ ID NO: 3), X2-X3-C4-X5-X6-X7- ⁇ A8-X9-W-X11-C12 (SEQ ID NO: 4) or X3-C4-X5-X6-X7- ⁇ A8-X9-W-X11- C12 (SEQ ID NO: 5), wherein X1 is independently ⁇ A, D-A, A, E, G, Q, D, L, S, F, or Y; X2 is independently P, A, G, Ahx, Ava, ⁇ Abu, ⁇ A or Sar; X3 is independently Y, F, W, V, L, H or I; X5 is independently V or L; X6 is independently Y, F
  • Residues C 4 and C 12 of an APY cyclic peptide disclosed herein form a disulfide bridge.
  • residue C12 is optionally amidated.
  • amino-terminal residue is optionally acetylated.
  • an APY cyclic peptide has the sequence X1-X2-X3-C4-X5-X6-X7- ⁇ A8- X9-W-X11-C12 (SEQ ID NO: 3), X2-X3-C4-X5-X6-X7- ⁇ A8-X9-W-X11-C12 (SEQ ID NO: 4) or X3-C4-X5-X6-X7- ⁇ A8- X9-W-X11-C12 (SEQ ID NO: 5), wherein in any residue position combination thereof X1 is independently ⁇ A, D-A, A, E, G or Q; X 2 is independently P or A; X 3 is independently Y, F, W, V, L or H; X 5 is independently V or L; X 6 is independently Y, F, W or H; X 7 is independently any amino acid except P; X 9 is independently any amino acid except P; and X11 is independently any
  • an APY cyclic peptide has the sequence X1-X2-X3-C4-X5-X6-X7- ⁇ A8-X9-W-X11-C12 (SEQ ID NO: 3), X 2 -X 3 -C 4 -X 5 -X 6 -X 7 - ⁇ A 8 -X 9 -W-X 11 -C 12 (SEQ ID NO: 4) or X 3 -C 4 -X 5 -X 6 -X 7 - ⁇ A 8 -X 9 -W-X 11 -C 12 (SEQ ID NO: 5), wherein in any residue position combination thereof X 1 is independently ⁇ A, D-A, A, E, G or Q; X 2 is independently P or A; X3 is independently Y, F, W, V, L or H; X5 is independently V or L; X6 is independently Y, F, W or H; X7 is independently R, T, N, D, S, Q
  • an APY cyclic peptide has the sequence X 1 -X 2 -X 3 -C 4 -X 5 -X 6 -X 7 - ⁇ A 8 -X 9 - W-X11-C12 (SEQ ID NO: 3), X2-X3-C4-X5-X6-X7- ⁇ A8-X9-W-X11-C12 (SEQ ID NO: 4) or X3-C4-X5-X6-X7- ⁇ A8-X9- W-X11-C12 (SEQ ID NO: 5), wherein in any residue position combination thereof X1 is independently ⁇ A, D- A, A, E, G or Q; X2 is independently P or A; X3 is independently Y, F, W, V, L or H; X5 is independently V or L; X 6 is independently Y, F, W or H; X 7 is independently R, T, N, D, S, or Q; X 9 is independently
  • an APY cyclic peptide has the sequence X1-X2-X3-C4-X5-X6-X7- ⁇ A8-X9-W-X11-C12 (SEQ ID NO: 3), X2-X3- C4-X5-X6-X7- ⁇ A8-X9-W-X11-C12 (SEQ ID NO: 4) or X3-C4-X5-X6-X7- ⁇ A8-X9-W-X11-C12 (SEQ ID NO: 5), wherein in any residue position combination thereof X 1 is independently ⁇ A, D-A, A, E, G or Q; X 2 is independently P or A; X 3 is independently Y, F, W, V, L or H; X 5 is independently V or L; X 6 is independently Y, F, W or H; X 7 is independently R, T, N, D, S, or Q; X 9 is independently S, E, T, V, D,
  • an APY cyclic peptide has the sequence X1-X2-X3-C4-X5-X6-X7- ⁇ A8-X9-W-X11-C12 (SEQ ID NO: 3), X2-X3-C4-X5-X6-X7- ⁇ A8-X9-W-X11-C12 (SEQ ID NO: 4) or X3-C4-X5-X6-X7- ⁇ A8-X9-W-X11-C12 (SEQ ID NO: 5), wherein in any residue position combination thereof X 1 is independently ⁇ A, D-A, A, E, G or Q; X 2 is independently P or A; X 3 is independently Y, F, W, V, L or H; X 5 is independently V or L; X 6 is independently Y, F, W or H; X 7 is independently R, T, or N; X9 is independently S, E, T or V; and X11 is independently S, E
  • an APY cyclic peptide has the sequence X 1 -X 2 -X 3 -C 4 -X 5 -X 6 -X 7 - ⁇ A 8 - X9-W-X11-C12 (SEQ ID NO: 3), X2-X3-C4-X5-X6-X7- ⁇ A8-X9-W-X11-C12 (SEQ ID NO: 4) or X3-C4-X5-X6-X7- ⁇ A8- X9-W-X11-C12 (SEQ ID NO: 5), wherein in any residue position combination thereof X1 is independently ⁇ A, D-A, A or E; X2 is independently P or A; X3 is independently Y, F, W, V, L or H; X5 is independently V or L; X 6 is independently Y, F, W or H; X 7 is independently any amino acid except P; X 9 is independently any amino acid except P; and
  • an APY cyclic peptide has the sequence X1-X2-X3-C4-X5-X6-X7- ⁇ A8-X9-W-X11-C12 (SEQ ID NO: 3), X2-X3-C4-X5-X6-X7- ⁇ A8-X9-W-X11-C12 (SEQ ID NO: 4) or X3-C4-X5-X6-X7- ⁇ A8-X9-W-X11-C12 (SEQ ID NO: 5), wherein in any residue position combination thereof X 1 is independently ⁇ A, D-A, A or E; X 2 is independently P or A; X 3 is independently Y, F, W, V, L or H; X 5 is independently V or L; X 6 is independently Y, F, W or H; X7 is independently R, T, N, D, S, Q, Y, K, A, G or E; X9 is independently S, E, T
  • an APY cyclic peptide has the sequence X 1 -X 2 -X 3 -C 4 -X 5 -X 6 -X 7 - ⁇ A 8 -X 9 -W-X 11 -C 12 (SEQ ID NO: 3), X 2 -X 3 -C 4 -X 5 -X 6 -X 7 - ⁇ A 8 -X 9 -W-X 11 -C 12 (SEQ ID NO: 4) or X 3 -C 4 -X 5 -X 6 -X 7 - ⁇ A 8 -X 9 -W-X 11 -C 12 (SEQ ID NO: 5), wherein in any residue position combination thereof X1 is independently ⁇ A, D-A, A or E; X2 is independently P or A; X3 is independently Y, F, W, V, L or H; X5 is independently V or L; X6 is independently Y, F, W or H; X7 is independently R, T
  • an APY cyclic peptide has the sequence X 1 -X 2 -X 3 -C 4 -X 5 -X 6 -X 7 - ⁇ A 8 -X 9 -W-X 11 -C 12 (SEQ ID NO: 3), X 2 -X 3 -C 4 -X 5 -X 6 -X 7 - ⁇ A 8 -X 9 -W- X11-C12 (SEQ ID NO: 4) or X3-C4-X5-X6-X7- ⁇ A8-X9-W-X11-C12 (SEQ ID NO: 5), wherein in any residue position combination thereof X1 is independently ⁇ A, D-A, A or E; X2 is independently P or A; X3 is independently Y, F, W, V, L or H; X 5 is independently V or L; X 6 is independently Y, F, W or H; X 7 is independently R, T, N, D, S, or
  • an APY cyclic peptide has the sequence X1-X2-X3-C4-X5- X6-X7- ⁇ A8-X9-W-X11-C12 (SEQ ID NO: 3), X2-X3-C4-X5-X6-X7- ⁇ A8-X9-W-X11-C12 (SEQ ID NO: 4) or X3-C4-X5- X 6 -X 7 - ⁇ A 8 -X 9 -W-X 11 -C 12 (SEQ ID NO: 5), wherein in any residue position combination thereof X 1 is independently ⁇ A, D-A, A or E; X 2 is independently P or A; X 3 is independently Y, F, W, V, L or H; X 5 is independently V or L; X6 is independently Y, F, W or H; X7 is independently R, T, or N; X9 is independently S, E, T or V; and X11 is independently
  • an APY cyclic peptide has the sequence X 1 -X 2 -X 3 -C 4 -X 5 -X 6 -X 7 - ⁇ A 8 - X9-W-X11-C12 (SEQ ID NO: 3), X2-X3-C4-X5-X6-X7- ⁇ A8-X9-W-X11-C12 (SEQ ID NO: 4) or X3-C4-X5-X6-X7- ⁇ A8- X9-W-X11-C12 (SEQ ID NO: 5), wherein X1 is independently ⁇ A, D-A, A or E; X2 is independently P or A; X3 is independently Y, F or W; X 5 is independently V or L; X 6 is independently Y, F or W; X 7 is independently any amino acid except P; X 9 is independently any amino acid except P; and X 11 is independently any amino acid except P.
  • an APY cyclic peptide has the sequence X1-X2-X3-C4- X5-X6-X7- ⁇ A8-X9-W-X11-C12 (SEQ ID NO: 3), X2-X3-C4-X5-X6-X7- ⁇ A8-X9-W-X11-C12 (SEQ ID NO: 4) or X3-C4- X5-X6-X7- ⁇ A8-X9-W-X11-C12 (SEQ ID NO: 5), wherein X1 is independently ⁇ A, D-A, A or E; X2 is independently P or A; X 3 is independently Y, F or W; X 5 is independently V or L; X 6 is independently Y, F or W; X 7 is independently R, T, N, D, S, Q, Y, K, A, G or E; X 9 is independently S, E, T, V, D, Y, Q, V,
  • an APY cyclic peptide has the sequence X1-X2-X3-C4-X5-X6-X7- ⁇ A8-X9-W-X11-C12 (SEQ ID NO: 3), X 2 -X 3 -C 4 -X 5 -X 6 -X 7 - ⁇ A 8 -X 9 -W-X 11 -C 12 (SEQ ID NO: 4) or X 3 -C 4 -X 5 -X 6 -X 7 - ⁇ A 8 -X 9 -W-X 11 -C 12 (SEQ ID NO: 5), wherein X 1 is independently ⁇ A, D-A, A or E; X 2 is independently P or A; X 3 is independently Y, F or W; X5 is independently V or L; X6 is independently Y, F or W; X7 is independently R, T, N, D, S, or Q; X9 is independently S, E, T, V, W,
  • an APY cyclic peptide has the sequence X1-X2-X3-C4-X5-X6-X7- ⁇ A8-X9-W-X11- C 12 (SEQ ID NO: 3), X 2 -X 3 -C 4 -X 5 -X 6 -X 7 - ⁇ A 8 -X 9 -W-X 11 -C 12 (SEQ ID NO: 4) or X 3 -C 4 -X 5 -X 6 -X 7 - ⁇ A 8 -X 9 -W-X 11 - C12 (SEQ ID NO: 5), wherein X1 is independently ⁇ A, D-A, A or E; X2 is independently P or A; X3 is independently Y, F or W; X5 is independently V or L; X6 is independently Y, F or W; X7 is independently R, T, N, D, S, or Q; X9 is independently S, E, T, V, D, D,
  • an APY cyclic peptide has the sequence X 1 -X 2 -X 3 -C 4 -X 5 -X 6 -X 7 - ⁇ A 8 -X 9 - W-X 11 -C 12 (SEQ ID NO: 3), X 2 -X 3 -C 4 -X 5 -X 6 -X 7 - ⁇ A 8 -X 9 -W-X 11 -C 12 (SEQ ID NO: 4) or X 3 -C 4 -X 5 -X 6 -X 7 - ⁇ A 8 -X 9 - W-X11-C12 (SEQ ID NO: 5), wherein X1 is independently ⁇ A, D-A, A or E; X2 is independently P or A; X3 is independently Y, F or W; X5 is independently V or L; X6 is independently Y, F or W; X7 is independently R, T, or N; X 9 is independently S, E, T or V
  • an APY cyclic peptide has the sequence X1-P2-X3-C4-X5-X6-X7- ⁇ A8-X9-W10- X11-C12 (SEQ ID NO: 6), X1-P2-X3-C4-X5-X6-X7- ⁇ A8-X9-W10-X11-C12 (SEQ ID NO: 7) or X1-P2-X3-C4-X5-X6- X7- ⁇ A8-X9-W10-X11-C12 (SEQ ID NO: 8), wherein X1 is independently ⁇ A, D-A, A, E, G or Q; X3 is independently Y, F, W, V, L or H; X 5 is independently V or L; X 6 is independently Y, F, W or H; X 7 is independently any amino acid except P; X 9 is independently any amino acid except P; and X 11 is independently any amino acid except P.
  • Residues C4 and C12 of an APY cyclic peptide disclosed herein form a disulfide bridge.
  • residue C12 is optionally amidated.
  • amino-terminal residue is optionally acetylated.
  • an APY cyclic peptide has the sequence X1-P2-X3-C4-X5-X6-X7- ⁇ A8- X 9 -W 10 -X 11 -C 12 (SEQ ID NO: 6), P 2 -X 3 -C 4 -X 5 -X 6 -X 7 - ⁇ A 8 -X 9 -W 10 -X 11 -C 12 (SEQ ID NO: 7) or X 3 -C 4 -X 5 -X 6 -X 7 - ⁇ A 8 -X 9 -W 10 -X 11 -C 12 (SEQ ID NO: 8), wherein X 1 is independently ⁇ A, D-A, A, E, G or Q; X 3 is independently Y, F, W, V, L or H; X5 is independently V or L; X6 is independently Y, F, W or H; X7 is independently R, T, N, D, S, Q, Y
  • an APY cyclic peptide has the sequence X1-P2-X3-C4-X5-X6-X7- ⁇ A8-X9-W10-X11-C12 (SEQ ID NO: 6), P2-X3-C4- X5-X6-X7- ⁇ A8-X9-W10-X11-C12 (SEQ ID NO: 7) or X3-C4-X5-X6-X7- ⁇ A8-X9-W10-X11-C12 (SEQ ID NO: 8), wherein X 1 is independently ⁇ A, D-A, A, E, G or Q; X 3 is independently Y, F, W, V, L or H; X 5 is independently V or L; X 6 is independently Y, F, W or H; X 7 is independently R, T, N, D, S, or Q; X 9 is independently S, E, T, V, D, Y; and X11 is independently S, E
  • an APY cyclic peptide has the sequence X1-P2-X3-C4-X5-X6-X7- ⁇ A8-X9-W10-X11-C12 (SEQ ID NO: 6), P 2 -X 3 -C 4 -X 5 -X 6 -X 7 - ⁇ A 8 -X 9 -W 10 -X 11 -C 12 (SEQ ID NO: 7) or X 3 -C 4 -X 5 -X 6 -X 7 - ⁇ A 8 -X 9 -W 10 -X 11 -C 12 (SEQ ID NO: 8), wherein X 1 is independently ⁇ A, D-A, A, E, G or Q; X 3 is independently Y, F, W, V, L or H; X 5 is independently V or L; X6 is independently Y, F, W or H; X7 is independently R, T, or N; X9 is independently S, E, T or V; and
  • an APY cyclic peptide has the sequence X 1 -P 2 -X 3 -C 4 -X 5 -X 6 -X 7 - ⁇ A 8 - X9-W10-X11-C12 (SEQ ID NO: 6), P2-X3-C4-X5-X6-X7- ⁇ A8-X9-W10-X11-C12 (SEQ ID NO: 7) or X3-C4-X5-X6-X7- ⁇ A8-X9-W10-X11-C12 (SEQ ID NO: 8), wherein X1 is independently ⁇ A, D-A, A or E; X3 is independently Y, F or W; X 5 is independently V or L; X 6 is independently Y, F or W; X 7 is independently R, T, N, D, S, Q, Y, K, A, G or E; X 9 is independently S, E, T, V, D, Y
  • an APY cyclic peptide has the sequence X1-P2-X3-C4-X5-X6-X7- ⁇ A8-X9-W10-X11-C12 (SEQ ID NO: 6), P2-X3-C4-X5-X6-X7- ⁇ A8-X9-W10-X11-C12 (SEQ ID NO: 7) or X 3 -C 4 -X 5 -X 6 -X 7 - ⁇ A 8 -X 9 -W 10 -X 11 -C 12 (SEQ ID NO: 8), wherein X 1 is independently ⁇ A, D-A, A or E; X 3 is independently Y, F or W; X 5 is independently V or L; X 6 is independently Y, F or W; X 7 is independently R, T, N, D, S, or Q; X9 is independently S, E, T, V, W, R, L, D, Y; and X11 is independently S,
  • an APY cyclic peptide has the sequence X1-P2-X3-C4-X5-X6-X7- ⁇ A8-X9-W10-X11-C12 (SEQ ID NO: 6), P2-X3-C4-X5-X6-X7- ⁇ A8-X9-W10-X11-C12 (SEQ ID NO: 7) or X 3 -C 4 -X 5 -X 6 -X 7 - ⁇ A 8 -X 9 -W 10 -X 11 -C 12 (SEQ ID NO: 8), wherein X 1 is independently ⁇ A, D-A, A or E; X 3 is independently Y, F or W; X 5 is independently V or L; X 6 is independently Y, F or W; X 7 is independently R, T, N, D, S, or Q; X9 is independently S, E, T, V, D, Y; and X11 is independently S, E, L, N
  • an APY cyclic peptide has the sequence X1-P2-X3- C 4 -X 5 -X 6 -X 7 - ⁇ A 8 -X 9 -W 10 -X 11 -C 12 (SEQ ID NO: 6), P 2 -X 3 -C 4 -X 5 -X 6 -X 7 - ⁇ A 8 -X 9 -W 10 -X 11 -C 12 (SEQ ID NO: 7) or X 3 -C 4 -X 5 -X 6 -X 7 - ⁇ A 8 -X 9 -W 10 -X 11 -C 12 (SEQ ID NO: 8), wherein X 1 is independently ⁇ A, D-A, A or E; X 3 is independently Y, F or W; X5 is independently V or L; X6 is independently Y, F or W; X7 is independently R, T, or N; X9 is independently S, E, T or V; and X11 is
  • an APY cyclic peptide has the sequence X 1 -X 2 -X 3 -C 4 -V 5 -X 6 -X 7 - ⁇ A 8 -X 9 -W 10 - X11-C12 (SEQ ID NO: 9), X2-X3-C4-V5-X6-X7- ⁇ A8-X9-W10-X11-C12 (SEQ ID NO: 10) or X3-C4-V5-X6-X7- ⁇ A8-X9- W10-X11-C12 (SEQ ID NO: 11), wherein X1 is independently ⁇ A, D-A, A, E, G or Q; X2 is independently P, A, G, Ahx, Ava, ⁇ Abu, ⁇ A or Sar; X3 is independently Y, F, W, V, L or H; X6 is independently Y, F, W or H; X7 is independently any amino acid except P; X 9
  • Residues C 4 and C 12 of an APY cyclic peptide disclosed herein form a disulfide bridge.
  • residue C 12 is optionally amidated.
  • the amino-terminal residue is optionally acetylated.
  • an APY cyclic peptide has the sequence X1-X2-X3-C4-V5-X6-X7- ⁇ A8- X 9 -W 10 -X 11 -C 12 (SEQ ID NO: 9), X 2 -X 3 -C 4 -V 5 -X 6 -X 7 - ⁇ A 8 -X 9 -W 10 -X 11 -C 12 (SEQ ID NO: 10) or X 3 -C 4 -V 5 -X 6 -X 7 - ⁇ A 8 -X 9 -W 10 -X 11 -C 12 (SEQ ID NO: 11), wherein X 1 is independently ⁇ A, D-A, A, E, G or Q; X 2 is independently P or A; X3 is independently Y, F, W, V, L or H; X6 is independently Y, F, W or H; X7 is independently R, T, N, D, S, Q,
  • an APY cyclic peptide has the sequence X 1 -X 2 -X 3 -C 4 -V 5 -X 6 -X 7 - ⁇ A 8 -X 9 -W 10 -X 11 -C 12 (SEQ ID NO: 9), X 2 -X 3 -C 4 -V 5 -X 6 -X 7 - ⁇ A8-X9-W10-X11-C12 (SEQ ID NO: 10) or X3-C4-V5-X6-X7- ⁇ A8-X9-W10-X11-C12 (SEQ ID NO: 11), wherein X1 is independently ⁇ A, D-A, A, E, G or Q; X2 is independently P or A; X3 is independently Y, F, W, V, L or H; X6 is independently Y, F, W or H; X7 is independently R, T, N, D, S, or Q; X9 is independently S, E
  • an APY cyclic peptide has the sequence X 1 -X 2 -X 3 -C 4 -V 5 -X 6 -X 7 - ⁇ A 8 -X 9 -W 10 -X 11 -C 12 (SEQ ID NO: 9), X 2 -X 3 -C 4 - V5-X6-X7- ⁇ A8-X9-W10-X11-C12 (SEQ ID NO: 10) or X3-C4-V5-X6-X7- ⁇ A8-X9-W10-X11-C12 (SEQ ID NO: 11), wherein X1 is independently ⁇ A, D-A, A, E, G or Q; X2 is independently P or A; X3 is independently Y, F, W, V, L or H; X 6 is independently Y, F, W or H; X 7 is independently R, T, N, D, S, or Q; X 9 is independently S, E, T,
  • an APY cyclic peptide has the sequence X1-X2-X3-C4-V5-X6-X7- ⁇ A8-X9-W10-X11-C12 (SEQ ID NO: 9), X2-X3-C4- V5-X6-X7- ⁇ A8-X9-W10-X11-C12 (SEQ ID NO: 10) or X3-C4-V5-X6-X7- ⁇ A8-X9-W10-X11-C12 (SEQ ID NO: 11), wherein X 1 is independently ⁇ A, D-A, A, E, G or Q; X 2 is independently P or A; X 3 is independently Y, F, W, V, L or H; X 6 is independently Y, F, W or H; X 7 is independently R, T, or N; X 9 is independently S, E, T or V; and X11 is independently S, E, L or N.
