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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
  • C07K16/2827—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 B7 molecules, e.g. CD80, CD86
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
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  • A61P35/00—Antineoplastic agents
• • C—CHEMISTRY; METALLURGY
  • C07—ORGANIC CHEMISTRY
  • C07K—PEPTIDES
  • 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
• • 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
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  • C07K2317/00—Immunoglobulins specific features
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  • C07K2317/31—Immunoglobulins specific features characterized by aspects of specificity or valency multispecific
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  • C07K—PEPTIDES
  • C07K2317/00—Immunoglobulins specific features
  • C07K2317/50—Immunoglobulins specific features characterized by immunoglobulin fragments
  • C07K2317/52—Constant or Fc region; Isotype
  • C07K2317/526—CH3 domain
• • C—CHEMISTRY; METALLURGY
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  • 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]
• • C—CHEMISTRY; METALLURGY
  • C07—ORGANIC CHEMISTRY
  • C07K—PEPTIDES
  • C07K2317/00—Immunoglobulins specific features
  • C07K2317/60—Immunoglobulins specific features characterized by non-natural combinations of immunoglobulin fragments
  • C07K2317/62—Immunoglobulins specific features characterized by non-natural combinations of immunoglobulin fragments comprising only variable region components
  • C07K2317/622—Single chain antibody (scFv)
• • 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
  • C07K2317/71—Decreased effector function due to an Fc-modification
• • 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
  • C07K2317/72—Increased effector function due to an Fc-modification
• • 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
• • 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
  • C07K2317/94—Stability, e.g. half-life, pH, temperature or enzyme-resistance
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
  • Y02A—TECHNOLOGIES FOR ADAPTATION TO CLIMATE CHANGE
  • Y02A50/00—TECHNOLOGIES FOR ADAPTATION TO CLIMATE CHANGE in human health protection, e.g. against extreme weather
  • Y02A50/30—Against vector-borne diseases, e.g. mosquito-borne, fly-borne, tick-borne or waterborne diseases whose impact is exacerbated by climate change

Definitions

• the invention relates to antibodies and antigen-binding fragments thereof that bind to programmed-death ligand 1 (PD-L1 ).
• the antibodies or antigen-binding fragments thereof comprise a CDR-based antigen-binding site for PD-L1.
• Antibodies or antigen-binding fragments thereof of the invention may find application, for example, in cancer therapy.
• PD-1 Programmed cell death 1
• PD-L1 CD274, B7-H1
• PD-L2 B7-DC
• PD-L1 is transiently expressed on all immune cells and some tumour cells.
• PD-L1 is a type I transmembrane protein with two Ig-like domains within the extracellular region, a transmembrane domain and a short cytoplasmic domain.
• the complete human PD-L1 (hPD- L1 ) sequence can be found under GENBANK ® Accession No. Q9NZQ7.
• the cytoplasmic domain has no known signal transduction motif suggesting that there is no signalling by PD-L1 on interaction of the ligand with its receptor.
• the molecular weight of PD-L1 is 40 kDa (290 amino acids), it is encoded by the CD274 gene on human chromosome 9 and on mouse chromosome 19.
• PD-L1 is a member of the B7 protein family and shares approximately 20 % amino acid sequence identity with B7.1 and B7.2. Human PD-L1 shares 70 % and 93 % amino acid identity with the murine and cynomolgus orthologs of PD-L1 , respectively.
• Human PD-L1 binds to its receptor, PD-1 , with an affinity (KD) of 770 nM.
• PD-1 is expressed on activated T cells, B cells, and myeloid cells; it modulates activation or inhibition of cellular immune responses. Binding of PD-L1 to PD-1 delivers an inhibitory signal, reducing cytokine production and suppressing proliferation of T cells. Consequently, PD-L1 expression by cells can mediate protection against cytotoxic T lymphocyte (CTL) killing and is a regulatory mechanism that dampens chronic immune responses during viral infections.
• CTL cytotoxic T lymphocyte
• IFNy In the context of an active immune response, IFNy also upregulates the expression of PD-L1.
• PD-L1 also mediates immune suppression through interaction with another protein, B7.1 (also known as CD80), blocking its ability to deliver one of the secondary signals of activation on T cells through CD28.
• B7.1 also known as CD80
• PD-L1 expression has been shown in a wide variety of solid tumours. Of 654 samples examined in one study, spanning 19 tumours from different sites, 89 (14%) were PD-L1 positive (>5% frequency). The highest PD-L1 positive frequencies were seen in head and neck (17/54; 31 %), cervical (10/34; 29%), cancer of unknown primary origin (CUP; 8/29; 28%), glioblastoma multiforme (GBM; 5/20; 25%), bladder (8/37; 21 %), oesophageal (16/80; 20%), triple negative (TN) breast (6/33; 18%), and hepatocarcinoma (6/41 ; 15%) (Grosso et al., 2013). Tumour- associated expression of PD-L1 has been shown to confer immune resistance and potentially protect tumour cells from T cell mediated apoptosis.
• Atezolizumab (MPDL3280A, RG7466, TECENTRIGTM) is a humanized lgG1 antibody which binds to PD-L1. It is in clinical trials as a monotherapy and also in combination with other biologic and/or small molecule therapies for treatment of solid cancers, including colorectal cancer, breast cancer, non-small-cell lung carcinoma, bladder cancer, and renal cell carcinoma. Treatment with atezolizumab resulted in objective response rates (ORR) of 23% in NSCLC, 36% melanoma, 33% bladder, 14% in RCC, and 13% in head and neck cancers (Herbst et al., 2014; Powles et al., 2014).
• ORR objective response rates
• Avelumab (MSB0010718C, BAVENCIOTM) is a fully human lgG1 antibody which binds to PD-L1 and is undergoing clinical testing in a number of cancers including bladder cancer, gastric cancer, head and neck cancer, mesothelioma, non-small-cell lung carcinoma, ovarian cancer, renal cancer and Merkel-cell carcinoma.
• Avelumab received orphan drug designation by the European Medicines Agency (EMA) for the treatment of gastric cancer in January 2017. In 2017 the FDA and the EMA approved avelumab for Merkel-cell carcinoma (an aggressive skin cancer) in adults and pediatric patients 12 years and older. Approval was based on data from an open-label, single arm, multi-center clinical trial (JAVELIN Merkel 200 trial).
• the most common serious adverse reactions to avelumab were immune-mediated adverse reactions (pneumonitis, hepatitis, colitis, adrenal insufficiency, hypo- and hyperthyroidism, diabetes mellitus, and nephritis) and life-threatening infusion reactions.
• immune-mediated adverse reactions pneumonitis, hepatitis, colitis, adrenal insufficiency, hypo- and hyperthyroidism, diabetes mellitus, and nephritis
• life-threatening infusion reactions Among the 88 patients enrolled in the JAVELIN Merkel 200 trial, the most common adverse reactions were fatigue, musculoskeletal pain, diarrhea, nausea, infusion-related reaction, rash, decreased appetite, and peripheral edema. Serious adverse reactions that occurred in more than one patient in the trial were acute kidney injury, anemia, abdominal pain, ileus, asthenia, and cellulitis.
• Durvalumab (MEDI4736, IMFINZITM) is a human lgG1 antibody which binds to PD-L1 and is being tested in clinical trials alone or in combination with tremelimumab in non-small-cell lung cancer, squamous cell carcinoma of the head and neck, bladder cancer, pancreatic cancer and with other biologic and small molecules in trials for additional solid cancers such as gastric cancers, melanoma and unresectable hepatocellular carcinoma.
• Durvalumab was approved by the FDA for the treatment of patients with locally advanced or metastatic urothelial carcinoma who either have disease progression during or following platinum- containing chemotherapy or have disease progression within 12 months of neoadjuvant or adjuvant treatment with platinum-containing chemotherapy.
• a phase 1 B clinical trial of durvalumab and tremelimumab showed some activity in non-small cell lung cancer (NSCLC).
• NSCLC non-small cell lung cancer
• AstraZeneca announced that a phase III trial of durvalumab with tremelimumab as a first-line treatment of non-small cell lung cancer had failed to meet its primary endpoint of progression-free survival.
• phase I trial combining durvalumab and gefitinib in lung cancer patients were reported to have "showed promise”.
• a phase 1 clinical trial is in progress using durvalumab with a TLR 7/8 agonist (MEDI 9197) for solid tumors.
• a Phase 1 b/2a trial is in progress combining durvalumab with an HPV DNA vaccine (MEDI 0457) in patients with HPV-associated recurrent/metastatic head and neck cancer.
• Durvalumab increased the median progression-free survival from 5.6 months (placebo) to 16.8 months (durvalumab); the 12 month progression-free survival rate was increased from 35.3% (placebo) to 55.9% (durvalumab), and the 18 month progression-free survival rate was increased from 27.0% (placebo) to 44.2% (durvalumab).
• the median time to death or distant metastases increased from 14.6 months (placebo) to 23.2 months (durvalumab). However, extreme side effects were also increased from 26.1 % of patients (placebo) to 29.9% of patients (durvalumab).
• Adverse effects were reported following exposure to durvalumab in 182 patients with locally advanced or metastatic urothelial carcinoma whose disease has progressed during or after one standard platinum-based regimen. Patients received 10 mg/kg durvalumab via intravenous infusion every 2 weeks. The median duration of exposure was 10.2 weeks (range: 0.14, 52.4). Thirty-one percent (31 %) of patients had a drug delay or interruption for an adverse reaction. The most common (> 2%) were liver injury (4.9%), urinary tract infection (3.3%), acute kidney injury (3.3%), and musculoskeletal pain (2.7%).
• anti-PD-L1 antibodies including BMS-936559 have been tested in clinical trials, and others are in preclinical testing.
• WO2013181634 (Sorrento Therapeutics) describes PD-L1 antibodies. Only one antibody disclosed,“SH1 E2” (SEQ ID NO: 147/148 in that application), is said to exhibit improved T-cell activation, measured by the percentage of CD25 positive cells, when compared to PD-L1 antibodies 10A5 and YW234.55S70 disclosed in the art.
• PD-L1 Infectious diseases show many parallels with oncology. It is thought that the role of PD-L1 in immune regulation could be harnessed to maximize the immune response against pathogens. Immunomodulation in infectious disease is an emerging area of medicine and early reviews suggest that PD-L1 blockade may improve biological responses to infection, in particular, by helping to counteract T cell exhaustion, manage immune-mediated clearance and generate long term immunity (Wykes and Lewin, 2017). Thus, there also remains a need in the art for additional molecules which can target PD-L1 and which find application in the treatment of infectious diseases. Antibodies that target PD-L1 may also be useful to treat conditions associated with inflammation, such as vascular inflammation and stroke.
• anti-PD-L1 antibodies Whilst there are various anti-PD-L1 therapeutics in development, current data shows that overall treatment with existing anti-PD-L1 monotherapies results in a response in less than 50% of cancer patients. The spectrum and severity of reported adverse reactions differs between antibodies in clinical testing. To increase the objective response rate (ORR), and/or seek to reduce adverse effects, anti-PD-L1 antibodies may be combined with other biologies, such as antibodies against other checkpoint regulators, as well as with small molecule therapies and other immune system activating approaches, such as tumour vaccines.
• ORR objective response rate
• the present inventors have prepared anti-PD-L1 antibodies by screening a phage library, followed by mutagenesis, screening, selection, and light chain shuffling to isolate anti-PD-L1 antibodies with affinity for PD-L1 and activity in a T cell activation assay.
• the above approach enabled identification of anti-PD-L1 antibodies which showed excellent binding to PD-L1 and activity in T cell activation assays. Based on these characteristics, it is expected that the antibodies of the invention will find application in the treatment of human cancers, as well as infectious and inflammatory diseases, through inhibition of PD-L1.
• Antibodies of the invention were also shown to have a high affinity for cynomolgus PD-L1 , comparable to their affinity for human PD-L1. Antibodies of the invention also showed measurable affinity for mouse PD-L1.
• antibodies to PD-L1 were identified that had a relatively high melting temperature, which can be expected to have enhanced stability, beneficial in the manufacture and storage of the antibodies.
• the invention provides:
• An antibody or antigen-binding fragment thereof capable of binding specifically to PD-L1 , comprising a variable heavy (VH) domain comprising heavy chain complementarity determining regions (CDRs): HCDR1 , HCRD2 and HCDR3, characterised in that the amino acid sequence of HCDR1 (amino acids 31 to 35) is SYGIS (SEQ ID NO: 1 ); the amino acid sequence of HCDR2 is WISAYX1X2X3X4NYAQKLQG (SEQ ID NO: 2); and the amino acid sequence of HCDR3 is DLFPTIFGVSYYYY (SEQ ID NO: 3); wherein X1 is S or N or G; X 2 is G or S; X 3 is or G, N or S; and X 4 is T or A, and wherein the sequences are defined by Kabat nomenclature.
• HCDR1 amino acids 31 to 35
• amino acid sequence of HCDR2 amino acids 31 to 35
• amino acid sequence of HCDR2 is WISAYX1X2X3X4NYAQKLQG
• amino acid sequence of HCDR3 is DLFPTIFGVSYYYY (SEQ ID NO: 3); wherein X1 is S or N; X 2 is G or S; X3 is G or N; and X4 is T, and wherein the sequences are defined by Kabat nomenclature.
• sequence X1X2X3X4 (residues 54-57) of HCDR2 is selected from SGGT (SEQ ID NO: 5), NSNT (SEQ ID NO: 6), GGST (SEQ ID NO: 7) and SGNA (SEQ ID NO: 8).
• VL variable light
• the VL is a kappa VL and the amino acid sequence of LCDR1 is RASQSIX 5 X 6 RLA (SEQ ID NO: 9); the amino acid sequence of LCDR2 is EASXzXeEXg iSEQ ID NO: 10); and the amino acid sequence of LCDR3 is QQX 10 X 11 X 12 X 13 PX 14 X 15 X 16 (SEQ ID NO: 1 1 ); wherein X 5 is G or S; Xe is N or G; X 7 is T or N; X 8 is S or L; X 9 is T or S; X 10 is S or A; Xu is Y or N; X 12 is S or T; X 13 is T, W or F; X 14 is absent or R; X 15 is Y, R or V; and Xi 6 is T or S; or,
• the VL is a lambda VL and the amino acid sequence of LCDR1 is TGTSSDVGGYNX17VS (SEQ ID NO: 12); the amino acid sequence of LCDR2 is EVTNRPS (SEQ ID NO: 13); and the amino acid sequence of LCDR3 is SSFKRGSTLW (SEQ ID NO: 14); wherein X 17 is Y or S; and wherein the sequences are defined by Kabat nomenclature.
