Classifications

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  • C07K16/00—Immunoglobulins [IGs], e.g. monoclonal or polyclonal antibodies
  • C07K16/18—Immunoglobulins [IGs], e.g. monoclonal or polyclonal antibodies against material from animals or humans
  • C07K16/28—Immunoglobulins [IGs], e.g. monoclonal or polyclonal antibodies against material from animals or humans against receptors, cell surface antigens or cell surface determinants
  • C07K16/2803—Immunoglobulins [IGs], e.g. monoclonal or polyclonal antibodies against material from animals or humans against receptors, cell surface antigens or cell surface determinants against the immunoglobulin superfamily
  • C07K16/2818—Immunoglobulins [IGs], e.g. monoclonal or polyclonal antibodies against material from animals or humans against receptors, cell surface antigens or cell surface determinants against the immunoglobulin superfamily against CD28 or CD152
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61P—SPECIFIC THERAPEUTIC ACTIVITY OF CHEMICAL COMPOUNDS OR MEDICINAL PREPARATIONS
  • A61P31/00—Antiinfectives, i.e. antibiotics, antiseptics, chemotherapeutics
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61P—SPECIFIC THERAPEUTIC ACTIVITY OF CHEMICAL COMPOUNDS OR MEDICINAL PREPARATIONS
  • A61P31/00—Antiinfectives, i.e. antibiotics, antiseptics, chemotherapeutics
  • A61P31/12—Antivirals
  • A61P31/14—Antivirals for RNA viruses
  • A61P31/18—Antivirals for RNA viruses for HIV
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61P—SPECIFIC THERAPEUTIC ACTIVITY OF CHEMICAL COMPOUNDS OR MEDICINAL PREPARATIONS
  • A61P35/00—Antineoplastic agents
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61P—SPECIFIC THERAPEUTIC ACTIVITY OF CHEMICAL COMPOUNDS OR MEDICINAL PREPARATIONS
  • A61P37/00—Drugs for immunological or allergic disorders
  • A61P37/02—Immunomodulators
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61P—SPECIFIC THERAPEUTIC ACTIVITY OF CHEMICAL COMPOUNDS OR MEDICINAL PREPARATIONS
  • A61P37/00—Drugs for immunological or allergic disorders
  • A61P37/02—Immunomodulators
  • A61P37/06—Immunosuppressants, e.g. drugs for graft rejection
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61P—SPECIFIC THERAPEUTIC ACTIVITY OF CHEMICAL COMPOUNDS OR MEDICINAL PREPARATIONS
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  • C07K16/00—Immunoglobulins [IGs], e.g. monoclonal or polyclonal antibodies
  • C07K16/08—Immunoglobulins [IGs], e.g. monoclonal or polyclonal antibodies against material from viruses
  • C07K16/10—Immunoglobulins [IGs], e.g. monoclonal or polyclonal antibodies against material from viruses from RNA viruses
  • C07K16/1036—Retroviridae, e.g. leukemia viruses
  • C07K16/1045—Lentiviridae, e.g. HIV, FIV, SIV
  • C07K16/1063—Lentiviridae, e.g. HIV, FIV, SIV env, e.g. gp41, gp110/120, gp160, V3, PND, CD4 binding site
• • G—PHYSICS
  • G01—MEASURING; TESTING
  • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
  • G01N33/00—Investigating or analysing materials by specific methods not covered by groups G01N1/00 - G01N31/00
  • G01N33/48—Biological material, e.g. blood, urine; Haemocytometers
  • G01N33/50—Chemical analysis of biological material, e.g. blood, urine; Testing involving biospecific ligand binding methods; Immunological testing
  • G01N33/68—Chemical analysis of biological material, e.g. blood, urine; Testing involving biospecific ligand binding methods; Immunological testing involving proteins, peptides or amino acids
  • G01N33/6893—Chemical analysis of biological material, e.g. blood, urine; Testing involving biospecific ligand binding methods; Immunological testing involving proteins, peptides or amino acids related to diseases not provided for elsewhere
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61K—PREPARATIONS FOR MEDICAL, DENTAL OR TOILETRY PURPOSES
  • A61K39/00—Medicinal preparations containing antigens or antibodies
  • A61K2039/505—Medicinal preparations containing antigens or antibodies comprising antibodies
  • A61K2039/507—Comprising a combination of two or more separate antibodies
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  • C07—ORGANIC CHEMISTRY
  • C07K—PEPTIDES
  • C07K2317/00—Immunoglobulins specific features
  • C07K2317/20—Immunoglobulins specific features characterized by taxonomic origin
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  • C07K—PEPTIDES
  • C07K2317/00—Immunoglobulins specific features
  • C07K2317/20—Immunoglobulins specific features characterized by taxonomic origin
  • C07K2317/24—Immunoglobulins specific features characterized by taxonomic origin containing regions, domains or residues from different species, e.g. chimeric, humanized or veneered
• • C—CHEMISTRY; METALLURGY
  • C07—ORGANIC CHEMISTRY
  • C07K—PEPTIDES
  • C07K2317/00—Immunoglobulins specific features
  • C07K2317/30—Immunoglobulins specific features characterized by aspects of specificity or valency
  • C07K2317/31—Immunoglobulins specific features characterized by aspects of specificity or valency multispecific
• • C—CHEMISTRY; METALLURGY
  • C07—ORGANIC CHEMISTRY
  • C07K—PEPTIDES
  • C07K2317/00—Immunoglobulins specific features
  • C07K2317/50—Immunoglobulins specific features characterized by immunoglobulin fragments
  • C07K2317/56—Immunoglobulins specific features characterized by immunoglobulin fragments variable (Fv) region, i.e. VH and/or VL
  • C07K2317/565—Complementarity determining region [CDR]
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  • C07—ORGANIC CHEMISTRY
  • C07K—PEPTIDES
  • C07K2317/00—Immunoglobulins specific features
  • C07K2317/70—Immunoglobulins specific features characterized by effect upon binding to a cell or to an antigen
  • C07K2317/74—Inducing cell proliferation
• • C—CHEMISTRY; METALLURGY
  • C07—ORGANIC CHEMISTRY
  • C07K—PEPTIDES
  • C07K2317/00—Immunoglobulins specific features
  • C07K2317/70—Immunoglobulins specific features characterized by effect upon binding to a cell or to an antigen
  • C07K2317/75—Agonist effect on antigen
• • C—CHEMISTRY; METALLURGY
  • C07—ORGANIC CHEMISTRY
  • C07K—PEPTIDES
  • C07K2317/00—Immunoglobulins specific features
  • C07K2317/70—Immunoglobulins specific features characterized by effect upon binding to a cell or to an antigen
  • C07K2317/76—Antagonist effect on antigen, e.g. neutralization or inhibition of binding
• • C—CHEMISTRY; METALLURGY
  • C07—ORGANIC CHEMISTRY
  • C07K—PEPTIDES
  • C07K2317/00—Immunoglobulins specific features
  • C07K2317/90—Immunoglobulins specific features characterized by (pharmaco)kinetic aspects or by stability of the immunoglobulin
  • C07K2317/92—Affinity (KD), association rate (Ka), dissociation rate (Kd) or EC50 value

Definitions

• This disclosure relates to binding agents with specificity for programmed cell death 1 (PD-1 ) (e.g., human PD-1 ) and to methods for using the same to treat and / or prevent infection (e.g., by human immunodeficiency virus (HIV)), cancer and / or autoimmunity.
• PD-1 programmed cell death 1
• HAV human immunodeficiency virus
• CD4 T-cells latently infected with HIV has been identified in the blood as an important component of the HIV cell reservoir and as the primary cause of HIV persistence.
• the life-span of this latent cell reservoir is estimated to be approximately 70 years in the presence of full HIV suppression with ART.
• two populations of CD4 T-cells resident in lymph nodes serve as the primary CD4 T-cell compartment for HIV infection, replication and production.
• These two CD4 T-cell populations are defined by the expression of PD-1 and CXCR5 and include the PD-1 +CXCR5+, i.e. T follicular helper cells (Tfh) and PD-1 +CXCR5- CD4 T-cell populations.
• infiltrating tumor-specific CD8 T-cells are dysfunctional with regard their ability to proliferate and to mediate cytotoxic activity.
• the large majority of infiltrating tumor-specific CD8 T-cells are in a so-called exhaustion functional state.
• the primary mechanism responsible for the exhaustion of infiltrating tumor-specific CD8 T-cells is the increased expression of a number of regulatory receptors and particularly PD-1 regulatory receptor.
• the observation that the blockade of the PD-1/PDL-1/2 (PD-1 ligands) is associated with the recovery of CD8 T-cells from exhaustion has provided the rationale for developing intervention strategies targeting the PD-1 molecule expressed by exhaustedCD8 T-cells.