  • an APY cyclic peptide has the sequence X 1 -X 2 -X 3 -C 4 -V 5 -X 6 -X 7 - ⁇ A 8 - X 9 -W 10 -X 11 -C 12 (SEQ ID NO: 9), X 2 -X 3 -C 4 -V 5 -X 6 -X 7 - ⁇ A 8 -X 9 -W 10 -X 11 -C 12 (SEQ ID NO: 10) or X 3 -C 4 -V 5 -X 6 -X 7 - ⁇ A8-X9-W10-X11-C12 (SEQ ID NO: 11), wherein X1 is independently ⁇ A, D-A, A or E; X2 is independently P or A; X3 is independently Y, F or W; X6 is independently Y, F or W; X7 is independently R, T, N, D, S, Q, Y, K, A, G
  • an APY cyclic peptide has the sequence X1-X2-X3-C4-V5-X6-X7- ⁇ A8-X9-W10-X11-C12 (SEQ ID NO: 9), X2-X3-C4-V5-X6-X7- ⁇ A8-X9-W10-X11-C12 (SEQ ID NO: 10) or X3-C4-V5-X6-X7- ⁇ A8-X9-W10-X11-C12 (SEQ ID NO: 11), wherein X1 is independently ⁇ A, D-A, A or E; X2 is independently P or A; X3 is independently Y, F or W; X6 is independently Y, F or W; X7 is independently R, T, N, D, S, or Q; X 9 is independently S, E, T, V, W, R, L, D, Y; and X 11 is independently S, E, L, N, T,
  • an APY cyclic peptide has the sequence X1-X2-X3-C4-V5-X6-X7- ⁇ A8-X9-W10-X11-C12 (SEQ ID NO: 9), X2-X3-C4-V5-X6-X7- ⁇ A8-X9-W10-X11-C12 (SEQ ID NO: 10) or X3-C4-V5-X6-X7- ⁇ A8-X9-W10-X11-C12 (SEQ ID NO: 11), wherein X1 is independently ⁇ A, D-A, A or E; X 2 is independently P or A; X 3 is independently Y, F or W; X 6 is independently Y, F or W; X 7 is independently R, T, N, D, S, or Q; X 9 is independently S, E, T, V, D, Y; and X 11 is independently S, E, L, N, K, V, I or H
  • an APY cyclic peptide has the sequence X1-X2-X3- C4-V5-X6-X7- ⁇ A8-X9-W10-X11-C12 (SEQ ID NO: 9), X2-X3-C4-V5-X6-X7- ⁇ A8-X9-W10-X11-C12 (SEQ ID NO: 10) or X 3 -C 4 -V 5 -X 6 -X 7 - ⁇ A 8 -X 9 -W 10 -X 11 -C 12 (SEQ ID NO: 11), wherein X 1 is independently ⁇ A, D-A, A or E; X 2 is independently P or A; X 3 is independently Y, F or W; X 6 is independently Y, F or W; X 7 is independently R, T, or N; X9 is independently S, E, T or V; and X11 is independently S, E, L or N.
  • an APY cyclic peptide has the sequence X 1 -P 2 -X 3 -C 4 -V 5 -X 6 -X 7 - ⁇ A 8 -X 9 -W 10 - X 11 -C 12 (SEQ ID NO: 12), P 2 -X 3 -C 4 -V 5 -X 6 -X 7 - ⁇ A 8 -X 9 -W 10 -X 11 -C 12 (SEQ ID NO: 13) or X 3 -C 4 -V 5 -X 6 -X 7 - ⁇ A 8 - X9-W10-X11-C12 (SEQ ID NO: 14), wherein X1 is independently ⁇ A, D-A, A, E, G or Q; X3 is independently Y, F, W, V, L or H; X6 is independently Y, F, W or H; X7 is independently any amino acid except P; X9 is independently any amino acid except P; and
  • Residues C 4 and C 12 of an APY cyclic peptide disclosed herein form a disulfide bridge.
  • residue C12 is optionally amidated.
  • amino-terminal residue is optionally acetylated.
  • an APY cyclic peptide has the sequence X1-P2-X3-C4-V5-X6-X7- ⁇ A8- X9-W10-X11-C12 (SEQ ID NO: 12), P2-X3-C4-V5-X6-X7- ⁇ A8-X9-W10-X11-C12 (SEQ ID NO: 13) or X3-C4-V5-X6- X7- ⁇ A8-X9-W10-X11-C12 (SEQ ID NO: 14), wherein X1 is independently ⁇ A, D-A, A, E, G or Q; X3 is independently Y, F, W, V, L or H; X 6 is independently Y, F, W or H; X 7 is independently R, T, N, D, S, Q, Y, K, A, G or E; X 9 is independently S, E, T, V, D, Y, Q, V, W
  • an APY cyclic peptide has the sequence X1-P2-X3-C4-V5-X6-X7- ⁇ A8-X9-W10-X11-C12 (SEQ ID NO: 12), P2-X3-C4-V5-X6-X7- ⁇ A8-X9-W10-X11- C 12 (SEQ ID NO: 13) or X 3 -C 4 -V 5 -X 6 -X 7 - ⁇ A 8 -X 9 -W 10 -X 11 -C 12 (SEQ ID NO: 14), wherein X 1 is independently ⁇ A, D-A, A, E, G or Q; X 3 is independently Y, F, W, V, L or H; X 6 is independently Y, F, W or H; X 7 is independently R, T, N, D, S, or Q; X9 is independently S, E, T, V, W, R, L, D, Y; and X11 is
  • an APY cyclic peptide has the sequence X1-P2-X3-C4-V5-X6-X7- ⁇ A8-X9-W10-X11-C12 (SEQ ID NO: 12), P2-X3-C4-V5-X6-X7- ⁇ A8-X9-W10-X11-C12 (SEQ ID NO: 13) or X 3 -C 4 -V 5 -X 6 -X 7 - ⁇ A 8 -X 9 -W 10 -X 11 -C 12 (SEQ ID NO: 14), wherein X 1 is independently ⁇ A, D-A, A, E, G or Q; X 3 is independently Y, F, W, V, L or H; X 6 is independently Y, F, W or H; X 7 is independently R, T, N, D, S, or Q; X9 is independently S, E, T, V, D, Y; and X11 is independently S, E,
  • an APY cyclic peptide has the sequence X1-P2-X3-C4-V5-X6-X7- ⁇ A8- X 9 -W 10 -X 11 -C 12 (SEQ ID NO: 12), P 2 -X 3 -C 4 -V 5 -X 6 -X 7 - ⁇ A 8 -X 9 -W 10 -X 11 -C 12 (SEQ ID NO: 13) or X 3 -C 4 -V 5 -X 6 - X 7 - ⁇ A 8 -X 9 -W 10 -X 11 -C 12 (SEQ ID NO: 14), wherein X 1 is independently ⁇ A, D-A, A, E, G or Q; X 3 is independently Y, F, W, V, L or H; X6 is independently Y, F, W or H; X7 is independently R, T, or N; X9 is independently S, E, T or V; and X11 is
  • an APY cyclic peptide has the sequence X1-P2-X3-C4-V5-X6-X7- ⁇ A8- X9-W10-X11-C12 (SEQ ID NO: 12), P2-X3-C4-V5-X6-X7- ⁇ A8-X9-W10-X11-C12 (SEQ ID NO: 13) or X3-C4-V5-X6- X7- ⁇ A8-X9-W10-X11-C12 (SEQ ID NO: 14), wherein X1 is independently ⁇ A, D-A, A or E; X3 is independently Y, F or W; X 6 is independently Y, F or W; X 7 is independently R, T, N, D, S, Q, Y, K, A, G or E; X 9 is independently S, E, T, V, D, Y, Q, V, W, R, N, L, K or H; and
  • an APY cyclic peptide has the sequence X1-P2-X3-C4- V5-X6-X7- ⁇ A8-X9-W10-X11-C12 (SEQ ID NO: 12), P2-X3-C4-V5-X6-X7- ⁇ A8-X9-W10-X11-C12 (SEQ ID NO: 13) or X 3 -C 4 -V 5 -X 6 -X 7 - ⁇ A 8 -X 9 -W 10 -X 11 -C 12 (SEQ ID NO: 14), wherein X 1 is independently ⁇ A, D-A, A or E; X 3 is independently Y, F or W; X 6 is independently Y, F or W; X 7 is independently R, T, N, D, S, or Q; X 9 is independently S, E, T, V, W, R, L, D, Y; and X 11 is independently S, E, L, N, T, K
  • an APY cyclic peptide has the sequence X1-P2-X3-C4-V5-X6-X7- ⁇ A8-X9-W10- X11-C12 (SEQ ID NO: 12), P2-X3-C4-V5-X6-X7- ⁇ A8-X9-W10-X11-C12 (SEQ ID NO: 13) or X3-C4-V5-X6-X7- ⁇ A8- X9-W10-X11-C12 (SEQ ID NO: 14), wherein X1 is independently ⁇ A, D-A, A or E; X3 is independently Y, F or W; X 6 is independently Y, F or W; X 7 is independently R, T, N, D, S, or Q; X 9 is independently S, E, T, V, D, Y; and X 11 is independently S, E, L, N, K, V, I or H.
  • an APY cyclic peptide has the sequence X1-P2-X3-C4-V5-X6-X7- ⁇ A8-X9-W10-X11-C12 (SEQ ID NO: 12), P2-X3-C4-V5- X6-X7- ⁇ A8-X9-W10-X11-C12 (SEQ ID NO: 13) or X3-C4-V5-X6-X7- ⁇ A8-X9-W10-X11-C12 (SEQ ID NO: 14), wherein X 1 is independently ⁇ A, D-A, A or E; X 3 is independently Y, F or W; X 6 is independently Y, F or W; X 7 is independently R, T, or N; X 9 is independently S, E, T or V; and X 11 is independently S, E, L or N.
  • an APY cyclic peptide has the sequence X1-P2-Y3-C4-V5-X6-X7- ⁇ A8-X9-W10- X 11 -C 12 (SEQ ID NO: 15), P 2 -Y 3 -C 4 -V 5 -X 6 -X 7 - ⁇ A 8 -X 9 -W 10 -X 11 -C 12 (SEQ ID NO: 16), Y 3 -C 4 -V 5 -X 6 -X 7 - ⁇ A 8 -X 9 - W 10 -X 11 -C 12 (SEQ ID NO: 17), wherein X 1 is independently ⁇ A, D-A, A, E, G or Q; X 6 is independently Y, F, W or H; X7 is independently any amino acid except P; X9 is independently any amino acid except P; and X11 is independently any amino acid except P.
  • Residues C4 and C12 of an APY cyclic peptide disclosed herein form a disulfide bridge.
  • residue C 12 is optionally amidated.
  • the amino-terminal residue is optionally acetylated.
  • an APY cyclic peptide has the sequence X 1 -P 2 -Y 3 -C 4 -V 5 -X 6 -X 7 - ⁇ A 8 - X 9 -W 10 -X 11 -C 12 (SEQ ID NO: 15), P 2 -Y 3 -C 4 -V 5 -X 6 -X 7 - ⁇ A 8 -X 9 -W 10 -X 11 -C 12 (SEQ ID NO: 16), Y 3 -C 4 -V 5 -X 6 -X 7 - ⁇ A8-X9-W10-X11-C12 (SEQ ID NO: 17), wherein X1 is independently ⁇ A, D-A, A, E, G or Q; X6 is independently Y, F, W or H; X7 is independently R, T, N, D, S, Q, Y, K, A, G or E; X9 is independently S, E, T, V, D
  • an APY cyclic peptide has the sequence X 1 -P 2 -Y 3 -C 4 -V 5 -X 6 -X 7 - ⁇ A 8 -X 9 -W 10 -X 11 -C 12 (SEQ ID NO: 15), P 2 -Y 3 -C 4 -V 5 -X 6 -X 7 - ⁇ A 8 -X 9 -W 10 -X 11 -C 12 (SEQ ID NO: 16), Y 3 -C 4 -V 5 -X 6 -X 7 - ⁇ A 8 -X 9 -W 10 -X 11 -C 12 (SEQ ID NO: 17), wherein X1 is independently ⁇ A, D-A, A, E, G or Q; X6 is independently Y, F, W or H; X7 is independently R, T, N, D, S, or Q; X9 is independently S, E, T, V, W, R, L, D, Y; and
  • an APY cyclic peptide has the sequence X 1 -P 2 -Y 3 -C 4 -V 5 -X 6 -X 7 - ⁇ A 8 -X 9 -W 10 -X 11 -C 12 (SEQ ID NO: 15), P 2 -Y 3 -C 4 -V 5 -X 6 -X 7 - ⁇ A 8 -X 9 -W 10 -X 11 -C 12 (SEQ ID NO: 16), Y3-C4-V5-X6-X7- ⁇ A8-X9-W10-X11-C12 (SEQ ID NO: 17), wherein X1 is independently ⁇ A, D-A, A, E, G or Q; X6 is independently Y, F, W or H; X7 is independently R, T, N, D, S, or Q; X9 is independently S, E, T, V, D, Y; and X11 is independently S, E, L, N, K
  • an APY cyclic peptide has the sequence X 1 -P 2 -Y 3 -C 4 -V 5 -X 6 -X 7 - ⁇ A 8 -X 9 -W 10 -X 11 -C 12 (SEQ ID NO: 15), P 2 -Y 3 - C4-V5-X6-X7- ⁇ A8-X9-W10-X11-C12 (SEQ ID NO: 16), Y3-C4-V5-X6-X7- ⁇ A8-X9-W10-X11-C12 (SEQ ID NO: 17), wherein X1 is independently ⁇ A, D-A, A, E, G or Q; X6 is independently Y, F, W or H; X7 is independently R, T, or N; X9 is independently S, E, T or V; and X11 is independently S, E, L or N.
  • an APY cyclic peptide has the sequence X1-P2-Y3-C4-V5-X6-X7- ⁇ A8- X9-W10-X11-C12 (SEQ ID NO: 15), P2-Y3-C4-V5-X6-X7- ⁇ A8-X9-W10-X11-C12 (SEQ ID NO: 16), Y3-C4-V5-X6-X7- ⁇ A 8 -X 9 -W 10 -X 11 -C 12 (SEQ ID NO: 17), wherein X 1 is independently ⁇ A, D-A, A or E; X 6 is independently Y, F or W; X 7 is independently R, T, N, D, S, Q, Y, K, A, G or E; X 9 is independently S, E, T, V, D, Y, Q, V, W, R, N, L, K or H; and X 11 is independently S, E,
  • an APY cyclic peptide has the sequence X1-P2-Y3-C4-V5-X6-X7- ⁇ A8-X9-W10-X11-C12 (SEQ ID NO: 15), P2-Y3-C4-V5-X6-X7- ⁇ A8-X9-W10-X11-C12 (SEQ ID NO: 16), Y3-C4-V5-X6-X7- ⁇ A8-X9-W10-X11-C12 (SEQ ID NO: 17), wherein X1 is independently ⁇ A, D-A, A or E; X6 is independently Y, F or W; X7 is independently R, T, N, D, S, or Q; X 9 is independently S, E, T, V, W, R, L, D, Y; and X 11 is independently S, E, L, N, T, K, V, I or H.
  • an APY cyclic peptide has the sequence X 1 -P 2 -Y 3 -C 4 - V5-X6-X7- ⁇ A8-X9-W10-X11-C12 (SEQ ID NO: 15), P2-Y3-C4-V5-X6-X7- ⁇ A8-X9-W10-X11-C12 (SEQ ID NO: 16), Y3- C4-V5-X6-X7- ⁇ A8-X9-W10-X11-C12 (SEQ ID NO: 17), wherein X1 is independently ⁇ A, D-A, A or E; X6 is independently Y, F or W; X 7 is independently R, T, N, D, S, or Q; X 9 is independently S, E, T, V, D, Y; and X 11 is independently S, E, L, N, K, V, I or H.
  • an APY cyclic peptide has the sequence X1-P2-Y3-C4-V5-X6-X7- ⁇ A8-X9-W10-X11-C12 (SEQ ID NO: 15), P2-Y3-C4-V5-X6-X7- ⁇ A8-X9- W10-X11-C12 (SEQ ID NO: 16), Y3-C4-V5-X6-X7- ⁇ A8-X9-W10-X11-C12 (SEQ ID NO: 17), wherein X1 is independently ⁇ A, D-A, A or E; X6 is independently Y, F or W; X7 is independently R, T, or N; X9 is independently S, E, T or V; and X 11 is independently S, E, L or N.
  • an APY cyclic peptide has the sequence X1-P2-X3-C4-V5-Y6-X7- ⁇ A8-X9-W10- X 11 -C 12 (SEQ ID NO: 18), P 2 -X 3 -C 4 -V 5 -Y 6 -X 7 - ⁇ A 8 -X 9 -W 10 -X 11 -C 12 (SEQ ID NO: 19) or X 3 -C 4 -V 5 -Y 6 -X 7 - ⁇ A 8 - X 9 -W 10 -X 11 -C 12 (SEQ ID NO: 20), wherein X 1 is independently ⁇ A, D-A, A, E, G or Q; X 3 is independently Y, F, W, V, L or H; X7 is independently any amino acid except P; X9 is independently any amino acid except P; and X11 is independently any amino acid except P.
  • Residues C4 and C12 of an APY cyclic peptide disclosed herein form a disulfide bridge.
  • residue C 12 is optionally amidated.
  • the amino-terminal residue is optionally acetylated.
  • an APY cyclic peptide has the sequence X1-P2-X3-C4-V5-Y6-X7- ⁇ A8- X 9 -W 10 -X 11 -C 12 (SEQ ID NO: 18), P 2 -X 3 -C 4 -V 5 -Y 6 -X 7 - ⁇ A 8 -X 9 -W 10 -X 11 -C 12 (SEQ ID NO: 19) or X 3 -C 4 -V 5 -Y 6 - X 7 - ⁇ A 8 -X 9 -W 10 -X 11 -C 12 (SEQ ID NO: 20), wherein X 1 is independently ⁇ A, D-A, A, E, G or Q; X 3 is independently Y, F, W, V, L or H; X7 is independently R, T, N, D, S, Q, Y, K, A, G or E; X9 is independently S, E, T, V, D
  • an APY cyclic peptide has the sequence X 1 -P 2 -X 3 -C 4 -V 5 -Y 6 -X 7 - ⁇ A 8 - X 9 -W 10 -X 11 -C 12 (SEQ ID NO: 18), P 2 -X 3 -C 4 -V 5 -Y 6 -X 7 - ⁇ A 8 -X 9 -W 10 -X 11 -C 12 (SEQ ID NO: 19) or X 3 -C 4 -V 5 -Y 6 - X7- ⁇ A8-X9-W10-X11-C12 (SEQ ID NO: 20), wherein X1 is independently ⁇ A, D-A, A, E, G or Q; X3 is independently Y, F, W, V, L or H; X7 is independently R, T, N, D, S, or Q; X9 is independently S, E, T, V, W, R, L, D, Y
  • an APY cyclic peptide has the sequence X 1 -P 2 -X 3 -C 4 -V 5 -Y 6 -X 7 - ⁇ A 8 -X 9 -W 10 -X 11 -C 12 (SEQ ID NO: 18), P 2 - X3-C4-V5-Y6-X7- ⁇ A8-X9-W10-X11-C12 (SEQ ID NO: 19) or X3-C4-V5-Y6-X7- ⁇ A8-X9-W10-X11-C12 (SEQ ID NO: 20), wherein X1 is independently ⁇ A, D-A, A, E, G or Q; X3 is independently Y, F, W, V, L or H; X7 is independently R, T, N, D, S, or Q; X9 is independently S, E, T, V, D, Y; and X11 is independently S, E, L, N, K, V,
  • an APY cyclic peptide has the sequence X 1 -P 2 -X 3 - C 4 -V 5 -Y 6 -X 7 - ⁇ A 8 -X 9 -W 10 -X 11 -C 12 (SEQ ID NO: 18), P 2 -X 3 -C 4 -V 5 -Y 6 -X 7 - ⁇ A 8 -X 9 -W 10 -X 11 -C 12 (SEQ ID NO: 19) or X3-C4-V5-Y6-X7- ⁇ A8-X9-W10-X11-C12 (SEQ ID NO: 20), wherein X1 is independently ⁇ A, D-A, A, E, G or Q; X 3 is independently Y, F, W, V, L or H; X 7 is independently R, T, or N; X 9 is independently S, E, T or V; and X 11 is independently S, E, L or N.
  • an APY cyclic peptide has the sequence X1-P2-X3-C4-V5-Y6-X7- ⁇ A8- X 9 -W 10 -X 11 -C 12 (SEQ ID NO: 18), P 2 -X 3 -C 4 -V 5 -Y 6 -X 7 - ⁇ A 8 -X 9 -W 10 -X 11 -C 12 (SEQ ID NO: 19) or X 3 -C 4 -V 5 -Y 6 - X 7 - ⁇ A 8 -X 9 -W 10 -X 11 -C 12 (SEQ ID NO: 20), wherein X 1 is independently ⁇ A, D-A, A or E; X 3 is independently Y, F or W; X7 is independently R, T, N, D, S, Q, Y, K, A, G or E; X9 is independently S, E, T, V, D, Y, Q, V, W,
  • an APY cyclic peptide has the sequence X 1 -P 2 -X 3 -C 4 -V 5 -Y 6 -X 7 - ⁇ A 8 -X 9 -W 10 -X 11 -C 12 (SEQ ID NO: 18), P 2 -X 3 -C 4 -V 5 -Y 6 -X 7 - ⁇ A 8 -X 9 -W 10 -X 11 -C 12 (SEQ ID NO: 19) or X 3 -C 4 -V 5 -Y 6 -X 7 - ⁇ A 8 -X 9 -W 10 -X 11 -C 12 (SEQ ID NO: 20), wherein X1 is independently ⁇ A, D-A, A or E; X3 is independently Y, F or W; X7 is independently R, T, N, D, S, or Q; X9 is independently S, E, T, V, W, R, L, D, Y; and X11 is independently
  • an APY cyclic peptide has the sequence X 1 -P 2 -X 3 -C 4 -V 5 -Y 6 -X 7 - ⁇ A 8 -X 9 -W 10 -X 11 -C 12 (SEQ ID NO: 18), P 2 -X 3 -C 4 -V 5 -Y 6 -X 7 - ⁇ A 8 -X 9 -W 10 -X 11 -C 12 (SEQ ID NO: 19) or X 3 -C 4 -V 5 -Y 6 -X 7 - ⁇ A 8 -X 9 -W 10 -X 11 -C 12 (SEQ ID NO: 20), wherein X 1 is independently ⁇ A, D-A, A or E; X3 is independently Y, F or W; X7 is independently R, T, N, D, S, or Q; X9 is independently S, E, T, V, D, Y; and X11 is independently S, E, L
  • an APY cyclic peptide has the sequence X 1 -P 2 -X 3 -C 4 -V 5 -Y 6 -X 7 - ⁇ A 8 -X 9 -W 10 -X 11 -C 12 (SEQ ID NO: 18), P 2 -X 3 -C 4 -V 5 -Y 6 -X 7 - ⁇ A 8 -X 9 -W 10 -X 11 -C 12 (SEQ ID NO: 19) or X 3 -C 4 -V 5 -Y 6 -X 7 - ⁇ A 8 -X 9 -W 10 -X 11 -C 12 (SEQ ID NO: 20), wherein X 1 is independently ⁇ A, D-A, A or E; X3 is independently Y, F or W; X7 is independently R, T, or N; X9 is independently S, E, T or V; and X11 is independently S, E, L or N.
  • an APY cyclic peptide has the sequence X1-P2-Y3-C4-V5-Y6-X7- ⁇ A8-X9-W10- X11-C12 (SEQ ID NO: 21), P2-Y3-C4-V5-Y6-X7- ⁇ A8-X9-W10-X11-C12 (SEQ ID NO: 22) or Y3-C4-V5-Y6-X7- ⁇ A8- X9-W10-X11-C12 (SEQ ID NO: 23), wherein X1 is independently ⁇ A, D-A, A, E, G or Q; X7 is independently any amino acid except P; X 9 is independently any amino acid except P; and X 11 is independently any amino acid except P.
  • Residues C 4 and C 12 of an APY cyclic peptide disclosed herein form a disulfide bridge.
  • residue C12 is optionally amidated.
  • amino-terminal residue is optionally acetylated.