• VL domain is a kappa VL and the amino acid sequence of LCDR1 is RASQSIGNRLA (SEQ ID NO: 15), the amino acid sequence of LCDR2 is EASTSET (SEQ ID NO: 16), and the amino acid sequence of LCDR3 is QQSYSTPYT (SEQ ID NO: 17).
• an antibody or antigen-binding fragment thereof comprising an antigen-binding site comprising the CDRs (HCDR1 , HCRD2, HCDR3, LCDR1 , LCDR2 and LCDR3, respectively) of antibody: (a) G1AA/E12v2 of SEQ ID NO: 1 , 18, 3, 15, 16 and 17;
• G G1/280_02_G02 of SEQ ID NO: 45 and 46, respectively; wherein the sequences are defined according to the Kabat nomenclature.
• the antibody molecule comprises the heavy chain and / or light chain of antibody: (a) G1AA/E12v2 of SEQ ID NO: 47 and 48, respectively;
• An antibody or antigen-binding fragment thereof comprising the HCDRs (HCDR1 , HCDR2 and HCDR3) and / or LCDRs (LCDR1 , LCDR2 and LCDR3); VH and / or VL; Fab; light chain and / or heavy chain of antibody G1AA/E12v2, G1AA/G12v2 or G1AA/E05v2. 12.
• the antibody or antigen-binding fragment thereof comprising the HCDRs (HCDR1 , HCDR2 and HCDR3) and / or LCDRs (LCDR1 , LCDR2 and LCDR3); VH and / or VL; Fab; light chain and / or heavy chain of antibody G1AA/E12v2 or G1/E12v2.
• VH has at least 95, 96, 97, 98 or 99 % identity to the VH of an antibody selected from G1AA/E12v2 of SEQ ID NO: 27, G1AA/G12v2 of SEQ ID NO: 29, G1AA/E05v2 of SEQ ID NO: 31 , G1/887_04_E12 of SEQ ID NO: 33, G1/887_04_G12 of SEQ ID NO: 35, G1/894_08_E05 of SEQ ID NO: 37, G 1 /894_08_A05 of SEQ ID NO: 39 G1AA/lambdav3 of SEQ ID NO: 41 , G1/280_02_G02_NS of SEQ ID NO: 43 and G1/280_02_G02 of SEQ ID NO: 45.
• An antibody or antigen-binding fragment thereof according to any preceding clause, wherein the antibody molecule, or antigen-binding fragment, binds to human PD-L1.
• an antibody or antigen-binding fragment thereof wherein the antibody or antigen-binding fragment has an affinity (KD) for recombinant human PD-L1 and for recombinant cynomolgus PD-L1 of less than 2 nM, preferably less than 1 nM, more preferably less than 0.75 nM, yet more preferably less than 0.5 nM when measured by SPR (e.g., Biacore).
• KD affinity for recombinant human PD-L1 and for recombinant cynomolgus PD-L1 of less than 2 nM, preferably less than 1 nM, more preferably less than 0.75 nM, yet more preferably less than 0.5 nM when measured by SPR (e.g., Biacore).
• An antibody or antigen-binding fragment thereof according to any preceding clause, wherein the antibody or antigen-binding fragment thereof enhances T-cell activation when assessed in a Mixed Lymphocyte Reaction (MLR) assay.
• MLR Mixed Lymphocyte Reaction
• an antibody or antigen-binding fragment thereof is a multispecific, preferably a bispecific, molecule comprising at least a second antigen-binding site.
• an antibody or antigen-binding fragment according to any preceding clause, wherein the antibody or antigen-binding fragment thereof, comprises a second antigen-binding site located in a constant domain of the antibody or antigen-binding fragment.
• the second antigen-binding site comprises:
• An antibody or antigen-binding fragment thereof according to any preceding clause, wherein the antibody is an immunoglobulin G (IgG), or antigen-binding fragment thereof.
• the second antigen-binding site may bind to an inhibitory checkpoint molecule, such as CTLA-4, LAG-3, TIGIT, TIM-3, VISTA, CD73, CSF-1 R, KIR. B7-H3, B7-H4, 2B4, NKG2A, CD47, SIRPa, BTLA, CCR4, CD200R, or TGFbeta.
• an inhibitory checkpoint molecule such as CTLA-4, LAG-3, TIGIT, TIM-3, VISTA, CD73, CSF-1 R, KIR.
• the second antigen-binding site may bind to and be an agonist for a costimulatory molecule expressed by T cells such as 0X40, ICOS, CD40, HVEM, NKG2D, or TNFR2.
• the second antigen-binding site may bind to a tumour-associated antigen (TAA), such as c-Met, B7-H3, B7- H4, EGFR, HER-2, EPCAM, CEACAM, FAP, VEGF, MSLN, GPC3, CD38, CD19, or CD20.
• TAA tumour-associated antigen
• a conjugate or fusion comprising an antibody or antigen-binding fragment thereof according to any preceding clause and an immune system modulator (agonist or antagonist), a cytotoxic molecule, or a radioisotope.
• nucleic acid molecule or set of nucleic acid molecules encoding an antibody, antigen binding fragment thereof, conjugate or fusion according to any preceding clause.
• 37 A nucleic acid molecule or set of nucleic acid molecules according to clause 36, wherein the nucleic acid molecule or set of nucleic acid molecules comprises cDNA sequence encoding one or more of the VH and / or VL, Fab, heavy and / or light chain of:
• the first nucleic acid sequence comprises a VH cDNA sequence encoding the VH of antibody G1AA/E12v2 of SEQ ID NO: 27 and the second nucleic acid sequence comprises a VL cDNA sequence encoding the VL of antibody G1 AA/E12v2 of SEQ ID NO: 28;
• the first nucleic acid sequence comprises a VH cDNA sequence encoding the VH of antibody G1AA/G12v2 of SEQ ID NO: 29 and the second nucleic acid sequence comprises a VL cDNA sequence encoding the VL of antibody G1 AA/G12v2 of SEQ ID NO: 30;
• the first nucleic acid sequence comprises a VH cDNA sequence encoding the VH of antibody G1AA/E05v2 of SEQ ID NO: 31 and the second nucleic acid sequence comprises a VL cDNA sequence encoding the VL of antibody G1 AA/E05v2 of SEQ ID NO: 32;
• the first nucleic acid sequence comprises a VH cDNA sequence encoding the VH of antibody G1/887_04_E12 of SEQ ID NO: 33 and the second nucleic acid sequence comprises the VL cDNA sequence of antibody G1/887_04_E12 of SEQ ID NO: 34;
• the first nucleic acid sequence comprises a VH cDNA sequence encoding the VH of antibody G1/887_04_G12 of SEQ ID NO: 35 and the second nucleic acid sequence comprises a VL cDNA sequence encoding the VL of antibody G1/887_04_G12 of SEQ ID NO: 36;
• the first nucleic acid sequence comprises a VH cDNA sequence encoding the VH of antibody G1/894_08_E05 of SEQ ID NO: 37 and the second nucleic acid sequence comprises a VL cDNA sequence encoding the VL of antibody G1/894_08_E05 of SEQ ID NO: 38;
• the first nucleic acid sequence comprises a VH cDNA sequence encoding the VH of antibody G1/894_08_A05 of SEQ ID NO: 39 and the second nucleic acid sequence comprises a VL cDNA sequence encoding the VL of antibody G1/894_08_A05 of SEQ ID NO: 40;
• the first nucleic acid sequence comprises a VH cDNA sequence encoding the VH of antibody
• G1 AA/lambdav3 of SEQ ID NO: 41 and the second nucleic acid sequence comprises a VL cDNA sequence encoding the VL of antibody G1AA/lambdav3 of SEQ ID NO: 42;
• the first nucleic acid sequence comprises a VH cDNA sequence encoding the VH of antibody G1/280_02_G02_NS of SEQ ID NO: 43 and the second nucleic acid sequence comprises a VL cDNA sequence encoding the VL of antibody G1/280_02_G02_NS of SEQ ID NO: 44; or
• the first nucleic acid sequence comprises a VH cDNA sequence encoding the VH of antibody G1/280_02_G02 of SEQ ID NO: 45 and the second nucleic acid sequence comprises a VL cDNA sequence encoding the VL of antibody G1/280_02_G02 of SEQ ID NO: 46.
• a vector or set of vectors comprising the nucleic acid molecule or set of nucleic acid molecules of any of clauses 36 to 38.
• a recombinant host cell comprising a nucleic acid molecule or set of nucleic acid molecules of any of clauses 36 to 38, or the vector or set of vectors of clause 39.
• a method of producing an antibody antigen-binding fragment thereof, conjugate or fusion according to any preceding clause comprising culturing the recombinant host cell of clause 40 under conditions suitable for production of the antibody, antigen-binding fragment, conjugate or fusion.
• clause 41 The method of clause 41 further comprising isolating and/or purifying the antibody, antigen binding fragment, conjugate or fusion.
• a composition e.g., pharmaceutical composition
• an excipient e.g., pharmaceutically-acceptable excipient
• a method for treatment of a disease or disorder in a patient comprising administering to the patient a therapeutically-effective amount of an antibody, antigen-binding fragment thereof, conjugate or fusion according to any of clauses 1 to 35 or composition according to clause 43.
• 46. The use of an antibody, antigen-binding fragment thereof, conjugate or fusion according to any of clauses 1 to 35 or composition according to clause 43 in the manufacture of a medicament for the treatment of the human or animal body.
• a method of detecting a disease or disorder in a patient comprising the use of an antibody, antigen-binding fragment thereof, conjugate or fusion according to any of clauses 1 to 35 or of a composition according to clause 43.
• cancer such as ovarian cancer, prostate cancer, colorectal cancer, fibrosarcoma, renal cell carcinoma, melanoma (advanced and metastatic melanoma), pancreatic cancer, breast cancer, glioblastoma multiforme, lung cancer (such as non-small cell lung cancer and small cell lung cancer), head and neck cancer (such as head and neck squamous cell carcinoma), stomach cancer (gastric cancer), bladder cancer, cervical cancer, uterine cancer (uterine endometrial cancer, uterine cervical cancer), vulvar cancer, testicular cancer, penile cancer, esophageal cancer, hepatocellular carcinoma, nasopharyngeal cancer, Merkel cell carcinoma, mesothelioma, DNA mismatch repair deficient colorectal cancer, DNA mismatch repair deficient endometrial cancer, thyroid cancer, Hodgkin’s lymph
• melanoma colorectal cancer
• breast cancer bladder cancer
• renal cell carcinoma gastric cancer
• head and neck cancer such as squamous cell carcinoma of the head and neck
• mesothelioma lung cancer (such as non-small-cell lung cancer)
• ovarian cancer Merkel-cell carcinoma, pancreatic cancer, melanoma and hepatocellular carcinoma using anti- PD-L1 antibodies
• the cancer to be treated using an antibody or antigen-binding fragment thereof of the invention may be a melanoma, colorectal cancer, breast cancer, bladder cancer, renal cell carcinoma, bladder cancer, gastric cancer, head and neck cancer (such as squamous cell carcinoma of the head and neck), mesothelioma, lung cancer (such as non-small-cell lung cancer), ovarian cancer, Merkel cell carcinoma, pancreatic cancer, melanoma, or hepatocellular carcinoma.
• Cancer may be characterised by the abnormal proliferation of malignant cancer cells. Where the application refers to a particular type of cancer, such as breast cancer, this refers to a malignant transformation of the relevant tissue, in this case a breast tissue.
• a cancer which originates from malignant transformation of a different tissue may result in metastatic lesions in another location in the body, such as the breast, but is not thereby a breast cancer as referred to herein but an ovarian cancer.
• the cancer may be a primary or secondary cancer.
• an antibody or antigen-binding fragment thereof of the invention may be for use in a method of treating cancer in a patient, wherein the cancer is a primary tumour and/or a tumour metastasis.
• an antibody or antigen-binding fragment thereof of the invention may also be expected to find application in the treatment of infectious diseases, such as viral, bacterial, fungal and/or parasitic infections.
• infectious diseases such as viral, bacterial, fungal and/or parasitic infections.
• the infectious disease is a viral, bacterial or fungal disease, more preferably a viral or bacterial disease, most preferably a viral disease.
• the infectious disease may be chronic or acute, but is preferably chronic.
• viral diseases which may be treated with an antibody or antigen-binding fragment thereof according to the invention include: human immunodeficiency virus (HIV), influenza virus, enterovirus, hepatitis B virus (HBV), hepatitis C virus (HCV), hepatitis A virus (HAV), hepatitis D virus (HDV), and hepatitis E virus (HEV), respiratory syncytial virus (RSV), herpesvirus (such as Epstein-Barr virus, herpes simplex virus 1 (HSV-1 ), herpes simplex virus 2 (HSV-2), cytomegalovirus (CMV)), and papillomavirus infection.
• HCV human immunodeficiency virus
• HBV hepatitis B virus
• HCV hepatitis C virus
• HAV hepatitis D virus
• HEV hepatitis E virus
• RSV respiratory syncytial virus
• herpesvirus such as Epstein-Barr virus, herpes simplex
• bacterial diseases which may be treated with an antibody or antigen-binding fragment thereof of the invention include: Mycobacterium tuberculosis, gram-negative bacteria (such as Acinetobacter, Klebisella, Enterobacter), gram-positive bacteria (such as Clostridium difficile, Staphylococcus aureus), and Listeria ⁇ e.g., Listeria monocytogenes) infection.
• gram-negative bacteria such as Acinetobacter, Klebisella, Enterobacter
• gram-positive bacteria such as Clostridium difficile, Staphylococcus aureus
• fungal diseases which may be treated with an antibody or antigen-binding fragment thereof of the invention include: Aspergillus and Candida infection.
• Examples of parasitic diseases which may be treated with an antibody or antigen-binding fragment thereof of the invention include: Malaria, Toxoplasma, and Leishmania infection.
• An antibody or antigen-binding fragment thereof according to the invention is designed to be used in methods of treatment of patients, preferably human patients.
• An antibody or antigen-binding fragment thereof of the invention will usually be administered in the form of a pharmaceutical composition, which may comprise at least one additional component, such as a pharmaceutically acceptable excipient.
• a pharmaceutical composition of the invention may comprise, in addition to the antibody or antigen-binding fragment thereof, a pharmaceutically-acceptable excipient, carrier, buffer, stabiliser or other materials well known to those skilled in the art. Such materials should be non-toxic and should not interfere with the efficacy of the antibody or antigen binding fragment thereof.