• Figure 1 A. Mouse PD-1 .
• Figure 2 CFSE assay to evaluate the functional effect of anti-PD1 antibodies on the proliferation of HIV specific CD8 T cells.
• Figure 5a-f Proliferation relative to controls (NEG and Peptide 8).
• Figure 6a-b Restoration of HIV peptide specific CD8 T-cell proliferation mediated by anti-PD-1 antibodies binding to different epitopes in a functional exhaustion recovery assay.
• Figure 7 Enhanced restoration of HIV peptide specific CD8 T-cell proliferation mediated by the combination of anti-PD-1 antibodies binding to different PD-1 epitopes in a functional exhaustion recovery assay.
• Figure 8 Synergy between a first binding agent that blocks the interaction of PD-1 and PD-L1 with a second binding agent that does not block the interaction of PD-1 and PD-L1.
• This disclosure relates to binding agents with specificity for programmed cell death 1 (PD-1 ) (e.g., human PD-1 ) and to methods for using the same such as to treat, prevent and / or ameliorate infection (e.g., by human immunodeficiency virus (HIV)), cancer and / or an autoimmune condition.
• PD-1 programmed cell death 1
• Functional assays for identifying binding agents that interact with PD-1 are also provided.
• Combinations of binding agents such as a first binding agent that blocks the interaction of PD-1 and PD-L1 with a second binding agent that does not block the interaction of PD-1 and PD-L1 , are also provided that act synergistically to rescue T cells from exhaustion.
• This disclosure relates to binding agents that bind programmed cell death (PD-1 ) protein (e.g., SEQ ID NO: 1 , Fig. 1A, Fig. 1 B of U.S. Pat. No. 5,698,520 (Honjo, et al.) which is hereby incorporated by reference in its entirety) (e.g., human PD-1) on the surface of cells in vitro and / or in vivo.
• PD-1 programmed cell death
• the binding agents may also bind isolated PD-1 polypeptide (e.g., human PD-1 ) and / or fragments and / or derivatives thereof, typically in vitro.
• binding agents may be antibodies (e.g., monoclonal antibodies) that may react with and / or bind to the epitopes of PD-1 .
• the "binding agents" described herein may include, for example, an agonist or an antagonist of PD-1.
• An agonist binding agent is one that is not typically capable of restoring T-cell function and / or expression of PD-1 .
• An agonist PD-1 binding agent may be useful for treating autoimmune diseases and others in which PD-1 expressing cells are involved in disease progression.
• an antagonist binding agent is one capable for restoring T-cell function and / or expression of PD-1 .
• a PD-1 antagonist binding agent may be capable of restoring the function of PD-1 expressing T-cells from functional exhaustion as is known to occur in HIV infection and in a variety of tumors. Restoration of T cell function may be determined by, for instance, measuring proliferation, cytokine production, cytotoxic activity or other characteristics of such cells.
• Another use for the binding agents described herein is the selective targeting and elimination of HIV-infected CD4 T-cell populations containing replication competent HIV (e.g., in a latent and / or replication state).
• replication competent HIV e.g., in a latent and / or replication state.
• Such PD-1 expressing cells expressing PD-1 are known to serve as a major cell reservoir for replication competent HIV.
• a potential mechanism for the elimination of these CD4 T-cell populations is antibody-dependent cellular cytotoxicity (ADCC) using the binding agents described herein (e.g., mono- and / or bi-specific PD-1 antibodies).
• ADCC antibody-dependent cellular cytotoxicity
• one or more PD-1 antagonistic binding agents having, for instance, different specificities (e.g., recognizing different epitopes) may be combined to induce rescue of antigen-specific CD8 T-cells from functional exhaustion caused by PD-1 expression in those cells (e.g., restoring or improving proliferation, cytokine production and / or cytotoxic activity).
• the binding agents described herein may also provide for the selective elimination and / or suppression of PD-1 expressing cells.
• the PD-1 agonist binding agents described herein may be used to supress and / or eliminate PD-1 expressing cells to treat, for instance, infectious diseases (e.g., HIV), cancer, and / or, especially, autoimmune conditions.
• infectious diseases e.g., HIV
• the binding agents may be antibodies such as monoclonal antibodies that may comprise, for instance, any one or more of the amino acid sequences shown in Table 1 (and / or one or more fragments and / or derivatives thereof).
• This disclosure also provides for the use of such monoclonal antibodies to isolate, identify, and / or target cells expressing PD-1.
• these monoclonal antibodies may be reactive against PD-1 expressed on the surface of cells.
• antibody or “antibodies” may refer to whole or fragmented antibodies in unpurified or partially purified form (e.g., hybridoma supernatant, ascites, polyclonal antisera) or in purified form.
• the antibodies may be of any suitable origin or form including, for example, murine (e.g., produced by murine hybridoma cells), or expressed as humanized antibodies, chimeric antibodies, human antibodies, and the like.
• antibodies may be wholly or partially dervied from human (e.g., IgG (lgG1 , lgG2, lgG2a, Ig2b, lgG3, lgG4), IgM, IgA (lgA1 and lgA2), IgD, and IgE), canine (e.g., IgGA, IgGB, IgGC, IgGD), chicken (e.g., IgA, IgD, IgE, IgG, IgM, IgY), goat (e.g., IgG), mouse (e.g., IgG, IgD, IgE, IgG, IgM), and / or pig (e.g., IgG, IgD, IgE
• the antibodies may be contained within hybridoma supernatant or ascites and utilized either directly as such or following concentration using standard techniques.
• the antibodies may be further purified using, for example, salt fractionation and ion exchange chromatography, or affinity chromatography using Protein A, Protein G, Protein A/G, and / or Protein L ligands covalently coupled to a solid support such as agarose beads, or combinations of these techniques.
• the antibodies may be stored in any suitable format, including as a frozen preparation (e.g., -20°C or -70°C), in lyophilized form, or under normal refrigeration conditions (e.g., 4°C).
• the binding agent When stored in liquid form, for instance, it is preferred that a suitable buffer such as Tris-buffered saline (TBS) or phosphate buffered saline (PBS) is utilized.
• TBS Tris-buffered saline
• PBS phosphate buffered saline
• the binding agent may be prepared as an injectable preparation, such as in suspension in a non-toxic parenterally acceptable diluent or solvent.
• Suitable vehicles and solvents that may be utilized include water, Ringer's solution, and isotonic sodium chloride solution, TBS and / or PBS, among others.
• Such preparations may be suitable for use in vitro or in vivo may be prepared as is known in the art and the exact preparation may depend on the particular application.
• the binding agents described are not in any way limited to antibodies.
• the binding agent may be any compound exhibiting similar binding properties as another (e.g., a mimetic).
• an exemplary binding agent may be one that binds PD-1 and / or can compete with binding agent having specificity therefor (e.g., a monoclonal antibody).
• the mimetic may exhibit substantially the same affinity in binding assays as the binding agent (e.g., monoclonal antibody) to which it is being compared.
• the affinity a particular binding agent may be measured by any suitable assay including but not limited to FACS staining of endogenous cell surface PD-1 on activated CD4 T cells as described in the Examples.
• One binding agent may be said to have "substantially the same affinity" as another where the measurements (e.g., nm) are within about any of 1 - 20, 1-5, 5-10, 10-15, or 15-20 percent of one another.
• exemplary mimetics may include, for example, organic compounds that specifically bind PD-1 , or an affibody (Nygren, et al. FEBS J. 275 (1 1 ): 2668-76 (2008)), affilin (Ebersbach, et al. J. Mol. Biol. 372 (1 ): 172-85 (2007)), affitin (Krehenbrink, et al. J. Mol. Biol. 383 (5): 1058-68 (2008)), anticalin (Skerra, A.
• Other mimetics may include, for example, a derivative of an antibody (of, for example, the monoclonal antibody 1 E4, 1 G10, and / or 1 G1) such as, for example, an F ab , F ab2 , Fab' single chain antibody, F v , single domain antibody, mono-specific antibody, bi-specific antibody, tri-specific antibody, multi-valent antibody, chimeric antibody, canine-human chimeric antibody, canine-mouse chimeric antibody, antibody comprising a canine Fc, humanized antibody, human antibody, caninized, CDR-grafted antibody, shark antibody, nanobody, canelid antibody, microbody, and / or intrabody, or derivative thereof.
• Other binding agents are also provided herein as would be understood by one of ordinary skill in the art.
• any method known to those of ordinary skill in the art may be used to generate binding agents having specificity for (e.g., binding to) PD-1 .
• an animal such as a mouse may be administered (e.g., immunized) with one or more PD-1 proteins (e.g., PD-1 Fc fusion protein and / or PD-1 His tag protein).