  • an APY cyclic peptide has the sequence X1-P2-Y3-C4-V5-Y6-X7- ⁇ A8- X9-W10-X11-C12 (SEQ ID NO: 21), P2-Y3-C4-V5-Y6-X7- ⁇ A8-X9-W10-X11-C12 (SEQ ID NO: 22) or Y3-C4-V5-Y6- X7- ⁇ A8-X9-W10-X11-C12 (SEQ ID NO: 23), wherein X1 is independently ⁇ A, D-A, A, E, G or Q; X7 is independently R, T, N, D, S, Q, Y, K, A, G or E; X 9 is independently S, E, T, V, D, Y, Q, V, W, R, N, L, K or H; and X11 is independently S, E, L, N, V, I, H, K
  • an APY cyclic peptide has the sequence X1-P2-Y3-C4-V5-Y6-X7- ⁇ A8-X9-W10-X11-C12 (SEQ ID NO: 21), P2-Y3- C4-V5-Y6-X7- ⁇ A8-X9-W10-X11-C12 (SEQ ID NO: 22) or Y3-C4-V5-Y6-X7- ⁇ A8-X9-W10-X11-C12 (SEQ ID NO: 23), wherein X 1 is independently ⁇ A, D-A, A, E, G or Q; X 7 is independently R, T, N, D, S, or Q; X 9 is independently S, E, T, V, W, R, L, D, Y; and X 11 is independently S, E, L, N, T, K, V, I or H.
  • an APY cyclic peptide has the sequence X1-P2-Y3-C4-V5-Y6-X7- ⁇ A8-X9-W10- X11-C12 (SEQ ID NO: 21), P2-Y3-C4-V5-Y6-X7- ⁇ A8-X9-W10-X11-C12 (SEQ ID NO: 22) or Y3-C4-V5-Y6-X7- ⁇ A8- X 9 -W 10 -X 11 -C 12 (SEQ ID NO: 23), wherein X 1 is independently ⁇ A, D-A, A, E, G or Q; X 7 is independently R, T, N, D, S, or Q; X 9 is independently S, E, T, V, D, Y; and X 11 is independently S, E, L, N, K, V, I or H.
  • an APY cyclic peptide has the sequence X 1 -P 2 -Y 3 -C 4 -V 5 -Y 6 -X 7 - ⁇ A8-X9-W10-X11-C12 (SEQ ID NO: 21), P2-Y3-C4-V5-Y6-X7- ⁇ A8-X9-W10-X11-C12 (SEQ ID NO: 22) or Y3-C4-V5- Y6-X7- ⁇ A8-X9-W10-X11-C12 (SEQ ID NO: 23), wherein X1 is independently ⁇ A, D-A, A, E, G or Q; X7 is independently R, T, or N; X9 is independently S, E, T or V; and X11 is independently S, E, L or N.
  • an APY cyclic peptide has the sequence X1-P2-Y3-C4-V5-Y6-X7- ⁇ A8- X9-W10-X11-C12 (SEQ ID NO: 21), P2-Y3-C4-V5-Y6-X7- ⁇ A8-X9-W10-X11-C12 (SEQ ID NO: 22) or Y3-C4-V5-Y6- X 7 - ⁇ A 8 -X 9 -W 10 -X 11 -C 12 (SEQ ID NO: 23), wherein X 1 is independently ⁇ A, D-A, A or E; X 7 is independently R, T, N, D, S, Q, Y, K, A, G or E; X 9 is independently S, E, T, V, D, Y, Q, V, W, R, N, L, K or H; and X 11 is independently S, E, L, N, V, I, H,
  • an APY cyclic peptide has the sequence X1-P2-Y3-C4-V5-Y6-X7- ⁇ A8-X9-W10-X11-C12 (SEQ ID NO: 21), P2-Y3-C4-V5-Y6-X7- ⁇ A8-X9-W10-X11-C12 (SEQ ID NO: 22) or Y3-C4-V5-Y6-X7- ⁇ A8-X9-W10-X11-C12 (SEQ ID NO: 23), wherein X1 is independently ⁇ A, D-A, A or E; X 7 is independently R, T, N, D, S, or Q; X 9 is independently S, E, T, V, W, R, L, D, Y; and X 11 is independently S, E, L, N, T, K, V, I or H.
  • an APY cyclic peptide has the sequence X1-P2-Y3-C4-V5-Y6-X7- ⁇ A8-X9-W10-X11-C12 (SEQ ID NO: 21), P2- Y3-C4-V5-Y6-X7- ⁇ A8-X9-W10-X11-C12 (SEQ ID NO: 22) or Y3-C4-V5-Y6-X7- ⁇ A8-X9-W10-X11-C12 (SEQ ID NO: 23), wherein X 1 is independently ⁇ A, D-A, A or E; X 7 is independently R, T, N, D, S, or Q; X 9 is independently S, E, T, V, D, Y; and X 11 is independently S, E, L, N, K, V, I or H.
  • an APY cyclic peptide has the sequence X1-P2-Y3-C4-V5-Y6-X7- ⁇ A8-X9-W10-X11-C12 (SEQ ID NO: 21), P2- Y3-C4-V5-Y6-X7- ⁇ A8-X9-W10-X11-C12 (SEQ ID NO: 22) or Y3-C4-V5-Y6-X7- ⁇ A8-X9-W10-X11-C12 (SEQ ID NO: 23), wherein X 1 is independently ⁇ A, D-A, A or E; X 7 is independently R, T, or N; X 9 is independently S, E, T or V; and X 11 is independently S, E, L or N.
  • an APY cyclic peptide has the sequence X1-P2-Y3-C4-V5-Y6-R7- ⁇ A8-X9- W 10 -X 11 -C 12 (SEQ ID NO: 24), P 2 -Y 3 -C 4 -V 5 -Y 6 -R 7 - ⁇ A 8 -X 9 -W 10 -X 11 -C 12 (SEQ ID NO: 25) or Y 3 -C 4 -V 5 -Y 6 -R 7 - ⁇ A 8 -X 9 -W 10 -X 11 -C 12 (SEQ ID NO: 26), wherein X 1 is independently ⁇ A, D-A, A, E, G or Q; X 9 is independently any amino acid except P; and X11 is independently any amino acid except P.
  • Residues C4 and C12 of an APY cyclic peptide disclosed herein form a disulfide bridge.
  • residue C12 is optionally amidated.
  • amino-terminal residue is optionally acetylated.
  • an APY cyclic peptide has the sequence X1-P2-Y3-C4-V5-Y6-R7- ⁇ A8- X 9 -W 10 -X 11 -C 12 (SEQ ID NO: 24), P 2 -Y 3 -C 4 -V 5 -Y 6 -R 7 - ⁇ A 8 -X 9 -W 10 -X 11 -C 12 (SEQ ID NO: 25) or Y 3 -C 4 -V 5 -Y 6 - R7- ⁇ A8-X9-W10-X11-C12 (SEQ ID NO: 26), wherein X1 is independently ⁇ A, D-A, A, E, G or Q; X9 is independently S, E, T, V, D, Y, Q, V, W, R, N, L, K or H; and X11 is independently S, E, L, N, V, I, H, K, M, D, W, T or G.
  • an APY cyclic peptide has the sequence X1-P2-Y3-C4- V 5 -Y 6 -R 7 - ⁇ A 8 -X 9 -W 10 -X 11 -C 12 (SEQ ID NO: 24), P 2 -Y 3 -C 4 -V 5 -Y 6 -R 7 - ⁇ A 8 -X 9 -W 10 -X 11 -C 12 (SEQ ID NO: 25) or Y 3 -C 4 -V 5 -Y 6 -R 7 - ⁇ A 8 -X 9 -W 10 -X 11 -C 12 (SEQ ID NO: 26), wherein X 1 is independently ⁇ A, D-A, A, E, G or Q; X9 is independently S, E, T, V, W, R, L, D, Y; and X11 is independently S, E, L, N, T, K, V, I or H.
  • an APY cyclic peptide has the sequence X1-P2-Y3-C4-V5-Y6-R7- ⁇ A8-X9- W 10 -X 11 -C 12 (SEQ ID NO: 24), P 2 -Y 3 -C 4 -V 5 -Y 6 -R 7 - ⁇ A 8 -X 9 -W 10 -X 11 -C 12 (SEQ ID NO: 25) or Y 3 -C 4 -V 5 -Y 6 -R 7 - ⁇ A 8 -X 9 -W 10 -X 11 -C 12 (SEQ ID NO: 26), wherein X 1 is independently ⁇ A, D-A, A, E, G or Q; X 9 is independently S, E, T, V, D, Y; and X 11 is independently S, E, L, N, K, V, I or H.
  • an APY cyclic peptide has the sequence X1-P2-Y3-C4-V5-Y6-R7- ⁇ A8-X9-W10-X11-C12 (SEQ ID NO: 24), P2- Y3-C4-V5-Y6-R7- ⁇ A8-X9-W10-X11-C12 (SEQ ID NO: 25) or Y3-C4-V5-Y6-R7- ⁇ A8-X9-W10-X11-C12 (SEQ ID NO: 26), wherein X1 is independently ⁇ A, D-A, A, E, G or Q; X9 is independently S, E, T or V; and X11 is independently S, E, L or N.
  • an APY cyclic peptide has the sequence X1-P2-Y3-C4-V5-Y6-R7- ⁇ A8- X 9 -W 10 -X 11 -C 12 (SEQ ID NO: 24), P 2 -Y 3 -C 4 -V 5 -Y 6 -R 7 - ⁇ A 8 -X 9 -W 10 -X 11 -C 12 (SEQ ID NO: 25) or Y 3 -C 4 -V 5 -Y 6 - R 7 - ⁇ A 8 -X 9 -W 10 -X 11 -C 12 (SEQ ID NO: 26), wherein X 1 is independently ⁇ A, D-A, A or E; X 9 is independently S, E, T, V, D, Y, Q, V, W, R, N, L, K or H; and X11 is independently S, E, L, N, V, I, H, K, M, D, W, T or G
  • an APY cyclic peptide has the sequence X1-P2-Y3-C4-V5-Y6-R7- ⁇ A8- X9-W10-X11-C12 (SEQ ID NO: 24), P2-Y3-C4-V5-Y6-R7- ⁇ A8-X9-W10-X11-C12 (SEQ ID NO: 25) or Y3-C4-V5-Y6- R 7 - ⁇ A 8 -X 9 -W 10 -X 11 -C 12 (SEQ ID NO: 26), wherein X 1 is independently ⁇ A, D-A, A or E; X 9 is independently S, E, T, V, W, R, L, D, Y; and X 11 is independently S, E, L, N, T, K, V, I or H.
  • an APY cyclic peptide has the sequence X1-P2-Y3-C4-V5-Y6-R7- ⁇ A8-X9-W10-X11-C12 (SEQ ID NO: 24), P2-Y3-C4-V5-Y6-R7- ⁇ A8-X9-W10-X11-C12 (SEQ ID NO: 25) or Y3-C4-V5-Y6-R7- ⁇ A8-X9-W10-X11-C12 (SEQ ID NO: 26), wherein X 1 is independently ⁇ A, D-A, A or E; X 9 is independently S, E, T, V, D, Y; and X 11 is independently S, E, L, N, K, V, I or H.
  • an APY cyclic peptide has the sequence X1-P2-Y3-C4-V5-Y6-R7- ⁇ A8-X9-W10-X11-C12 (SEQ ID NO: 24), P2-Y3-C4-V5-Y6-R7- ⁇ A8-X9- W10-X11-C12 (SEQ ID NO: 25) or Y3-C4-V5-Y6-R7- ⁇ A8-X9-W10-X11-C12 (SEQ ID NO: 26), wherein X1 is independently ⁇ A, D-A, A or E; X 9 is independently S, E, T or V; and X 11 is independently S, E, L or N.
  • an APY cyclic peptide has the sequence APYCVYR ⁇ ASWSC (SEQ ID NO: 35), APYCVYR ⁇ ASWSC-am (SEQ ID NO: 36), APYCVYK ⁇ ASWSC-am (SEQ ID NO: 45), ⁇ APYCVYR ⁇ ASWSC (SEQ ID NO: 46), ⁇ APYCVYR ⁇ ASWSC-am (SEQ ID NO: 47), ⁇ APYCVYK ⁇ ASWSC- am (SEQ ID NO: 48), ⁇ APYCVYR ⁇ AEWEC (SEQ ID NO: 49), ⁇ APYCVYR ⁇ AEWEC-am (SEQ ID NO: 50), D-APYCVYR ⁇ ASWSC (SEQ ID NO: 51), D-APYCVYR ⁇ ASWSC-am (SEQ ID NO: 52), APYCVWR ⁇ ASWSC (SEQ ID NO: 53), APYCVYT ⁇ AEWLC (SEQ ID NO: 54),
  • an APY cyclic peptide has the sequence APYCVYR ⁇ ASWSC-am (SEQ ID NO: 36), APYCVYK ⁇ ASWSC-am (SEQ ID NO: 45), ⁇ APYCVYR ⁇ ASWSC (SEQ ID NO: 46), ⁇ APYCVYR ⁇ ASWSC-am (SEQ ID NO: 47), ⁇ APYCVYR ⁇ AEWEC-am (SEQ ID NO: 50), D-APYCVYR ⁇ ASWSC-am (SEQ ID NO: 52), APYCVWR ⁇ ASWSC (SEQ ID NO: 53), APYCVYT ⁇ AEWLC (SEQ ID NO: 54), APYCVYN ⁇ ATWNC (SEQ ID NO: 55) or APYCVYR ⁇ AVWEC (SEQ ID NO: 56).
  • an APY cyclic peptide has the sequence APYCVYR ⁇ ASWSC-am (SEQ ID NO: 36), ⁇ APYCVYR ⁇ ASWSC-am (SEQ ID NO: 47) or ⁇ APYCVYR ⁇ AEWEC-am (SEQ ID NO: 50).
  • an EphA4 antagonist like an APY cyclic peptide disclosed herein, that selectively binds to the ephrin-binding pocket in the EphA4 ligand binding domain. Selective binding includes binding properties such as, e.g., binding affinity and binding specificity.
  • Binding affinity refers to the length of time an EphA4 antagonist, like an APY cyclic peptide disclosed herein, resides at the ephrin-binding pocket in the EphA4 ligand binding domain, and can be viewed as the strength with which an EphA4 antagonist binds to the ephrin-binding pocket. Binding affinity can be described by EphA4 antagonist’s equilibrium dissociation constant (KD), which is defined as the ratio Kd/Ka at equillibrium. Where Ka is the EphA4 antagonist’s association rate constant and kd is the EphA4 antagonist’s dissociation rate constant.
  • KD equilibrium dissociation constant
  • Binding affinity is determined by both the association and the dissociation and alone neither high association or low dissociation can ensure high affinity.
  • the association rate constant (Ka), or on-rate constant (Kon) measures the number of binding events per unit time, or the propensity of the EphA4 antagonist and the ephrin-binding pocket in the EphA4 ligand binding domain to associate reversibly into its ligand-receptor complex.
  • the association rate constant is expressed in M-1 s-1, and is symbolized as follows: [Ligand] x [Receptor] x Kon.
  • the dissociation rate constant (Kd), or off-rate constant (Koff) measures the number of dissociation events per unit time propensity of an ligand- receptor complex to separate (dissociate) reversibly into its component molecules, namely the EphA4 antagonist and EphA4.
  • the dissociation rate constant is expressed in s-1, and is symbolized as follows: [Ligand + Receptor] x Koff.
  • the equilibrium dissociation constant (K D ) measures the rate at which new ligand-receptor complexes formed equals the rate at which ligand-receptor complexes dissociate at equilibrium.
  • the smaller the equilibrium dissociation constant the more tightly bound the EphA4 antagonist is to the ephrin-binding pocket in the EphA4 ligand binding domain, or the higher the binding affinity between an EphA4 antagonist and EphA4.
  • the binding affinity of an EphA4 antagonist may have an association rate constant for an EpHA4 receptor of, e.g., less than 1 x 10 5 M -1 s -1 , 5 x 10 5 M -1 s -1 , less than 1 x 10 6 M -1 s -1 , less than 5 x 10 6 M -1 s -1 , less than 1 x 10 7 M -1 s -1 , less than 5 x 10 7 M -1 s -1 or less than 1 x 10 8 M -1 s -1 .
  • an EphA4 antagonist like an APY cyclic peptide disclosed herein
  • an EphA4 antagonist like an APY cyclic peptide disclosed herein
  • the binding affinity of an EphA4 antagonist may have an association rate constant for an EpHA4 receptor of between 1 x 10 5 M -1 s -1 to 1 x 10 8 M -1 s -1 , 1 x 10 6 M -1 s -1 to 1 x 10 8 M -1 s -1 , 1 x 10 5 M -1 s -1 to 1 x 10 7 M -1 s -1 or 1 x 10 6 M -1 s -1 to 1 x 10 7 M -1 s -1 .
  • the binding affinity of an EphA4 antagonist may have an association rate constant for an ephrin receptor other than an EpHA4 receptor of, e.g., less than 1 x 10 0 M -1 s -1 , 5 x 10 0 M -1 s -1 , less than 1 x 10 1 M -1 s -1 , less than 5 x 10 1 M -1 s -1 , less than 1 x 10 2 M -1 s -1 , less than 5 x 10 2 M -1 s -1 , less than 1 x 10 3 M -1 s -1 , less than 5 x 10 3 M -1 s -1 or less than 1 x 10 4 M -1 s -1 .
  • the binding affinity of an EphA4 antagonist may have an association rate constant for an ephrin receptor other than an EpHA4 receptor of, e.g., at most 1 x 10 0 M -1 s -1 , at most 5 x 10 0 M -1 s -1 , at most 1 x 10 1 M -1 s -1 , at most 5 x 10 1 M -1 s -1 , at most 1 x 10 2 M -1 s -1 , at most 5 x 10 2 M -1 s -1 , at most 1 x 10 3 M -1 s -1 , at most 5 x 10 3 M -1 s -1 or at most 1 x 10 4 M -1 s -1 .
  • the binding affinity of an EphA4 antagonist may have a disassociation rate constant for an EpHA4 receptor of, e.g., less than 1 x 10- 3 s -1 , 5 x 10 -3 s -1 , less than 1 x 10 -4 s -1 , less than 5 x 10 -4 s -1 or less than 1 x 10 -5 s -1 .
  • the binding affinity of an ⁇ -HIV antibody disclosed herein may have a disassociation rate constant for an EpHA4 receptor of, e.g., less than 1.0 x 10 -4 s -1 , less than 2.0 x 10 -4 s -1 , less than 3.0 x 10- 4 s -1 , less than 4.0 x 10 -4 s -1 , less than 5.0 x 10 -4 s -1 , less than 6.0 x 10 -4 s -1 , less than 7.0 x 10 -4 s -1 , less than 8.0 x 10 -4 s -1 or less than 9.0 x 10 -4 s -1 .
  • the binding affinity an EphA4 antagonist may have a disassociation rate constant for an EpHA4 receptor of, e.g., more than 1 x 10 -3 s -1 , more than 5 x 10 -3 s -1 , more than 1 x 10 -4 s -1 , more than 5 x 10 -4 s -1 or more than 1 x 10 -5 s -1 .
  • the binding affinity of an EphA4 antagonist may have a disassociation rate constant for an EpHA4 receptor of, e.g., more than 1.0 x 10 -4 s -1 , more than 2.0 x 10 -4 s -1 , more than 3.0 x 10 -4 s -1 , more than 4.0 x 10 -4 s -1 , more than 5.0 x 10 -4 s -1 , more than 6.0 x 10 -4 s -1 , more than 7.0 x 10 -4 s -1 , more than 8.0 x 10 -4 s -1 or more than 9.0 x 10 -4 s -1 .
  • the binding affinity of an EphA4 antagonist may have a disassociation rate constant for an EpHA4 receptor of between 1 x 10 -3 s -1 to 1 x 10 -5 s -1 , 1 x 10 -3 s -1 to 1 x 10 -4 s -1 or 1 x 10 -4 s -1 to 1 x 10 -5 s -1 .
  • the binding affinity of a modified EphA4 antagonist may have an equilibrium disassociation constant for an EpHA4 receptor of less than 500 nM.
  • the binding affinity of a modified EphA4 antagonist may have an equilibrium disassociation constant for an EpHA4 receptor of, e.g., less than 500 nM, less than 450 nM, less than 400 nM, less than 350 nM, less than 300 nM, less than 250 nM, less than 200 nM, less than 150 nM, less than 100 nM, less than 75 nM, less than 50 nM, less than 25 nM, less than 20 nM, less than 15 nM, less than 10 nM, less than 5 nM, less than 1 nM, less than 0.5 nM, or less than 0.1 nM.
  • an equilibrium disassociation constant for an EpHA4 receptor of, e.g., less than 500 nM, less than 450 nM, less than 400 nM, less than 350 nM, less than 300 nM, less than 250 nM, less than 200 nM, less than 150 nM, less than 100 nM
  • the binding affinity of a modified EphA4 antagonist may have an equilibrium disassociation constant for an EpHA4 receptor of, e.g., about 0.1 nM to about 10 nM, about 0.1 nM to about 25 nM, about 0.1 nM to about 75 nM, about 0.1 nM to about 100 nM, about 0.1 nM to about 125 nM, about 0.1 nM to about 150 nM, about 0.5 nM to about 10 nM, about 0.5 nM to about 25 nM, about 0.5 nM to about 75 nM, about 0.5 nM to about 100 nM, about 0.5 nM to about 125 nM, about 0.5 nM to about 150 nM, about 1 nM to about 10 nM, about 1 nM to about 25 nM, about 1 nM to about 75 nM, about 1 nM
  • Binding specificity is the ability of an EphA4 antagonist, like an APY cyclic peptide disclosed herein, to discriminate between a molecule containing the ephrin-binding pocket in the EphA4 ligand binding domain and a molecule that does not contain this ephrin-binding pocket.
  • One way to measure binding specificity is to compare the Kon association rate of an EphA4 antagonist for a molecule containing the ephrin-binding pocket in the EphA4 ligand binding domain relative to the Kon association rate of the EphA4 antagonist for a molecule that does not contain this ephrin-binding pocket.
  • association rate constant (Ka) of an EphA4 antagonist like an APY cyclic peptide disclosed herein, that selectively binds to the ephrin-binding pocket in the EphA4 ligand binding domain relative to an ephrin- binding pocket to an Eph receptor other than EphA4.
  • an EphA4 antagonist like an APY cyclic peptide disclosed herein, may have an association rate constant (Ka) for an ephrin- binding pocket to an ephrin receptor other than an EphA4 receptor of, e.g., less than 1 x 10 0 M -1 s -1 , less than 1 x 10 1 M -1 s -1 , less than 1 x 10 2 M -1 s -1 , less than 1 x 10 3 M -1 s -1 or less than 1 x 10 4 M -1 s -1 .
  • Ka association rate constant
  • an EphA4 antagonist like an APY cyclic peptide disclosed herein, have an association rate constant (Ka) for an ephrin-binding pocket to an ephrin receptor other than an EphA4 receptor of, e.g., at most 1 x 10 0 M -1 s -1 , at most 1 x 10 1 M -1 s -1 , at most 1 x 10 2 M -1 s -1 , at most 1 x 10 3 M -1 s -1 or at most 1 x 10 4 M -1 s -1 .
  • Ka association rate constant
  • an EphA4 antagonist like an APY cyclic peptide disclosed herein, may have an association rate constant (Ka) for the ephrin-binding pocket in the EphA4 ligand binding domain relative to an ephrin-binding pocket of an ephrin receptor other than an EphA4 receptor of, e.g., at least 2-fold more, at least 3-fold more, at least 4-fold more, at least 5-fold more, at least 6-fold more, at least 7-fold more, at least 8-fold more, or at least 9-fold more.