• the precise nature of the carrier or other material will depend on the route of administration, which may be by injection, e.g., intravenous or subcutaneous.
• the antibody or antigen-binding fragment thereof may be administered intravenously, or subcutaneously.
• Liquid pharmaceutical compositions generally comprise a liquid carrier such as water or physiological saline solution.
• a liquid carrier such as water or physiological saline solution.
• the antibody or antigen-binding fragment thereof, or pharmaceutical composition comprising the antibody or antigen-binding fragment thereof is preferably in the form of a parenterally acceptable aqueous solution which is pyrogen-free and has suitable pH, isotonicity and stability.
• a composition comprising an antibody or antigen-binding fragment thereof according to the invention may be administered alone or in combination with other treatments, concurrently or sequentially or as a combined preparation with another therapeutic agent or agents, dependent upon the condition to be treated.
• an antibody or fragment thereof of the invention may be administered in combination with an existing therapeutic agent for the disease to be treated, e.g., a cancer as mentioned above.
• an antibody or fragment thereof of the invention may be administered to the patient in combination with a second anti-cancer therapy, such as chemotherapy, anti-tumour vaccination (also referred to as a cancer vaccination), radiotherapy, immunotherapy, an oncolytic virus, chimeric antigen receptor (CAR) T-cell therapy, or hormone therapy.
• a second anti-cancer therapy such as chemotherapy, anti-tumour vaccination (also referred to as a cancer vaccination), radiotherapy, immunotherapy, an oncolytic virus, chimeric antigen receptor (CAR) T-cell therapy, or hormone therapy.
• the antibody or fragment thereof of the invention may act as an adjuvant in anti cancer therapy, such as chemotherapy, anti-tumour vaccination, or radiotherapy.
• anti cancer therapy such as chemotherapy, anti-tumour vaccination, or radiotherapy.
• administration of the antibody or fragment thereof to the patient as part of chemotherapy, anti-tumour vaccination, or radiotherapy will trigger a greater immune response against the cancer associated antigen PD-L1 , than is achieved with chemotherapy, anti-tumour vaccination, or radiotherapy alone.
• a method of treating cancer in a patient may thus comprise administering to the patient a therapeutically effective amount of an antibody or fragment thereof according to the invention in combination with a chemotherapeutic agent, anti-tumour vaccine, radionuclide, immunotherapeutic agent, oncolytic virus, CAR-T cell, or agent for hormone therapy.
• the chemotherapeutic agent, anti-tumour vaccine, radionuclide, immunotherapeutic agent, oncolytic virus, CAR-T cell, or agent for hormone therapy is preferably a chemotherapeutic agent, anti tumour vaccine, radionuclide, immunotherapeutic agent, oncolytic virus, CAR-T cell, or agent for hormone therapy for the cancer in question, i.e., a chemotherapeutic agent, anti-tumour vaccine, radionuclide, immunotherapeutic agent, oncolytic virus, CAR-T cell, or agent for hormone therapy which has been shown to be effective in the treatment of the cancer in question.
• chemotherapeutic agent anti-tumour vaccine, radionuclide, immunotherapeutic agent, oncolytic virus, CAR-T cell, or agent for hormone therapy, which have been shown to be effective for the cancer in question, is well within the capabilities of the skilled practitioner.
• the method comprises administering to the patient a therapeutically effective amount of an antibody or fragment thereof according to the invention in combination with a chemotherapeutic agent
• the chemotherapeutic agent may be selected from the group consisting of: taxanes, cytotoxic antibiotics, tyrosine kinase inhibitors, PARP inhibitors, B_RAF enzyme inhibitors, alkylating agents, platinum analogues, nucleoside analogues, thalidomide derivatives, antineoplastic chemotherapeutic agents and others.
• Taxanes include docetaxel, paclitaxel and nab-paclitaxel; cytotoxic antibiotics include actinomycin, bleomycin, anthracyclines, doxorubicin and valrubicin; tyrosine kinase inhibitors include sunitinib, erlotinib, gefitinib, axitinib, PLX3397, imatinib, cobemitinib and trametinib; PARP inhibitors include piraparib; B-Raf enzyme inhibitors include vemurafenib and dabrafenib; alkylating agents include dacarbazine, cyclophosphamide, temozolomide; platinum analogues include carboplatin, cisplatin and oxaliplatin; nucleoside analogues include gemcitabine and azacitidine; antineoplastics include fludarabine.
• chemotherapeutic agents suitable for use in the invention include methotrexate, defactinib, entinostat, pemetrexed, capecitabine, eribulin, irinotecan, fluorouracil, and vinblastine.
• Vaccination strategies for the treatment of cancers have been implemented in the clinic and discussed in detail within scientific literature (such as Rosenberg S. Development of Cancer Vaccines. ASCO Educational Book Spring: 60-62 (2000)). This mainly involves strategies to prompt the immune system to respond to various cellular markers expressed by autologous or allogenic cancer cells by using those cells as a vaccination method, both with or without granulocyte-macrophage colony-stimulating factor (GM-CSF). GM-CSF provokes a strong response in antigen presentation and works particularly well when employed with said strategies.
• GM-CSF granulocyte-macrophage colony-stimulating factor
• a method of the invention comprises administering to the patient a therapeutically-effective amount of an antibody or fragment thereof according to the invention in combination with an immunotherapeutic agent
• the immunotherapeutic agent may be selected from the group consisting of: antibodies binding to a checkpoint inhibitor, costimulatory molecule or soluble factor, such as antibodies binding to CTLA-4, LAG-3, TIGIT, TIM-3, VISTA, CD73, CSF-1 R, KIR, 0X40, CD40, HEVM, TGFB, IL-10, CSF-1.
• the immunotherapeutic agent may one or more cytokines or cytokine-based therapies selected from the group consisting of IL-2, prodrug of conjugated IL2, GM-CSF, IL-7, IL-12, IL-9, IL-15, IL-18, IL-21 , and type I interferon.
• cytokines or cytokine-based therapies selected from the group consisting of IL-2, prodrug of conjugated IL2, GM-CSF, IL-7, IL-12, IL-9, IL-15, IL-18, IL-21 , and type I interferon.
• Administration may be in a "therapeutically effective amount", this being an amount which is sufficient to show benefit to a patient. Such benefit may be at least amelioration of at least one symptom.
• “treatment” of a specified disease refers to amelioration of at least one symptom.
• the actual amount administered, and rate and time-course of administration, will depend on the nature and severity of what is being treated, the particular patient being treated, the clinical condition of the individual patient, the cause of the disorder, the site of delivery of the composition, the type of antibody or fragment thereof, the method of administration, the scheduling of administration and other factors known to medical practitioners.
• Prescription of treatment is within the responsibility of general practitioners and other medical doctors, and may depend on the severity of the symptoms and/or progression of a disease being treated.
• Appropriate doses of antibody or fragment thereof are well known in the art (Ledermann et al. (1991 ) Int. J. Cancer 47: 659-664; and Bagshawe et al. (1991 ) Antibody, Immunoconjugates and Radiopharmaceuticals 4: 915-922).
• Specific dosages indicated herein, or in the Physician's Desk Reference (2003) as appropriate for an antibody or fragment thereof being administered, may be used.
• a therapeutically-effective amount or suitable dose of an antibody or fragment thereof can be determined by comparing its in vitro activity and in vivo activity in an animal model. Methods for extrapolation of effective dosages in mice and other test animals to humans are known. The precise dose will depend upon a number of factors, including the size and location of the area to be treated, and the precise nature of the specific binding member. Treatments may be repeated at daily, twice-weekly, weekly or monthly intervals, at the discretion of the physician. Treatment may be given before and/or after surgery, and may be administered or applied directly at the anatomical site of surgical treatment. Detailed Description
• the invention relates to antibodies and antigen-binding fragments thereof that comprise a CDR- based antigen-binding site for PD-L1.
• An antibody or antigen-binding fragment thereof of the invention may be produced by recombinant means.
• A“recombinant antibody” is an antibody which has been produced by a recombinantly engineered host cell.
• An antibody or antigen-binding fragment thereof in accordance with the invention is optionally isolated or purified.
• PD-L1 may refer to human PD-L1 , murine, in particular mouse PD-L1 , and/or cynomolgus monkey PD-L1 , unless the context requires otherwise.
• the term“PD-L1” refers to human PD-L1 , unless the context requires otherwise.
• antibody molecule describes an immunoglobulin whether natural or partly or wholly synthetically produced.
• the antibody molecule may be human or humanised.
• the antibody molecule is preferably a monoclonal antibody molecule.
• Examples of antibodies are the immunoglobulin isotypes, such as immunoglobulin G, and their isotypic subclasses, such as lgG1 , lgG2, lgG3 and lgG4, as well as fragments thereof.
• the four human subclasses (lgG1 , lgG2, lgG3 and lgG4) each contain a different heavy chain; but they are highly homologous and differ mainly in the hinge region and the extent to which they activate the host immune system.
• lgG1 and lgG4 contain two inter-chain disulphide bonds in the hinge region, lgG2 has 4 and lgG3 has 1 1 inter-chain disulphide bonds.
• antibody and“antibody molecule”, as used herein, includes antibody fragments, such as Fab and scFv fragments, provided that said fragments comprise a CDR-based antigen binding site for PD-L1. Unless the context requires otherwise, the terms“antibody” or“antibody molecule”, as used herein, is thus equivalent to“antibody or antigen-binding fragment thereof.
• Antibodies are immunoglobulins, which have the same basic structure consisting of two heavy and two light chains forming two Fab arms containing identical domains that are attached by a flexible hinge region to the stem of the antibody, the Fc domain, giving the classical ⁇ ’ shape.
• the Fab domains consist of two variable and two constant domains, with a variable heavy (VH) and constant heavy 1 (CH1 ) domain on the heavy chain and a variable light (VL) and constant light (CL) domain on the light chain.
• the two variable domains (VH and VL) form the variable fragment (Fv), which provides the CDR-based antigen specificity of the antibody, with the constant domains (CH1 and VL) acting as a structural framework.
• Each variable domain contains three hypervariable loops, known as complementarity determining regions (CDRs).
• CDRs complementarity determining regions
• the CDRs provide a specific antigen recognition site on the surface of the antibody.
• VH variable heavy domain
• HCDR1 HCDR1 , HCRD2 and HCDR3, each flanked by framework (FW) regions
• the amino acid sequence of HCDR1 is GYXiFTSYG (SEQ ID NO: 67);
• the amino acid sequence of HCDR2 is ISAYX2X3X4X5 (SEQ ID NO: 68);
• the amino acid sequence of HCDR3 is ARDLFPTI FGVSYYYY (SEQ ID NO: 69);
• X1 is P or T;
• X 2 is S, N or G, preferably S or N;
• X 3 is G or S;
• X 4 is G, N or S, preferably G or N; and
• X5 is T or A, preferably T, and wherein the sequences are defined by the ImMunoGeneTics (IMGT) nomenclature.
• IMGT ImMunoGeneTics
• VL variable light
• the VL is a kappa VL and the amino acid sequence of LCDR1 is QSIX6X7R (SEQ ID NO: 70); the amino acid sequence of LCDR2 is EAS (SEQ ID NO: 71 ); and the amino acid sequence of LCDR3 is QQXeXgXioTPYT (SEQ ID NO: 72), QQX 8 X 9 X IO TPRVT (SEQ ID NO: 73), QQXeXgXioFPRVS (SEQ ID NO: 74), or QQX 8 X 9 X I0 WPRT (SEQ ID NO: 75); wherein X 6 is G or S; X7 is N or G; X 8 is S or A; Xg is Y or N; and X10 is S or T; or, (b) the VL is a lambda VL and the amino acid sequence of LCDR1 is SSDVGGYNXn (SEQ ID NO: 76), the amino acid sequence of LCDR2 is E
• antibody should be construed as covering antibody fragments, derivatives, functional equivalents and homologues of antibodies, including any polypeptide comprising an immunoglobulin binding domain, whether natural or wholly or partially synthetic. Chimeric molecules comprising an immunoglobulin binding domain, or equivalent, fused to another polypeptide are therefore included. Cloning and expression of chimeric antibodies are described in EP-A- 0120694 and EP-A-0125023. An example of an antibody fragment comprising both CDR sequences and CH3 domain is a minibody, which comprises a scFv joined to a CH3 domain (Hu et al., 1996).
• An antibody or antigen-binding fragment of the invention binds to PD-L1 , in particular human PD- L1. Binding in this context may refer to specific binding.
• the term “specific” may refer to the situation in which the antibody molecule will not show any significant binding to molecules other than its specific binding partner(s), here PD-L1.
• the term“specific” is also applicable where the antibody molecule is specific for particular epitopes, such as epitopes on PD-L1 , that are carried by a number of antigens in which case the antibody molecule will be able to bind to the various antigens carrying the epitope.
• Amino acids may be referred to by their one letter or three letter codes, or by their full name.
• the one and three letter codes, as well as the full names, of each of the twenty standard amino acids are set out below.
• the PD-L1 antibody of the invention comprises the HCDR3 sequence of E12v2 (SEQ ID NO: 3); it is preferred that the antibody further comprises the HCDR2 sequence of E12v2 (SEQ ID NO: 18); it is preferred that the PD-L1 antibody of the invention yet further comprises the HCDR1 sequence of E12v2 (SEQ ID NO: 1 ).
• the HCDR2 sequence is HCDR2 sequence of E12v2 (SEQ ID NO: 18) and the amino acid at position 28 in the VH (Kabat) is proline.
• the PD-L1 antibody of the invention comprises the HCDR3 sequence of SEQ ID NO: 3, the HCDR2 sequence of SEQ ID NO: 18 and the amino acid at position 28 in the VH (Kabat) is proline.
• the PD-L1 antibody of the invention comprises the HCDR3 sequence of SEQ ID NO: 3, the HCDR2 sequence of SEQ ID NO: 18, and the HCDR1 sequence of SEQ ID NO: 1 and the amino acid at position 28 in the VH (Kabat) is proline.
• Antibodies of the invention may comprise one or more, e.g., 1 , 2, 3, 4, 5, 6, 7, 8, 9 or 10 further amino acid modifications in the VH and / or VL sequences, provided that functional properties of the antibody are retained.
• a modification may be an amino acid substitution, deletion or insertion.
• the modification is a substitution.
• the substitutions may conservative substitutions, for example according to the following chart.