• Animals exhibiting serum reactivity to PD-1 expressed on activated human T lymphocytes (as determined by, for instance, flow cytometry and / or microscopy) may then be selected for generation of anti-PD-1 hybridoma cell lines. This may be repeated for multiple rounds.
• the primary criteria for the first round of binding agent selection may be include but are not limited to: i) level of staining of PD-1 on activated human T lymphocytes by flow cytometry; (ii) diversity of CDR VH and VL sequences as compared to those of the existing anti-PD-1 antibodies; and, (iii) epitope mapping performed by competitive binding studies with PD-1 conjugated Luminex beads pre-coupled with PD-L1 or one of several commercially available anti-PD-1 antibodies binding to different epitopes on PD-1.
• An exemplary first or second round of selection may also include, for instance, affinity binding (not a primary criteria since it may not correlate with the stimulatory potential of anti- PD-1 antibodies); and / or, functional characterization to identify the binding agent as an agonist or an antagonist.
• test binding agents may be assayed for the ability to rescue immune cells such as T cells from exhaustion. This may be determined by measuring the ability of a binding agent to restore proliferation to such cells in the presence of an antigen, such as a test peptide derived from a virus such as human immunodeficiency virus (HIV). Proliferation is measured in a CFSE assay in comparison to a control, such as the test peptide alone or a positive control anti-PD-1 antibody such as MK-3475 (pembrolizumab).
• an antigen such as a test peptide derived from a virus such as human immunodeficiency virus (HIV).
• HIV human immunodeficiency virus
• Proliferation is measured in a CFSE assay in comparison to a control, such as the test peptide alone or a positive control anti-PD-1 antibody such as MK-3475 (pembrolizumab).
• a binding agent is determined to restore proliferation where the comparison shows a signficant difference (such as a P value of ⁇ 0.001) compared to either a peptide alone control or peptide with an isotype control mouse lgG1 antibody.
• This assay may be used to identify binding agents (such as antibodies) that compete with other binding agents for binding to PD-1 (such as PD-L1 or PD-L2) and / or lead to the functional restoration of immune cells.
• Example 1 also describes two methods of epitope mapping the antibodies listed in Table 2 using Luminex-based assays.
• Example 1 describes four classes of monoclonal antibodies binding to distinct epitopes on PD-1 that were: class 1 (competitive with a first monoclonal antibody that blocks the interaction of PD-1 with PD-L1 ), class 2 (competitive with a second monoclonal antibody that binds PD-1 but does not block the interaction of PD-1 with PD-L1 ), class 3 (competitive with both the first and second monoclonal antibodies), and class 4 (non-competitive with either the first or second antibodies).
• Combinations of binding agents may also be identified, such as those described in Example 2.
• the combinations may be identified to provide statistically significant differences from results obtained using only one or more of the binding agents and not others.
• combinations exhibiting synergistic ability to restore immune cell function may be identified.
• the combination may comprise a first binding agent that blocks the interaction of PD-1 and PD-L1 with a second binding agent that does not block the interaction of PD-1 and PD-L1.
• the first and second binding agents may be different entities such as two or more different monoclonal antibodies or derivatives thereof, or may be found on the same entity such as a bi-functional antibody (a single antibody or derivative thereof comprising multiple binding specificities).
• an exemplary bi-functional antibody may comprise a first binding region that blocks the interaction of PD-1 and PD-L1 and a second binding region that does not block the interaction of PD-1 and PD-L1 .
• combinations that provide multiple types of each binding agent may comprise multiple types of binding agents that block the interaction of PD-1 and PD-L1 with one or more that does not block the interaction of PD-1 and PD-L1 .
• the combination may comprise one or more of binding agents that block the interaction of PD-1 and PD-L1 with multiple binding agents that do not block the interaction of PD-1 and PD-L1 .
• the combination may comprise multiple binding agents that block the interaction of PD-1 and PD-L1 with multiple binding agents that do not block the interaction of PD-1 and PD-L1.
• Such combinations as described herein may also be combined with one or more other agents that may effect immune cell function such as antibodies against CTLA-4 and the like.
• One of ordindary skill in the art would recognize that many such combinations may be suitable for use as descrbed herein.
• the binding agent is an antibody
• it may be identified with reference to the nucleotide and / or amino acid sequence corresponding to the variability and / or complementarity determining regions ("CDRs") thereof.
• the variable region / CDR sequences may be used in combination with one or more other variable region / CDR amino acid sequences.
• the variable region / CDR amino acid sequences may alternatively and / or also be adjoined to one or more types of constant region polypeptides of an antibody molecule.
• the CDR amino acid sequences shown in Tables 1A and 1 B may be adjoined to or associated with the constant regions of any antibody molecule of the same or a different species (e.g., human, goat, rat, sheep, chicken) and / or antibody subtype of that from which the CDR amino acid sequence was derived.
• an exemplary binding agent may be, or may be derived from, or may be related to the monoclonal antibody produced by the hybridomas listed in, and / or may have about the same affinity and / or proliferation effect, and / or exhibit the same binding class shown in Table 2, and / or may have any one or more of the amino acid sequences of SEQ ID NOS. 1 -138 and / or as shown in Tables 1A and 1 B.
• the binding agent may comprise an antibody heavy and / or a light chain that each comprises one or more constant and / or variable regions.
• the variable regions typically comprise one or more CDRs that may determine the binding specificity of the antibody.
• the monoclonal antibodies may also be identified by analysis of the amino acid sequences of (e.g., which may be encoded by such nucleotide sequences) such variable regions.
• exemplary amino acid sequences of the heavy chain CDRs of binding agents that bind PD-1 may include any one or more of comprising at least one amino acid sequence selected from the group consisting of SEQ ID NOS. 1 -138, and/or any other shown in Tables 1A and / or 1 B.
• any of the amino acid sequences described herein, and / or any fragments and / or derivatives thereof may also be combined with any other variable region and / or CDR in any order and / or combination to form hybrid and / or fusion binding agents and / or inserted into other heavy and / or light chain variable regions using standard techniques.
• Exemplary combinations of CDRs e.g., combination of heavy and / or light chain CDR1 , CDR2 and CDR3 amino acid sequences
• PD-1 e.g., human PD-1
• binding agent of this disclosure may include, for instance, the embodiments shown in Tables 1A and / or 1 B.
• any of SEQ ID NOS. 1 -69 may be combined with any one or more of SEQ ID NOS. 1 -69.
• the heavy chain CDRs of each clone are combined with their respective light chain CDRs into a binding agent.
• the binding agent may comprise the heavy chain CDRs and light chain CDRs shown below:
• 140A1 (SEQ ID NOS. 10, 33, 56, 79, 102, and 125);
• 135G1 (SEQ ID NOS. 15, 38, 61 , 84, 107, and 130);
• 135C12 (SEQ ID NOS. 17, 40, 63, 86, 109, and 132);
• 140G5 (SEQ ID NOS. 21 , 44, 67, 90, 1 13, and 136);
• Binding agents comprising the CDRs of Tables 1A and/or 1 B, or those of the immediately preceding paragraph, may also exhibit the following characteristics:
• Binding class was determined by Luminex assay competitive binding studies. Binding class 1 mAb clones are competitive with the EH 12.2H7 clone commercial antibody, class 2 mAb clones are competitive with the J 1 16 clone commercial antibody, class 3 mAb clones are competitive with both EH12.2H7 and J 1 16 antibodies and class 4 mAb clones bind in the presence of both EH12.2H7 and J 1 16 antibodies.
• PBMCs isolated from a chronically infected HIV subject were stimulated with an HIV specific peptide in the presence and absence of an anti- PD-1 antibody. Following a 6 day incubation, proliferation of HIV specific CD8 T cells was evaluated in the anti-PD-1 treated samples relative to the peptide alone control.
• Binding affinity may be determined by any technique available to those of ordinary skill in the art.
• the binding affinity data presented in Table 2 was evaluated by flow cytometry staining of endogenous cell surface PD-1 on CD4 T cells that were stimulated for a period of 3 to 6 days with phytohaemagglutinin (PHA).
• Binding class may also be determined by any technique available to those of ordinary skill in the art.
• the binding class data presented in Table 2 was determined by Luminex assay competitive binding studies. In Table 2, binding class 1 mAb antibodies are those determined to be competitive with the EH12.2H7 clone commercial antibody (available from BioLegend, San Diego, CA (e.g., Cat. No.
• class 2 antibodies are those determined to be competitive with the J 1 16 clone commercial antibody (available from Affymetrix eBioscience, San Diego, CA (e.g., Cat. No. 16-9989-80)); and class 3 antibodies are those determined to be competitive with both EH12.2H7 and J 1 16 antibodies; and class 4 mAb clone antibodies are those determined to bind PD-1 in the presence of both EH12.2H7 and J1 16 antibodies.