  • Ka association rate constant
  • an EphA4 antagonist like an APY cyclic peptide disclosed herein, may have an association rate constant (Ka) for the ephrin-binding pocket in the EphA4 ligand binding domain relative to an ephrin-binding pocket of an ephrin receptor other than an EphA4 receptor of, e.g., at least 10-fold more, at least 20-fold more, at least 30-fold more, at least 40-fold more, at least 50-fold more, at least 60-fold more, at least 70-fold more, at least 80-fold more, at least 90-fold more, at least 100-fold more, at least 200-fold more, at least 300-fold more, at least 400-fold more, at least 500-fold more, at least 600-fold more, at least 700-fold more, at least 800-fold more, at least 900-fold more, at least 1,000-fold more, at least 1,200-fold more, at least 1,400-fold more, at least 1,600-fold more
  • Ka association rate constant
  • an ephrin-binding pocket of an ephrin receptor other than an EphA4 receptor includes an EphA2 receptor, an EphA3 receptor, an EphA5 receptor, an EphA6 receptor, an EphA7 receptor, an EphA8 receptor, an EphB1 receptor, an EphB2 receptor, an EphB3 receptor, an EphB4 receptor, an EphB6 receptor, or any combination thereof.
  • an EphA4 antagonist like an APY cyclic peptide disclosed herein, may have an association rate constant (Ka) for the ephrin-binding pocket in the EphA4 ligand binding domain relative to an ephrin-binding pocket of an ephrin receptor other than an EphA4 receptor of, e.g., at most 1-fold more, at most 2-fold more, at most 3-fold more, at most 4-fold more, at most 5-fold more, at most 6-fold more, at most 7-fold more, at most 8-fold more, or at most 9-fold more.
  • Ka association rate constant
  • an EphA4 antagonist like an APY cyclic peptide disclosed herein, may have an association rate constant (Ka) for the ephrin-binding pocket in the EphA4 ligand binding domain relative to an ephrin-binding pocket of an ephrin receptor other than an EphA4 receptor of, e.g., at most 10-fold more, at most 20-fold more, at most 30-fold more, at most 40-fold more, at most 50-fold more, at most 60- fold more, at most 70-fold more, at most 80-fold more, at most 90-fold more, at most 100-fold more, at most 200-fold more, at most 300-fold more, at most 400-fold more, at most 500-fold more, at most 600-fold more, at most 700-fold more, at most 800-fold more, at most 900-fold more, at most 1,000-fold more, at most 1,200-fold more, at most 1,400-fold more, at most 1,600-fold more
  • Ka association rate constant
  • an ephrin-binding pocket of an ephrin receptor other than an EphA4 receptor includes an EphA2 receptor, an EphA3 receptor, an EphA5 receptor, an EphA6 receptor, an EphA7 receptor, an EphA8 receptor, an EphB1 receptor, an EphB2 receptor, an EphB3 receptor, an EphB4 receptor, an EphB6 receptor, or any combination thereof.
  • the binding specificity of an EphA4 antagonist may also be characterized as a ratio that such an EphA4 antagonist can discriminate the ephrin-binding pocket in the EphA4 ligand binding domain relative to an ephrin-binding pocket of an ephrin receptor other than an EphA4 receptor.
  • an EphA4 antagonist like an APY cyclic peptide disclosed herein, may have a binding specificity ratio for the ephrin-binding pocket in the EphA4 ligand binding domain relative to an ephrin-binding pocket of an ephrin receptor other than an EphA4 receptor of, e.g., at least 2:1, at least 3:1, at least 4:1, at least 5:1, at least 64:1, at least 7:1, at least 8:1, at least 9:1, at least 10:1, at least 15:1, at least 20:1, at least 25:1, at least 30:1, at least 35:1, or at least 40:1.
  • an ephrin-binding pocket of an ephrin receptor other than an EphA4 receptor includes an EphA2 receptor, an EphA3 receptor, an EphA5 receptor, an EphA6 receptor, an EphA7 receptor, an EphA8 receptor, an EphB1 receptor, an EphB2 receptor, an EphB3 receptor, an EphB4 receptor, an EphB6 receptor, or any combination thereof.
  • an EphA4 antagonist like an APY cyclic peptide disclosed herein, that exhibits physiological stability.
  • Physiological stability includes properties such as, e.g., biological half-life and plasma half-life.
  • a biological half-life is the time required for one half of the total amount of a particular substance in a biological system to be degraded or eliminated by biological processes such as, e.g., through the kidney, liver and excretion functions when the rate of removal is nearly exponential.
  • a biological half-life is measured by assaying a pharmacologic and/or physiologic property of the substance.
  • a plasma half-life is the time required for one half of the total concentration of a particular substance in a biological system to reach its steady-state value in blood plasma.
  • the relationship between the biological and plasma half-lives of a substance can be complex, due to factors including accumulation in tissues, active metabolites, and receptor interactions.
  • an EphA4 antagonist like an APY cyclic peptide disclosed herein, may exhibit a therapeutically effective biological half-life.
  • an EphA4 antagonist like an APY cyclic peptide disclosed herein, may exhibit a biological half-life of, e.g., about 12 hours, about 18 hours, about 24 hours, about 30 hours, about 36 hours, about 42 hours, about 48 hours, about 54 hours, about 60 hours, about 66 hours, about 72 hours, about 78 hours, about 84 hours, about 90 hours or about 96 hours.
  • an EphA4 antagonist like an APY cyclic peptide disclosed herein, may exhibit a biological half-life of, e.g., at least 12 hours, at least 18 hours, at least 24 hours, at least 30 hours, at least 36 hours, at least 42 hours, at least 48 hours, at least 54 hours, at least 60 hours, at least 66 hours, at least 72 hours, at least 78 hours, at least 84 hours, at least 90 hours or at least 96 hours.
  • an EphA4 antagonist like an APY cyclic peptide disclosed herein, may exhibit a biological half-life of, e.g., at most 12 hours, at most 18 hours, at most 24 hours, at most 30 hours, at most 36 hours, at most 42 hours, at most 48 hours, at most 54 hours, at most 60 hours, at most 66 hours, at most 72 hours, at most 78 hours, at most 84 hours, at most 90 hours or at most 96 hours.
  • an EphA4 antagonist may exhibit a biological half-life of, e.g., about 12 hours to about 24 hours, about 12 hours to about 36 hours, about 12 hours to about 48 hours, about 12 hours to about 60 hours, about 12 hours to about 72 hours, about 12 hours to about 84 hours, about 12 hours to about 96 hours, about 24 hours to about 36 hours, about 24 hours to about 48 hours, about 24 hours to about 60 hours, about 24 hours to about 72 hours, about 24 hours to about 84 hours, about 24 hours to about 96 hours, about 36 hours to about 48 hours, about 36 hours to about 60 hours, about 36 hours to about 72 hours, about 36 hours to about 84 hours, about 36 hours to about 96 hours, about 48 hours to about 60 hours, about 48 hours to about 72 hours, about 48 hours to about 84 hours, about 48 hours to about 96 hours, about 60 hours to about 72 hours, about 60 hours to about 84 hours, about 60 hours to about 96 hours, about 60 hours to about 72 hours, about 60 hours to about 84 hours, about 60 hours to about
  • an EphA4 antagonist like an APY cyclic peptide disclosed herein, may exhibit a therapeutically effective plasma half-life.
  • an EphA4 antagonist like an APY cyclic peptide disclosed herein, may exhibit a plasma half-life of, e.g., about 12 hours, about 18 hours, about 24 hours, about 30 hours, about 36 hours, about 42 hours, about 48 hours, about 54 hours, about 60 hours, about 66 hours, about 72 hours, about 78 hours, about 84 hours, about 90 hours or about 96 hours.
  • an EphA4 antagonist like an APY cyclic peptide disclosed herein, may exhibit a plasma half-life of, e.g., at least 12 hours, at least 18 hours, at least 24 hours, at least 30 hours, at least 36 hours, at least 42 hours, at least 48 hours, at least 54 hours, at least 60 hours, at least 66 hours, at least 72 hours, at least 78 hours, at least 84 hours, at least 90 hours or at least 96 hours.
  • an EphA4 antagonist like an APY cyclic peptide disclosed herein, may exhibit a plasma half-life of, e.g., at most 12 hours, at most 18 hours, at most 24 hours, at most 30 hours, at most 36 hours, at most 42 hours, at most 48 hours, at most 54 hours, at most 60 hours, at most 66 hours, at most 72 hours, at most 78 hours, at most 84 hours, at most 90 hours or at most 96 hours.
  • an EphA4 antagonist may exhibit a plasma half-life of, e.g., about 12 hours to about 24 hours, about 12 hours to about 36 hours, about 12 hours to about 48 hours, about 12 hours to about 60 hours, about 12 hours to about 72 hours, about 12 hours to about 84 hours, about 12 hours to about 96 hours, about 24 hours to about 36 hours, about 24 hours to about 48 hours, about 24 hours to about 60 hours, about 24 hours to about 72 hours, about 24 hours to about 84 hours, about 24 hours to about 96 hours, about 36 hours to about 48 hours, about 36 hours to about 60 hours, about 36 hours to about 72 hours, about 36 hours to about 84 hours, about 36 hours to about 96 hours, about 48 hours to about 60 hours, about 48 hours to about 72 hours, about 48 hours to about 84 hours, about 48 hours to about 96 hours, about 60 hours to about 72 hours, about 60 hours to about 84 hours, about 60 hours to about 96 hours, about 60 hours to about 72 hours, about 60 hours to about 84 hours, about 60 hours to about
  • composition is synonymous with “therapeutic composition” or “pharmaceutically acceptable therapeutic composition” and refers to a composition comprising a therapeutically effective concentration of an active ingredient, such as, e.g., an EphA4 antagonist, like an APY cyclic peptide disclosed herein.
  • a pharmaceutical composition disclosed herein may comprise a single EphA4 antagonist, like an APY cyclic peptide disclosed herein.
  • a pharmaceutical composition disclosed herein may comprise a plurality of EphA4 antagonists, like the APY cyclic peptides disclosed herein.
  • pharmaceutical composition disclosed herein may comprise about one, about two, about three, about four, or about five EphA4 antagonists, like the APY cyclic peptides disclosed herein.
  • pharmaceutical composition disclosed herein may comprise one or more, two or more, three or more, four or more or five or more EphA4 antagonists, like the APY cyclic peptides disclosed herein.
  • pharmaceutical composition disclosed herein may comprise at most one, at most two, at most three, at most four, or at most five EphA4 antagonists, like the APY cyclic peptides disclosed herein.
  • pharmaceutical composition disclosed herein may comprise about one to about two, about one to about three, about one to about four, about one to about five, about two to about three, about two to about four, about two to about five, about three to about four, about three to about five or about four to about five, EphA4 antagonists, like the APY cyclic peptides disclosed herein.
  • EphA4 antagonists like the APY cyclic peptides disclosed herein.
  • the amount of EphA4 antagonist, like an APY cyclic peptide disclosed herein, included in a pharmaceutical composition is an amount sufficient to elicit an appropriate therapeutic response in the individual. Typically, this amount is also one that does not cause significant adverse side effects.
  • EphA4 antagonist(s) like an APY cyclic peptide disclosed herein
  • An optimal amount for a particular pharmaceutical composition can be ascertained by standard studies involving observation of antibody titers and other responses in individuals.
  • an effective and safe amount of EphA4 antagonist, like an APY cyclic peptide disclosed herein, included in a pharmaceutical composition varies from about 1 ng to 1,000 ⁇ g.
  • an amount of an EphA4 antagonist, like an APY cyclic peptide disclosed herein, included in a therapeutic composition may be, e.g., about 1 ng, about 2 ng, about 3 ng, about 4 ng, about 5 ng, about 6 ng, about 7 ng, about 8 ng, about 9 ng, about 10 ng, about 15 ng, about 20 ng, about 25 ng, about 30 ng, about 35 ng, about 40 ng, about 45 ng, about 50 ng, about 55 ng, about 60 ng, about 65 ng, about 70 ng, about 75 ng, about 80 ng, about 85 ng, about 90 ng, about 95 ng, about 100 ng, about 110 ng, about 120 ng, about 130 ng, about 140 ng, about 150 ng, about 160 ng, about 170 ng, about 180 ng, about 190 ng, about 200 ng, about 210 ng, about 220 ng, about 230 ng
  • an amount of an EphA4 antagonist, like an APY cyclic peptide disclosed herein, included in a pharmaceutical composition may be, e.g., at least 1 ng, at least 2 ng, at least 3 ng, at least 4 ng, at least 5 ng, at least 6 ng, at least 7 ng, at least 8 ng, at least 9 ng, at least 10 ng, at least 15 ng, at least 20 ng, at least 25 ng, at least 30 ng, at least 35 ng, at least 40 ng, at least 45 ng, at least 50 ng, at least 55 ng, at least 60 ng, at least 65 ng, at least 70 ng, at least 75 ng, at least 80 ng, at least 85 ng, at least 90 ng, at least 95 ng, at least 100 ng, at least 110 ng, at least 120 ng, at least 130 ng, at least 140 ng, at least 150 ng, at least 160 ng,
  • an amount of an EphA4 antagonist, like an APY cyclic peptide disclosed herein, included in a pharmaceutical composition may be, e.g., at most 1 ng, at most 2 ng, at most 3 ng, at most 4 ng, at most 5 ng, at most 6 ng, at most 7 ng, at most 8 ng, at most 9 ng, at most 10 ng, at most 15 ng, at most 20 ng, at most 25 ng, at most 30 ng, at most 35 ng, at most 40 ng, at most 45 ng, at most 50 ng, at most 55 ng, at most 60 ng, at most 65 ng, at most 70 ng, at most 75 ng, at most 80 ng, at most 85 ng, at most 90 ng, at most 95 ng, at most 100 ng, at most 110 ng, at most 120 ng, at most 130 ng, at most 140 ng, at most 150 ng, at most 160 ng
  • an amount of an EphA4 antagonist, like an APY cyclic peptide disclosed herein, included in a pharmaceutical composition may be in the range of, e.g., about 1 ng to about 10 ng, about 1 ng to about 20 ng, about 1 ng to about 30 ng, about 1 ng to about 40 ng, about 1 ng to about 50 ng, about 1 ng to about 60 ng, about 1 ng to about 70 ng, about 1 ng to about 80 ng, about 1 ng to about 90 ng, about 1 ng to about 100 ng, about 1 ng to about 110 ng, about 1 ng to about 120 ng, about 1 ng to about 130 ng, about 1 ng to about 140 ng, about 1 ng to about 150 ng, about 5 ng to about 10 ng, about 5 ng to about 20 ng, about 5 ng to about 30 ng, about 5 ng to about 40 ng, about 5 ng to about 50 ng
  • an amount of an EphA4 antagonist, like an APY cyclic peptide disclosed herein, included in a pharmaceutical composition may be in the range of, e.g., about 100 ng to about 125 ng, about 100 ng to about 150 ng, about 100 ng to about 175 ng, about 100 ng to about 200 ng, about 100 ng to about 225 ng, about 100 ng to about 250 ng, about 100 ng to about 275 ng, about 100 ng to about 300 ng, about 100 ng to about 325 ng, about 100 ng to about 350 ng, about 100 ng to about 375 ng, about 100 ng to about 400 ng, about 100 ng to about 425 ng, about 100 ng to about 450 ng, about 100 ng to about 475 ng, about 100 ng to about 500 ng, about 100 ng to about 525 ng, about 100 ng to about 550 ng, about 100 ng to about 575
  • an amount of an EphA4 antagonist, like an APY cyclic peptide disclosed herein, included in a pharmaceutical composition may be in the range of, e.g., about 250 ng to about 275 ng, about 250 ng to about 300 ng, about 250 ng to about 325 ng, about 250 ng to about 350 ng, about 250 ng to about 375 ng, about 250 ng to about 400 ng, about 250 ng to about 425 ng, about 250 ng to about 450 ng, about 250 ng to about 475 ng, about 250 ng to about 500 ng, about 250 ng to about 525 ng, about 250 ng to about 550 ng, about 250 ng to about 575 ng, about 250 ng to about 600 ng, about 250 ng to about 625 ng, about 250 ng to about 650 ng, about 250 ng to about 675 ng, about 250 ng to about 700 ng, about 250 ng to about 7
  • an amount of an EphA4 antagonist, like an APY cyclic peptide disclosed herein, included in a pharmaceutical composition may be in the range of, e.g., about 500 ng to about 525 ng, about 500 ng to about 550 ng, about 500 ng to about 575 ng, about 500 ng to about 600 ng, about 500 ng to about 625 ng, about 500 ng to about 650 ng, about 500 ng to about 675 ng, about 500 ng to about 700 ng, about 500 ng to about 725 ng, about 500 ng to about 750 ng, about 500 ng to about 775 ng, about 500 ng to about 800 ng, about 500 ng to about 825 ng, about 500 ng to about 850 ng, about 500 ng to about 875 ng, about 500 ng to about 900 ng, about 500 ng to about 925 ng, about 500 ng to about 950 ng, about 500 ng
  • an amount of an EphA4 antagonist, like an APY cyclic peptide disclosed herein, included in a pharmaceutical composition may be, e.g., about 1 ⁇ g, about 2 ⁇ g, about 3 ⁇ g, about 4 ⁇ g, about 5 ⁇ g, about 6 ⁇ g, about 7 ⁇ g, about 8 ⁇ g, about 9 ⁇ g, about 10 ⁇ g, about 15 ⁇ g, about 20 ⁇ g, about 25 ⁇ g, about 30 ⁇ g, about 35 ⁇ g, about 40 ⁇ g, about 45 ⁇ g, about 50 ⁇ g, about 55 ⁇ g, about 60 ⁇ g, about 65 ⁇ g, about 70 ⁇ g, about 75 ⁇ g, about 80 ⁇ g, about 85 ⁇ g, about 90 ⁇ g, about 95 ⁇ g, about 100 ⁇ g, about 110 ⁇ g, about 120 ⁇ g, about 130 ⁇ g, about 140 ⁇ g, about 150 ⁇ g, about 160 ⁇ g, about
  • an amount of an EphA4 antagonist, like an APY cyclic peptide disclosed herein, included in a pharmaceutical composition may be, e.g., at least 1 ⁇ g, at least 2 ⁇ g, at least 3 ⁇ g, at least 4 ⁇ g, at least 5 ⁇ g, at least 6 ⁇ g, at least 7 ⁇ g, at least 8 ⁇ g, at least 9 ⁇ g, at least 10 ⁇ g, at least 15 ⁇ g, at least 20 ⁇ g, at least 25 ⁇ g, at least 30 ⁇ g, at least 35 ⁇ g, at least 40 ⁇ g, at least 45 ⁇ g, at least 50 ⁇ g, at least 55 ⁇ g, at least 60 ⁇ g, at least 65 ⁇ g, at least 70 ⁇ g, at least 75 ⁇ g, at least 80 ⁇ g, at least 85 ⁇ g, at least 90 ⁇ g, at least 95 ⁇ g, at least 100 ⁇ g, at least 110 ⁇ g, at
  • an amount of an EphA4 antagonist, like an APY cyclic peptide disclosed herein, included in a pharmaceutical composition may be, e.g., at most 1 ⁇ g, at most 2 ⁇ g, at most 3 ⁇ g, at most 4 ⁇ g, at most 5 ⁇ g, at most 6 ⁇ g, at most 7 ⁇ g, at most 8 ⁇ g, at most 9 ⁇ g, at most 10 ⁇ g, at most 15 ⁇ g, at most 20 ⁇ g, at most 25 ⁇ g, at most 30 ⁇ g, at most 35 ⁇ g, at most 40 ⁇ g, at most 45 ⁇ g, at most 50 ⁇ g, at most 55 ⁇ g, at most 60 ⁇ g, at most 65 ⁇ g, at most 70 ⁇ g, at most 75 ⁇ g, at most 80 ⁇ g, at most 85 ⁇ g, at most 90 ⁇ g, at most 95 ⁇ g, at most 100 ⁇ g, at most 110 ⁇ g,
  • an amount of an EphA4 antagonist, like an APY cyclic peptide disclosed herein, included in a pharmaceutical composition may be in the range of, e.g., about 1 ⁇ g to about 10 ⁇ g, about 1 ⁇ g to about 20 ⁇ g, about 1 ⁇ g to about 30 ⁇ g, about 1 ⁇ g to about 40 ⁇ g, about 1 ⁇ g to about 50 ⁇ g, about 1 ⁇ g to about 60 ⁇ g, about 1 ⁇ g to about 70 ⁇ g, about 1 ⁇ g to about 80 ⁇ g, about 1 ⁇ g to about 90 ⁇ g, about 1 ⁇ g to about 100 ⁇ g, about 1 ⁇ g to about 110 ⁇ g, about 1 ⁇ g to about 120 ⁇ g, about 1 ⁇ g to about 130 ⁇ g, about 1 ⁇ g to about 140 ⁇ g, about 1 ⁇ g to about 150 ⁇ g, about 5 ⁇ g to about 10 ⁇ g, about 5 ⁇ g to about
  • an amount of an EphA4 antagonist, like an APY cyclic peptide disclosed herein, included in a pharmaceutical composition may be in the range of, e.g., about 100 ⁇ g to about 125 ⁇ g, about 100 ⁇ g to about 150 ⁇ g, about 100 ⁇ g to about 175 ⁇ g, about 100 ⁇ g to about 200 ⁇ g, about 100 ⁇ g to about 225 ⁇ g, about 100 ⁇ g to about 250 ⁇ g, about 100 ⁇ g to about 275 ⁇ g, about 100 ⁇ g to about 300 ⁇ g, about 100 ⁇ g to about 325 ⁇ g, about 100 ⁇ g to about 350 ⁇ g, about 100 ⁇ g to about 375 ⁇ g, about 100 ⁇ g to about 400 ⁇ g, about 100 ⁇ g to about 425 ⁇ g, about 100 ⁇ g to about 450 ⁇ g, about 100 ⁇ g to about 475 ⁇ g, about 100 ⁇ g to about 500 ⁇
  • an amount of an EphA4 antagonist, like an APY cyclic peptide disclosed herein, included in a pharmaceutical composition may be in the range of, e.g., about 250 ⁇ g to about 275 ⁇ g, about 250 ⁇ g to about 300 ⁇ g, about 250 ⁇ g to about 325 ⁇ g, about 250 ⁇ g to about 350 ⁇ g, about 250 ⁇ g to about 375 ⁇ g, about 250 ⁇ g to about 400 ⁇ g, about 250 ⁇ g to about 425 ⁇ g, about 250 ⁇ g to about 450 ⁇ g, about 250 ⁇ g to about 475 ⁇ g, about 250 ⁇ g to about 500 ⁇ g, about 250 ⁇ g to about 525 ⁇ g, about 250 ⁇ g to about 550 ⁇ g, about 250 ⁇ g to about 575 ⁇ g, about 250 ⁇ g to about 600 ⁇ g, about 250 ⁇ g to about 625 ⁇ g, about 250 ⁇ g to about 650
  • an amount of an EphA4 antagonist, like an APY cyclic peptide disclosed herein, included in a pharmaceutical composition may be in the range of, e.g., about 500 ⁇ g to about 525 ⁇ g, about 500 ⁇ g to about 550 ⁇ g, about 500 ⁇ g to about 575 ⁇ g, about 500 ⁇ g to about 600 ⁇ g, about 500 ⁇ g to about 625 ⁇ g, about 500 ⁇ g to about 650 ⁇ g, about 500 ⁇ g to about 675 ⁇ g, about 500 ⁇ g to about 700 ⁇ g, about 500 ⁇ g to about 725 ⁇ g, about 500 ⁇ g to about 750 ⁇ g, about 500 ⁇ g to about 775 ⁇ g, about 500 ⁇ g to about 800 ⁇ g, about 500 ⁇ g to about 825 ⁇ g, about 500 ⁇ g to about 850 ⁇ g, about 500 ⁇ g to about 875 ⁇ g, about 500 ⁇ g to about
  • a pharmaceutical composition disclosed herein can optionally include one or more pharmaceutically acceptable carriers that facilitate processing of an active ingredient into therapeutic compositions.