• amino acids in the same category in the middle column are substituted for one another, i.e. a non-polar amino acid is substituted with another non-polar amino acid, for example.
• amino acids in the same line in the rightmost column are substituted for one another.
• substitution(s) may be functionally conservative. That is, in some embodiments the substitution may not affect (or may not substantially affect) one or more functional properties (e.g., binding affinity) of the antibody molecule comprising the substitution as compared to the equivalent unsubstituted antibody molecule.
• a PD-L1 antibody of the invention may comprise a VH and / or VL domain sequence with one or more amino acid sequence alterations (addition, deletion, substitution and/or insertion of an amino acid residue), preferably 20 alterations or fewer, 15 alterations or fewer, 10 alterations or fewer, 5 alterations or fewer, 4 alterations or fewer, 3 alterations or fewer, 2 alterations or fewer, or 1 alteration compared with the VH and / or VL sequences of the invention set forth herein.
• an antibody of the invention comprises the HCDR3 domain of E12v2 set forth in SEQ ID NO: 3.
• an antibody of the invention comprises the VH domain of E12v2 set forth in SEQ ID NO: 27 or a VH domain with an amino acid sequence which has at least 95%, at least 96%, at least 97%, at least 98%, or at least 99% sequence identity to the sequence set forth in SEQ ID NO: 27.
• an antibody of the invention comprises a VH domain comprising the HCDR3 set forth in SEQ ID NO: 3 and the VH domain has an amino acid sequence with at least 70%, at least 75%, at least 80%, at least 85%, at least 90%, at least 95%, at least 96%, at least 97%, at least 98%, or at least 99% sequence identity to the sequence set forth in SEQ ID NO: 27.
• an antibody of the invention comprises a VH domain comprising the HCDR3 of E12v2 set forth in SEQ ID NO: 3 and a HCDR2 selected from those set forth in SEQ ID NO: 18, 23 or 24 and the VH domain has an amino acid sequence with at least 70%, at least 75%, at least 80%, at least 85%, at least 90%, at least 95%, at least 96%, at least 97%, at least 98%, or at least 99% sequence identity to the sequence set forth in SEQ ID NO: 27.
• an antibody of the invention comprises a VH domain comprising the HCDR3 of E12v2 set forth in SEQ ID NO: 3, a HCDR2 domain selected from those set forth in SEQ ID NO: 18, 23 or 24, a proline at position 28, and the VH domain has an amino acid sequence with at least 70%, at least 75%, at least 80%, at least 85%, at least 90%, at least 95%, at least 96%, at least 97%, at least 98%, or at least 99% sequence identity to the sequence set forth in SEQ ID NO: 27.
• an antibody of the invention comprises a VL domain comprising a VL domain of E12v2 set forth in SEQ ID NO: 28 or an amino acid sequence with at least 70%, at least 75%, at least 80%, at least 85%, at least 90%, at least 95%, at least 96%, at least 97%, at least 98%, or at least 99% sequence identity to the sequence set forth in SEQ ID NO: 28.
• GAP Garnier GCG package, Accelerys Inc, San Diego USA.
• GAP uses the Needleman and Wunsch algorithm to align two complete sequences, maximising the number of matches and minimising the number of gaps. Generally, default parameters are used, with a gap creation penalty equalling 12 and a gap extension penalty equalling 4.
• Use of GAP may be preferred but other algorithms may be used, e.g., BLAST (which uses the method of Altschul et al. (1990) J. Mol. Biol. 215: 405-410), FASTA (which uses the method of Pearson and Lipman (1988) PNAS USA 85: 2444-2448), or the Smith- Waterman algorithm (Smith and Waterman (1981 ) J. Mol Biol.
• the antibody may comprise a CH2 domain.
• the CH2 domain is preferably located at the N- terminus of the CH3 domain, as in the case in a human IgG molecule.
• the CH2 domain of the antibody is preferably the CH2 domain of human lgG1 , lgG2, lgG3, or lgG4, more preferably the CH2 domain of human lgG1.
• the sequences of human IgG domains are known in the art.
• the antibody may comprise an immunoglobulin hinge region, or part thereof, at the N-terminus of the CH2 domain.
• the immunoglobulin hinge region allows the two CH2-CH3 domain sequences to associate and form a dimer.
• the hinge region, or part thereof is a human lgG1 , lgG2, lgG3 or lgG4 hinge region, or part thereof. More preferably, the hinge region, or part thereof, is an lgG1 hinge region, or part thereof.
• the CH3 domain is not particularly limited.
• the CH3 domain is a human immunoglobulin G domain, such as a human lgG1 , lgG2, lgG3, or lgG4 CH3 domain, most preferably a human lgG1 CH3 domain.
• An antibody of the invention may comprise a human lgG1 , lgG2, lgG3, or lgG4 constant region.
• the sequences of human lgG1 , lgG2, lgG3, or lgG4 CH3 domains are known in the art.
• the heavy chain of the antibody molecule may optionally comprise an additional lysine residue (K) at the C-terminus of the heavy chain CH3 domain sequence.
• Immunoglobulins are known to have a modular architecture comprising discrete domains, which can be combined in a multitude of different ways to create multispecific, e.g., bispecific, trispecific, or tetraspecific antibody formats. Exemplary multispecific antibody formats are described in Spiess et al., 2015 and Kontermann, 2012, for example. The antibodies of the invention may be employed in such multispecific formats.
• an antibody of the invention may be a heterodimeric antibody molecule, such as a heterodimeric complete immunoglobulin molecule, or a fragment thereof.
• one part of the antibody will have a sequence or sequences as described herein.
• the antibody of the invention is a bispecific heterodimeric antibody molecule
• the antibody may comprise a heavy chain and light chain as described herein paired with a heavy chain and light chain comprising a VH domain and a VL domain, respectively, which bind an antigen other than PD-L1.
• T echniques for preparing heterodimeric antibodies are known in the art and include knobs- into-holes (KIHs) technology, which involves engineering the CH3 domains of an antibody molecule to create either a“knob” or a“hole” to promote chain heterodimerization.
• KHs knobs- into-holes
• heterodimeric antibodies can be prepared through the introduction of charge pairs into the antibody molecule to avoid homodimerization of CH3 domains by electrostatic repulsion and to direct heterodimerization by electrostatic attraction.
• Examples of heterodimeric antibody formats include CrossMab, mAb-Fv, SEED-body, and KIH IgG.
• a multispecific antibody molecule may comprise a complete immunoglobulin molecule or a fragment thereof and an additional antigen-binding moiety or moieties.
• the antigen binding moiety may for example be an Fv, scFv or single domain antibody, and may be fused to the complete immunoglobulin molecule or a fragment thereof.
• Examples of multispecific antibody molecules comprising additional antigen-binding moieties fused to a complete immunoglobulin molecule include DVD-lgG, DVI-lgG, scFv4-lgG, IgG-scFv, and scFv-lgG molecules (Spiess et al., 2015; Figure 1 ).
• multispecific antibody molecules comprising additional antigen binding moieties fused to an immunoglobulin fragment
• immunoglobulin fragment examples include BiTE molecules, diabodies, and DART molecules, for example (Spiess et al., 2015; Figure 1 ).
• Other suitable formats would be readily apparent to the skilled person.
• the antibody may further comprise one or more additional antigen-binding sites to create a bi- or multi-specific molecule.
• the antibody may comprise a CH3-based or CH2-based antigen-binding site.
• CDR- based antigen binding sites are found in naturally-occurring immunoglobulin molecules and their structure is well-known in the art.
• the antibody or antigen-binding fragment thereof comprises a CDR-based antigen binding site
• the antibody or antigen-binding fragment thereof is preferably an antibody molecule.
• the bi- or multispecific antibody molecule may comprise a CDR- based antigen binding site for PD-L1 and a CH3-based or CH2-based binding site for a second target.
• the antibody molecule is a human immunoglobulin G molecule, such as a human lgG1 , lgG2, lgG3 or lgG4 molecule, more preferably a human lgG1 molecule.
• antibody or antigen-binding fragments thereof of the invention may have a second antigen-binding site located in a constant domain, preferably CH3 or CH2, of the antibody.
• an antibody or antigen-binding fragment thereof of the invention may comprise a further CDR-based antigen-binding site (e.g., as formed by a VH and a VL) for a second or third target antigen.
• a further CDR-based antigen-binding site e.g., as formed by a VH and a VL
• an antibody molecule, or antigen-binding fragment thereof, according to the invention may be a multispecific, preferably a bispecific, molecule comprising a second antigen-binding site.
• the second antigen binding site when present, may be a CH3-based or CH2-based antigen binding site or a CDR-based antigen-binding site, and may bind an antigen such that the binding of said antigen is expected to be beneficial in the context of cancer treatment.
• the antibody molecule may be a mAb 2 (TM) bispecific antibody.
• TM mAb 2 bispecific antibody
• a mAb 2 bispecific antibody as referred to herein, is an IgG immunoglobulin which includes a CDR-based antigen binding site in each of its variable regions and at least one antigen binding site in a constant domain of the antibody molecule.
• the second antigen binding site may bind to a non-redundant and complementary inhibitory checkpoint molecule, such as CTLA-4, LAG-3, TIGIT, TIM-3, VISTA, CD73, CSF-1 R, KIR, B7- H3, B7-H4, 2B4, NKG2A, CD47, SIRPa, BTLA, CCR4, CD200R, or TGFbeta.
• a non-redundant and complementary inhibitory checkpoint molecule such as CTLA-4, LAG-3, TIGIT, TIM-3, VISTA, CD73, CSF-1 R, KIR, B7- H3, B7-H4, 2B4, NKG2A, CD47, SIRPa, BTLA, CCR4, CD200R, or TGFbeta.
• an antibody or antigen binding fragment thereof of the invention may comprise a second antigen-binding site, e.g., a CH3-based, CH2-based or CDR-based antigen-binding site, and the second antigen binding site may bind to, and be an agonist for, a costimulatory molecule expressed by T cells such as 0X40, ICOS, CD40, HVEM, NKG2D, or TNFR2.
• the antibody or antigen-binding fragment thereof of the invention may comprise a second antigen-binding site, e.g., a CH3-based, CH2-based or CDR-based antigen binding site, and the second antigen-binding site may bind to a tumour associated antigen (TAA).
• TAA tumour associated antigen
• Such antibody or antigen-binding fragment thereof is expected to result in tumour-specific T cell responses through localised immune activation.
• TAAs are c-Met, B7-H3, B7-H4, EGFR, HER-2, EPCAM, CEACAM, FAP, VEGF, MSLN, GPC3, CD38, CD19, and CD20.
• infectious diseases show many parallels with oncology.
• the role of PD-L1 in immune regulation could be harnessed to maximise the immune response against pathogens.
• Immunomodulation in the context of treatment of infectious diseases is an emerging area of medicine and early reviews suggest that PD-L1 blockade may improve biological responses to infection, in particular, helping to counteract T-cell exhaustion, manage immune-mediated clearance, and generate long-term immunity (Wykes and Lewin, 2017).
• an antibody or antigen-binding fragment thereof of the invention comprising a second antigen-binding site may find application in the treatment of these diseases by localising beneficial immunomodulatory activity to the pathogen environment.
• an antibody or antigen-binding fragment thereof of the invention comprising a second antigen-binding site which binds to an immune cell target, either for agonism or antagonism, may result in increased T-cell specificity and activity.
• the second antigen binding site may bind to an immune cell target, such as PD-1 , PD-L2, CTLA-4, LAG-3, TIGIT, TIM3, 0X40, CD40, ICOS, CD28, or CD80.
• an immune cell target such as PD-1 , PD-L2, CTLA-4, LAG-3, TIGIT, TIM3, 0X40, CD40, ICOS, CD28, or CD80.
• the second antigen-binding site may bind to a pathogenic target, namely an antigen expressed by a human pathogen.
• the pathogen may be a virus, bacterium, fungus, or parasite.
• the pathogen is a virus, bacterium or fungus. More preferably, the pathogen is a virus or bacterium. Most preferably, the pathogen is a virus.
• viral antigens examples include proteins p24, gp120, and gp41 expressed by human immunodeficiency virus (HIV), hepatitis B surface antigen (HBsAg) expressed by hepatitis B virus (HBV), and hemagglutinin and neuraminidase expressed by influenza virus.
• bacterial antigens include Rv1733, Rv2389 and Rv2435n expressed by Mycobacterium tuberculosis.
• the second antigen-binding site of the antibody of the invention may not bind to 0X40. In addition, or alternatively, the second antigen-binding site of an antibody of the invention may not bind to CD137. In addition, or alternatively, the second antigen-binding site of an antibody of the invention may not bind to CD27. In addition, or alternatively, the second antigen-binding site of an antibody of the invention may not bind to glucocorticoid-induced TNFR- related protein (GITR). In addition, or alternatively, the second antigen-binding site of an antibody of the invention may not bind to lymphocyte-activation gene 3 (LAG-3). In addition, or alternatively, the second antigen-binding site of an antibody of the invention may not bind to Inducible T-cell COStimulator (ICOS).
• ICOS Inducible T-cell COStimulator
• An antibody of the invention may be conjugated to an immune system modulator, cytotoxic molecule, radioisotope or detectable label.
• the immune system modulator may be a cytotoxic molecule, such as a cytokine.
• the antibody molecule may be conjugated to a bioactive molecule or a detectable label. In this case, the antibody molecule may be referred to as a conjugate.
• conjugates find application in the treatment and/or diagnosis of diseases as described herein.
• the bioactive molecule may be an immune system modulator, such as a cytokine, preferably a human cytokine.
• the cytokine may be a cytokine which stimulates T cell activation and/or proliferation.
• cytokines for conjugation to the antibody molecule include IL-2, IL-10, IL-12, IL-15, IL-21 , GM-CSF and IFN-gamma.
• the bioactive molecule may be a ligand trap, such as a ligand trap of a cytokine, e.g., of TGF-beta or IL-6.
• Suitable detectable labels which may be conjugated to antibody molecules include radioisotopes such as iodine-125, iodine-131 , yttrium-90, indium-1 1 1 and technetium- 99; fluorochromes, such as fluorescein, rhodamine, phycoerythrin, Texas Red and cyanine dye derivatives for example, Cy7 and Alexa750; chromogenic dyes, such as diaminobenzidine; latex beads; enzyme labels such as horseradish peroxidase; phosphor or laser dyes with spectrally isolated absorption or emission characteristics; and chemical moieties, such as biotin, which may be detected via binding to a specific cognate detectable moiety, e.g., labelled avidin.