• Proliferative effect may be determined by any technique available to those of ordinary skill in the art. For instance, the EFRA system described above and used in Example 1 may be used. Such an assay was used to determine the proliferative effect data presented in Table 2. Briefly, a carboxyfluorescein succinimidyl ester (CFSE) assay in which peripheral blood mononuclear cells (PBMCs) were isolated from a chronically infected HIV subject and stimulated with an HIV-specific peptide in the presence and absence of an anti-PD-1 antibody. A control anti-PD1 antibody (the Merck antibody MK-3475) was also tested as a positive control. Following a six-day incubation, proliferation of HIV-specific CD8 T cells was evaluated in the anti-PD-1 treated samples relative to the peptide alone control and the result expressed as a percentage above control ("Proliferation effect").
• CFSE carboxyfluorescein succinimidyl ester
• the techniques used to identify and characterize PD-1 binding agents such as antibodies may be combined to provide a system for identifying and characterizing such binding agents.
• one or more candidate binding agents such one or more monoclonal antibodies may be assayed by EFRA or a similar assay to determine the ability of the candidate binding agent to restore function to immune cells as measured by, for instance, proliferation in the presence of an immunogenic peptide.
• this type of assay may be used as an initial screen to ensure the candidate binding agents to be further studied are capable of restoring immune cell function.
• these types of assays may be followed by one for determining the binding affinity to immune cells such as activated peripheral blood mononuclear cells (PBMCs).
• PBMCs peripheral blood mononuclear cells
• this assay may use a technique such as fluorescence activated cell sorting (FACS).
• FACS fluorescence activated cell sorting
• the assay may include the presence or absence of non-specific binding and / or competitive binding studies using known binding reagents such as anti-PD1 antibody (e.g., the Merck antibody MK-3475, also know as pembrolizumab). These assays may then be followed by sequencing of the CDRs of the candidate binding agents such as provided in Tables 1A and/or 1 B above. Together, then, the EFRA, affinity determination, epitope mapping studies and CDR identification methods described herein provide a system with which a candidate binding agent may be identified.
• any of the amino acid sequences of Tables 1A and/or 1 B may be also substituted by any other amino acid as desired by one of ordinary skill in the art.
• one of skill in the art may make conservative substitutions by replacing particular amino acids with others as shown in Table 3 below.
• the specific amino acid substitution selected may depend on the location of the site selected.
• conservative amino acid substitutions may involve a substitution of a native amino acid residue with a non-native residue such that there is little or no effect on the size, polarity, charge, hydrophobicity, or hydrophilicity of the amino acid residue at that position and, in particular, does not result in decreased PD-1 binding.
• Table 3
• this disclosure provides binding agents with multiple specificities such that PD-1 and at least one other secondary antigen (e.g., a cell surface protein) may be bound by a single binding agent.
• the secondary antigen may be one expressed by cells infected by an infectious agent.
• an exemplary secondary antigen may be HIV Env antigen.
• binding agents may bind the secondary antigen and / or may serve to neutralize the infectious agent.
• a bi-specific binding agent having dual specificity for PD-1 and an HIV antigen such as env and / or another antigen, for instance.
• the HIV immunogen may be derived from any of the subtypes described herein, or any other.
• such binding agents may include: PD-1 agonist / Env binding; PD-1 agonist PD-1 / Env binding and neutralization; PD-1 antagonist / Env binding; and / or PD-1 antagonist / PD-1 / Env binding and neutralization.
• it may be preferable to select antigens from HIV-1 subtypes B and / or C. It may also be desirable to include binding agents having specificity for antigens from multiple HIV subtypes (e.g., HIV-1 subtypes B and C, HIV-2 subtypes A and B, or a combination of HIV-1 and HIV-2 subtypes) in a single composition.
• PD-1 specificities e.g., bi-specific PD-1 a/PD1 b antagonist PD-1 antibodies specific to two different epitopes
• tumor antigens e.g., cancer-testis (CT) antigen (i.e., MAGE, NY-ESO-1 ); melanocyte differentiation antigen (i.e., Melan A/MART-1 , tyrosinase, gp100); mutational antigen (i.e., MUM-1 , p53, CDK-4); overexpressed 'self antigen (i.e., HER-2/neu, p53); and / or viral antigens (i.e., HPV, EBV)).
• CT cancer-testis
• MAGE MAGE
• NY-ESO-1 melanocyte differentiation antigen
• mutational antigen i.e., MUM-1 , p53, CDK-4
• overexpressed 'self antigen i.e., HER-2/neu, p53
• binding agents e.g., monoclonal antibodies
• the specificities of such binding agents may be recombined into a single binding agent using techniques that are widely available to those of ordinary skill in the art.
• multiple single specifity binding agents may also be combined and used (e.g., administered) to provide an effective multiple specificity reagent.
• the binding agents described herein may be conjugated to active agents to target and inhibit the function of and /or eliminate cell populations expressing PD-1 (and / or another antigen in the case of binding agents with multiple specificities).
• CD4 + T-cell populations containing replication competent HIV may be targeted and eliminated using binding agent / drug conjugates (e.g., antibody-drug conjugates (ADC)).
• ADC antibody-drug conjugates
• Mono- and/or bi-specific candidate binding agents may be conjugated with one or more types of drugs (e.g., drugs damaging DNA, targeting microtubules).
• the binding agents described herein and/ or derivatives thereof may also be adjoined to and / or conjugated to functional agents for in vitro and / or in vivo use.
• the binding agent may be adjoined to and / or conjugated to functional moieties such as cytotoxic drugs or toxins, and / or active fragments thereof such as diphtheria A chain, exotoxin A chain, ricin A chain, abrin A chain, curcin, crotin, phenomycin, enomycin, among others.
• Suitable functional moieties may also include radiochemicals.
• Binding agents, such as antibodies, may be adjoined to and / or conjugated to the one or more functional agents using standard techniques in the art.
• the binding agents may be administered in conjunction with other agents such as anti-infective agents (e.g., antibiotics, anti-viral medications).
• anti-infective agents e.g., antibiotics, anti-viral medications
• the binding agents described herein may be combined with monoclonal antibodies and / or other reagents such as Nivolumab (also known as MDX-1 106, BMS-936558 (Topalian, et al. N. Eng. J. Med.
• the PD-1 binding agents described herein may be used to treat and / or prevent and / or ameliorate the symptoms of infection by HIV.
• HIV isolates are now classified into discrete genetic subtypes. HIV-1 is known to comprise at least ten subtypes (A1 , A2, A3, A4, B, C, D, E, F1 , F2, G, H, J and K) (Taylor et al, NEJM, 359(18):1965-1966 (2008)). HIV-2 is known to include at least five subtypes (A, B, C, D, and E).
• Subtype B has been associated with the HIV epidemic in homosexual men and intravenous drug users worldwide. Most HIV-1 immunogens, laboratory adapted isolates, reagents and mapped epitopes belong to subtype B. In sub-Saharan Africa, India and China, areas where the incidence of new HIV infections is high, HIV-1 subtype B accounts for only a small minority of infections, and subtype HIV-1 C appears to be the most common infecting subtype. Any of these types of isolates may be addressed using the binding agents described herein.
• One or more binding agents may also be administered with or in conjunction with one or more agents used to prevent, treat and / or ameliorate HIV such as for example, a protease inhibitor, an HIV entry inhibitor, a reverse transcriptase inhibitor, and / or an anti- retroviral nucleoside analog.
• agents used to prevent, treat and / or ameliorate HIV such as for example, a protease inhibitor, an HIV entry inhibitor, a reverse transcriptase inhibitor, and / or an anti- retroviral nucleoside analog.
• Suitable compounds include, for example, Agenerase (amprenavir), Combivir (Retrovir / Epivir), Crixivan (indinavir), Emtriva (emtricitabine), Epivir (3tc / lamivudine), Epzicom, Fortovase / Invirase (saquinavir), Fuzeon (enfuvirtide), Hivid (ddc / zalcitabine), Kaletra (lopinavir), Lexiva (Fosamprenavir), Norvir (ritonavir), Rescriptor (delavirdine), Retrovir / AZT (zidovudine), Reyatax (atazanavir, BMS-232632), Sustiva (efavirenz), Trizivir (abacavir / zidovudine / lamivudine), Truvada (Emtricitabine / Tenofovir DF), Videx (ddl / didanosine), Videx EC (
• the PD-1 binding agents described herein may be used to treat and / or prevent and / or ameliorate the symptoms of cancer.
• exemplary cancers may include, for instance, any of the breast, blood, colon, stomach, rectum, skeletal tissue, skin (e.g., melanoma) brain, lung, bladder, kidney, ovary, and / or liver, among others.