  • pharmaceutically acceptable refers to any molecular entity or composition that does not produce an adverse, allergic or other untoward or unwanted reaction when administered to an individual.
  • pharmaceutically acceptable carriers is synonymous with “pharmacological carriers” and means any compound that has substantially no long term or permanent detrimental effect when administered and encompasses terms such as“pharmacologically acceptable vehicle, stabilizer, diluent, additive, auxiliary or excipient.”
  • Such a carrier generally is mixed with an active compound, or permitted to dilute or enclose the active compound and can be a solid, semi-solid, or liquid agent.
  • the active ingredients can be soluble or can be delivered as a suspension in the desired carriers.
  • Any of a variety of pharmaceutically acceptable carrier can be used including, without limitation, aqueous media such as, e.g., water, saline, glycine, hyaluronic acid and the like; solid carriers such as, e.g., mannitol, lactose, starch, magnesium stearate, sodium saccharin, talcum, cellulose, glucose, sucrose, magnesium carbonate, and the like; solvents; dispersion media; coatings; antibacterial and antifungal agents; isotonic and absorption delaying agents; or any other inactive ingredient. Selection of a pharmacologically acceptable carrier can depend on the mode of administration.
  • any pharmacologically acceptable carrier is incompatible with the active ingredient, its use in pharmaceutically acceptable compositions is contemplated.
  • Non-limiting examples of specific uses of such pharmaceutical carriers can be found in PHARMACEUTICAL DOSAGE FORMS AND DRUG DELIVERY SYSTEMS (Howard C. Ansel et al., eds., Lippincott Williams & Wilkins Publishers, 7 th ed. 1999); REMINGTON: THE SCIENCE AND PRACTICE OF PHARMACY (Alfonso R. Gennaro ed., Lippincott, Williams & Wilkins, 20 th ed.
  • a pharmaceutical composition disclosed herein may optionally include, without limitation, other pharmaceutically acceptable components (or pharmaceutical components), including, without limitation, buffers, preservatives, tonicity adjusters, salts, antioxidants, osmolality adjusting agents, physiological substances, pharmacological substances, bulking agents, emulsifying agents, wetting agents, sweetening or flavoring agents, and the like.
  • buffers include, without limitation, acetate buffers, citrate buffers, phosphate buffers, neutral buffered saline, phosphate buffered saline and borate buffers.
  • antioxidants include, without limitation, sodium metabisulfite, sodium thiosulfate, acetylcysteine, butylated hydroxyanisole and butylated hydroxytoluene.
  • Useful preservatives include, without limitation, benzalkonium chloride, chlorobutanol, thimerosal, phenylmercuric acetate, phenylmercuric nitrate, a stabilized oxy chloro composition and chelants, such as, e.g., DTPA or DTPA-bisamide, calcium DTPA, and CaNaDTPA-bisamide.
  • Tonicity adjustors useful in a pharmaceutical composition include, without limitation, salts such as, e.g., sodium chloride, potassium chloride, mannitol or glycerin and other pharmaceutically acceptable tonicity adjustor.
  • An active ingredient such as, e.g., an ⁇ -HIV antibody disclosed herein, may be provided as a salt and can be formed with many acids, including but not limited to, hydrochloric, sulfuric, acetic, lactic, tartaric, malic, succinic, etc. Salts tend to be more soluble in aqueous or other protonic solvents than are the corresponding free base forms. It is understood that these and other substances known in the art of pharmacology can be included in a therapeutic composition.
  • a pharmaceutical composition comprising one or more EphA4 antagonist, like an APY cyclic peptide disclosed herein, is useful for medical and veterinary applications.
  • a pharmaceutical composition may be administered to an individual alone, or in combination with other supplementary active ingredients, agents, drugs or hormones.
  • the pharmaceutical compositions may be manufactured using any of a variety of processes, including, without limitation, conventional mixing, dissolving, granulating, dragee-making, levigating, emulsifying, encapsulating, entrapping, and lyophilizing.
  • the pharmaceutical composition can take any of a variety of forms including, without limitation, a sterile solution, suspension, emulsion, lyophilizate, tablet, pill, pellet, capsule, powder, syrup, elixir or any other dosage form suitable for administration.
  • An EphA4-based disease, disorder or pathology refers to any condition, disease or disorder or pathology where a pathophysiology effect is due to dysregulation of EphA4 signaling in a manner that causes EphA4 signaling hyperactivity in cells or spatially or temporally aberrant EphA4 signaling.
  • Such methods include therapeutic (following onset of an EphA4-based disease) and prophylactic (prior to onset of an EphA4-based disease).
  • therapeutic and prophylactic methods of treating an individual for an EphA4-based disease, disorder or pathology include treating an individual at risk of having an EphA4-based disease, disorder or pathology, treating an individual having an EphA4-based disease, disorder or pathology, and methods of protecting an individual from an EphA4-based disease, disorder or pathology, to decrease or reduce the probability of an EphA4-based disease, disorder or pathology in an individual, to decrease or reduce susceptibility of an individual to an EphA4-based disease, disorder or pathology, or to inhibit or prevent an EphA4-based disease, disorder or pathology in an individual, and to decrease, reduce, inhibit or suppress transmission of an EphA4-based disease, disorder or pathology from an afflicted individual to an unafflicted individual.
  • Such methods include administering a pharmaceutical composition disclosed herein to therapeutically or prophylactically treat an individual having or at risk of having an EphA4-based disease, disorder or pathology. Accordingly, methods can treat an EphA4-based disease or pathology, or provide the individual with protection from an EphA4-based disease, disorder or pathology (e.g., prophylactic protection).
  • a method of treating an EphA4-based disease, disorder or pathology comprises administering one or more EphA4 antagonists, like one or more APY cyclic peptides disclosed herein, or a pharmaceutical composition disclosed herein to an individual in need thereof in an amount sufficient to reduce one or more physiological conditions or symptom associated with an EphA4-based disease, disorder or pathology, thereby treating the EphA4-based disease, disorder or pathology.
  • an EphA4-based disease, disorder or pathology includes, without limitation, a neurodegenerative disease, a hearing loss, promotion of nerve regeneration, promotion of neuroprotection, and a cancer.
  • Neurodegenerative diseases are conditions that affect brain or peripheral nerve function.
  • EphA4 signaling activity has important functions in both categories. For example, increased expression of EphA4 and its activation by ephrin ligands contribute to the pathogenesis of ALS, Alzheimer's disease, multiple sclerosis, stroke and traumatic brain injury and other neurodegenerative disease because EphA4 signaling leads to abnormal inhibition of axon growth, aberrant synaptic function and poor neuronal survival.
  • an EphA4 antagonist like an APY cyclic peptide disclosed herein, or a pharmaceutical composition disclosed herein can be useful in treating any neurodegenerative disease expressing high EphA4 levels because these APY cyclic peptides inhibit EphA4 signaling.
  • a neurodegenerative disease includes, without limitation, an Alexander disease, an Alper’s disease, Alzheimer’s disease, an amyotrophic lateral sclerosis, an ataxia telangiectasia, a Canavan disease, a Cockayne syndrome, a corticobasal degeneration, a Creutzfeldt-Jakob disease, a Guillain-Barre Syndrome a HIV-induced neurodegeneration, a Huntington disease, a Kennedy’s disease, a Krabbe disease, a Lewy body dementia, a Machado-Joseph disease, a multiple sclerosis, a Parkinson’s disease, a Pelizaeus-Merzbacher disease, a Pick’s disease, a primary lateral sclerosis, a Refsum’s disease, a Sandhoff disease, a Schilder’s disease, a spinal cord injury, a Steele-Richardson-Olszewski disease, a stroke, a tabes dorsali
  • Symptoms associated with a neurodegenerative disease include, without limitation, abnormal movement, abnormal sensation, limb grasping, muscle weakness, atrophy, paralysis, abnormal inhibition of axon growth, abnormal axonal transport, aberrant synaptic function, synaptic transmission loss, impaired synaptic plasticity, synaptic loss, neuronal degeneration, motor neuron degeneration, motor neuron loss, poor neuronal survival, memory loss, impaired learning, dementia, ⁇ -amyloid plaque deposits, aberrant neurofilament accumulation, reactive astroglia and/or reactive microglia.
  • a method of treating an EphA4-based disease, disorder or pathology includes a method of treating a neurodegenerative disease.
  • a method of treating a neurodegenerative disease comprises administering one or more EphA4 antagonists, like one or more APY cyclic peptides disclosed herein, or a pharmaceutical composition disclosed herein to an individual in need thereof in an amount sufficient to reduce one or more physiological conditions or symptom associated with a neurodegenerative disease, thereby treating the neurodegenerative disease.
  • EphA4 antagonists like one or more APY cyclic peptides disclosed herein, or a pharmaceutical composition disclosed herein to an individual in need thereof in an amount sufficient to reduce one or more physiological conditions or symptom associated with a neurodegenerative disease, thereby treating the neurodegenerative disease.
  • Such damage can occur due to hereditary and/or environmental causes.
  • hair cell degenerate and/or death can be caused by lack of essential growth factors, exogenous toxins (such as ototoxic drugs), overstimulation by noise or sound, viral or bacterial infections, autoimmune conditions or hereditary disease.
  • exogenous toxins such as ototoxic drugs
  • human cochlear hair cells are incapable of regeneration, damaged cells cannot be replaced, and as such, their loss leads to permanent hearing loss.
  • Symptoms associated with a neurodegenerative disease include, without limitation, decreased hearing sensitivity and/or sensorineural hearing loss. It is now known that EpHA4 signaling prevents the generation of new cochlear hair cells suggesting that inhibition of EpHA4 activity could be an effective therapy in the treatment of hearing loss.
  • a method of treating an EphA4-based disease, disorder or pathology includes a method of treating a hearing loss.
  • a method of treating a hearing loss comprises administering one or more EphA4 antagonists, like one or more APY cyclic peptides disclosed herein, or a pharmaceutical composition disclosed herein to an individual in need thereof in an amount sufficient to reduce one or more physiological conditions or symptom associated with a hearing loss, thereby treating the hearing loss.
  • administration of one or more EphA4 antagonists, like one or more APY cyclic peptides disclosed herein, or a pharmaceutical composition disclosed herein promotes the generation of cochlear sensory hair cells.
  • Nerve regeneration or neuroregeneration refers to the regrowth or repair of nervous tissues, cells or cell products. Such mechanisms may include generation of new neurons, glia, axons, myelin, or synapses.
  • PNS peripheral nervous system
  • CNS central nervous system
  • EphA4 signaling contribute to the inhibition of axon regeneration following injury.
  • an EphA4 antagonist like an APY cyclic peptide disclosed herein, or a pharmaceutical composition disclosed herein can be useful in promoting neuroregeneration by inhibiting the activity of EphA4 signaling.
  • Symptoms associated with a lack of nerve regeneration include, without limitation, abnormal movement, abnormal sensation, limb grasping, muscle weakness, atrophy, paralysis, loss of neuronal function, loss of motor neuron function, loss of sensory neuron function, inhibited neuronal growth, inhibited axon growth, inhibited synaptic plasticity, synaptic loss, astrocytic gliosis and/or glial scaring.
  • a method of treating an EphA4-based disease, disorder or pathology includes a method of promoting nerve regeneration.
  • a method of promoting nerve regeneration comprises administering one or more EphA4 antagonists, like one or more APY cyclic peptides disclosed herein, or a pharmaceutical composition disclosed herein to an individual in need thereof in an amount sufficient to stimulate of facilitate neuronal differentiation and/or growth, thereby promoting nerve regeneration.
  • EphA4 antagonists like one or more APY cyclic peptides disclosed herein, or a pharmaceutical composition disclosed herein to an individual in need thereof in an amount sufficient to stimulate of facilitate neuronal differentiation and/or growth, thereby promoting nerve regeneration.
  • EphA4 signaling is known to inhibit neuronal growth following neuronal injury.
  • an EphA4 antagonist like an APY cyclic peptide disclosed herein, or a pharmaceutical composition disclosed herein can be useful in providing neuroprotection that minimizes this subsequent damage, where the secondary tissue damage is dependent EphA4 signaling activity because these APY cyclic peptides inhibit EphA4 signaling.
  • a method of treating an EphA4-based disease, disorder or pathology includes a method of promoting neuroprotection.
  • a method of promoting neuroprotection comprises administering one or more EphA4 antagonists, like one or more APY cyclic peptides disclosed herein, or a pharmaceutical composition disclosed herein to an individual in need thereof in an amount sufficient to protect neurons or nerve tissue from damage, thereby promoting neuroprotection.
  • EphA4 antagonists like one or more APY cyclic peptides disclosed herein, or a pharmaceutical composition disclosed herein to an individual in need thereof in an amount sufficient to protect neurons or nerve tissue from damage, thereby promoting neuroprotection.
  • A- and B-class receptors were shown to be overexpressed in a wide variety of tumors, including malignant melanoma, glioma, prostate cancer, breast cancer, small cell lung cancer, endometrial cancer, esophageal cancer, gastric cancer, and colorectal cancer.
  • Eph receptors regulate critical steps of blood vessel formation (vasculogenesis) and remodeling (angiogenesis) and hence tumor growth.
  • glioblastoma glioblastoma
  • gastric cancer pancreatic cancer
  • breast cancer breast cancer
  • EphA4 downregulation studies have suggested a role for EphA4 in leukemia, prostate cancer, pancreatic cancer and gastric cancer cell growth and in liver cancer metastasis.
  • High EphA4 expression has also been correlated with shorter survival in breast and gastric cancer patients, although the opposite correlation was found in lung cancer patients.
  • EphA4 is also highly upregulated in Sezary syndrome, a leukemic variant of cutaneous T-cell lymphomas.
  • EphA4 can enhance the oncogenic effects of fibroblast growth factor receptor 1 in glioblastoma cells.
  • a method of treating an EphA4-based disease, disorder or pathology includes a method of treating a cancer.
  • a method of treating a cancer comprising administering one or more EphA4 antagonists, like one or more APY cyclic peptides disclosed herein, or a pharmaceutical composition disclosed herein to an individual in need thereof in an amount sufficient to reduce one or more physiological conditions or symptom associated with a cancer, thereby treating the cancer.
  • An EphA4 antagonist like an APY cyclic peptide disclosed herein, or a pharmaceutical composition disclosed herein can be useful in treating any cancer expressing high EphA4 levels.
  • a cancer includes, without limitation, glioblastoma, a gastric cancer, a pancreatic cancer, a prostate cancer, a breast cancer, a liver cancer, a leukemia and Sezary syndrome, a leukemic variant of cutaneous T-cell lymphomas.
  • An individual comprises any mammal including a human, and a human can be a patient.
  • aspects of the present invention provide, in part, administering an APY cyclic peptide disclosed herein, or a pharmaceutical composition disclosed herein.
  • administering refers to any delivery mechanism that provides an APY cyclic peptide disclosed herein, or a pharmaceutical composition disclosed herein to an individual that potentially results in a clinically, therapeutically, or experimentally beneficial result.
  • the actual delivery mechanism used to administer an APY cyclic peptide disclosed herein, or a pharmaceutical composition disclosed herein to an individual can be determined by a person of ordinary skill in the art by taking into account factors, including, without limitation, the type of Eph4A-based disease, the location of the Eph4A-based disease, the cause of the Eph4A-based disease, the severity of the Eph4A-based disease, the degree of relief desired for Eph4A-based disease, the duration of relief desired for Eph4A-based disease, the particular APY cyclic peptide or a pharmaceutical composition used, the rate of excretion of the particular APY cyclic peptide or a pharmaceutical composition used, the pharmacodynamics of the particular APY cyclic peptide or a pharmaceutical composition used, the nature of the other compounds to be included in the pharmaceutical composition, the particular route of administration, the particular characteristics, history and risk factors of the individual, such as, e.g., age, weight, general health and the like, or any combination thereof
  • a composition disclosed herein can be administered to an individual using a cellular uptake approach.
  • Administration of a composition disclosed herein using a cellular uptake approach comprise a variety of enteral or parenteral approaches including, without limitation, oral administration in any acceptable form, such as, e.g., tablet, liquid, capsule, powder, or the like; topical administration in any acceptable form, such as, e.g., drops, spray, creams, gels or ointments; intravascular administration in any acceptable form, such as, e.g., intravenous injection, intravenous infusion, intra-arterial injection, intra- arterial infusion and catheter instillation into the vasculature; peri- and intra-tissue administration in any acceptable form, such as, e.g., intraperitoneal injection, intramuscular injection, subcutaneous injection, subcutaneous infusion, intraocular injection, retinal injection, sub-retinal injection, intrathecal injection, intracerebroventricular injection or epidural injection; intravesicular administration in any acceptable
  • An APY cyclic peptide disclosed herein, or a pharmaceutical composition disclosed herein is administered in an amount sufficient to treat an EphA4-based disease, disorder or pathology.
  • the amount of an APY cyclic peptide disclosed herein, or a pharmaceutical composition disclosed herein administered is an amount sufficient to reduce one or more physiological conditions or symptom associated with an EphA4-based disease, disorder or pathology or an amount sufficient to protect the individual against an EphA4-based disease, disorder or pathology.
  • the term“amount sufficient“ includes“effective amount”,“effective dose”,“therapeutically effective amount” or“therapeutically effective dose” and refers to the minimum amount of an APY cyclic peptide disclosed herein, or a pharmaceutical composition disclosed herein necessary to achieve the desired therapeutic effect and includes an amount sufficient to reduce or inhibit one or more physiological conditions or symptom associated with an EphA4-based disease, disorder or pathology.
  • an effective amount of an APY cyclic peptide disclosed herein, or a pharmaceutical composition disclosed herein reduces or inhibits one or more physiological conditions or symptom associated with an EphA4-based disease, disorder or pathology by, e.g., at least 10%, at least 20%, at least 30%, at least 40%, at least 50%, at least 60%, at least 70%, at least 80%, at least 90% or at least 100%.
  • an effective amount of an APY cyclic peptide disclosed herein, or a pharmaceutical composition disclosed herein reduces or inhibits one or more physiological conditions or symptom associated with an EphA4-based disease, disorder or pathology by, e.g., at most 10%, at most 20%, at most 30%, at most 40%, at most 50%, at most 60%, at most 70%, at most 80%, at most 90% or at most 100%.
  • an effective amount of an APY cyclic peptide disclosed herein, or a pharmaceutical composition disclosed herein reduces or inhibits one or more physiological conditions or symptom associated with an EphA4-based disease, disorder or pathology by, e.g., about 10% to about 100%, about 10% to about 90%, about 10% to about 80%, about 10% to about 70%, about 10% to about 60%, about 10% to about 50%, about 10% to about 40%, about 20% to about 100%, about 20% to about 90%, about 20% to about 80%, about 20% to about 20%, about 20% to about 60%, about 20% to about 50%, about 20% to about 40%, about 30% to about 100%, about 30% to about 90%, about 30% to about 80%, about 30% to about 70%, about 30% to about 60%, or about 30% to about 50%.
  • an effective amount of an APY cyclic peptide disclosed herein, or a pharmaceutical composition disclosed herein reduces or inhibits one or more physiological conditions or symptom associated with an EphA4-based disease, disorder or pathology for, e.g., at least one week, at least one month, at least two months, at least three months, at least four months, at least five months, at least six months, at least seven months, at least eight months, at least nine months, at least ten months, at least eleven months, or at least twelve months.
  • the actual effective amount of an APY cyclic peptide disclosed herein, or a pharmaceutical composition disclosed herein to be administered to an individual can be determined by a person of ordinary skill in the art by taking into account factors, including, without limitation, the type of EphA4-based disease, disorder or pathology, the location of the EphA4-based disease, disorder or pathology, the cause of the EphA4-based disease, disorder or pathology, the severity of the EphA4-based disease, disorder or pathology, the degree of relief desired for EphA4-based disease, disorder or pathology, the duration of relief desired for EphA4-based disease, disorder or pathology, the particular APY cyclic peptide or a pharmaceutical composition used, the rate of excretion of the particular APY cyclic peptide or a pharmaceutical composition used, the pharmacodynamics of the particular APY cyclic peptide or a pharmaceutical composition used, the nature of the other compounds to be included in the pharmaceutical composition, the particular route of administration used,
  • an effective amount of an APY cyclic peptide disclosed herein, or a pharmaceutical composition disclosed herein can be extrapolated from in vitro assays and in vivo administration studies using animal models prior to administration to humans. Wide variations in the necessary effective amount are to be expected in view of the differing efficiencies of the various routes of administration.
  • an effective amount of an APY cyclic peptide disclosed herein, or a pharmaceutical composition disclosed herein generally is in the range of about 0. 001 ⁇ g/kg/day to about 100 ⁇ g/kg/day.
  • an effective amount of an APY cyclic peptide disclosed herein, or a pharmaceutical composition disclosed herein may be, e.g., at least 0.001 ⁇ g/kg/day, at least 0.01 ⁇ g/kg/day, at least 0.1 ⁇ g/kg/day, at least 1.0 ⁇ g/kg/day, at least 5.0 ⁇ g/kg/day, at least 10 ⁇ g/kg/day, at least 15 ⁇ g/kg/day, at least 20 ⁇ g/kg/day, at least 25 ⁇ g/kg/day, at least 30 ⁇ g/kg/day, at least 35 ⁇ g/kg/day, at least 40 ⁇ g/kg/day, at least 45 ⁇ g/kg/day, or at least 50 ⁇ g/kg/day.