• radioisotopes such as iodine-125, iodine-131 , yttrium-90, indium-1 1 1 and technetium- 99
• fluorochromes such as flu
• the antibody of the invention may be conjugated to the bioactive molecule or detectable label by means of any suitable covalent or non-covalent linkage, such as a disulphide or peptide bond.
• the bioactive molecule is a cytokine
• the cytokine may be joined to the antibody molecule by means of a peptide linker.
• Suitable peptide linkers are known in the art and may be 5 to 25, 5 to 20, 5 to 15, 10 to 25, 10 to 20, or 10 to 15 amino acids in length.
• the bioactive molecule may be conjugated to the antibody by a cleavable linker.
• the linker may allow release of the bioactive molecule from the antibody at a site of therapy.
• Linkers may include amide bonds (e.g., peptidic linkers), disulphide bonds or hydrazones.
• Peptide linkers for example may be cleaved by site-specific proteases, disulphide bonds may be cleaved by the reducing environment of the cytosol and hydrazones may be cleaved by acid-mediated hydrolysis.
• the conjugate may be a fusion protein comprising the antibody of the invention and the bioactive molecule.
• the bioactive molecule may be conjugated to the antibody by means of a peptide linker or peptide bond.
• the antibody is a multichain molecule, such as where the antibody molecule is or comprises an Fcab or is a mAb 2
• the bioactive molecule may be conjugated to one or more chains of the antibody molecule.
• the bioactive molecule may be conjugated to one or both of the heavy chains of the mAb 2 molecule. Fusion proteins have the advantage of being easier to produce and purify, facilitating the production of clinical-grade material.
• the invention also provides a nucleic acid or set of nucleic acids encoding an antibody or antigen binding fragment of the invention, as well as a vector comprising such a nucleic acid or set of nucleic acids.
• nucleic acid encodes the VH and VL domain, or heavy and light chain, of an antibody molecule of the invention
• the two domains or chains may be encoded on two separate nucleic acid molecules.
• An isolated nucleic acid molecule may be used to express an antibody molecule of the invention.
• the nucleic acid will generally be provided in the form of a recombinant vector for expression.
• Another aspect of the invention thus provides a vector comprising a nucleic acid as described above.
• Suitable vectors can be chosen or constructed, containing appropriate regulatory sequences, including promoter sequences, terminator fragments, polyadenylation sequences, enhancer sequences, marker genes and other sequences as appropriate.
• the vector contains appropriate regulatory sequences to drive the expression of the nucleic acid in a host cell.
• Vectors may be plasmids, viral e.g., phage, or phagemid, as appropriate.
• a nucleic acid molecule or vector as described herein may be introduced into a host cell.
• Techniques for the introduction of nucleic acid or vectors into host cells are well established in the art and any suitable technique may be employed.
• a range of host cells suitable for the production of recombinant antibody molecules are known in the art, and include bacterial, yeast, insect or mammalian host cells.
• a preferred host cell is a mammalian cell, such as a CHO, NS0, or HEK cell, for example a HEK293 cell.
• a recombinant host cell comprising a nucleic acid or the vector of the invention is also provided. Such a recombinant host cell may be used to produce an antibody of the invention.
• a method of producing an antibody of the invention comprising culturing the recombinant host cell under conditions suitable for production of the antibody.
• the method may further comprise a step of isolating and/or purifying the antibody molecule.
• the invention provides a method of producing an antibody molecule of the invention comprising expressing a nucleic acid encoding the antibody molecule in a host cell and optionally isolating and/or purifying the antibody molecule thus produced.
• Methods for culturing host cells are well-known in the art.
• Techniques for the purification of recombinant antibody molecules are well-known in the art and include, for example HPLC, FPLC or affinity chromatography, e.g., using Protein A or Protein L.
• purification may be performed using an affinity tag on antibody molecule.
• the method may also comprise formulating the antibody molecule into a pharmaceutical composition, optionally with a pharmaceutically-acceptable excipient or other substance as described below.
• the antibodies of the invention are expected to find application in therapeutic applications, in particular therapeutic applications in humans, such as cancer treatment and the treatment of infectious diseases.
• a composition such as a pharmaceutical composition
• an excipient such as a pharmaceutically-acceptable excipient.
• the invention further provides an antibody molecule of the invention, for use in a method of treatment. Also provided is a method of treating a patient, wherein the method comprises administering to the patient a therapeutically-effective amount of an antibody molecule according to the invention. Further provided is the use of an antibody molecule according to the invention for use in the manufacture of a medicament.
• a patient as referred to herein, is preferably a human patient.
• the invention also provides an antibody molecule of the invention, for use in a method of treating cancer in a patient. Also provided is a method of treating cancer in a patient, wherein the method comprises administering to the patient a therapeutically-effective amount of an antibody molecule according to the invention. Further provided is the use of an antibody molecule according to the invention for use in the manufacture of a medicament for the treatment of cancer in a patient.
• the treatment may further comprise administering to the patient a second anti-cancer agent and/or therapy, such as an anti-tumour vaccine and/or a chemotherapeutic agent.
• the second anti cancer agent and/or therapy may be administered to the patient simultaneously, separately, or sequentially to the antibody molecule of the invention.
• the invention relates to an antibody that binds to PD-L1 for use in a) treating cancer, b) delaying progression of cancer, c) prolonging the survival of a patient suffering from cancer, or d) stimulating a cell-mediated immune response.
• the invention also provides an antibody of the invention, for use in a method of treating an infectious disease in a patient. Also provided is a method of treating an infectious disease in a patient, wherein the method comprises administering to the patient a therapeutically-effective amount of an antibody according to the invention. Further provided is the use of an antibody according to the invention for use in the manufacture of a medicament for the treatment of an infectious disease in a patient. The treatment may further comprise administering to the patient a second agent and/or therapy for the treatment of the infectious disease. The second agent and/or therapy may be administered to the patient simultaneously, separately, or sequentially to the antibody or antigen-binding fragment thereof or antibody molecule of the invention.
• the antibody molecules as described herein may thus be useful for therapeutic applications, in particular in the treatment of cancer.
• the antibody molecules are expected to be useful in the treatment of infectious diseases, such as persistent infectious diseases.
• An antibody molecule as described herein may be used in a method of treatment of the human or animal body.
• Related aspects of the invention provide;
• the individual may be a patient, preferably a human patient.
• Treatment may be any treatment or therapy in which some desired therapeutic effect is achieved, for example, the inhibition or delay of the progress of the condition, and includes a reduction in the rate of progress, a halt in the rate of progress, amelioration of the condition, cure or remission (whether partial or total) of the condition, preventing, ameliorating, delaying, abating or arresting one or more symptoms and/or signs of the condition or prolonging survival of an individual or patient beyond that expected in the absence of treatment.
• Treatment as a prophylactic measure is also included.
• an individual susceptible to or at risk of the occurrence or re-occurrence of a disease such as cancer may be treated as described herein. Such treatment may prevent or delay the occurrence or re occurrence of the disease in the individual.
• a method of treatment as described may be comprise administering at least one further treatment to the individual in addition to the antibody molecule.
• the antibody molecule described herein may thus be administered to an individual alone or in combination with one or more other treatments.
• the additional treatment may be administered to the individual concurrently with, sequentially to, or separately from the administration of the antibody molecule.
• the additional treatment is administered concurrently with the antibody molecule, the antibody molecule and additional treatment may be administered to the individual as a combined preparation.
• the additional therapy may be a known therapy or therapeutic agent for the disease to be treated.
• antibody molecules Whilst an antibody molecule may be administered alone, antibody molecules will usually be administered in the form of a pharmaceutical composition, which may comprise at least one component in addition to the antibody molecule.
• a pharmaceutical composition comprising an antibody molecule as described herein.
• a method comprising formulating an antibody molecule into a pharmaceutical composition is also provided.
• compositions may comprise, in addition to the antibody molecule, a pharmaceutically acceptable excipient, carrier, buffer, stabilizer or other materials well known to those skilled in the art.
• pharmaceutically acceptable as used herein pertains to compounds, materials, compositions, and/or dosage forms which are, within the scope of sound medical judgement, suitable for use in contact with the tissues of a subject (e.g., human) without excessive toxicity, irritation, allergic response, or other problem or complication, commensurate with a reasonable benefit/risk ratio.
• Each carrier, excipient, etc. must also be“acceptable” in the sense of being compatible with the other ingredients of the formulation.
• the precise nature of the carrier or other material will depend on the route of administration, which may be by infusion, injection or any other suitable route, as discussed below.
• the pharmaceutical composition comprising the antibody molecule may be in the form of a parenterally acceptable aqueous solution which is pyrogen-free and has suitable pH, isotonicity and stability.
• a parenterally acceptable aqueous solution which is pyrogen-free and has suitable pH, isotonicity and stability.
• isotonic vehicles such as Sodium Chloride Injection, Ringer's Injection, Lactated Ringer's Injection.
• buffers such as phosphate, citrate and other organic acids
• antioxidants such as ascorbic acid and methionine
• preservatives such as octadecyldimethylbenzyl ammonium chloride; hexamethonium chloride; benzalkonium chloride; benzethonium chloride; phenol, butyl or benzyl alcohol; alkyl parabens, such as methyl or propyl paraben; catechol; resorcinol; cyclohexanol; 3’-pentanol; and m-cresol); low molecular weight polypeptides; proteins, such as serum albumin, gelatin or immunoglobulins; hydrophilic polymers, such as polyvinylpyrrolidone; amino acids, such as glycine, glutamine, asparagines, histidine, arginine, or ly
• antibody molecules may be provided in a lyophilised form for reconstitution prior to administration.
• lyophilised antibody molecules may be re-constituted in sterile water or saline prior to administration to an individual.
• Administration may be in a "therapeutically effective amount", this being sufficient to show benefit to an individual.
• the actual amount administered, and rate and time-course of administration will depend on the nature and severity of what is being treated, the particular individual being treated, the clinical condition of the individual, the cause of the disorder, the site of delivery of the composition, the type of antibody molecule, the method of administration, the scheduling of administration and other factors known to medical practitioners. Prescription of treatment, e.g., decisions on dosage etc., is within the responsibility of general practitioners and other medical doctors, and may depend on the severity of the symptoms and/or progression of a disease being treated. Appropriate doses of antibody molecules are well known in the art (Ledermann et al., 1991 ; Bagshawe et al., 1991 ).
• a therapeutically effective amount or suitable dose of an antibody molecule can be determined by comparing in vitro activity and in vivo activity in an animal model. Methods for extrapolation of effective dosages in mice and other test animals to humans are known. The precise dose will depend upon a number of factors, including whether the size and location of the area to be treated, and the precise nature of the antibody molecule.
• a typical antibody dose is in the range 100 pg to 1 g for systemic applications, and 1 pg to 1 mg for topical applications.
• An initial higher loading dose, followed by one or more lower doses, may be administered. This is a dose for a single treatment of an adult individual, which may be proportionally adjusted for children and infants, and also adjusted for other antibody formats in proportion to molecular weight.
• Treatments may be repeated at daily, twice-weekly, weekly or monthly intervals, at the discretion of the physician.
• the treatment schedule for an individual may be dependent on the pharmocokinetic and pharmacodynamic properties of the antibody composition, the route of administration and the nature of the condition being treated.
• Treatment may be periodic, and the period between administrations may be about two weeks or more, e.g., about three weeks or more, about four weeks or more, about once a month or more, about five weeks or more, or about six weeks or more. For example, treatment may be every two to four weeks or every four to eight weeks. Suitable formulations and routes of administration are described above.
• an antibody molecule as described herein may be for use in a method of treating cancer.
• Cancer may be characterised by the abnormal proliferation of malignant cancer cells. Where a particular type of cancer, such as breast cancer, is referred to, this refers to an abnormal proliferation of malignant cells of the relevant tissue, such as breast tissue.
• the cancer may be a primary or a secondary cancer.
• an antibody molecule as described herein may be for use in a method of treating cancer in an individual, wherein the cancer is a primary tumour and/or a tumour metastasis.
• a tumour of a cancer to be treated using an antibody molecule as described herein may comprise cells that express PD-L1 , e.g., on their cell surface.
• the tumour may have been determined to comprise cells that express PD-L1 .
• Methods for determining the expression of an antigen on a cell surface are known in the art and include, for example, flow cytometry.
• the cancer to be treated using an antibody molecule as described herein may be selected from the group consisting of leukaemias, such as acute myeloid leukaemia (AML), chronic myeloid leukaemia (CML), acute lymphoblastic leukaemia (ALL) and chronic lymphocytic leukaemia (CLL); lymphomas, such as Hodgkin lymphoma, non-Hodgkin lymphoma and multiple myeloma; and solid cancers, such as sarcomas (e.g., soft tissue sarcomas), skin cancer (e.g., Merkel cell carcinoma), melanoma, bladder cancer (e.g., urothelial carcinoma), brain cancer (glioblastoma multiforme), breast cancer, uterine/endometrial cancer, ovarian cancer (e.g., ovarian serous cystadenoma), prostate cancer, lung cancer (e.g., non-small cell lung carcinoma (NSCLC) and small cell lung cancer (
• the cancer to be treated using an antibody molecule as described herein is a solid cancer. More preferably, the cancer to be treated using an antibody molecule as described herein is a solid cancer selected from the group consisting of: sarcoma, melanoma, bladder cancer, brain cancer, breast cancer, ovarian cancer, uterine/endometrial cancer, prostate cancer, lung cancer, colorectal cancer, cervical cancer, liver cancer, head and neck cancer, pancreatic cancer, renal cancer and stomach cancer.
• treatment may include inhibiting cancer growth, including complete cancer remission, and/or inhibiting cancer metastasis, as well as inhibiting cancer recurrence.
• Cancer growth generally refers to any one of a number of indices that indicate change within the cancer to a more developed form.
• indices for measuring an inhibition of cancer growth include a decrease in cancer cell survival, a decrease in tumour volume or morphology (for example, as determined using computed tomographic (CT), sonography, or other imaging method), a delayed tumour growth, a destruction of tumour vasculature, improved performance in delayed hypersensitivity skin test, an increase in the activity of anti-cancer immune cells or other anti-cancer immune responses, and a decrease in levels of tumour-specific antigens.
• Activating or enhancing immune responses to cancerous tumours in an individual may improve the capacity of the individual to resist cancer growth, in particular growth of a cancer already present in the subject and/or decrease the propensity for cancer growth in the individual.