• binding agents may also be combined with and / or administered with or in conjunction with one or more agents used to prevent, treat and / or ameliorate cancer such as for example, an alkylating agent (e.g., any nitrogen mustard, nitrosourea, tetrazine, aziridine, cisplatin and / or derivative thereof), anti-metabolite (e.g., any of the methotrexates, pemetrexeds, fluoropyrimidines and / or derivative thereof), anti-microbtubule agent (e.g., vinca alkyloids, taxanes, podophyllotoxin and / or derivative thereof), topoisomerase I and / or II inhibitors (e.g., a camptothecin, irinotecan, topotecan, etoposide, doxorubicin, mitoxantrone, teniposide, novobiocin, merbarone, aclarubicin and / or
• the one or more binding agents may also, or alternatively, be combined with one or more other binding agents available to those of ordinary skill in the art for treating, preventing and / or ameliorating cancer such as, for example, Nivolumab, Lambrolizumab, Pidilizumab and / or other similar agents and / or derivatives thereof.
• Other suitable agents are known to those of skill in the art and may be suitable for use as described herein. Such agents may either be used prior to, during, or after administration of the binding agents and / or use of the methods described herein.
• the PD-1 binding agents described herein may be used to treat and / or prevent and / or ameliorate the symptoms of autoimmunity.
• exemplary autoimmune conditions may include, for instance, any in which PD-1 is involved in maintaining self-tolerance and / or one involving inflammatory T cells (e.g., autoreactive or self antigen-specific T cells) such as, for instance, systemic lupus erythematosus (SLE), type I diabetes, rheumatoid arthritis, glomerulonephritis, and multiple sclerosis.
• SLE systemic lupus erythematosus
• type I diabetes rheumatoid arthritis
• glomerulonephritis glomerulonephritis
• multiple sclerosis multiple sclerosis.
• Such PD-1 binding agents may also be combined with other agents such as anti-CTLA-4 agents (e.g., ipilimumab).
• One or more of the binding agents may also be combined with and / or administered with or in conjunction with one or more agents used to prevent, treat and / or ameliorate autoimmunity such as, for example, glucocorticoids, cytostatics (e.g., alkylating agent, anti-metabolite, methotrexate, azathioprine, mercaptopurine, cytotoxic antibiotics (e.g., dactinomycin, anthracyclines, mitomycin C, bleomycin, mithramycin), antibodies (e.g., Atgam, Thymoglobuline, Simulect, Zenapax), drugs acting on immunophilins (e.g,.
• cytostatics e.g., alkylating agent, anti-metabolite, methotrexate, azathioprine, mer
• ciclosporin tacrolimus, sirolimus
• interferons opioids
• TNF-binding agents e.g., Remicade, Enbrel, Humira
• mycophenolate e.g., fingolimod, myriocin, and / or derivatives thereof.
• suitable agents are known to those of skill in the art and may be suitable for use as described herein. Such agents may either be used prior to, during, or after administration of the binding agents and / or use of the methods described herein.
• the binding agents may be adjoined to and / or conjugated to one or more detectable labels.
• suitable detectable labels may include, for instance, fluorosceins (e.g., DyLight, Cy3, Cy5, FITC, HiLyte Fluor 555, HiLyte Fluor 647; 5- carboxy-2,7-dichlorofluorescein; 5-Carboxyfluorescein (5-FAM); 5-HAT (Hydroxy Tryptamine); 5-Hydroxy Tryptamine (HAT); 6-JOE; 6-carboxyfluorescein (6-FAM); FITC; 6- carboxy-1 ,4-dichloro-2',7'-dichlorofluorescein (TET); 6-carboxy-1 ,4-dichloro-2',4', 5', 7'-tetra- chlorofluorescein (HEX); 6-carboxy-4',5'-dichloro-2', 7'
• fluorosceins
• binding agents such as antibodies, may be adjoined to and / or conjugated to the one or more detectable labels using standard techniques in the art.
• a nucleic acid molecule encoding one or more binding agents described herein may be inserted into one or more expression vectors, as discussed below in greater detail.
• the binding agent may be encoded by nucleotides corresponding to the amino acid sequence.
• the particular combinations of nucleotides (codons) that encode the various amino acids (AA) are well known in the art, as described in various references used by those skilled in the art (e.g., Lewin, B. Genes V, Oxford University Press, 1994).
• the nucleotide sequences encoding the amino acids of said binding agents may be ascertained with reference to Table 4, for example. Nucleic acid variants may use any combination of nucleotides that encode the binding agent.
• nucleotide sequence encoding a particular amino acid sequence may be easily derived from the amino acid sequence and the information presented in Table 4. For instance, it may be deduced from the amino acid sequence DDFLH (SEQ ID NO.: 1 ) and the information presented in Table 4 that the amino acid sequence may be encoded by the nucleotide sequence GAT GAT TTT TTA CAT (SEQ ID NO.:139). Those of ordinary skill in the art would understand that nucleotide sequences encoding SEQ ID NOS. 2-138 may be deduced in the same way, and such nucleotide sequences are contemplated herein.
• nucleotide sequences encoding the variable regions thereof may also be isolated from the phage and / or hybridoma cells expressing the same cloned into expression vectors to produce certain preparations (e.g., humanized antibodies). Methods for producing such preparations are well- known in the art.
• hybridoma cells from mice immunized with a PD-1 antigen / immunogen may be selected using the functional assays described herein and cloning techniques that are readily available to those of ordinary skill in the art. For instance, to isolate and sequence nucleic acids encoding the heavy and light chain variable regions of the selected hybridomas, total RNA may be extracted from fresh hybridoma cells using TRIzol reagent according to the manufacturer's protocol.
• cDNA may be synthesized from the RNA using isotype-specific anti- sense primers or universal primers using standard techniques (e.g., following the technical manual of PrimeScriptTM 1 st Strand cDNA Synthesis Kit).
• Polymerase chain reaction (PCR) may then be performed to amplify the nucleic acids encoding the variable regions (heavy and light chains) of the antibody produced by the selected hybridoma, which may then be cloned into a standard cloning vector separately and sequenced.
• Colony PCR screening may then be performed to identify clones with inserts of correct sizes. Preferably, no less than five single colonies with inserts of correct sizes are sequenced for each antibody variable region.
• Standard protocols may then be used for the expression and purification of the anti-PD-1 antibodies.
• hybridoma clones may be grown in serum-free medium and the cell culture broth centrifuged and then filtered.
• the filtered supernatant containing the antibody may then be loaded onto an affinity column (e.g., Protein A) column, washed and eluted with an appropriate buffer (e.g., Pierce IgG elute buffer).
• an appropriate buffer e.g., Pierce IgG elute buffer
• the eluted fractions may then be pooled and buffer-exchanged into PBS, pH 7.2.
• the purified antibody may then be analyzed by SDS- PAGE and Western blot by using standard protocols for molecular weight, yield and purity.
• Size exclusion chromatography HPLC may then be performed on an appropriate column (e.g., TSK GEL-G3000 SWXL column (Tosoh)) for biophysical characterization in order to ensure high antibody purity (generally >90%) with low presence of protein aggregates.
• TSK GEL-G3000 SWXL column Tosoh
• These procedures were used in isolating and sequencing nucleic acids encoding SEQ ID NOS. 1 -138 from selected hybridoma cells. These techniques, variations thereof, and/or other may also be of use for these purposes as would be understood by those of ordinary skill in the art.
• Nucleic acid molecules encoding one or more PD-1 binding agents may be contained within a viral and / or a non-viral vector.
• a DNA vector is utilized to deliver nucleic acids encoding one or more PD-1 binding agents to the patient.
• various strategies may be utilized to improve the efficiency of such mechanisms including, for example, the use of self-replicating viral replicons (Caley, et al. 1999. Vaccine, 17: 3124- 2135; Dubensky, et al. 2000. Mol. Med. 6: 723-732; Leitner, et al. 2000. Cancer Res. 60: 51 - 55), codon optimization (Liu, et al. 2000. Mol. Ther.
• Various viral vectors that have been successfully utilized for introducing a nucleic acid to a host include retrovirus, adenovirus, adeno-associated virus (AAV), herpes virus, and poxvirus, among others.
• the vectors may be constructed using standard recombinant techniques widely available to one skilled in the art.
• Non-viral plasmid vectors may also be suitable in certain embodiments.
• Preferred plasmid vectors are compatible with bacterial, insect, and / or mammalian host cells.
• Such vectors include, for example, PCR-ii, PCR3, and pcDNA3.1 (Invitrogen, San Diego, CA), pBSii (Stratagene, La Jolla, CA), pet15 (Novagen, Madison, Wl), pGEX (Pharmacia Biotech, Piscataway, NJ), pEGFp-n2 (Clontech, Palo Alto, CA), pETI (Bluebacii, Invitrogen), pDSR-alpha (PCT pub. No.