  • an effective amount of an APY cyclic peptide disclosed herein, or a pharmaceutical composition disclosed herein may be in the range of, e.g., about 0.001 ⁇ g/kg/day to about 10 ⁇ g/kg/day, about 0.001 ⁇ g/kg/day to about 15 ⁇ g/kg/day, about 0.001 ⁇ g/kg/day to about 20 ⁇ g/kg/day, about 0.001 ⁇ g/kg/day to about 25 ⁇ g/kg/day, about 0.001 ⁇ g/kg/day to about 30 ⁇ g/kg/day, about 0.001 ⁇ g/kg/day to about 35 ⁇ g/kg/day, about 0.001 ⁇ g/kg/day to about 40 ⁇ g/kg/day, about 0.001 ⁇ g/kg/day to about 45 ⁇ g/kg/day, about 0.001 ⁇ g/kg/day to about 50 ⁇ g/kg/day, about 0.001 ⁇ g/kg/day, about 0.001
  • an effective amount of an APY cyclic peptide disclosed herein, or a pharmaceutical composition disclosed herein may be in the range of, e.g., about 0.01 ⁇ g/kg/day to about 10 ⁇ g/kg/day, about 0.01 ⁇ g/kg/day to about 15 ⁇ g/kg/day, about 0.01 ⁇ g/kg/day to about 20 ⁇ g/kg/day, about 0.01 ⁇ g/kg/day to about 25 ⁇ g/kg/day, about 0.01 ⁇ g/kg/day to about 30 ⁇ g/kg/day, about 0.01 ⁇ g/kg/day to about 35 ⁇ g/kg/day, about 0.01 ⁇ g/kg/day to about 40 ⁇ g/kg/day, about 0.01 ⁇ g/kg/day to about 45 ⁇ g/kg/day, about 0.01 ⁇ g/kg/day to about 50 ⁇ g/kg/day, about 0.01 ⁇ g/kg/day to about 75 ⁇ g/kg/
  • an effective amount of an APY cyclic peptide disclosed herein, or a pharmaceutical composition disclosed herein may be in the range of, e.g., about 0.1 ⁇ g/kg/day to about 10 ⁇ g/kg/day, about 0.1 ⁇ g/kg/day to about 15 ⁇ g/kg/day, about 0.1 ⁇ g/kg/day to about 20 ⁇ g/kg/day, about 0.1 ⁇ g/kg/day to about 25 ⁇ g/kg/day, about 0.1 ⁇ g/kg/day to about 30 ⁇ g/kg/day, about 0.1 ⁇ g/kg/day to about 35 ⁇ g/kg/day, about 0.1 ⁇ g/kg/day to about 40 ⁇ g/kg/day, about 0.1 ⁇ g/kg/day to about 45 ⁇ g/kg/day, about 0.1 ⁇ g/kg/day to about 50 ⁇ g/kg/day, about 0.1 ⁇ g/kg/day to about 75 ⁇ g/kg/
  • an effective amount of an APY cyclic peptide disclosed herein, or a pharmaceutical composition disclosed herein may be in the range of, e.g., about 1 ⁇ g/kg/day to about 10 ⁇ g/kg/day, about 1 ⁇ g/kg/day to about 15 ⁇ g/kg/day, about 1 ⁇ g/kg/day to about 20 ⁇ g/kg/day, about 1 ⁇ g/kg/day to about 25 ⁇ g/kg/day, about 1 ⁇ g/kg/day to about 30 ⁇ g/kg/day, about 1 ⁇ g/kg/day to about 35 ⁇ g/kg/day, about 1 ⁇ g/kg/day to about 40 ⁇ g/kg/day, about 1 ⁇ g/kg/day to about 45 ⁇ g/kg/day, about 1 ⁇ g/kg/day to about 50 ⁇ g/kg/day, about 1 ⁇ g/kg/day to about 75 ⁇ g/kg/day, or about 1 ⁇
  • an effective amount of an APY cyclic peptide disclosed herein, or a pharmaceutical composition disclosed herein may be in the range of, e.g., about 5 ⁇ g/kg/day to about 10 ⁇ g/kg/day, about 5 ⁇ g/kg/day to about 15 ⁇ g/kg/day, about 5 ⁇ g/kg/day to about 20 ⁇ g/kg/day, about 5 ⁇ g/kg/day to about 25 ⁇ g/kg/day, about 5 ⁇ g/kg/day to about 30 ⁇ g/kg/day, about 5 ⁇ g/kg/day to about 35 ⁇ g/kg/day, about 5 ⁇ g/kg/day to about 40 ⁇ g/kg/day, about 5 ⁇ g/kg/day to about 45 ⁇ g/kg/day, about 5 ⁇ g/kg/day to about 50 ⁇ g/kg/day, about 5 ⁇ g/kg/day to about 75 ⁇ g/kg/day, or about 5 ⁇ g/kg
  • an effective amount of an APY cyclic peptide disclosed herein, or a pharmaceutical composition disclosed herein generally is in the range of about 0. 001 ⁇ g/day to about 100 ⁇ g/day.
  • an effective amount of an APY cyclic peptide disclosed herein, or a pharmaceutical composition disclosed herein may be, e.g., at least 0.001 ⁇ g/day, at least 0.01 ⁇ g/day, at least 0.1 ⁇ g/day, at least 1.0 ⁇ g/day, at least 5.0 ⁇ g/day, at least 10 ⁇ g/day, at least 15 ⁇ g/day, at least 20 ⁇ g/day, at least 25 ⁇ g/day, at least 30 ⁇ g/day, at least 35 ⁇ g/day, at least 40 ⁇ g/day, at least 45 ⁇ g/day, or at least 50 ⁇ g/day.
  • an effective amount of an APY cyclic peptide disclosed herein, or a pharmaceutical composition disclosed herein may be in the range of, e.g., about 0.001 ⁇ g/day to about 10 ⁇ g/day, about 0.001 ⁇ g/day to about 15 ⁇ g/day, about 0.001 ⁇ g/day to about 20 ⁇ g/day, about 0.001 ⁇ g/day to about 25 ⁇ g/day, about 0.001 ⁇ g/day to about 30 ⁇ g/day, about 0.001 ⁇ g/day to about 35 ⁇ g/day, about 0.001 ⁇ g/day to about 40 ⁇ g/day, about 0.001 ⁇ g/day to about 45 ⁇ g/day, about 0.001 ⁇ g/day to about 50 ⁇ g/day, about 0.001 ⁇ g/day to about 75 ⁇ g/day, or about 0.001 ⁇ g/day to about 100 ⁇ g/day.
  • an effective amount of an APY cyclic peptide disclosed herein, or a pharmaceutical composition disclosed herein may be in the range of, e.g., about 0.01 ⁇ g/day to about 10 ⁇ g/day, about 0.01 ⁇ g/day to about 15 ⁇ g/day, about 0.01 ⁇ g/day to about 20 ⁇ g/day, about 0.01 ⁇ g/day to about 25 ⁇ g/day, about 0.01 ⁇ g/day to about 30 ⁇ g/day, about 0.01 ⁇ g/day to about 35 ⁇ g/day, about 0.01 ⁇ g/day to about 40 ⁇ g/day, about 0.01 ⁇ g/day to about 45 ⁇ g/day, about 0.01 ⁇ g/day to about 50 ⁇ g/day, about 0.01 ⁇ g/day to about 75 ⁇ g/day, or about 0.01 ⁇ g/day to about 100 ⁇ g/day.
  • an effective amount of an APY cyclic peptide disclosed herein, or a pharmaceutical composition disclosed herein may be in the range of, e.g., about 0.1 ⁇ g/day to about 10 ⁇ g/day, about 0.1 ⁇ g/day to about 15 ⁇ g/day, about 0.1 ⁇ g/day to about 20 ⁇ g/day, about 0.1 ⁇ g/day to about 25 ⁇ g/day, about 0.1 ⁇ g/day to about 30 ⁇ g/day, about 0.1 ⁇ g/day to about 35 ⁇ g/day, about 0.1 ⁇ g/day to about 40 ⁇ g/day, about 0.1 ⁇ g/day to about 45 ⁇ g/day, about 0.1 ⁇ g/day to about 50 ⁇ g/day, about 0.1 ⁇ g/day to about 75 ⁇ g/day, or about 0.1 ⁇ g/day to about 100 ⁇ g/day.
  • an effective amount of an APY cyclic peptide disclosed herein, or a pharmaceutical composition disclosed herein may be in the range of, e.g., about 1 ⁇ g/day to about 10 ⁇ g/day, about 1 ⁇ g/day to about 15 ⁇ g/day, about 1 ⁇ g/day to about 20 ⁇ g/day, about 1 ⁇ g/day to about 25 ⁇ g/day, about 1 ⁇ g/day to about 30 ⁇ g/day, about 1 ⁇ g/day to about 35 ⁇ g/day, about 1 ⁇ g/day to about 40 ⁇ g/day, about 1 ⁇ g/day to about 45 ⁇ g/day, about 1 ⁇ g/day to about 50 ⁇ g/day, about 1 ⁇ g/day to about 75 ⁇ g/day, or about 1 ⁇ g/day to about 100 ⁇ g/day.
  • an effective amount of an APY cyclic peptide disclosed herein, or a pharmaceutical composition disclosed herein may be in the range of, e.g., about 5 ⁇ g/day to about 10 ⁇ g/day, about 5 ⁇ g/day to about 15 ⁇ g/day, about 5 ⁇ g/day to about 20 ⁇ g/day, about 5 ⁇ g/day to about 25 ⁇ g/day, about 5 ⁇ g/day to about 30 ⁇ g/day, about 5 ⁇ g/day to about 35 ⁇ g/day, about 5 ⁇ g/day to about 40 ⁇ g/day, about 5 ⁇ g/day to about 45 ⁇ g/day, about 5 ⁇ g/day to about 50 ⁇ g/day, about 5 ⁇ g/day to about 75 ⁇ g/day, or about 5 ⁇ g/day to about 100 ⁇ g/day.
  • Dosing can be single dosage or cumulative (serial dosing), and can be readily determined by one skilled in the art.
  • treatment of an EphA4-based disease, disorder or pathology may comprise a one-time administration of an effective amount of an APY cyclic peptide disclosed herein, or a pharmaceutical composition disclosed herein.
  • an effective amount of an APY cyclic peptide disclosed herein, or a pharmaceutical composition disclosed herein can be administered once to an individual, e.g., as a single injection or deposition.
  • treatment of a HIV-based disease may comprise multiple administrations of an effective amount of an APY cyclic peptide disclosed herein, or a pharmaceutical composition disclosed herein carried out over a range of time periods, such as, e.g., daily, once every few days, weekly, monthly or yearly.
  • an APY cyclic peptide disclosed herein, or a pharmaceutical composition disclosed herein can be administered one, two, three, four, five or six times yearly to an individual.
  • the timing of administration can vary from individual to individual, depending upon such factors as the severity of an individual’s symptoms.
  • an effective amount of an APY cyclic peptide disclosed herein, or a pharmaceutical composition disclosed herein can be administered to an individual once every three months for an indefinite period of time, or until the individual no longer requires therapy.
  • a person of ordinary skill in the art will recognize that the condition of the individual can be monitored throughout the course of treatment and that the effective amount of an APY cyclic peptide disclosed herein, or a pharmaceutical composition disclosed herein that is administered can be adjusted accordingly.
  • An APY cyclic peptide disclosed herein, or a pharmaceutical composition disclosed herein can also be administered to an individual in combination with other therapeutic compounds to increase the overall therapeutic effect of the treatment. The use of multiple compounds to treat an indication can increase the beneficial effects while reducing the presence of side effects.
  • An EphA4 receptor antagonist comprising a cyclic peptide comprising or consisting essentially or consisting of the sequence X1-X2-X3-C4-X5-X6-X7- ⁇ A8-X9-W-X11-C12 (SEQ ID NO: 3), X2-X3-C4-X5-X6- X7- ⁇ A8-X9-W-X11-C12 (SEQ ID NO: 4), or X3-C4-X5-X6-X7- ⁇ A8-X9-W-X11-C12 (SEQ ID NO: 5), wherein X1 is independently ⁇ A, D-A, A, E, G, Q, D, L, S, F, or Y; X 2 is independently P, A, G, Ahx, Ava, ⁇ Abu, ⁇ A or Sar; X 3 is independently Y, F, W, V, L, H or I; X 5 is independently V or L; X 6 is independently Y, F
  • EphA4 receptor antagonist according to embodiment 1, wherein X 1 is independently ⁇ A, D-A, A, E, G or Q.
  • EphA4 receptor antagonist according to embodiment 1 or embodiment 2, wherein X1 is independently ⁇ A, D-A, A or E.
  • EphA4 receptor antagonist according to any one of embodiments 1-3, wherein X 2 is P. 5. The EphA4 receptor antagonist according to any one of embodiments 1-4, wherein X 3 is independently Y, F, W, V, L or H.
  • EphA4 receptor antagonist according to any one of embodiments 1-5, wherein X3 is independently Y, F or W.
  • EphA4 receptor antagonist according to any one of embodiments 1-6, wherein X5 is V.
  • EphA4 receptor antagonist according to any one of embodiments 1-7, wherein X 6 is independently Y, F or W.
  • EphA4 receptor antagonist according to any one of embodiments 1-8, wherein X7 is independently any amino acid except P; X9 is independently any amino acid except P; and X11 is independently any amino acid except P.
  • EphA4 receptor antagonist according to any one of embodiments 1-9, wherein X 7 is independently R, T, N, D, S, Q, Y, K, A, G or E; X9 is independently S, E, T, V, D, Y, Q, V, W, R, N, L, K or H; and X11 is independently S, E, L, N, V, I, H, K, M, D, W, T or G.
  • EphA4 receptor antagonist according to any one of embodiments 1-10, wherein X7 is independently R, T, N, D, S, or Q; X 9 is independently S, E, T, V, W, R, L, D, Y; and X 11 is independently S, E, L, N, T, K, V, I or H.
  • EphA4 receptor antagonist according to any one of embodiments 1-11, wherein X7 is independently R, T, N, D, S, or Q; X9 is independently S, E, T, V, D, Y; and X11 is independently S, E, L, N, K, V, I or H.
  • EphA4 receptor antagonist according to any one of embodiments 1-12, wherein X 7 is independently R, T, or N; X9 is independently S, E, T or V; and X11 is independently S, E, L or N.
  • EphA4 receptor antagonist according to any one of embodiments 1, 2, 4, 5 or 10-13, wherein the sequence comprises or consists essentially of or consists of X 1 -P 2 -X 3 -C 4 -X 5 -X 6 -X 7 - ⁇ A 8 -X 9 -W 10 -X 11 -C 12 (SEQ ID NO: 6), P 2 -X 3 -C 4 -X 5 -X 6 -X 7 - ⁇ A 8 -X 9 -W 10 -X 11 -C 12 (SEQ ID NO: 7) or X 3 -C 4 -X 5 -X 6 -X 7 - ⁇ A 8 -X 9 -W 10 - X11-C12 (SEQ ID NO: 8), wherein X1 is independently ⁇ A, D-A, A, E, G or Q; X3 is independently Y, F, W, V, L or H; X5 is independently V or L; X6 is independently Y, F, W,
  • EphA4 receptor antagonist according to embodiment 14 or embodiment 15, wherein X 3 is independently Y, F or W.
  • EphA4 receptor antagonist according to any one of embodiments 14-16, wherein X5 is V.
  • EphA4 receptor antagonist according to any one of embodiments 14-17, wherein X6 is independently Y, F or W.
  • EphA4 receptor antagonist according to any one of embodiments 14-18, wherein X 7 is independently R, T, N, D, S, Q, Y, K, A, G or E; X9 is independently S, E, T, V, D, Y, Q, V, W, R, N, L, K or H; and X11 is independently S, E, L, N, V, I, H, K, M, D, W, T or G. 20.
  • EphA4 receptor antagonist according to any one of embodiments 14-10, wherein X 7 is independently R, T, N, D, S, or Q; X 9 is independently S, E, T, V, W, R, L, D, Y; and X 11 is independently S, E, L, N, T, K, V, I or H.
  • EphA4 receptor antagonist according to any one of embodiments 14-20, wherein X7 is independently R, T, N, D, S, or Q; X9 is independently S, E, T, V, D, Y; and X11 is independently S, E, L, N, K, V, I or H.
  • EphA4 receptor antagonist according to any one of embodiments 23-27, wherein X 7 is independently R, T, N, D, S, Q, Y, K, A, G or E; X9 is independently S, E, T, V, D, Y, Q, V, W, R, N, L, K or H; and X11 is independently S, E, L, N, V, I, H, K, M, D, W, T or G.
  • EphA4 receptor antagonist according to any one of embodiments 23-28, wherein X7 is independently R, T, N, D, S, or Q; X 9 is independently S, E, T, V, W, R, L, D, Y; and X 11 is independently S, E, L, N, T, K, V, I or H.
  • EphA4 receptor antagonist according to any one of embodiments 23-29, wherein X7 is independently R, T, N, D, S, or Q; X9 is independently S, E, T, V, D, Y; and X11 is independently S, E, L, N, K, V, I or H.
  • EphA4 receptor antagonist according to embodiment 32, wherein X1 is independently ⁇ A, D-A, A or E.
  • EphA4 receptor antagonist according to embodiment 32 or embodiment 33, wherein X3 is independently Y, F or W.
  • EphA4 receptor antagonist according to any one of embodiments 32-34, wherein X 6 is independently Y, F or W.
  • EphA4 receptor antagonist according to any one of embodiments 32-35, wherein X7 is independently R, T, N, D, S, Q, Y, K, A, G or E; X 9 is independently S, E, T, V, D, Y, Q, V, W, R, N, L, K or H; and X 11 is independently S, E, L, N, V, I, H, K, M, D, W, T or G.
  • EphA4 receptor antagonist according to any one of embodiments 32-36, wherein X7 is independently R, T, N, D, S, or Q; X9 is independently S, E, T, V, W, R, L, D, Y; and X11 is independently S, E, L, N, T, K, V, I or H.
  • EphA4 receptor antagonist according to any one of embodiments 32-37, wherein X 7 is independently R, T, N, D, S, or Q; X9 is independently S, E, T, V, D, Y; and X11 is independently S, E, L, N, K, V, I or H.
  • EphA4 receptor antagonist according to embodiment 40 or embodiment 41, wherein X 6 is independently Y, F or W.
  • EphA4 receptor antagonist according to any one of embodiments 40-42, wherein X7 is independently R, T, N, D, S, Q, Y, K, A, G or E; X 9 is independently S, E, T, V, D, Y, Q, V, W, R, N, L, K or H; and X 11 is independently S, E, L, N, V, I, H, K, M, D, W, T or G.
  • EphA4 receptor antagonist according to any one of embodiments 40-43, wherein X7 is independently R, T, N, D, S, or Q; X9 is independently S, E, T, V, W, R, L, D, Y; and X11 is independently S, E, L, N, T, K, V, I or H.
  • EphA4 receptor antagonist according to any one of embodiments 40-44, wherein X 7 is independently R, T, N, D, S, or Q; X9 is independently S, E, T, V, D, Y; and X11 is independently S, E, L, N, K, V, I or H.
  • EphA4 receptor antagonist according to embodiment 47 or embodiment 48, wherein X 3 is independently Y, F or W.
  • EphA4 receptor antagonist according to any one of embodiments 47-49, wherein X7 is independently R, T, N, D, S, Q, Y, K, A, G or E; X9 is independently S, E, T, V, D, Y, Q, V, W, R, N, L, K or H; and X11 is independently S, E, L, N, V, I, H, K, M, D, W, T or G.
  • EphA4 receptor antagonist according to any one of embodiments 47-50, wherein X 7 is independently R, T, N, D, S, or Q; X9 is independently S, E, T, V, W, R, L, D, Y; and X11 is independently S, E, L, N, T, K, V, I or H.
  • EphA4 receptor antagonist according to any one of embodiments 47-51, wherein X7 is independently R, T, N, D, S, or Q; X 9 is independently S, E, T, V, D, Y; and X 11 is independently S, E, L, N, K, V, I or H.
  • EphA4 receptor antagonist according to embodiment 54 wherein X1 is independently ⁇ A, D-A, A or E.
  • EphA4 receptor antagonist according to embodiment 54 or embodiment 55, wherein X 7 is independently R, T, N, D, S, Q, Y, K, A, G or E; X 9 is independently S, E, T, V, D, Y, Q, V, W, R, N, L, K or H; and X11 is independently S, E, L, N, V, I, H, K, M, D, W, T or G.
  • EphA4 receptor antagonist according to any one of embodiments 54-56, wherein X7 is independently R, T, N, D, S, or Q; X9 is independently S, E, T, V, W, R, L, D, Y; and X11 is independently S, E, L, N, T, K, V, I or H.
  • EphA4 receptor antagonist according to any one of embodiments 54-57, wherein X7 is independently R, T, N, D, S, or Q; X9 is independently S, E, T, V, D, Y; and X11 is independently S, E, L, N, K, V, I or H. 59.
  • EphA4 receptor antagonist according to any one of embodiments 1, 2 or 10-13, wherein the sequence comprises or consists essentially of or consists of X1-P2-Y3-C4-V5-Y6-R7- ⁇ A8-X9-W10-X11-C12 (SEQ ID NO: 24), P2-Y3-C4-V5-Y6-R7- ⁇ A8-X9-W10-X11-C12 (SEQ ID NO: 25) or Y3-C4-V5-Y6-R7- ⁇ A8-X9- W 10 -X 11 -C 12 (SEQ ID NO: 26), wherein X 1 is independently ⁇ A, D-A, A, E, G or Q; X 9 is independently any amino acid except P; and X 11 is independently any amino acid except P; wherein C 4 and C 12 form a disulfide bridge; wherein C12 is optionally amidated; and wherein the amino-terminal residue is optionally acetylated.
  • EphA4 receptor antagonist according to embodiment 60 wherein X 1 is independently ⁇ A, D-A, A or E.
  • EphA4 receptor antagonist according to embodiment 60 or embodiment 61, wherein X9 is independently S, E, T, V, D, Y, Q, V, W, R, N, L, K or H; and X11 is independently S, E, L, N, V, I, H, K, M, D, W, T or G.
  • EphA4 receptor antagonist according to any one of embodiments 60-62, wherein X 9 is independently S, E, T, V, W, R, L, D, Y; and X11 is independently S, E, L, N, T, K, V, I or H.
  • EphA4 receptor antagonist according to any one of embodiments 60-63, wherein X9 is independently S, E, T, V, D, Y; and X11 is independently S, E, L, N, K, V, I or H.
  • EphA4 receptor antagonist according to any one of embodiments 60-64 wherein X 9 is independently S, E, T or V; and X 11 is independently S, E, L or N.
  • EphA4 receptor antagonist according to any one of embodiments 1-65, wherein C12 is amidated.
  • EphA4 receptor antagonist according to any one of embodiments 1-67, having a length 12 amino acids.
  • EphA4 receptor antagonist according to any one of embodiments 1-68, wherein the sequence is APYCVYR ⁇ ASWSC (SEQ ID NO: 35), APYCVYR ⁇ ASWSC-am (SEQ ID NO: 36), APYCVYK ⁇ ASWSC-am (SEQ ID NO: 45), ⁇ APYCVYR ⁇ ASWSC (SEQ ID NO: 46), ⁇ APYCVYR ⁇ ASWSC-am (SEQ ID NO: 47), ⁇ APYCVYK ⁇ ASWSC-am (SEQ ID NO: 48), ⁇ APYCVYR ⁇ AEWEC (SEQ ID NO: 49), ⁇ APYCVYR ⁇ AEWEC-am (SEQ ID NO: 50), D- APYCVYR ⁇ ASWSC (SEQ ID NO: 51), D-APYCVYR ⁇ ASWSC-am (SEQ ID NO: 52), APYCVWR ⁇ ASWSC (SEQ ID NO: 53), APYCVYT ⁇ AEWLC (SEQ ID NO:
  • EphA4 receptor antagonist according to embodiment 69, wherein the sequence is APYCVYR ⁇ ASWSC-am (SEQ ID NO: 36), APYCVYK ⁇ ASWSC-am (SEQ ID NO: 45), ⁇ APYCVYR ⁇ ASWSC (SEQ ID NO: 46), ⁇ APYCVYR ⁇ ASWSC-am (SEQ ID NO: 47), ⁇ APYCVYR ⁇ AEWEC-am (SEQ ID NO: 50), D-APYCVYR ⁇ ASWSC-am (SEQ ID NO: 52), APYCVWR ⁇ ASWSC (SEQ ID NO: 53), APYCVYT ⁇ AEWLC (SEQ ID NO: 54), APYCVYN ⁇ ATWNC (SEQ ID NO: 55) or APYCVYR ⁇ AVWEC (SEQ ID NO: 56).