• an antibody molecule as described herein may be administered to an individual in combination with another anti-cancer therapy or therapeutic agent, such as an anti-cancer therapy or therapeutic agent which has been shown to be suitable, or is expected to be suitable, for the treatment of the cancer in question.
• the antibody molecule may be administered to the individual in combination with a chemotherapeutic agent, radiotherapy, an immunotherapeutic agent, an anti-tumour vaccine, an oncolytic virus, an adoptive cell transfer (ACT) therapy (such as adoptive NK cell therapy or therapy with chimeric antigen receptor (CAR) T-cells, autologous tumour infiltrating lymphocytes (TILs), or gamma/delta T cells, or an agent for hormone therapy.
• ACT adoptive cell transfer
• CAR chimeric antigen receptor
• TILs autologous tumour infiltrating lymphocytes
• gamma/delta T cells or an agent for hormone therapy.
• the antibody molecule described herein may act as an adjuvant in anti-cancer therapy. Specifically, it is thought that administration of the antibody molecule to an in individual in combination with chemotherapy and/or radiotherapy, or in combination with an anti-tumour vaccine, for example, will trigger a greater immune response against the cancer than is achieved with chemotherapy and/or radiotherapy, or with an anti tumour vaccine, alone.
• One or more chemotherapeutic agents for administration in combination with an antibody of the invention as described herein may be selected from the group consisting of: taxanes, cytotoxic antibiotics, tyrosine kinase inhibitors, PARP inhibitors, B-Raf enzyme inhibitors, MEK inhibitors, c-MET inhibitors, VEGFR inhibitors, PDGFR inhibitors, alkylating agents, platinum analogues, nucleoside analogues, antifolates, thalidomide derivatives, antineoplastic chemotherapeutic agents and others.
• Taxanes include docetaxel, paclitaxel and nab-paclitaxel; cytotoxic antibiotics include actinomycin, bleomycin, and anthracyclines such as doxorubicin, mitoxantrone and valrubicin; tyrosine kinase inhibitors include erlotinib, gefitinib, axitinib, PLX3397, imatinib, cobemitinib and trametinib; PARP inhibitors include piraparib; B-Raf enzyme inhibitors include vemurafenib and dabrafenib; alkylating agents include dacarbazine, cyclophosphamide and temozolomide; platinum analogues include carboplatin, cisplatin and oxaliplatin; nucleoside analogues include azacitidine, capecitabine, fludarabine, fluorouracil and gemcitabine; antifo
• Preferred therapeutic agents for administration with an antibody molecule as described herein are doxorubicin, mitoxantrone, cyclophosphamide, cisplatin, and oxaliplatin.
• a radiotherapy for administration in combination with an antibody molecule as described herein may be external beam radiotherapy or brachytherapy.
• An immunotherapeutic agent for administration in combination with an antibody molecule as described herein may be a therapeutic antibody molecule, nucleic acid, cytokine, or cytokine- based therapy.
• the therapeutic antibody molecule may bind to an immune regulatory molecule, e.g., an inhibitory checkpoint molecule or an immune costimulatory molecule, a receptor of the innate immune system, or a tumour antigen, e.g., a cell surface tumour antigen or a soluble tumour antigen.
• immune regulatory molecules to which the therapeutic antibody molecule may bind include CTLA-4, LAG-3, TIGIT, TIM-3, VISTA, PD-1 , CD47, CD73, CSF-1 R, KIR, 0X40, CD40, HVEM, IL-10 and CSF-1.
• receptors of the innate immune system to which the therapeutic antibody molecule may bind include TLR1 , TLR2, TLR4, TLR5, TLR7, TLR9, RIG-l-like receptors (e.g., RIG-I and MDA-5), and STING.
• tumour antigens to which the therapeutic antibody molecule may bind include HER2, EGFR, CD20 and TGF-beta.
• the nucleic acid for administration in combination with an antibody molecule as described herein may be a siRNA.
• the cytokines or cytokine-based therapy may be selected from the group consisting of: IL-2, prodrug of conjugated IL-2, GM-CSF, IL-7, IL-12, IL-9, IL-15, IL-18, IL-21 , and type I interferon.
• Anti-tumour vaccines for the treatment of cancer have both been implemented in the clinic and discussed in detail within scientific literature (such as Rosenberg S. Development of Cancer Vaccines. ASCO Educational Book Spring: 60-62 (2000)). This mainly involves strategies to prompt the immune system to respond to various cellular markers expressed by autologous or allogenic cancer cells by using those cells as a vaccination method, both with or without granulocyte-macrophage colony-stimulating factor (GM-CSF). GM-CSF provokes a strong response in antigen presentation and works particularly well when employed with said strategies.
• GM-CSF granulocyte-macrophage colony-stimulating factor
• the chemotherapeutic agent, radiotherapy, immunotherapeutic agent, anti-tumour vaccine, oncolytic virus, ACT therapy, or agent for hormone therapy is preferably a chemotherapeutic agent, radiotherapy, immunotherapeutic agent, anti-tumour vaccine, oncolytic virus, ACT therapy, or agent for hormone therapy for the cancer in question, i.e. a chemotherapeutic agent, radiotherapy, immunotherapeutic agent, anti-tumour vaccine, oncolytic virus, ACT therapy, or agent for hormone therapy which has been shown to be effective in the treatment of the cancer in question.
• chemotherapeutic agent radiotherapy, immunotherapeutic agent, anti-tumour vaccine, oncolytic virus, ACT therapy, or agent for hormone therapy which has been shown to be effective for the cancer in question is well within the capabilities of the skilled practitioner.
• an antibody that does not activate effector functions is preferred.
• lgG4 has been used but this sub-class to undergo Fab-arm exchange, where heavy chains can be swapped between lgG4 in vivo. Due to their lack of effector functions, lgG4 antibodies represent the preferred IgG subclass for receptor blocking without cell depletion. lgG4 molecules can exchange half-molecules in a dynamic process termed Fab-arm exchange. This phenomenon can occur between therapeutic antibodies and endogenous lgG4. The S228P mutation has been shown to prevent this recombination process allowing the design of less unpredictable therapeutic lgG4 antibodies.
• the CH2 domain is known bind to Fey receptors and complement. Binding of the CH2 domain to Fey receptors is required antibody-dependent cell-mediated cytotoxicity (ADCC), while binding to complement is required complement-dependent cytotoxicity (CDC).
• the CH2 domain of the antibody molecule preferably comprise one or more mutations that reduce or abrogate binding of the CH2 domain to one or more Fey receptors, such as FcyRI, FcyRIla, FcyRIIb, FcyRIII, and/or to complement.
• the inventors postulate that reducing or abrogating binding to Fey receptors will decrease or eliminate ADCC mediated by the antibody molecule. Similarly, reducing or abrogating binding to complement is expected to reduce or eliminate CDC mediated by the antibody molecule.
• this is expected to reduce or avoid liver inflammation when the antibody molecule is administered to a patient.
• reducing or abrogating binding to Fey receptors is expected to be useful where the antibody molecule comprises a second antigen-binding site for an immune cell antigen as described herein, where ADCC and/or CDC-mediated killing of immune cells bound by the antibody molecule should be avoided.
• Mutations to decrease or abrogate binding of the CH2 domain to one or more Fey receptors and/or complement are known in the art (Wang et al., 2018).
• complement activation (C1q binding) and ADCC are known to be reduced through mutation of the proline at IMGT position 114 of the CH2 domain to alanine or glycine (P1 14A or P1 14G) (Idusogie et al., 2000; Klein et al., 2016). These mutations may also be combined in order to generate antibody molecules with further reduced or no ADCC or CDC activity.
• the antibody molecule may comprise a CH2 domain, wherein the CH2 domain preferably comprises:
• amino acid residue numbering is according to the IMGT numbering scheme.
• the antibody molecule comprises a CH2 domain, wherein the CH2 domain comprises:
• amino acid residue numbering is according to the IMGT numbering scheme.
• the antibody molecule comprises a CH2 domain, wherein the CH2 domain comprises:
• amino acid residue numbering is according to the IMGT numbering scheme.
• IgG naturally persists for a prolonged period in serum due to FcRn-mediated recycling, giving it a typical half life of approximately 21 days.
• pH dependant interaction of the Fc domain with FcRn has been engineered to increase affinity at pH 6.0 while retaining minimal binding at pH 7.4
• the mutations T250Q/M428L conferred an approximately 2-fold increase in IgG half-life in rhesus monkeys.
• the M252Y/S254T/T256E variant (dubbed YTE), conferred an approximately 4-fold increase in IgG half-life in cynomolgus monkeys.
• a longer half-life is desirable in some circumstances to decrease the frequency of administration whilst maintaining or improving efficacy of the administered antibody.
• Antibodies of the invention may be provided as half-life extended variants, engineered to extend half-life in vivo serum following administration, thus antibodies of the invention may be provided as T250G/M428L or M252Y/S254T/T256E variants.
• the antibody molecules of the invention may be useful in the detection of PD-L1 , in particular in the detection of cells comprising PD-L1 at their cell surface, i.e. cells expressing cell-surface bound PD-L1.
• the cells may be immune cells, such as CD8 + T cells, CD4 + T cells, Treg cells, B cells, NK cells, NKT cells, dendritic cells, or TILs, but preferably are CD8 + T cells or TILs.
• the present invention relates to the use of an antibody molecule for detecting the presence of PD-L1 , preferably the presence of cells comprising PD-L1 at their cell surface, in a sample.
• the antibody molecule may be conjugated to a detectable label as described elsewhere herein.
• an in vitro method of detecting PD-L1 comprises incubating the antibody molecule with a sample of interest, and detecting binding of the antibody molecule to the sample, wherein binding of the antibody to the sample indicates the presence of PD-L1. Binding of the antibody molecule to a sample may be detected using an ELISA, for example.
• the present invention relates to an in vitro method of detecting cells comprising PD-L1 at their cell surface, wherein the method comprises incubating the antibody molecule with a cell sample of interest, and determining binding of the antibody molecule to cells present in the sample, wherein binding of the antibody to cells present in sample indicates the presence of cells comprising PD-L1 at their cell surface.
• Methods for detecting binding of an antibody molecule to cells are known in the art and include ELISAs, and flow-cytometry.
• the cell sample of interest may be a tumour sample obtained from an individual.
• the antibody molecules of the invention may thus be useful in the detection or diagnosis of disease or disorder, in particular the detection or diagnosis of cancer.
• the cancer may be a cancer which can be treated with an antibody molecule of the invention as described herein.
• kits for use in a method of detecting or diagnosing a disease or disorder in an individual comprising an antibody molecule as described herein.
• Figure 1 Mixed Leukocyte Reaction Assay.
• Figure 2 D01 1.10 mouse T cell activation assay.
• the functional activity of the anti-PD-L1 kappa clones, G1/894_8_E05, G1/887_4_E12 and G1/887_4_G12, towards mouse PD-L1 was tested in a T cell assay with LK35.2 overexpressing mouse PD-L1 and DO11.10 T cells. All anti-PD-L1 mAbs showed potent activity with low nanomolar EC50 values. No activity was observed for the negative control G1AA/4420.
• Figure 3 Pharmacokinetics of anti-PD-L1 mAbs in non-tumour bearing mice.
• Figure 4 Mixed Leukocyte Reaction Assay.
• the functional activity of the anti-PD-L1 kappa clones, G1AA/E05v2, G1AA/E12v2 and G1AA/G12v2 was tested in a mixed leukocyte reaction assay. All anti-PD-L1 mAbs showed potent activity with EC50 values below 0.055 nM. No activity was observed for the negative control G1 AA/4420.
• the aim of these experiments was to generate an anti-human-PD-L1 mAb that was cross-reactive with mouse and/or cynomolgus PD-L1 and which was a potent inhibitor (blocker) of PD-1/PD-L1 activity.
• Example 1 Isolation of naive anti-PD-L1 binding mAb: 280_02_G02
• Human and mouse PD-L1 antigens with fusion proteins were generated for use in antibody selections and screening. Antigens were expressed with either a monomeric C-terminal rat CD4, domains 3 and 4 (rCd4) tag (Brown and Barclay, 1994) or a dimeric human lgG1 Fc domain (resulting in hPD-L1-rCD4-His (SEQ ID NO: 79), hPD-L1-Fc-His (SEQ ID NO: 80), mPD-L1-rCD4- His (SEQ ID NO: 81 ) and mPD-L1-Fc-His (SEQ ID NO: 82).
• antigens in two different formats enabled the elimination of tag binders during sequential antibody phage display pannings.
• Expression plasmids encoding the antigens were transfected into HEK293 cells as described by Chappie et al., 2006. Supernatants were harvested 5 days after transfection and the secreted antigens were purified by Ni-NTA sepharose affinity chromatography (Schofield et al., 2007).
• Biotinylated antigen was prepared using EZ-link Sulfo-NHS-Biotin reagent (Thermo Fisher Scientific, product code 21326) following the manufacturer’s recommendations. The biotinylation reaction product was gel filtered and the monomeric fraction was collected.
• the monomeric fraction was used for all solution-phase phage-display selections.
• the average number of biotins per molecule was 1 to 3 biotins per PD-L1 monomer as determined using Fluorescence Biotin Quantitation kit (Thermo Fisher Scientific, product code 46610).
• The“IONTAS 1” human antibody phage display library (IONTAS Ltd.) was employed to select for anti-PD-L1 clones.
• the antibody genes used to construct the IONTAS 1 library were derived from human lymphocytes (42 buffy coat donations) and one tonsil tissue sample. Both the buffy coats and tonsil tissue were obtained under Local Research Ethical Committee approval.
• the first, second and third selection rounds employed human PD-L1-Fc- His (SEQ ID NO: 80), mouse PD-L1-rCD4-His (SEQ ID NO: 81 ) and human PD-L1-Fc-His (SEQ ID NO: 80), respectively.
• Nunc Maxisorp Immunotubes (Thermo Scientific, 444202) were coated overnight with 10 gg/nnl of human PD-L1-Fc-His for direct selection.
• the tubes were rinsed 2x in PBS and then blocked by filling to the top with PBS 2% Marvel/PBS (MPBS) and incubated for 1 hour, then the tubes were washed three times with PBS. Also, the IONTAS 1 antibody phage display library (500 pi) was blocked with 4% MPBS (500 pi) for 1 hour. To each antigen coated immunotube 2% MPBS (179.25 pi), Fc-His (10.75 pi, 2.8 mg/ml) and blocked IONTAS 1 antibody phage display library (1 10 pi, 2 x 10 12 colony forming units, 2% MPBS) was added.