• WO 90/14363 and pFASTBACdual (Gibco-BRL, Grand island, NY) as well as Bluescript ® plasmid derivatives (a high copy number COLel -based phagemid, Stratagene Cloning Systems, La Jolla, CA), PCR cloning plasmids designed for cloning TAQ-amplified PCR products (e.g., TOPOTM TA cloning ® kit, PCR2.1 plasmid derivatives, Invitrogen, Carlsbad, CA). Bacterial vectors may also be used.
• Bluescript ® plasmid derivatives a high copy number COLel -based phagemid, Stratagene Cloning Systems, La Jolla, CA
• PCR cloning plasmids designed for cloning TAQ-amplified PCR products e.g., TOPOTM TA cloning ® kit, PCR2.1 plasmid derivatives, Invitrogen
• vectors include, for example, Shigella, Salmonella, Vibrio cholerae, Lactobacillus, Bacille Calmette Guerin (BCG), and Streptococcus (see for example, WO 88/6626; WO 90/0594; WO 91/13157; WO 92/1796; and WO 92/21376).
• BCG Bacille Calmette Guerin
• Streptococcus see for example, WO 88/6626; WO 90/0594; WO 91/13157; WO 92/1796; and WO 92/21376).
• Other delivery techniques may also suffice including, for example, DNA- ligand complexes, adenovirus-ligand-DNA complexes, direct injection of DNA, CaP0 4 precipitation, gene gun techniques, electroporation, and colloidal dispersion systems.
• Colloidal dispersion systems include macromolecule complexes, nanocapsules, microspheres, beads, and lipid-based systems including oil-in-water emulsions, micelles, mixed micelles, and liposomes.
• the preferred colloidal system is a liposome, which are artificial membrane vesicles useful as delivery vehicles in vitro and in vivo.
• RNA, DNA and intact virions can be encapsulated within the aqueous interior and be delivered to cells in a biologically active form (Fraley, R., et ai, 1981 , Trends Biochem. Sci., 6: 77).
• the composition of the liposome is usually a combination of phospholipids, particularly high-phase-transition-temperature phospholipids, usually in combination with steroids, especially cholesterol. Other phospholipids or other lipids may also be used.
• the physical characteristics of liposomes depend on pH, ionic strength, and the presence of divalent cations. Examples of lipids useful in liposome production include phosphatidyl compounds, such as phosphatidylglycerol, phosphatidylcholine, phosphatidylserine, phosphatidylethanolamine, sphingolipids, cerebrosides, and gangliosides.
• diacylphosphatidylglycerols where the lipid moiety contains from 14-18 carbon atoms, particularly from 16-18 carbon atoms, and is saturated.
• Illustrative phospholipids include egg phosphatidylcholine, dipalmitoylphosphatidylcholine and distearoylphosphatidylcholine.
• a cultured cell comprising the vector is also provided.
• the cultured cell may be a cultured cell transfected with the vector or a progeny of the cell, wherein the cell expresses the immunogenic polypeptide.
• Suitable cell lines are known to those of skill in the art and are commercially available, for example, through the American Type Culture Collection (ATCC).
• ATCC American Type Culture Collection
• the transfected cells can be used in a method of producing an immunogenic polypeptide.
• the method comprises culturing a cell comprising the vector under conditions that allow expression of the immunogenic polypeptide, optionally under the control of an expression sequence.
• the immunogenic polypeptide can be isolated from the cell or the culture medium using standard protein purification methods.
• binding agents e.g., antibodies
• antibodies may be utilized to isolate PD-1 using, for example, immunoprecipitation or other capture-type assay.
• This well-known technique is performed by attaching the antibody to a solid support or chromatographic material (e.g., a bead coated with Protein A, Protein G and / or Protein L).
• the bound antibody is then introduced into a solution either containing or believed to contain the PD-1 (e.g., an HIV-infected T cell lysate).
• the binding agents may also be utilized to detect PD-1 within a biological sample.
• the antibodies may be used in assays such as, for example, flow cytometric analysis, ELISA, immunoblotting (e.g., western blot), in situ detection, immunocytochemistry, and / or immunhistochemistry. Methods of carrying out such assays are well-known in the art.
• the binding agents described herein may be also be used to determine the presence of a disease state in a patient, to predict prognosis, or to determine the effectiveness of a chemotherapeutic or other treatment regimen.
• Expression profile assays performed as described herein or as is otherwise known in the art, may be used to determine the relative level of expression of PD-1 . The level of expression may then be correlated with base (e.g., control) levels to determine whether a particular disease is present within the patient, the patient's prognosis, or whether a particular treatment regimen is effective.
• an increased or decreased level of expression of PD-1 in the patient's tissues may indicate the regimen is worsening or improving the load of the infectious agent in that host.
• the increase or decrease in expression may indicate the regimen is having or not having the desired effect and another therapeutic modality may therefore be selected.
• the binding agents described herein may be used to ascertain the effect of a drug candidate on the expression of the immunogenic target in a cell line, or a cell or tissue of a patient.
• the expression profiling technique may be combined with high throughput screening techniques to allow rapid identification of useful compounds and monitor the effectiveness of treatment with a drug candidate (see, for example, Zlokarnik, et al., Science 279, 84-8 (1998)).
• Drug candidates may be chemical compounds, nucleic acids, proteins, antibodies, or derivatives therefrom, whether naturally occurring or synthetically derived. Drug candidates thus identified may be utilized, among other uses, as pharmaceutical compositions for administration to patients or for use in further screening assays.
• the binding agents are in purified form.
• a "purified” binding agent e.g., antibody
• a purified binding agent may be one that is separated from at least about 50% of the proteins and / or other components with which it is initially found (e.g., as part of a hybridoma supernatant or ascites preparation in the case of a monoclonal antibody).
• a purified binding agent e.g., antibody
• polypeptides and nucleic acids described herein may be combined with one or more pharmaceutically acceptable carriers prior to administration to a host.
• a pharmaceutically acceptable carrier is a material that is not biologically or otherwise undesirable, e.g., the material may be administered to a subject, without causing any undesirable biological effects or interacting in a deleterious manner with any of the other components of the pharmaceutical composition in which it is contained.
• the carrier would naturally be selected to minimize any degradation of the active ingredient and to minimize any adverse side effects in the subject, as would be well known to one of skill in the art. Suitable pharmaceutical carriers and their formulations are described in, for example, Remington's: The Science and Practice of Pharmacy, 21 st Edition, David B.
• a pharmaceutically-acceptable salt is used in the formulation to render the formulation isotonic.
• the pharmaceutically-acceptable carriers include, but are not limited to, sterile water, saline, buffered solutions like Ringer's solution, and dextrose solution. The pH of the solution is generally from about 5 to about 8 or from about 7 to about 7.5.
• Other carriers include sustained-release preparations such as semipermeable matrices of solid hydrophobic polymers containing polypeptides or fragments thereof. Matrices may be in the form of shaped articles, e.g., films, liposomes or microparticles.
• Carriers are those suitable for administration of polypeptides and / or fragments thereof to humans or other subjects.
• Pharmaceutical compositions may also include carriers, thickeners, diluents, buffers, preservatives, surface active agents, adjuvants, immunostimulants, in addition to the immunogenic polypeptide.
• Pharmaceutical compositions may also include one or more active ingredients such as antimicrobial agents, antiinflammatory agents and anesthetics.
• the pharmaceutical composition may be administered orally, parentally, by inhalation spray, rectally, intranodally, or topically in dosage unit formulations containing conventional pharmaceutically acceptable carriers, adjuvants, and vehicles.
• pharmaceutically acceptable carrier or “physiologically acceptable carrier” as used herein refers to one or more formulation materials suitable for accomplishing or enhancing the delivery of a nucleic acid, polypeptide, or peptide as a pharmaceutical composition.
• a “pharmaceutical composition” is a composition comprising a therapeutically effective amount of a nucleic acid or polypeptide.
• effective amount and “therapeutically effective amount” each refer to the amount of a binding agent, nucleic acid or the like used to observe the desired therapeutic effect (e.g., restore T cell function).
• Methods for treating one or more disease conditions comprising administering to the mammal at least one or more effective doses of one or more binding agents (and / or derivative(s) thereof) described herein are also provided.
• the binding agent is a monoclonal antibody or fragment or derivative thereof comprising one or more of SEQ ID NOS. 1 -138 and / or shown in Tables 1A and 1 B.