  • EphA4 receptor antagonist according to embodiment 70 wherein the sequence is APYCVYR ⁇ ASWSC-am (SEQ ID NO: 36), ⁇ APYCVYR ⁇ ASWSC-am (SEQ ID NO: 47) or ⁇ APYCVYR ⁇ AEWEC-am (SEQ ID NO: 50).
  • EphA4 receptor antagonist according to any one of embodiments 1-71, wherein the amino-terminal residue is acetylated or wherein the amino-terminal residue is modified with carboxybenzyl or wherein the amino-terminal residue is not acetylated or is not modified with carboxybenzyl.
  • EphA4 receptor antagonist according to any one of embodiments 1-72, wherein the EphA4 receptor antagonist has an association rate constant for an EphA4 receptor of less than 1 x 10 5 M -1 s- 1 , 5 x 10 5 M -1 s -1 , less than 1 x 10 6 M -1 s -1 , less than 5 x 10 6 M -1 s -1 , less than 1 x 10 7 M -1 s -1 , less than 5 x 10 7 M -1 s -1 or less than 1 x 10 8 M -1 s -1 .
  • EphA4 receptor antagonist according to any one of embodiments 1-73, wherein the EphA4 receptor antagonist has an association rate constant for an EphA4 receptor of between 1 x 10 5 M -1 s -1 to 1 x 10 8 M -1 s -1 , 1 x 10 6 M -1 s -1 to 1 x 10 8 M -1 s -1 , 1 x 10 5 M -1 s -1 to 1 x 10 7 M -1 s -1 or 1 x 10 6 M -1 s -1 to 1 x 10 7 M -1 s -1 .
  • EphA4 receptor antagonist according to any one of embodiments 1-74, wherein the EphA4 receptor antagonist has a disassociation rate constant for an EphA4 receptor of less than 1 x 10 -3 s -1 , 5 x 10 -3 s -1 , less than 1 x 10 -4 s -1 , less than 5 x 10 -4 s -1 or less than 1 x 10 -5 s -1 .
  • EphA4 receptor antagonist according to any one of embodiments 1-75, wherein the EphA4 receptor antagonist has a disassociation rate constant for an EphA4 receptor of between 1 x 10 -3 s -1 to 1 x 10 -5 s -1 , 1 x 10 -3 s -1 to 1 x 10 -4 s -1 or 1 x 10 -4 s -1 to 1 x 10 -5 s -1 .
  • EphA4 receptor antagonist according to any one of embodiments 1-76, wherein the EphA4 receptor antagonist has a disassociation rate constant for an ephrin receptor other than an EpHA4 receptor of less than 1 x 10 0 M -1 s -1 , 5 x 10 0 M -1 s -1 , less than 1 x 10 1 M -1 s -1 , less than 5 x 10 1 M -1 s -1 , less than 1 x 10 2 M -1 s -1 , less than 5 x 10 2 M -1 s -1 , less than 1 x 10 3 M -1 s -1 , less than 5 x 10 3 M -1 s -1 or less than 1 x 10 4 M -1 s -1 .
  • EphA4 receptor antagonist according to any one of embodiments 1-77, wherein the EphA4 receptor antagonist has a disassociation rate constant for an ephrin receptor other than an EpHA4 receptor of at most 1 x 10 0 M -1 s -1 , at most 5 x 10 0 M -1 s -1 , at most 1 x 10 1 M -1 s -1 , at most 5 x 10 1 M -1 s- 1 , at most 1 x 10 2 M -1 s -1 , at most 5 x 10 2 M -1 s -1 , at most 1 x 10 3 M -1 s -1 , at most 5 x 10 3 M -1 s -1 or at most 1 x 10 4 M -1 s -1 .
  • EphA4 receptor antagonist according to any one of embodiments 1-78, wherein the EphA4 receptor antagonist has an equilibrium disassociation rate constant for an EphA4 receptor less than 500 nM, less than 450 nM, less than 400 nM, less than 350 nM, less than 300 nM, less than 250 nM, less than 200 nM, less than 150 nM, less than 100 nM, less than 75 nM, less than 50 nM, less than 25 nM, less than 20 nM, less than 15 nM, less than 10 nM, less than 5 nM, less than 1 nM, less than 0.5 nM or less than 0.1 nM.
  • EphA4 receptor antagonist according to any one of embodiments 1-79, wherein the EphA4 receptor antagonist has an equilibrium disassociation rate constant for an EphA4 receptor of between about 0.1 nM to about 10 nM, about 0.1 nM to about 25 nM, about 0.1 nM to about 75 nM, about 0.1 nM to about 100 nM, about 0.1 nM to about 125 nM, about 0.1 nM to about 150 nM, about 0.5 nM to about 10 nM, about 0.5 nM to about 25 nM, about 0.5 nM to about 75 nM, about 0.5 nM to about 100 nM, about 0.5 nM to about 125 nM, about 0.5 nM to about 150 nM, about 1 nM to about 10 nM, about 1 nM to about 25 nM, about 1 nM to about 75 nM, about 1 nM to about 100 nM, about 1 nM to about
  • EphA4 receptor antagonist according to any one of embodiments 1-80, wherein the EphA4 receptor antagonist has an association rate constant for an ephrin-binding pocket of an ephrin receptor other than an EphA4 receptor of less than 1 x 10 0 M -1 s -1 , less than 1 x 10 1 M -1 s -1 , less than 1 x 10 2 M- 1 s -1 , less than 1 x 10 3 M -1 s -1 or less than 1 x 10 4 M -1 s -1 .
  • EphA4 receptor antagonist according to any one of embodiments 1-81, wherein the EphA4 receptor antagonist has an association rate constant for an ephrin-binding pocket of an ephrin receptor other than an EphA4 receptor of at most 1 x 10 0 M -1 s -1 , at most 1 x 10 1 M -1 s -1 , at most 1 x 10 2 M -1 s -1 , at most 1 x 10 3 M -1 s -1 or at most 1 x 10 4 M -1 s -1 .
  • EphA4 receptor antagonist according to any one of embodiments 1-82, wherein the EphA4 receptor antagonist has an association rate constant for an ephrin-binding pocket of an ephrin receptor other than an EphA4 receptor of at least 2-fold more, at least 3-fold more, at least 4-fold more, at least 5-fold more, at least 6-fold more, at least 7-fold more, at least 8-fold more, or at least 9-fold more, at least 10-fold more, at least 20-fold more, at least 30-fold more, at least 40-fold more, at least 50-fold more, at least 60-fold more, at least 70-fold more, at least 80-fold more, at least 90-fold more, at least 100-fold more, at least 200-fold more, at least 300-fold more, at least 400-fold more, at least 500-fold more, at least 600-fold more, at least 700-fold more, at least 800-fold more, at least 900-fold more, at least 1,000-fold more, at least 2,500-fold more,
  • EphA4 receptor antagonist according to any one of embodiments 1-83, wherein the EphA4 receptor antagonist has an association rate constant for an ephrin-binding pocket of an ephrin receptor other than an EphA4 receptor of at most 1-fold more, at most 2-fold more, at most 3-fold more, at most 4-fold more, at most 5-fold more, at most 6-fold more, at most 7-fold more, at most 8-fold more, or at most 9-fold more, at most 10-fold more, at most 20-fold more, at most 30-fold more, at most 40-fold more, at most 50-fold more, at most 60-fold more, at most 70-fold more, at most 80-fold more, at most 90-fold more, at most 100-fold more, at most 200-fold more, at most 300-fold more, at most 400-fold more, at most 500-fold more, at most 600-fold more, at most 700-fold more, at most 800-fold more, at most 900-fold more, at most 1,000-fold more, at most
  • EphA4 receptor antagonist according to any one of embodiments 1-84, wherein the EphA4 receptor antagonist has a binding specificity ratio for the ephrin-binding pocket in the EphA4 ligand binding domain relative to an ephrin-binding pocket of an ephrin receptor other than an EphA4 receptor of at least 2:1, at least 3:1, at least 4:1, at least 5:1, at least 64:1, at least 7:1, at least 8:1, at least 9:1, at least 10:1, at least 15:1, at least 20:1, at least 25:1, at least 30:1, at least 35:1, or at least 40:1.
  • the EphA4 receptor antagonist has a binding specificity ratio for the ephrin-binding pocket in the EphA4 ligand binding domain relative to an ephrin-binding pocket of an ephrin receptor other than an EphA4 receptor of at least 2:1, at least 3:1, at least 4:1, at least 5:1, at least 64:1, at least 7
  • EphA4 receptor antagonist according to any one of embodiments 1-85, wherein the EphA4 receptor antagonist reduces EphA4 receptor activity by at least 10%, at least 20%, at least 30%, at least 40%, at least 50%, at least 60%, at least 70%, at least 80%, at least 60%, or at least 100%. 87.
  • EphA4 receptor antagonist according to any one of embodiments 1-86, wherein the EphA4 receptor antagonist has a biological half-life of at least 12 hours, at least 18 hours, at least 24 hours, at least 30 hours, at least 36 hours, at least 42 hours, at least 48 hours, at least 54 hours, at least 60 hours, at least 66 hours, at least 72 hours, at least 78 hours, at least 84 hours, at least 90 hours or at least 96 hours.
  • EphA4 receptor antagonist according to any one of embodiments 1-87, wherein the EphA4 receptor antagonist has a biological half-life of about 12 hours to about 24 hours, about 12 hours to about 36 hours, about 12 hours to about 48 hours, about 12 hours to about 60 hours, about 12 hours to about 72 hours, about 12 hours to about 84 hours, about 12 hours to about 96 hours, about 24 hours to about 36 hours, about 24 hours to about 48 hours, about 24 hours to about 60 hours, about 24 hours to about 72 hours, about 24 hours to about 84 hours, about 24 hours to about 96 hours, about 36 hours to about 48 hours, about 36 hours to about 60 hours, about 36 hours to about 72 hours, about 36 hours to about 84 hours, about 36 hours to about 96 hours, about 48 hours to about 60 hours, about 48 hours to about 72 hours, about 48 hours to about 84 hours, about 48 hours to about 96 hours, about 60 hours to about 72 hours, about 60 hours to about 84 hours, about 60 hours to about 96 hours, about 72 hours to about 84 hours, about 60
  • EphA4 receptor antagonist according to any one of embodiments 1-88, wherein the EphA4 receptor antagonist has a plasma half-life of at least 12 hours, at least 18 hours, at least 24 hours, at least 30 hours, at least 36 hours, at least 42 hours, at least 48 hours, at least 54 hours, at least 60 hours, at least 66 hours, at least 72 hours, at least 78 hours, at least 84 hours, at least 90 hours or at least 96 hours.
  • EphA4 receptor antagonist according to any one of embodiments 1-89, wherein the EphA4 receptor antagonist has a plasma half-life of about 12 hours to about 24 hours, about 12 hours to about 36 hours, about 12 hours to about 48 hours, about 12 hours to about 60 hours, about 12 hours to about 72 hours, about 12 hours to about 84 hours, about 12 hours to about 96 hours, about 24 hours to about 36 hours, about 24 hours to about 48 hours, about 24 hours to about 60 hours, about 24 hours to about 72 hours, about 24 hours to about 84 hours, about 24 hours to about 96 hours, about 36 hours to about 48 hours, about 36 hours to about 60 hours, about 36 hours to about 72 hours, about 36 hours to about 84 hours, about 36 hours to about 96 hours, about 48 hours to about 60 hours, about 48 hours to about 72 hours, about 48 hours to about 84 hours, about 48 hours to about 96 hours, about 60 hours to about 72 hours, about 60 hours to about 84 hours, about 60 hours to about 96 hours, about 72 hours to about 84 hours, about 60
  • a pharmaceutical composition comprising one or more EphA4 receptor antagonist according to any one of embodiments 1-90.
  • a method of treating an EphA4-based disease, disorder or pathology comprising administering an EphA4 receptor antagonist as defined in any one of embodiments 1-90 or a pharmaceutical composition as defined in any one of embodiments 90-93 to an individual in need thereof, wherein administration reduces one or more symptoms associated with the EphA4-based disease, disorder or pathology.
  • EphA4-based disease, disorder or pathology comprises a condition, a disease, a disorder and/or pathology where a pathophysiology effect is due to dysregulation of EphA4 signaling in a manner that causes EphA4 signaling hyperactivity in cells or spatially or temporally aberrant EphA4 signaling.
  • EphA4-based disease, disorder or pathology is a neurodegenerative disease, a hearing loss, a promotion of nerve regeneration, a promotion of neuroprotection, or a cancer.
  • a method of treating a neurodegenerative disease comprising administering an EphA4 receptor antagonist as defined in any one of embodiments 1-90 or a pharmaceutical composition as defined in any one of embodiments 90-93 to an individual in need thereof, wherein administration reduces one or more symptoms associated with the neurodegenerative disease.
  • the neurodegenerative disease is an Alexander disease, an Alper’s disease, Alzheimer’s disease, an amyotrophic lateral sclerosis, an ataxia telangiectasia, a Canavan disease, a Cockayne syndrome, a corticobasal degeneration, a Creutzfeldt- Jakob disease, a Guillain-Barre Syndrome a HIV-induced neurodegeneration, a Huntington disease, a Kennedy’s disease, a Krabbe disease, a Lewy body dementia, a Machado-Joseph disease, a multiple sclerosis, a Parkinson’s disease, a Pelizaeus-Merzbacher disease, a Pick’s disease, a primary lateral sclerosis, a Refsum’s disease, a Sandhoff disease, a Schilder’s disease, a spinal cord injury, a Steele- Richardson-Olszewski disease, a stroke, a tab
  • the one or more symptoms include abnormal movement, abnormal sensation, limb grasping, muscle weakness, atrophy, paralysis, abnormal inhibition of axon growth, abnormal axonal transport, aberrant synaptic function, synaptic transmission loss, impaired synaptic plasticity, synaptic loss, neuronal degeneration, motor neuron degeneration, motor neuron loss, poor neuronal survival, memory loss, impaired learning, dementia, ⁇ - amyloid plaque deposits, aberrant neurofilament accumulation, reactive astroglia and/or reactive microglia.
  • a method of treating a hearing loss comprising administering an EphA4 receptor antagonist as defined in any one of embodiments 1-90 or a pharmaceutical composition as defined in any one of embodiments 90-93 to an individual in need thereof, wherein administration reduces one or more symptoms associated with the hearing loss.
  • a method of promoting nerve regeneration comprising administering an EphA4 receptor antagonist as defined in any one of embodiments 1-90 or a pharmaceutical composition as defined in any one of embodiments 90-93 to an individual in need thereof in an amount sufficient to stimulate of facilitate neuronal differentiation and/or growth, thereby promoting nerve regeneration.
  • a method of promoting neuroprotection comprising administering an EphA4 receptor antagonist as defined in any one of embodiments 1-90 or a pharmaceutical composition as defined in any one of embodiments 90-93 to an individual in need thereof in an amount sufficient to protect neurons or nerve tissue from damage, thereby promoting neuroprotection.
  • a method of treating a cancer comprising administering an EphA4 receptor antagonist as defined in any one of embodiments 1-90 or a pharmaceutical composition as defined in any one of embodiments 90-93 to an individual in need thereof, wherein administration reduces one or more symptoms associated with the cancer.
  • the cancer comprises a condition, where a pathophysiology effect is due to dysregulation of EphA4 signaling in a manner that causes EphA4 signaling hyperactivity in cells or spatially or temporally aberrant EphA4 signaling.
  • the cancer is a glioblastoma, a gastric cancer, a pancreatic cancer, a prostate cancer, a breast cancer, a liver cancer, a leukemia or a Sezary syndrome.
  • an EphA4 receptor antagonist as defined in any one of embodiments 1-90 in the manufacture of a medicament for treating an EphA4-based disease, disorder or pathology.
  • an EphA4 receptor antagonist as defined in any one of embodiments 1-90 or a pharmaceutical composition as defined in any one of embodiments 90-93 in the treatment of an EphA4-based disease, disorder or pathology.
  • EphA4-based disease, disorder or pathology comprises a condition, a disease, a disorder and/or pathology where a pathophysiology effect is due to dysregulation of EphA4 signaling in a manner that causes EphA4 signaling hyperactivity in cells or spatially or temporally aberrant EphA4 signaling.
  • EphA4-based disease, disorder or pathology is a neurodegenerative disease, a hearing loss, a promotion of nerve regeneration, a promotion of neuroprotection, or a cancer.
  • EphA4 receptor antagonist as defined in any one of embodiments 1-90 in the manufacture of a medicament for treating a neurodegenerative disease.
  • an EphA4 receptor antagonist as defined in any one of embodiments 1-90 or a pharmaceutical composition as defined in any one of embodiments 90-93 in the treatment of a neurodegenerative disease.
  • the neurodegenerative disease is an Alexander disease, an Alper’s disease, Alzheimer’s disease, an amyotrophic lateral sclerosis, an ataxia telangiectasia, a Canavan disease, a Cockayne syndrome, a corticobasal degeneration, a Creutzfeldt-Jakob disease, a Guillain-Barre Syndrome a HIV-induced neurodegeneration, a Huntington disease, a Kennedy’s disease, a Krabbe disease, a Lewy body dementia, a Machado- Joseph disease, a multiple sclerosis, a Parkinson’s disease, a Pelizaeus-Merzbacher disease, a Pick’s disease, a primary lateral sclerosis, a Refsum’s
  • EphA4 receptor antagonist as defined in any one of embodiments 1-90 in the manufacture of a medicament for treating a hearing loss.
  • EphA4 receptor antagonist as defined in any one of embodiments 1-90 or a pharmaceutical composition as defined in any one of embodiments 90-93 in the promotion of neuroprotection.
  • EphA4 receptor antagonist as defined in any one of embodiments 1-90 in the manufacture of a medicament for treating cancer.
  • EphA4 receptor antagonist as defined in any one of embodiments 1-90 or a pharmaceutical composition as defined in any one of embodiments 90-93 in the treatment of cancer.
  • APY Cyclic Peptides [0120] APY cyclic peptides with a free amine at the N terminus and either an amidated C terminus or a free carboxylic acid at the C terminus were obtained from a commercial vendor (GenScript). Peptide amides were synthesized using manual synthetic cycles for 9-fluorenylmethoxycarbonyl (Fmoc) solid phase peptide synthesis. Typically syntheses were performed on a 0.2 mmol scale using Rink amide resin (0.69 mmol/g, Novabiochem).
  • the crude peptides were dissolved in 45% acetonitrile/water, 0.05% TFA and lyophilized. Samples were solubilized with 20% acetic acid prior to analysis by reversed-phase high- performance liquid chromatography (HPLC) and electrospray ionization mass spectrometry. If the sample was sufficiently homogeneous, it was oxidatively folded in 0.1 M NH 4 HCO 3 (pH 8) at a peptide concentration of 0.1 mg/mL followed by HPLC purification. If significant synthetic byproducts were present, the peptide was purified by HPLC prior to oxidation.
  • HPLC reversed-phase high- performance liquid chromatography
  • EphA4 ligand-binding domain has been crystallized in its unbound form and in complex with ephrin ligands, complexes containing peptides and small molecules that target the ephrin-binding pocket of EphA4 have evaded structural evaluation.
  • EphA4 ligand binding domain (residues 29-204 with Cys204 replaced by Ala) was cloned into the pETNKl-His-3C-LIC expression vector and expressed in E. coli origami 2(DE3) bacterial cells grown at 20°C overnight.
  • Crystallization trials were conducted using the sitting-drop vapor diffusion method with commercial screens. Single diffraction quality crystals were obtained after a second round of screening using the Additive Screen HT (Hampton Research) in 0.2 M MgCl2, 0.1 M TrisHCl (pH 8.5), 25% PEG3350 with the additives 4% 1,3-butanediol for APY or 3% 1,6-hexanediol for APY- ⁇ Ala8.am. Crystals were cryoprotected in reservoir solution with the addition of 20% glycerol and cryocooled in a nitrogen stream at 100 K.
  • the APY cyclic peptide not only functions as a competitive inhibitor that sterically precludes ephrin ligand binding to EphA4, but also promotes a conformation of the EphA4 ligand binding domain that would be unsuitable for ephrin binding (FIG. 1B). Binding of APY to the EphA4 ligand binding domain should also inhibit the receptor clustering interactions that have been proposed to facilitate ephrin-induced activation. Thus, the structure of the APY-EphA4 complex indicates that the APY cyclic peptide can effectively inhibit EphA4 signaling through multiple concerted mechanisms.
  • the structure also reveals a critical role for Gly8 in the APY cyclic peptide.
  • This enables formation of a "class 1, three-residue ⁇ -hairpin" structure that is essential for the correct alignment of the APY residues interacting with EphA4.
  • the P-turn around Gly8 (FIG.
  • FIG. 2B shows high strain, as indicated by the short unfavorable N-N distance between the Gly and Ser9 (FIG. 2B, dotted green lime, with distance in ⁇ shown in red).
  • APY forms five hydrogen bonds with the EphA4 ligand binding domain (between the backbone NH of Tyr3APY and backbone carbonyl of Cys73EphA4; the side chain hydroxyl of Tyr3APY and backbone carbonyl of Pro112EphA4; the backbone NH of Tyr6 APY and side chain carbonyl of Gln 71 EphA4 ; the backbone carbonyl of Tyr6 APY and side chain NH of Gln 71 EphA4 ; and the side chain NH of Trp10 APY and side chain hydroxyl of Thr104 EphA4 (FIG. 2D).
  • the side chain of Gln71EphA4 is positioned by a hydrogen bond with the side chain of neighboring Thr69EphA4 (FIG. 2E), in agreement with the loss of APY binding when Thr69EphA4 is replaced by Ala.
  • the I59A and A193S mutations have also been shown to abolish APY binding, and the structure shows that both of these EphA4 residues also participate in hydrophobic interactions with the peptide.
  • replacement of Thr104EphA4 with Ala did not decrease APY binding, suggesting that the Ala may compensate for the loss of the hydrogen bond by contributing to the hydrophobic patch that accommodates Tyr6APY and Trp10APY.
  • the crystal structure demonstrates that the APY peptide is an EphA4 competitive antagonist that also induces allosteric effects, with its cyclic scaffold representing an ideal solution for occupying the dynamic ephrin-binding pocket of EphA4.
  • C- terminally amidated peptides were generated and measured their ability to inhibit ephrin-A5 binding to EphA4 in ELISAs.
  • protein A coated 96- well plates (Pierce/Thermo Scientific) were incubated with 1 ⁇ g/mL EphA4 Fc in 80 ⁇ l/well TBST (50 mM Tris HCI, 150 mM NaCl (pH 7.5) containing 0.01 % Tween-20) for 1 hour at room temperature.
  • ephrin-A5 alkaline phosphatase AP
  • different concentrations of peptides in 40 ⁇ I/well TBST 40 ⁇ I/well TBST.
  • the wells were then washed and bound ephrin-A5 AP was quantified by adding 1 mg/mL p-nitrophenylphosphate substrate (Pierce/ThermoScientific) diluted in SEAP buffer (105 mM diethanolamine, 0.5 mM MgCl 2 , pH 9.8). OD 405 was measured and the absorbance from wells coated with Fc was subtracted as background.
  • SEAP buffer 105 mM diethanolamine, 0.5 mM MgCl 2 , pH 9.8
  • EphA4 ligand binding domain and APY cyclic peptides were diluted to obtain a final buffer containing 5% DMSO in 10 mM Hepes (pH 7.6) and 100 mM NaCl.