• MPBS Marvel/PBS
• Fc-His was added to the selection to remove anti-Fc binders binding to the solid phase immobilized Fc tagged antigen.
• the antibody phage display library was allowed to bind to the directly-immobilized antigen for 1.5 hours at room temperature. After this time, the immuno-tubes were washed 6 times with PBS-T (PBS, pH7.4, 0.1 % TweenTM-20), then washed 6 times with PBS. Bound phages were eluted and propagated using standard phage recovery procedures.
• the second round of antibody phage display selection was performed as above, except that mouse PD-L1-rCd4-His (SEQ ID NO: 81 ) was used to coat the Nunc immunosorb tube, rCd4-His was used instead of Fc-His for the de-selection and the round 1 output phage, selected against human PD-L1-Fc-His, was used as the input phage population.
• the third round with human PD-L1-Fc-His was performed exactly as round 1.
• variable heavy (VH) anti-PD-L1 antibody population was shuffled with a naive variable light (VL) antibody population as described by Dyson et al., 201 1 , and this shuffled, rescued, antibody-phage-display population was employed in solution phase selections.
• panning was performed with human PD-L1-rCd4-His (SEQ ID NO: 79) (10 nM), human PD-L1- rCd4-His (SEQ ID NO: 79) (200 pM) and mouse PD-L1-rCd4-His (SEQ ID NO: 81 ) (10 nM) at rounds 1 , 2 and 3, respectively, and this resulted in an output anti-PD-L1 scFv population termed “Selection 280”.
• This scFv population contained human and mouse anti-PD-L1 binding scFvs, as determined by a phage polyclonal ELISA performed as described by Dyson et al., 201 1 , and displayed minimal cross-reactivity with human PD1 or with rCd4 or Fc tags.
• the Selection 280 scFv population from Example 1.2.3 was screened by ELISA to identify the clones which bound best to human PD-L1.
• the scFv population was subcloned into the soluble scFv vector pSANGI O and E.coli cultures containing soluble scFvs were prepared as described (Martin et al., 2006; Studier, 2005). Soluble scFv were then used in a monoclonal ELISA with immobilised human PD-L1-rCd4-His (SEQ ID NO: 79).
• a total of 470 clones were screened and this resulted in the identification of 346 anti-PD-L1 clones with a binding signal for PD-L1 at least 10-fold above background compared with“empty” blocked wells containing no antigens.
• the 192 best anti-human PD-L1 clones assessed by primary ELISA signal were selected for further analysis.
• Biotinylated human PD-L1-Fc-His (SEQ ID NO: 79) (50 pi, 0.2 nM), was pre-mixed with E. coli culture supernatant containing scFv.
• the Nunc 96-well plates were washed 3 times with PBS, 0.1 % TweenTM-20 (PBS-T) and 3 times with PBS, then the human PD-L1-Fc-His / scFv mix was added and incubated for 1 hour at room temperature.
• the 183 anti-PD-L1 scFv clones identified were screened further for mouse PD-L1 cross-reactivity in a primary ELISA, as described in Example 1.3.1 , but using immobilised mouse PD-L1-rCD4-His instead of human PD-L1. This identified 50 mouse cross-reactive anti- PD-L1 clones, which were candidates for conversion to lgG1 format.
• the anti-PD-L1 scFv clones which blocked the interaction between PD-L1 and PD1 were converted to lgG1 format by sub-cloning the VL and VH genes into the lgG1 expression plasmid plNT3-lgG1 and were expressed in HEK293 at 4 ml scale as described by Chappie et al., 2006.
• the antibodies were batch affinity purified with Protein A sepharose beads (PC-A100) and Proteus “1-step batch” midi-spin columns (Generon, GEN-1 SB08) according to the manufacturer’s instructions. Dialysis of the purified antibodies was performed with GeBAflex maxi tubes, with an 8 kDa cut-off (Generon, D045). If necessary, the antibodies were concentrated to 2 pM by ultrafiltration.
• the functional activity of the purified anti-PD-L1 mAbs was then assessed in a co-culture reporter assay screen.
• This screen was performed using the GloResponse NFAT-luc2/PD-1 stable Jurkat cell line (Promega, CS187102) and Thaw-and-Use PD-L1 cells (Promega, CS178103) in accordance with the manufacturer’s instructions.
• the PD-L1 cells were plated in HAM’S-F12 medium containing 10% FBS.
• the next day PD-1 Jurkat reporter cells (Promega, CS187102) were resuspended in assay medium (90% RPMI 1640, 1 % FBS).
• the phage selections strategies employed identified more than 50 anti-human PD-L1 binding clones with potent in vitro PD-1/PD-L1 blocking activity as well as mouse PD-L1 cross-reactivity.
• G1/280_02_G02 showed potent activation in a cell-based PD-L1 reporter assay and was therefore selected for further optimisation.
• Example 2 Chain shuffling to generate kappa light chain-containing anti-PD-L1 clones
• the G1/280_02_G02_NS antibody possesses a lambda light chain.
• kappa light chains As most monoclonal antibodies used in a clinical context to date have kappa light chains (Jain et al., 2017), it was sought, by the use of a chain-shuffling campaign, to generate clones comprising the heavy chain of the G1/280_02_G02_NS antibody but paired with kappa light chains, which retained affinity for human PD-L1 and mouse cross-reactivity.
• the IONTASTM kappa-light-chain library in the phage display plasmid plONTAS-1 was used to prepare a light-chain-shuffled library of scFv clones comprising the heavy chain of the G1/280_02_G02_NS antibody coupled with light chain variants.
• a number of phage-display solution selections were performed in three rounds using biotinylated human PD-L1-rCD4-His (SEQ ID NO: 79) and mouse PD-L1-rCD4-His antigens (SEQ ID NO: 81 ).
• the selections were performed by decreasing the antigen concentrations in every round (varying from 100 to 0.02 nM) and for each round of selection a“no-antigen” control was used. Details of the selections are shown in Table 2. Table 2.
• the K D values of the clones were compared with that of clone 280_02_G02_NS in Ig1 format (G1/280_02_G02_NS). Ten clones of unique sequence were identified that showed higher affinity for human PD-L1 than clone G1/280_02_G02_NS and were therefore subjected to full kinetic analysis together with clone G1/280_02_G02_NS.
• the ability of the anti-PD-L1 clones containing a kappa light chain, G1/887_04_E12, G1/894_08_E05 and G1/887_04_G12, to block the interaction between PD1 and PD-L1 was assessed in a bioluminescent cell-based assay using a PD1/PD-L1 Blockade Bioassay product (Promega, J1250/J1255) in accordance with the manufacturer’s recommendations. The blocking activity was compared to the G1/280_02_G02_NS clone. Briefly, all antibodies were expressed and purified as described in section 1.3.3 and tested at 3- fold dilutions from 100 nM to 35 pM (eight concentrations) in duplicates.
• IC 50 values are shown in Table 3. All clones tested were shown to be potent inhibitors of the PD1/PD-L1 interaction, with the three kappa light chain-containing clones G1/887_04_E12, G1/894_08_E05 and G1/884_04_G12 exhibiting even better IC 50 values than the lambda light chain-containing clone G1/280 02 G02 NS.
• the anti-PD-L1 mAbs diluted in HBS-EP buffer (GE Healthcare, BR100188) at 2 pg/ml, were injected individually on flows cell 2, 3 and 4 of a Protein A chip (GE Healthcare, 29127556) at 30 pl/min to achieve a final response of approximately 1 10 RU.
• the binding affinities of the G1/894_08_E05, G1/887_04_E12 and G1/887_04_G12 clones were about 1.8 to 4.8 fold higher for human PD-L1 and 2.7 to 4.7 fold higher for cynomolgus PD-L1.
• the affinities of the clones for recombinant mouse PD-L1 were lower, with K D values ranging from 38 to 225 nM, with the highest affinity being observed for the G1/887_04_E12 clone.
• Human PD-L1 sequence (SEQ ID NO: 83) was subcloned into pcDNATM5/FRT vector (ThermoFisher Scientific Cat. No. V601020) using Kpnl and Notl restriction sites and the vector was then transformed into Flp-ln T-REx 293 cell line (Life Technologies, R780-07) using Lipofectamine 2000 (Life Technologies, 11668-019). Cells were grown in DMEM containing 10% FBS, 100 pg/nnl Hygromycin B (Melford Laboratories Ltd, Z2475) and 15 pg/nnl Blasticidin (Melford Laboratories Ltd, B1 105) for 3-4 weeks until colonies of stably transformed cells had formed.
• the anti-human PD-L1 mAbs, G1/894_08_E05, G1/887_04_E12 and G1/887_04_G12 were then tested for binding to HEK293 cells expressing human PD-L1 using flow cytometry. Non-specific binding was also assessed by testing binding to HEK293 parental cells lacking human PD-L1 (Flp-ln T-Rex 293 cell line, Life Technologies, R780-07).
• HEK293 and HEK293.hPD-L1 suspensions were prepared in PBS containing 0.5% BSA (Sigma, A7906) and seeded at 1 x 10 5 cell/well in 100 pi in round bottomed 96-well plates (VWR, 734- 1797). Cells were washed once in 100 pi 1x DPBS and mAbs G1/894_08_E05, G1/887_04_E12 and G1/887_04_G12 were diluted (1.10 -6 - 0.013 nM, 5-fold dilutions) in 100 pi 1x DPBS (Gibco, 14190-094).
• the washed cells were resuspended in the diluted antibody mixture, incubated at 4°C for 30 minutes, and then washed once in PBS.
• 100 pl/well of secondary antibody Alexa Fluor 647-AffiniPure Goat Anti-Human IgG, F(ab')2 Fragment Specific, Stratech Scientific, 109-605- 006-JIR
• secondary antibody Alexa Fluor 647-AffiniPure Goat Anti-Human IgG, F(ab')2 Fragment Specific, Stratech Scientific, 109-605- 006-JIR
• diluted 1 :1000 in PBS was then added, the cells/antibody mixture was incubated for 20 mins at 4°C, and the cells were then washed again with PBS and resuspended in 100 pi of PBS containing 7AAD (1 :1000, Biotium, 40043) before being analysed using a Canto II flow cytometer (BD Bioscience).
• GMFI geometric mean fluorescence intensity
• the G1/894_08_E05, G1/887_04_E12 and G1/887_04_G12 clones were found to bind to cell surface human PD-L1 with ECso values in the range of 0.26 - 0.29 nM (see Table 5). No binding to parental HEK293 cells was observed showing the specificity of the binding. Therefore, all mAb clones tested bound specifically to PD-L1 , with no non-specific binding observed.
• MLR Mixed Lymphocyte Reaction
• PBMCs were isolated from leukocyte cones by Ficoll gradient separation.
• CD4+ T cells were isolated using a Human CD4+ T Cell Isolation Kit (Miltenyi Biotec Ltd, 130-096-533) according to the manufacturer’s instructions.
• Human T-Activator CD3/CD28 Dynabeads (Life Technologies, 1 1131 D) were resuspended by vortexing. Beads were transferred to a sterile 15ml tube and 10ml RPMI (Life Technologies, 61870044) with 10% FBS (Life Technologies, 10270106) and 1x Penicillin Streptomycin (Life Technologies, 15140122) was added to wash the Dynabeads. The supernatant was discarded.
• CD4+ T cells at 1.0 x10 6 cells/ml in RPMI with 10% FBS and 1x Penicillin Streptomycin Solution and 50 lU/ml recombinant human IL2 (Peprotech, 200-02-50pg) with 3:1 bead to cell ratio was transferred to a T75 flask (Greiner Bio- one, 690195) and incubated at 37°C + 5% CO2. After 3 days the cells were gently resuspended and counted. The cell density was maintained between 0.8-1 x 10 6 cells/ml by adding fresh media (RPMI-10% FBS + Penicillin Streptomycin Solution 1X + 50IU/ml rhulL2) as needed.
• CD3/28 beads were removed and CD4+ T cells were rested overnight at 1 x 10 6 cells/ml fresh media RPMI-10% FBS + Penicillin Streptomycin Solution IX with reduced 10lU/ml rhulL2. The cells were stored frozen until required. 3.4.2 Generation of iDC
• monocytes were isolated from human PBMCs using a Human Pan Monocyte Isolation Kit, (Miltenyi Biotec Ltd, 130-096-537) following the manufacturer’s instructions. Monocytes were differentiated to iDCs using Human Mo-DC Differentiation Medium (Miltenyi Biotec Ltd, 130-094- 812) following the manufacturer’s instructions.
• Expanded T cells were thawed one day before the experiment, washed with AIM V Medium (Gibco, 12055-091 ) and incubated at 37 ° C, 5% CO2 in AIM V Medium overnight.
• the anti-human PD-L1 mAbs, G1/894_08_E05, G1/887_04_E12 and G1/887_04_G12 were diluted at 4x the final concentration in triplicate in 50 pi AIM V Medium in 96 well round bottom plates (VWR, 734-1797).
• An anti-FITC antibody, designated 4420 Bedzyk et al., 1989; Bedzyk et al., 1990), containing the LALA mutation was included as negative control.
• the anti-human PD-L1 mAbs showed potent activity in the MLR assay with EC 50 values of less than 0.030 nM and a maximum level of IFN-g (Emax) of greater than 10000 pg/ml (Table 6, representative Figure 1 ).
• the EC 50 indicates the concentration of mAb at which half of the response is achieved, whereas the E max is an absolute value that indicates the maximum concentration of IFN-g achieved in the assay. No activity was observed with the negative control G1AA/4420 mAb, as expected. Table 6.
• IL-2 release is a marker of T cell activation.
• T cells expressing endogenous murine PD-1 were transfected with empty vector (pLVX). B-cells were transfected with a mouse PD-L1 construct.
• Lentiviral transduction methodology was used to generate D01 1.10 cells (National Jewish Health) containing the empty lentiviral vector pLVX using the Lenti-X HTX Packaging System (Clontech, 631249).
• Lenti-X expression vector (pLVX) (Clontech, 631253) was co-transfected with a Lenti-X HTX Packaging Mix into the Lenti-X 293T Cell Line (Clontech, 632180) to generate virus.
• the DO11.10 cell line was transduced using the lentiviral particles produced with the Lenti-X HTX Packaging System.