• the one or more binding agents may be administered in a dosage amount of about 1 to about 50 mg / kg, about 1 to about 30 mg / kg, or about 5 to about 30 mg / kg (e.g., about any of 1 , 2, 3, 4, 5, 6, 7, 8, 9, 10, 1 1 , 12, 13, 14, 15, 16, 17, 18, 19, 20, 21 , 22, 23, 24, 25, 26, 27, 28, 29, 30, 35, or 40 mg / kg).
• the one or more binding agents may be administered to the mammal (e.g., intradermally, intravenously, orally, rectally) at about 10 mg / kg one or more times. When multiple doses are administered, the doses may comprise about the same or different amount of binding agent in each dose.
• the doses may also be separated in time from one another by the same or different intervals.
• the doses may be separated by about any of 6, 12, 24, 36, 48, 60, 72, 84, or 96 hours, one week, two weeks, three weeks, one month, two months, three months, four months, five months, six months, seven months, eight months, nine months, 10 months, 1 1 months, 12 months, 1 .5 years, 2 years, 3 years, 4 years, 5 years, or any time period before, after, and / or between any of these time periods.
• the binding agents may be administered in conjunction with other agents (e.g., anti-infective agents and/or chemotherapeutic agent). Such other agents may be administered about simultaneously with the binding agents, or at a different time and / or frequency. Other embodiments of such methods may also be appropriate as could be readily determined by one of ordinary skill in the art.
• kit format A kit including such antibodies and optionally other components necessary for using the antibodies to detect cells expressing PD-1 is provided.
• the antibodies of the kit may be provided in any suitable form, including frozen, lyophilized, or in a pharmaceutically acceptable buffer such as TBS or PBS.
• the kit may also include other reagents required for utilization of the antibodies in vitro or in vivo such as buffers (e.g., TBS, PBS), blocking agents (solutions including nonfat dry milk, normal sera, Tween-20 Detergent, BSA, or casein), and / or detection reagents (e.g., goat anti-mouse IgG biotin, streptavidin- HRP conjugates, allophycocyanin, B-phycoerythrin, R-phycoerythrin, peroxidase, detectable labels, and other labels and / or staining kits (e.g., ABC Staining Kit, Pierce)).
• buffers e.g., TBS, PBS
• blocking agents solutions including nonfat dry milk, normal sera, Tween-20 Detergent, BSA, or casein
• detection reagents e.g., goat anti-mouse IgG biotin, streptavidin- HRP conjugates, allophycocyan
• kits may also include other reagents and / or instructions for using the antibodies in commonly utilized assays described above such as, for example, flow cytometric analysis, ELISA, immunoblotting (e.g., western blot), in situ detection, immunocytochemistry, immunhistochemistry.
• the kit provides a binding agent in purified form.
• the binding agent may be provided in biotinylated form either alone or along with an avidin-conjugated detection reagent (e.g., antibody).
• the kit includes a binding agents comprising one or more detectable labels that may be used to directly detect PD-1 .
• kits and the like required for using any of these systems are well- known in the art and / or may be prepared by the end-user or provided as a component of the kit.
• the kit may also include a solid support containing positive- and negative-control protein and / or tissue samples.
• kits for performing spotting or western blot-type assays may include control cell or tissue lysates for use in SDS-PAGE or nylon or other membranes containing pre-fixed control samples with additional space for experimental samples.
• Kits for visualization of PD-1 in cells on slides may include pre-formatted slides containing control cell or tissue samples with additional space for experimental samples.
• Other embodiments of kits are also contemplated herein as would be understood by those of ordinary skill in the art.
• this disclosure provides a binding agent that binds PD-1 agonistically or antagonistically.
• the binding agent is a polypeptide comprising at least one amino acid sequence selected from the group consisting of SEQ ID NOS. 1 -138 and / or shown in Tables 1A and 1 B.
• the binding agent is a polypeptide comprising one or more combinations of SEQ ID NOS. 1 -138 (e.g., as shown in Tables 1A and/or 1 B).
• the binding agent is an antibody.
• the binding agent is a polypeptide such as an antibody comprising a heavy chain CDR1 amino acid sequence selected from the group consisting of SEQ ID NOS. 1-23.
• the binding agent is a polypeptide such as an antibody comprising a heavy chain CDR2 amino acid sequence selected from the group consisting of SEQ ID NOS. 24-46. In some embodiments, the binding agent is a polypeptide such as an antibody comprising a heavy chain CDR3 amino acid sequence selected from the group consisting of 47-69. In some embodiments, the binding agent is a polypeptide such as an antibody comprising a light chain CDR1 amino acid sequence selected from the group consisting of SEQ ID NOS. 70-92. In some embodiments, the binding agent is a polypeptide such as an antibody comprising a heavy chain CDR2 amino acid sequence selected from the group consisting of SEQ ID NOS. 93-1 15.
• the binding agent is a polypeptide such as an antibody comprising a heavy chain CDR3 amino acid sequence selected from the group consisting of 1 16-138.
• the binding agent comprises the combinations of CDRs shown in Tables 1A and / or 1 B and/or has the properties described in Table 2.
• the binding agent is derived from or related to (e.g., by sequence or derivation) a human antibody, human IgG, human lgG1 , human lgG2, human lgG2a, human lgG2b, human lgG3, human lgG4, human IgM, human IgA, human lgA1 , human lgA2, human IgD, human IgE, canine antibody, canine IgGA, canine IgGB, canine IgGC, canine IgGD, chicken antibody, chicken IgA, chicken IgD, chicken IgE, chicken IgG, chicken IgM, chicken IgY, goat antibody, goat IgG, mouse antibody, mouse IgG, pig antibody, and / or rat antibody, and / or a derivative thereof.
• a human antibody human IgG, human lgG1 , human lgG2, human lgG2a, human lgG2b, human lgG3,
• the derivative may be selected from the group consisting of an F ab , F ab2 , Fab' single chain antibody, F v , single chain, mono-specific antibody, bispecific antibody, trimeric antibody, multi-specific antibody, multivalent antibody, chimeric antibody, canine-human chimeric antibody, canine-mouse chimeric antibody, antibody comprising a canine Fc, humanized antibody, human antibody, caninized antibody, CDR- grafted antibody, shark antibody, nanobody, and / or canelid antibody.
• the binding agent comprises at least a least a first and second specificity, the first being against PD-1 and the second being against a different antigen (e.g., an antigen of an infectious agent such as HIV (e.g., env) and / or a tumor antigen).
• a different antigen e.g., an antigen of an infectious agent such as HIV (e.g., env) and / or a tumor antigen.
• the binding agent and / or derivative thereof may comprise a detectable label fixably attached thereto.
• the binding agent of any one and / or derivative thereof comprises an effector moiety (e.g., a cytotoxic drug, toxin, diphtheria A chain, exotoxin A chain, ricin A chain, abrin A chain, curcin, crotin, phenomycin, enomycin, and radiochemical) fixably attached thereto.
• an effector moiety e.g., a cytotoxic drug, toxin, diphtheria A chain, exotoxin A chain, ricin A chain, abrin A chain, curcin, crotin, phenomycin, enomycin, and radiochemical fixably attached thereto.
• polynucleotides encoding one or more binding agents are also provided (e.g.. as an expression vector). Host cells comprising and / or expressing the polypeptide products of such polynucleotides are also provided.
• compositions comprising at least one binding agent or derivative; at least one isolated polynucleotide; at least one expression vector; and / or, at least one host cell; or a combination thereof; and, a pharmaceutically acceptable carrier are also provided.
• This disclosure also provides methods for detecting PD-1 on a cell, the method comprising contacting a test biological sample with a binding agent or derivative described herein and detecting the binding agent bound to the biological sample or components thereof.
• Such methods may be an in vivo method or an in vitro method.
• the method may comprise comparing the amount of binding to the test biological sample or components thereof to the amount of binding to a control biological sample or components thereof, wherein increased binding to the test biological sample or components thereof relative to the control biological sample or components thereof indicates the presence of a cell expressing PD-1 in the test biological sample (e.g., mammalian blood).
• a system for identifying a PD-1 antibody binding agent by assaying the candidate binding agent by the exhaustion functional recovery assay (EFRA); determining the affinity of the candidate binding agent for PD-1 ; and, determining the nucleotide sequence of the CDR of the candidate binding agent is provided.
• kits for detecting the expression of PD-1 in or on a cell comprising a binding agent or derivative thereof and instructions for use.
• the binding agent and / or derivative thereof is in lyophilized form.
• this disclosure provides methods for treating, preventing and / or ameliorating an infectious disease, cancer and / or autoimmunity in a mammal comprising administering to the mammal at least one effective dose of a pharmaceutical composition comprising a binding agent or derivative thereof.
• the infectious disease is human immunodeficiency virus (HIV).
• the binding agent and / or derivative thereof used to treat infectious disease and / or cancer is a PD-1 antagonist.