  • ITC Isothermal Titration Calorimetry
  • experiments were carried out using an ITC200 calorimeter (Microcal). Two ⁇ l aliquots of a 1 mM peptide solution were injected into the cell containing 205 ⁇ L EphA4 ligand-binding domain solution at a concentration of 65-95 ⁇ M.
  • Experimental data were analyzed using the Origin software package (Microcal).
  • Eph receptor Fc fusion proteins were immobilized at 1 ⁇ g/mL on protein A-coated wells and incubated with 0.05 nM ephrin-A5 AP (for EphA receptors) or ephrin-B2 AP (for Eph B receptors) in the presence or in the absence of the peptide.
  • Ephrin- A5 AP and ephrin-B2 AP for the ELISAs were produced in transiently transfected HEK293T cells according to the method disclosed in Lamberto, et al., Distinctive Binding of Three Antagonistic Peptides to the Ephrin- Binding Pocket of the EphA4 Receptor, Biochem J. 445: 47-56 (2012), which is hereby incorporated by reference in its entirety. Bound ephrin-A5 values are normalized to that for bound ephrin-A5 in the absence of peptide and IC50 values are indicated under each curve. Importantly, despite the increased binding affinity, the peptide remains highly selective for EphA4.
  • the secondary phage display libraries were generated by using PAGE-purified oligonucleotides and the M13KE gIII cloning vector according to the recommendations of the manufacturer (New England BioLabs). The following primers were used to generate the libraries: library 1 SEQ ID NO: 115; library 2 SEQ ID NO: 116; library 3 SEQ ID NO: 117; library 4 SEQ ID NO: 118.
  • EphA4 Fc mouse EphA4 ectodomain fused to Fc
  • TBS Tris-buffered saline
  • a well without EphA4 Fc was used as a negative control.
  • E.coli ER2738 cells grown to about 0.6 OD600 in LB containing 10 ⁇ g/mL tetracycline were infected for 5 min with different dilutions of the phage eluted from wells coated with EphA4 Fc or from control wells, according to the manufacturer's recommendations (New England BioLabs).
  • Plaques from plates enriched in EphA4-binding phage were amplified according to the manufacturer's recommendations (New England BioLabs) and tested in ELISAs for EphA4 binding. Phage DNA was purified according to the recommendations of the manufacturer (New England BioLabs) and sequenced.
  • Phage binding was detected with the ABTS substrate dissolved in 50 mM citric acid (pH 4.0). OD 405 was measured and the absorbance from wells without EphA4 Fc was subtracted as background. [0139] To compare the strength of EphA4 binding of different phage clones, Ni-NT A HisSorb Strips were coated with EphA4 Fc or Fc (Fisher Scientific) as the background. The wells were incubated for 1 hour with a phage concentration corresponding to 1 OD280 in 50 ⁇ l TBS, 0.1 % Tween-20 in the presence of different concentrations of the KYL antagonist peptide or in the absence of KYL.
  • KYL peptide antagonist was used to compete phage binding to EphA4 in ELISAs.
  • the results suggest that peptides with Tyr, Phe, Trp, Val, Leu, His and Trp (but not Ile) at position 3 can bind strongly to EphA4 because high KYL concentrations were needed to inhibit phage binding (Table 5, libraries 1 and 4).
  • the displayed peptides isolated from libraries with variable positions 6 and/or 10 suggest that only aromatic amino acids are tolerated at position 6 and only Trp at position 10 (Table 5, libraries 1 and 2). This is consistent with the formation of an aromatic stack between the two residues, which is one of the key features of the APY-EphA4 hydrophobic interaction pattern.
  • EphA4-binding phage contained a variety of residues at position 1 (Table 4, library 4). At position 2, Pro was most frequent (8/12 peptides) with Ala present in the remaining peptides. However, only phage clones with Alal/Glul and Pro2 exhibited strong binding to EphA4 (Table 4, library 4). Thus, despite a lack of obviously important contacts in the crystal structure, the identity of all three residues outside the circular portion of APY is important for APY binding activity.
  • AY-d3.am has the sequence ⁇ APYCVYR ⁇ ASWSC-am (SEQ ID NO: 47) and has a ⁇ Ala (3-aminopropanoic acid) replacing both Ala1 and Gly8 and an amidated C terminus.
  • Another derivative (APY-d4.am) has the sequence ⁇ APYCVYR ⁇ AEWEC-am (SEQ ID NO: 50) and has a glutamine replacing both Ser9 and Ser11 in addition to having a ⁇ Ala (3-aminopropanoic acid) replacing both Ala1 and Gly8 and an amidated C terminus.
  • a third derivative (DAla1-PY- ⁇ Ala8.am) has the sequence D- APYCVYR ⁇ ASWSC-am (SEQ ID NO: 52) and has a D-Ala replacing Ala1, ⁇ Ala (3-aminopropanoic acid) replacing Gly8 and an amidated C terminus. [0144] In another set of experiments, the effects of position 7 was evaluated by substituting Arg7 with Lys.
  • One derivative (APY-Lys7- ⁇ Ala8.am) has the sequence APYCVYK ⁇ ASWSC-am (SEQ ID NO: 45) and has a Lys replacing Arg7, a ⁇ Ala (3-aminopropanoic acid) replacing Gly8 and an amidated C terminus.
  • Another derivative ( ⁇ Ala1-PY-Lys7- ⁇ Ala8.am) has the sequence ⁇ APYCVYK ⁇ AEWEC-am (SEQ ID NO: 48) and has a ⁇ Ala (3-aminopropanoic acid) replacing both Ala1 and Gly8, a Lys replacing Arg7 and an amidated C terminus.
  • APY-d3 specifically inhibits EphA4-ephrin binding with an IC 50 value of about 30 nM in ELISA and a KD measured also about 30 nM by ITC.
  • APY-d4 exhibited a 2-fold better performance over APY-d3, inhibiting EphA4-ephrin binding with an IC50 value of about 15 nM in ELISA. All APY cyclic peptides exhibit at least 35-fold more potent than any previously known EphA4 antagonist and at least 50-fold more potent than the original APY cyclic peptide.
  • APY-d3.am, APY-d4.am and APY-DAla1.am remain highly selective for EphA4.
  • ELISA measuring inhibition of ephrin-A5 AP binding to immobilized EphA Fc receptors and ephrin-B2 AP binding to EphB Fc receptors shows that APY-d3.am, APY-d4.am and APY-DAla1.am each selectively inhibits ephrin binding to EphA4 (Table 6).
  • the APY cyclic peptides disclosed herein do not inhibit other Eph receptors when used at a concentration of about 100- fold higher than the IC50 value for EphA4.
  • EphA4 receptor-mediate phosphorylation was determined using a cell culture assay. EphA4 was immunoprecipitated from stably transfected human embryonal kidney (HEK293) cells treated with ephrin- A5 Fc (+) or Fc control ( ⁇ ) in the presence of various concentrations of APY, APY- ⁇ Ala8.am or APY-d3.am. The immunoprecipitates were probed for phosphotyrosine (PTyr) and reprobed for EphA4.
  • HEK293 stably transfected human embryonal kidney
  • Explants were cultured overnight in DMEM-F12 containing 0.4% methylcellulose (Sigma-Aldrich), 0.45% glucose, N-2 supplement (Life Technologies), 2 mM L-Glutamine (Life Technologies), 1 mM sodium pyruvate, 0.1% BSA and antibiotics. The culture medium was then replaced with medium without methylcellulose and 3 hours later the retinal explants were incubated with 0.3 ⁇ M APY- ⁇ Ala8.am or 0.15 ⁇ M APY-d3.am for 30 min before stimulation with 1 ⁇ g/mL preclustered ephrin-A5 Fc or Fc as a control for 30 min in the continued presence of the APY cyclic peptide.
  • Ephrin-A5 Fc was preclustered by incubating it for 30 min on ice with 1/10 polyclonal ⁇ -Fc antibody (Jackson Laboratories). The explants were then fixed for 30 min in 3.7% formaldehyde, 4% sucrose in PBS at room temperature, permeabilized for 3 min with 0.1% Triton X-100 in PBS, and filamentous actin was stained with rhodamine-conjugated phalloidin (Life Technologies). Growth cones were photographed under a fluorescence microscope and scored in a blinded manner. A growth cone was scored as collapsed when no lamellipodia or filopodia were present at the tip of the neurite.
  • neurites treated with Fc and APY- ⁇ Ala8.am showed about 30% growth cone collapse while cells treated with Fc, ephrin-A5, and APY- ⁇ Ala8.am similarly exhibited only 30% growth cone collapse, a level comparable to the unstimulated neurites.
  • APY-d3.am potently inhibits EphA4-dependent neuronal growth cone collapse at a concentration of 0.15 ⁇ M.
  • control neurites treated only with Fc showed only 20% growth cone collapse while cells treated with Fc and ephrin-A5 exhibited about 70% growth cone collapse, a statistically significance increase in collapse.
  • neurites treated with Fc and APY-d3.am showed about 30% growth cone collapse while cells treated with Fc, ephrin-A5, and APY-d3.am only exhibited less than 40% growth cone collapse, a level comparable to the unstimulated neurites.
  • the APY cyclic peptides did not detectably affect the morphology of growth cones in the absence of ephrin, consistent with the lack of nonspecific effects or toxicity.
  • MTT 3-(4,S-dimethylthiazol-2-yl)-2,5- diphenyltetrazolium bromide
  • ephrin-A5 Fc was immobilized at 1 ⁇ g/mL for 1 hour at room temperature in protein A-coated 96-well plates as described above. Plasma or CSF containing the peptides were incubated in the wells at a 1:20 dilution (corresponding to final concentrations of 10 ⁇ M of the APY cyclic peptide in the absence of proteolytic degradation) with 0.05 nM EphA4 AP for 30 minutes at 4°C. These peptide concentrations yield about 80% inhibition of EphA4 AP binding to ephrin-A5 Fc. The amount of bound AP fusion protein was quantified by measuring the absorbance at 280 nm.
  • SOD1*G93A transgenic mice express human Cu/Zn superoxide dismutase 1 (SOD1) harboring a single amino acid substitution of glycine to alanine at codon 93.
  • This pathogenic mutation is associated with early- onset familial ALS with hemizygotic SOD1*G93A animals exhibit neuronal degeneration due to progressive accumulation of detergent–resistant SOD-ubiquitin aggregates and aberrant neurofilament accumulations in degenerating motor neurons as well as reactive astroglia and microglia.
  • the neuronal degeneration leads to limb grasping, widespread muscle weakness, atrophy and paralysis in one or more limbs due to loss of motor neurons from the spinal cord due to abnormal axonal transport.
  • Transgenic mice also have an abbreviated life span.
  • Both SOD1*G93A mice, as well as non-transgenic mice used as age-matched controls, will be administered an APY cyclic peptide, such as APY- ⁇ A8.am, APY-d3 or APY-d4, or APY-d3 dimers disclosed herein, into the cerebral ventricles of the brain using a minipump.
  • Behavioral analyses will reveal muscle function of SOD1*G93A mice compared to controls. Muscle and neuromuscular junction pathology of SOD1*G93A mice and controls then will be assayed using standard histological staining and immunohistochemistry using an amyloid beta (A ⁇ ) antibody.
  • EphA4 signaling inhibition by APY cyclic peptides was examined using an APP/PS1 or other mouse model for Alzheimer’s disease, including the TgCRND8 model encoding a double mutant form of amyloid precursor protein 695 (KM670/671NL+V717F) under the control of the PrP gene promoter. See, e.g., Chrishti, et al., Early-Onset Amyloid Deposition and Cognitive Deficits in Transgenic Mice Expressing a Double Mutant Form of Amyloid Precursor Protein 695, J. Biol.
  • APP/PS1 double transgenic mice express a chimeric mouse/human amyloid precursor protein (Mo/HuAPP695swe) and a mutant human presenilin 1 (PS1-dE9) both directed to CNS neurons. Both pathogenic mutations are associated with early-onset Alzheimer's disease with transgenic mice showing visible ⁇ -amyloid plaque deposits in the brains by 6 to 7 months of age resulting in synaptic loss.
  • APP/PS1 mice also exhibit certain behavioral abnormalities such as, impaired reversal learning of a food-rewarded four-arm spatial maze task, cognitive deficits in spatial learning and memory in the Morris water maze, and inhibition of hippocampal CA1 long-term potentiation (LTP).
  • LTP hippocampal CA1 long-term potentiation
  • Both APP/PS1 mice, as well as non-transgenic mice used as age-matched controls, will be administered an APY cyclic peptide, such as APY- ⁇ A8.am, APY-d3 or APY-d4, or APY-d3 dimers disclosed herein, into the brain by intracerebral infusion for about 3 weeks.
  • APY cyclic peptide such as APY- ⁇ A8.am, APY-d3 or APY-d4, or APY-d3 dimers disclosed herein
  • EphA4 signaling inhibition by APY cyclic peptides was examined using a mouse photothrombosis model for stroke. See, e.g., Lemmens, et al., Modifying Expression of EphA4 and its Downstream Targets Improves Functional Recovery after Stroke, Hum. Mol. Genet. 22(11): 2214-2220 (2013), which is hereby incorporated by reference in its entirety. Focal cortical ischemia will be induced by photothrombosis in a wild-type strain of mice aged 3-4 months.
  • Infarct volume will also be calculated using serial coronal sections immune-stained with antibodies against glial fibrillary acidic protein (GFAP) and compared to the contralateral side. Nerve regeneration will be evaluated by immunohistochemistry using antibodies against EphA4 and glial fibrillary acidic protein (GFAP).
  • GFAP glial fibrillary acidic protein
  • mice Three days after induction of experimental stroke, mice will be divided into a treated group and an untreated group that will be used as age-matched controls. Treated mice will be administered an APY cyclic peptide, such as APY- ⁇ A8.am, APY-d3 or APY-d4, or APY-d3 dimers disclosed herein once daily for four weeks. Motor performance evaluations of treated and untreated animals will be conducted on post- stroke days 1, 7, 13, 19, 26, and 34. Infarct volume will also be measured. [0159] These results will show that treatment with a APY cyclic peptide disclosed herein will substantially improve motor function after experimental stroke.
  • an APY cyclic peptide such as APY- ⁇ A8.am, APY-d3 or APY-d4, or APY-d3 dimers disclosed herein once daily for four weeks.
  • Motor performance evaluations of treated and untreated animals will be conducted on post- stroke days 1, 7, 13, 19, 26, and 34. Infarct volume will also
  • mice treated with an APY cyclic peptide disclosed herein will exhibit on improved rotarod performance relative to control animals (untreated) as well as increased axonal sprouting. These results will demonstrate the therapeutic effects of APY cyclic peptides disclosed herein in inhibiting EphA4 signaling and their usefulness in treating stroke.
  • Example 12
  • EphA4 signaling inhibition by APY cyclic peptides was examined using a mouse corticospinal tract injury model for nerve regeneration.
  • Spinal cord injury often leads to permanent incapacity because long axons cannot regenerate in the CNS.
  • Eph receptors inhibit axon extension through an effect on the actin cytoskeleton.
  • Severing of corticospinal axons causes EphA4 to accumulate at high levels in stumps of corticospinal axons, while a cognate ligand, ephrinB2, is upregulated at the lesion site so as to confine the injured axons.
  • Wild-type mice will be anesthetized and a spinal hemisection surgery will be performed in order to sever corticospinal axons in the T12-L1 region. Animals will be allowed to recover from the surgery and mice showing only complete paralysis will be used.
  • mice Both hemisectioned mice, as well as un-operated mice used as age-matched controls, will be administered an APY cyclic peptide, such as APY- ⁇ A8.am, APY-d3 or APY-d4 disclosed herein, into the cervical spinal cord region by intracerebral infusion.
  • mice Five weeks after spinal cord lesion, mice will be evaluated for nerve regeneration by using an anterograde tracing technique and immunohistochemistry using antibodies against EphA4 and glial fibrillary acidic protein (GFAP) as well as by using behavioral assessments before and after spinal hemisection like measuring stride length, ability to walk or climb on a grid and/or hindpaw grip strength.
  • APY cyclic peptide such as APY- ⁇ A8.am, APY-d3 or APY-d4 disclosed herein
  • a 46 year old male complains of muscle weakness and numbness in his hands and arms. After routine history and physical examination, a physician diagnosis the woman with ALS.
  • the man is treated by oral administration a pharmaceutical composition comprising an APY cyclic peptide disclosed herein taken twice daily. Alternatively, the man is treated by administering the pharmaceutical composition once every three days.
  • the man’s condition is monitored and after about one month of treatment the man indicates there is improvement in his health, the numbness is not as severe and some strength has returned to his hands and arms. At a three month check-up, the man indicates that his numbness is gone, he does not suffer from any muscle weakness.
  • a pharmaceutical composition disclosed herein may be used to treat other neurodegenerative diseases, such as, e.g., an Alexander disease, an Alper’s disease, Alzheimer’s disease, an ataxia telangiectasia, a Canavan disease, a Cockayne syndrome, a corticobasal degeneration, a Creutzfeldt-Jakob disease, a Guillain-Barre Syndrome a HIV- induced neurodegeneration, a Huntington disease, a Kennedy’s disease, a Krabbe disease, a Lewy body dementia, a Machado-Joseph disease, a multiple sclerosis, a Parkinson’s disease, a Pelizaeus-Merzbacher disease, a Pick’s disease, a primary lateral sclerosis, a Refsum’s disease, a Sandhoff disease, a Schilder’s disease, a spinal cord injury, a
  • a 69 year old male complains of forgetfulness and not being able to remember certain events or activities.
  • a physician diagnosis the woman with Alzheimer’s disease The man is treated by oral administration a pharmaceutical composition comprising an APY cyclic peptide disclosed herein taken twice daily. Alternatively, the man is treated by administering the pharmaceutical composition once every three days.
  • the man’s condition is monitored and after about one month of treatment the man indicates there is improvement in his health, his forgetfulness is not as severe and he can remember events or activities better. At a three month check-up, the man indicates that his forgetfulness and memory continue to improve. This reduction in symptoms in Alzheimer’s disease indicates successful treatment with the pharmaceutical composition disclosed herein.
  • a pharmaceutical composition disclosed herein may be used to treat other neurodegenerative diseases, such as, e.g., an Alexander disease, an Alper’s disease, an amyotrophic lateral sclerosis, an ataxia telangiectasia, a Canavan disease, a Cockayne syndrome, a corticobasal degeneration, a Creutzfeldt- Jakob disease, a Guillain-Barre Syndrome a HIV-induced neurodegeneration, a Huntington disease, a Kennedy’s disease, a Krabbe disease, a Lewy body dementia, a Machado-Joseph disease, a multiple sclerosis, a Parkinson’s disease, a Pelizaeus-Merzbacher disease, a Pick’s disease, a primary lateral sclerosis, a Refsum’s disease, a Sandhoff disease, a Schilder’s disease, a spinal cord injury, a Steele- Richardson-Olszewski
  • a 51 year old female complains of hand tremors, eye pain and blurred vision, and fatigue.
  • a physician diagnosis the woman with multiple sclerosis.
  • the woman is treated by oral administration a pharmaceutical composition comprising an APY cyclic peptide disclosed herein taken once daily.
  • the woman’s condition is monitored and after about one week of treatment the woman indicates there is improvement in her health, her eye pain and blurred vision has subsided, her hand tremors are less and some energy has returned.
  • the woman indicates that her eye pain and blurred vision is gone, she does not suffer from hand tremors, and she is not tired. This reduction in symptoms in multiple sclerosis indicates successful treatment with the pharmaceutical composition disclosed herein.
  • a pharmaceutical composition disclosed herein may be used to treat other neurodegenerative diseases, such as, e.g., an Alexander disease, an Alper’s disease, Alzheimer’s disease, an amyotrophic lateral sclerosis, an ataxia telangiectasia, a Canavan disease, a Cockayne syndrome, a corticobasal degeneration, a Creutzfeldt-Jakob disease, a Guillain-Barre Syndrome a HIV-induced neurodegeneration, a Huntington disease, a Kennedy’s disease, a Krabbe disease, a Lewy body dementia, a Machado-Joseph disease, a Parkinson’s disease, a Pelizaeus- Merzbacher disease, a Pick’s disease, a primary lateral sclerosis, a Refsum’s disease, a Sandhoff disease, a Schilder’s disease, a spinal cord injury, a Steele-Richardson-Olszewski disease
  • a 66 year old male complains of severe pain after losing consciousness.
  • a physician determines that the pain is due to central neuropathic pain caused by a stroke.
  • the man is treated by administering a pharmaceutical composition comprising an APY cyclic peptide disclosed herein taken once every other day.
  • the man is treated by administering the pharmaceutical composition once every three days.
  • the man’s condition is monitored and after about 7 days of treatment the man indicates that there is a reduction in pain. At one and three month check-ups, the man indicates that he continues to have reduced pain. Tests performed on the man indicate that neuronal regeneration is occurring. This reduction in central neuropathic pain symptoms and/or regenerative growth of neurons indicates successful treatment with the pharmaceutical composition disclosed herein.
  • a pharmaceutical composition disclosed herein may be used to promote neuroregeneration and/or neuroprotection caused by another condition, disease or disorder, such as hearing loss.
  • a 49 year old woman was diagnosed by her physician with advanced metastatic breast cancer.
  • the metastatic breast cancer consisted of tumors, including several found in both lungs.
  • the woman is treated by administering a pharmaceutical composition comprising an APY cyclic peptide disclosed herein taken once every third day.
  • the woman is treated by administering the pharmaceutical composition once daily.
  • the patient was administered a CAT scan, which revealed that tumor growth had stopped and the breast cancer did not progress in the patient during this period of treatment. This reduction in tumor growth indicates successful treatment with the pharmaceutical composition disclosed herein.
  • a pharmaceutical composition disclosed herein may be used to treat a different type of cancer, such as, a glioblastoma, a gastric cancer, a pancreatic cancer, a prostate cancer, a breast cancer, a liver cancer, a leukemia or a Sezary syndrome.
  • a glioblastoma a gastric cancer, a pancreatic cancer, a prostate cancer, a breast cancer, a liver cancer, a leukemia or a Sezary syndrome.

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WO2017011812A1 (en) * 2015-07-15 2017-01-19 Sanford Burnham Prebys Medical Discovery Institute Modified epha4 cyclic peptide antagonists for neuroprotection and neural repair
WO2019213620A1 (en) * 2018-05-04 2019-11-07 Iron Horse Therapeutics, Inc. Epha4 cyclic peptide antagonists and methods of use thereof
WO2024233346A1 (en) * 2023-05-05 2024-11-14 Sanford Burnham Prebys Medical Discovery Institute Epha4 antagonists and uses thereof

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AU2003268345A1 (en) * 2002-09-24 2004-04-19 The Burnham Institute Novel agents that modulate eph receptor activity
WO2006026820A1 (en) * 2004-09-08 2006-03-16 The University Of Queensland Treating gliosis, glial scarring, inflammation or inhibition of axonal growth in the nervous system by modulating eph receptor

Cited By (3)

* Cited by examiner, † Cited by third party
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WO2017011812A1 (en) * 2015-07-15 2017-01-19 Sanford Burnham Prebys Medical Discovery Institute Modified epha4 cyclic peptide antagonists for neuroprotection and neural repair
WO2019213620A1 (en) * 2018-05-04 2019-11-07 Iron Horse Therapeutics, Inc. Epha4 cyclic peptide antagonists and methods of use thereof
WO2024233346A1 (en) * 2023-05-05 2024-11-14 Sanford Burnham Prebys Medical Discovery Institute Epha4 antagonists and uses thereof

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