• the binding agent and / or derivative thereof used to treat an autoimmune condition is a PD-1 agonist.
• multiple doses are administered to the animal.
• the binding agent and / or derivative thereof may be administered in a dosage amount of about 1 to 50 mg / kg.
• this disclosure also provides combinations of PD-1 binding agents.
• the combination comprises a first binding agent that blocks the interaction of PD-1 and PD-L1 and a second binding agent that does not block the interaction of PD-1 and PD-L1 .
• Such combinations may be used for any use described herein or as may be otherwise ascertained by those of ordinary skill in the art. For instance, such combinations may be used in the methods for treating, preventing and / or ameliorating an infectious disease, cancer and / or autoimmunity in a mammal described herein.
• This disclosure also provides methods for producing the binding agents described herein by expressing the binding agent in a cell and isolating the binding agent from the cell or a culture supernatant of the cell. In some embodiments, such methods may further comprise expressing a nucleic acid encoding such binding agent(s). In some embodiments, such methods may also include combining the binding agent(s) following isolation with one or more pharmaceutically acceptable excipients.
• Methods for producing a combination(s) of binding agents are also provided by this disclosure.
• the second binding agent binds PD-1 .
• the first and / or second binding agents are antibodies such monoclonal antibodies or fragments or derivatives thereof.
• the second binding agent comprises the amino acid sequences SEQ ID NOS. 2, 25, 48, 71 , 94 and 1 17; or SEQ ID NOS. 17, 40, 63, 86, 109, and 132. In some embodiments, these methods may further include the addition of a pharmaceutically acceptable excipient.
• a subject or a host is meant to be an individual.
• the subject can include domesticated animals, such as cats and dogs, livestock (e.g., cattle, horses, pigs, sheep, and goats), laboratory animals (e.g., mice, rabbits, rats, guinea pigs) and birds.
• livestock e.g., cattle, horses, pigs, sheep, and goats
• laboratory animals e.g., mice, rabbits, rats, guinea pigs
• the subject is a mammal such as a primate or a human.
• Optional or optionally means that the subsequently described event or circumstance can or cannot occur, and that the description includes instances where the event or circumstance occurs and instances where it does not.
• the phrase optionally the composition can comprise a combination means that the composition may comprise a combination of different molecules or may not include a combination such that the description includes both the combination and the absence of the combination (i.e., individual members of the combination).
• Ranges may be expressed herein as from about one particular value, and/or to about another particular value. When such a range is expressed, another aspect includes from the one particular value and/or to the other particular value. Similarly, when values are expressed as approximations, by use of the antecedent about or approximately, it will be understood that the particular value forms another aspect. It will be further understood that the endpoints of each of the ranges are significant both in relation to the other endpoint, and independently of the other endpoint. Ranges (e.g., 90-100%) are meant to include the range per se as well as each independent value within the range as if each value was individually listed.
• combined or “in combination” or “in conjunction” may refer to a physical combination of agents that are administered together or the use of two or more agents in a regimen (e.g., administered separately, physically and / or in time) for treating, preventing and / or ameliorating a particular disease.
• treat, prevent, and / or ameliorate or derivatives thereof are used herein in connection with a given treatment for a given condition (e.g., preventing cancer infection by HIV), it is meant to convey that the treated patient either does not develop a clinically observable level of the condition at all, or develops it more slowly and/or to a lesser degree than he/she would have absent the treatment.
• a given treatment for a given condition e.g., preventing cancer infection by HIV
• a treatment will be said to have prevented the condition if it is given during exposure of a patient to a stimulus that would have been expected to produce a given manifestation of the condition, and results in the patient's experiencing fewer and/or milder symptoms of the condition than otherwise expected.
• a treatment can "prevent" infection by resulting in the patient's displaying only mild overt symptoms of the infection; it does not imply that there must have been no penetration of any cell by the infecting microorganism.
• reduce, reducing, and reduction as used herein in connection with prevention, treatment and / or amelioration of a given condition by a particular treatment typically refers to a subject developing an infection more slowly or to a lesser degree as compared to a control or basal level of developing an infection in the absence of a treatment (e.g., administration of one or more PD-1 binding agents).
• a reduction in the risk of infection may result in the patient's displaying only mild overt symptoms of the infection or delayed symptoms of infection; it does not imply that there must have been no penetration of any cell by the infecting microorganism.
• mice strains (total of 16 mice) have been immunized with two PD-1 proteins, i.e. human PD-1 Fc fusion protein and a human PD-1 monomeric protein.
• Mice showing serum reactivity to PD-1 expressed on activated human T lymphocytes have been selected for generation of anti-PD-1 hybridoma cell lines.
• a total of 240 PD-1 hybridoma cell lines were selected for producing antibodies that bind to recombinant PD-1 protein.
• the primary criteria for the first round of antibodies selection were: i) staining of PD-1 on activated human T lymphocytes by flow cytometry; ii) diversity of CDR VH and VL sequences as compared to those of the existing anti-PD-1 antibodies; and, iii) epitope mapping performed by competitive binding studies with PD-1 conjugated Luminex beads with two commercially available anti- PD-1 antibodies binding to different epitopes on PD-1 .
• a second round of selection was then carried out by: iv) affinity binding assays (not a primary criteria as it does not correlate with the stimulatory potential of anti-PD-1 antibodies); v) evaluation of anti-PD-1 antibodies that bind PD-1 and are either competitive, partially competitive or non-competitive with the binding of PD-L1 in a Luminex biochemical assay; and, vi) functional characterization of antibodies as agonist (not able to restore T-cells from functional exhaustion) or antagonist (able to restore T-cells from functional exhaustion). In these studies, the antibodies were tested and differentiated based on their ability to rescue proliferation in HIV-specific exhausted CD8 T- cells.
• the EFRA assay was carried out to evaluate the functional effect of anti-PD1 antibodies on the proliferation of HIV-specific CD8 T cells ( Figure 2).
• Antibody clones in the upper box (E8-3, C2-3, E1-3, F3-3, H8-3, C10-2, G2-1 , G3-2, H2-1 , and H4-2) act as PD-1 antagonists and stimulate proliferation while antibody clones in the lower box (C8-1 and G10- 2) are agonistic and promote the PD-1 negative regulatory effect.
• the level of proliferation induced by the peptide control (Pep 8) is indicated by the lower horizontal line (just below 1 %) and the induced proliferation by the Merck MK-3475 anti-PD1 antibody is shown in the upper horizontal line (just above 2%).
• Antibodies of interest identified by these processes underwent a second round of subcloning and the resulting hybridoma clones were used for the production and purification of the antibodies in Table 2. Binding assays were carried out with the purified anti-PD-1 antibodies to ensure that the subclones retained their affinity for PD-1.
• the concentration response binding of anti-PD-1 antibodies to cell surface PD-1 was evaluated on activated CD4 T-cells ( Figure 3).
• the EFRA provides for the selection of binding agents that restore T-cells from functional exhaustion but are not necessarily antagonistic, meaning those binding agents that do not necessarily interfere with the interaction between PD-1 and its biological ligand(s) (e.g., PD-L1 or PD-L2 ).
• An embodiment of the EFRA was to identify such binding agents (antibodies) that bind PD-1 .
• Epitope mapping of antibody binding to PD-1 was performed with two seperate biochemical assays. In one assay, competitive binding to PD-1 Fc fusion protein labeled beads was evaluated between one of two commercial anti-PD-1 antibodies (BMS-5C4 and MK3475) and the anti-PD-1 antibodies listed (also described in Table 2).
• class 1 competitive with the EH 12.2H7 commercial monoclonal antibody clone that blocks the interaction of PD-1 with PD-L1
• class 2 competitive with the J 1 16 commercial monoclonal antibody clone that binds PD-1 but does not effectively block the interaction of PD-1 with PD-L1
• class 3 competitive with both the EH12.2H7 and J1 16 commercial monoclonal antibodies
• class 4 non-competitive with either the EH12.2H7 or J1 16 commercial antibodies.
• the relative binding of these antibodies for cell surface PD- 1 is represented by the mean fluorescence intensity (MFI) relative to a control anti-PD-1 antibody in Figure 4. These results show that tight binding antibodies were identified from all four binding classes.
• a second Luminex binding assay was used to directly evaluate if an anti-PD-1 antibody blocks the interaction between PD-1 and PD-L1 . This assay was carried out using PD-1 Fc fusion protein coated beads that were incubated in the absence or presence of different concentrations of the anti-PD-1 antibodies listed in Table 2.
• the combination of a first binding agent that blocks the interaction of PD-1 and PD-L1 with a second binding agent that does not block the interaction of PD-1 and PD-L1 has been determined to act synergistically to rescue T cells from exhaustion.

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