• Lentiviral transduction methodology was used to generate LK35.2 B cell lymphoma cells (ATCC, HB-98) over-expressing mouse PD-L1 using the Lenti-X HTX Packaging System (Clontech,
• Lenti-X expression vector (Clontech, 631253) containing, mouse PD-L1 cDNA (encoding the mouse PD-L1 of SEC ID NO: 84), was co-transfected with a Lenti-X HTX Packaging Mix into the Lenti-X 293T Cell Line (Clontech, 632180) to generate virus.
• the LK35.2 cell line was transduced using the lentiviral vectors produced with the Lenti-X HTX Packaging System. 3.5.3 Mouse DO1 1.10 T cell activation assay
• Dilutions of the anti-PD-L1 mAbs G1/887_04_E12, G1/887_04_G12 and G1/894_08_E05 or the anti-FITC negative control mAb (G1AA/4420) were prepared in experimental media (DMEM (Gibco, 61965-026), 10% FBS (Gibco, 10270-106), 1 mM Sodium Pyruvate (Gibco, 11360-070)).
• the mAbs were mixed 1 : 1 with 4x10 5 /ml LK35.2 mPD-L1 cells in experimental media in presence of 2.46 pM OVA peptide (H-ISQAVHAAHAEINEAGR-OH, Pepscan) (100 pL LK35.2 mPD-L1 cells (B cell hybridoma transduced with a lentiviral vector containing mPD-L1 to overexpress mouse PD-L1 )/mAb mix per well in 96-round bottom plate) and incubated at 37°C, 5% CO2 for 1 hour.
• OVA peptide H-ISQAVHAAHAEINEAGR-OH, Pepscan
• DO1 1.10 pLVX cells DO1 1.10 T cell hybridoma transduced with an empty lentiviral vector
• 100 pi of the LK35.2 mPD-L1/ (mAbs) mix The cells were then mixed before being incubated at 37°C, 5% CO2 for 24 hours.
• Supernatants were collected and assayed with mouse IL-2 ELISA kit (eBioscience, 88-7024-88 or R&D systems, SM2000) following the manufacturer’s instructions. Plates were read at 450 nm using the plate reader with the Gen5 Software, BioTek. Absorbance values of 570 nm were subtracted from those of 450 nm (Correction).
• the standard curve for calculation of cytokine concentration was based on a four parameter logistic curve fit (Gen5 Software, BioTek). The concentration of mouse IL-2 was plotted vs the log concentration of mAb and the resulting curves were fitted using the log (agonist) vs response equation in GraphPad Prism.
• the results are shown in Figure 2 and Table 7.
• the anti-human PD-L1 mAbs showed significant activity in the mouse T cell activation assay with potencies (EC50) in the range of 1 -4.4 nM. No activity was observed with the negative control mAb as expected.
• G1/887_04_E12 which showed the highest affinity for recombinant mouse PD-L1 (see Table 4), was also the most potent clone in the T cell activation assay. The differences in potency were smaller than the measured affinities which is likely due to the high overexpression of mouse PD- L1 on the LK35.2 cells in this assay.
• the anti-PD-L1 mAbs G1/894_08_E05, G1/887_04_E12, and G1/887_04_G12 were tested in a research-grade PK study in which the mAbs were administered to non-tumour bearing mice and the concentrations in the blood serum were measured over time.
• mice Male 9-10 weeks old were divided into 4 groups of 3 animals to receive a single dose of the test antibody administered intravenously.
• the animals were dosed once with the anti- PD-L1 mAbs at 8 mg/kg.
• Antibodies were administered intravenously (100 pi, tail vein) and then blood samples (20 pi, tail vein) were collected at 7 different time points, from 3 mice per time point. The time points were 0.5, 1 , 6, 24, 48, 96 and 144 hours post-dosing. Blood was allowed to clot at room temperature for 2 hours, spun in a centrifuge at 2000 g for 20 min, then the serum was recovered and stored at -80° C.
• the anti-PD-L1 mAbs showed no initial rapid clearance and exposure levels were maintained at more than 24 pg/ml during the 6-day period (Figure 3). This data is as expected for mAbs and in line with published anti-PD-L1 mAb data (Deng et al., 2016).
• the anti-PD-L1 mAbs G1/894_08_E05, G1/887_04_E12, and G1/887_04_G12 were shown to be potent activators of human T cells in vitro, to have functional mouse crossreactivity, and to have satisfactory PK profiles in non-tumour bearing mice.
• the NSNT (SEQ ID NO: 6) sequence was changed in the four kappa light chain-containing clones by site-directed mutagenesis to either GGST (SEQ ID NO: 7), SGGT (SEQ ID NO: 5) or SGNA (SEQ ID NO: 8) to produce the variant clones identified in Table 8.
• the parent and resulting variant clones (all in lgG1 format) were transfected at 0.8 ml scale, and culture supernatants harvested five days after transfections were used to determine the affinities of the clones for human and cynomolgus PD-L1-rCD4-His by SPR. Cyno PD-L1-rCD4-His was generated as described in Example 1.1. With the exception of the variant clones derived from the G1/887_04_E12 clone, all variant clones retained their sub nanomolar affinities for human and cynomolgus PD-L1 as compared to their respective parent clone (see Table 8).
• the potential deamidation site (NSNT (SEQ ID NO: 6) at Kabat position 54 to 57) in the H-CDR2 loop of the G1/280_02_G02_NS clone was also modified to SGGT (SEQ ID NO: 5).
• a further potential deamidation site (NS motif) identified at Kabat positions 31 to 32 in the CDR1 of the lambda light chain of this clone was modified to NY by mutating serine 32 (Kabat numbering) to a tyrosine, as tyrosine is found at this position in several germline sequences, such as IGLV2-8-01 , IGLV2-8-02, IGLV2-8-03, IGLV2-11-01 , IGLV2-1 1-02, IGLV2-1 1-03 and IGLV2-14-01 , IGLV2-14-02, IGLV2-14-03, IGLV2-14-04.
• the combination of these modifications yielded the lambda light chain-containing clone G1/lambdav3, which was also selected for further characterisation.
• the threonine residue at Kabat position 28 in the VH region of the G1/929_01_A02“SGGT” variant clone identified in Example 4 was mutated to a proline, as is present at the same position in its parent clone G1/887_04_E12, with a view to improving its affinity for human and cynomolgus PD-L1.
• the heavy and light chain sequences respectively are shown in SEQ ID NO: 47 and SEQ ID NO: 48 for G1AA/E12v2; SEQ ID NO: 49 and SEQ ID NO: 50 for G1AA/G12v2; SEQ ID NO: 51 and SEQ ID NO: 52 for G1AA/E05v2, and SEQ ID NO: 61 and SEQ ID NO: 62 for G1AA/lambdav3.
• the CDR-based antigen-binding sites of a mAb can be combined with Fcab (fragment crystallisable antigen-binding) moieties generated in a constant domain to provide bispecific antibodies referred to as mAb 2 .
• the anti-PD-L1 antibodies of the invention were produced in anti-CD137/anti-PD-L1 mAb 2 format to test their specificity for human PD-L1.
• the mAb 2 were produced in lgG1 LALA format, with the heavy chain having an anti-human CD137 binding site in the CH3 domain of the Fcab moiety and a VH domain from anti-PD-L1 mAb clone G1AA/E12v2, G1AA/E05v2, G1AA/G12v2 or G1AA/lambdav3.
• the heavy chains were co-transfected with the corresponding light chain of the anti-PD-L1 mAbs.
• the mAb 2 were produced by transient expression in HEK293-6E cells and purified using mAb Select SuRe protein A columns to yield clones FS22-172-003AA/E12v2, FS22-172-003AA/G12v2, FS22-172-003AA/E05v2 and FS22- 172-003AA/lambdav3.
• the heavy and light chain sequences respectively are shown in SEQ ID NO: 85 and SEQ ID NO: 86 for FS22-172-003AA/E12v2, SEQ ID NO: 87 and SEQ ID NO: 88 for FS22-172-003AA/G12v2, SEQ ID NO: 89 and SEQ ID NO: 90 for FS22-172-003AA/E05v2, and SEQ ID NO: 91 and SEQ ID NO: 92 for FS22-172-003AA/lambdav3.
• G1AA/lambdav3 namely, NSNT (SEQ ID NO: 6) to SGGT (SEQ ID NO: 5) in the VH-CDR2, NS to NY in the VL-CDR1 , and the LALA mutation
• the kappa light chain-containing mAbs G1AA/E12v2, G1AA/E05v2, and G1 AA/G12v2 namely, the LALA mutation and, in G1 AA/E12v2 only, threonine to proline at Kabat position 28 in the VH region
• the affinities of these anti-PD-L1 mAbs for human and cynomolgus PD-L1 were determined as described in Example 3.2.
• the mAbs G1AA/lamdav3, G1AA/E05v2, G1AA/E12v2 and G1AA/G12v2 exhibited affinities for human and cynomolgus PD-L1 similar to those observed in Example 3.2 (Table 4) for mAbs G 1 AA/280_02_G02_N S , G1/894_08_E05, G1/887_04_E12 and G1/887_04_G12, demonstrating that the binding affinities of the mAbs and mAb 2 tested were not affected by the modification of the potential deamidation sites or the introduction of the LALA mutation.
• the G1AA/E12v2 mAb showed the lowest K D value of all four mAbs tested (0.21 nM for human PD-L1 , and 0.37 nM for cynomolgus PD-L1 ).
• the VH of G1AA/E12v2 differs from that of G1/929_01_A02 (Example 4, Table 8) by one residue; G1 AA/E12v2 has a proline at Kabat position 28 whereas G1/929_01_A02 has a threonine at this position.
• G1/929_01_A02 had a greater than 10-fold lower affinity for both human and cynomolgus PD-L1 when compared to G1AA/E12v2; this data demonstrates the importance of the proline residue at position 28 (Kabat nomenclature) in the VH of clone G1AA/E12v2 for its affinity for human and cynomolgus PD-L1.
• PD-L1 belongs to the B7 homology family of immune checkpoint regulators (Ni and Dong, 2017).
• the aim was to demonstrate specificity by showing no binding of the mAb 2 to closely-related antigens at a concentration of 1 pM, but showing binding to PD-L1 receptors at a concentration of 1 nM.
• Flow cells on CM5 chips were immobilised with approximately 1000 RU of either human PD-L2- Fc (R&D Biosystems, 1224-PL), CD80-Fc (R&D Biosystems, 140-B1 ), PD-1-His (R&D Biosystems, 8986-PD), B7-H3-His (F-star in-house production), PD-L1-Fc (R&D Biosystems, 156-B7) or PD-L1-His (Acrobiosystems, PD1-H83F3).
• Flow cell 1 was run as a blank immobilisation.
• the mAb 2 were diluted to 1 pM and 1 nM in 1x HBS-EP buffer (GE Healthcare, product code BR100188), allowed to flow over the chip for 3 min and then allowed to dissociate for 4 min. A 30-seconds injection of 10 mM glycine pH 1.5 was used for regeneration. Positive control mAbs were injected at 50-100 nM to demonstrate the coating of each antigen. Binding levels were determined at the end of the association phase and compared.
• 1x HBS-EP buffer GE Healthcare, product code BR100188
• Example 3.4 This difference is believed to be due to donor variability, as the response depends on the allogenic reaction between T cells from one donor and the monocyte derived dendritic cells from another donor.
• the potency of the anti-human PD-L1 mAbs was consistent with the data described in Example 3.4, as was the ranking of the clones by order of potency. No activity was observed for the negative control G1 AA/4420 mAb, as expected.
• the mAbs G1AA/E05v2, G1AA/E12v2 and G1AA/G12v2 were produced at lab-scale and characterised by the standard analytical methods of SEC and Differential Scanning Calorimetry (DSC).
• DNA sequences encoding the mAbs G1AA/E05v2, G1AA/E12v2 and G1AA/G12v2 were transfected into HEK293 6E (National Research Council Canada) cells using PEIpro (Polyplus, France). After 5 days, cell culture fluids were harvested, and purified on MabSelect Protein-A pre packed columns using AKTAxpress instrument (both GE Healthcare, Uppsala, Sweden). Equilibration of the columns was carried out in 50mM Tris, 250 mM NaCI at pH 7.0 followed by loading with harvested cell culture fluid. The resin was washed using 50mM Tris, 250 mM NaCI at pH 7.0 and this was followed by eluting the mAb using buffer at pH of less than 3.5.
• Post-purification SE-UPLC was performed within 24 hours of purification (material was stored at 4°C) using an Acquity H-Class Bio UPLC (Waters Corp. UK) to measure the percentage of monomer.
• An Acquity UPLC BEH200 SEC 1.7mm column (4.6 x 150mm) was used, the mobile phase consisted of 250mM sodium phosphate, 100 mM L-Arginine at pH 6.8. Quantification of monomer, low molecular and high molecular weight species was performed using Empower software (Waters Corp, UK).
• T m The melting temperature (T m ) of G1AA/E05v2, G1AA/E12v2 and G1AA/G12v2 was measured using a Microcal VP-capillary differential scanning calorimeter (DSC).
• DSC Microcal VP-capillary differential scanning calorimeter
• G1AA/lambdav3 was included to assess the difference between the kappa and lambda light chain-containing mAbs. Samples were measured in sample buffer at a concentration of 0.2 mg/ml. The scan rate was set at 60°C/hr and data were collected between 35°C and 100°C. Data analysis was performed with Origin 7.0 software. As the DSC peaks of the Fab and CH3 were overlapping, one value was reported.
• Curran MA Montalvo W, Yagita H, Allison JP. PD-1 and CTLA-4 combination blockade expands infiltrating T cells and reduces regulatory T and myeloid cells within B16 melanoma tumors. Proc. Natl. Acad. Sci. U.S.A. 107(9), 4275-80 (2010).
• Dyson MR Zheng Y, Zhang C, Colwill K, Pershad K, Kay BK, Pawson T, McCafferty J: Mapping protein interactions by combining antibody affinity maturation and mass spectrometry.
• Herbst RS Soria JC, Kowanetz M, Fine GD, Hamid O, Gordon MS, Sosman JA, McDermott DF, Powderly JD, Gettinger SN, Kohrt HE, Horn L, Lawrence DP, Rost S, Leabman M, Xiao Y, Mokatrin A, Koeppen H, Hegde PS, Mellman I, Chen DS, Hodi FS.
• Predictive correlates of response to the anti-PD-L1 antibody MPDL3280A in cancer patients. Nature 515(7528), 563-7 (2014).
• Minibody A novel engineered anti-carcinoembryonic antigen antibody fragment (single-chain Fv- CH3) which exhibits rapid, high-level targeting of xenografts. Cancer Res. 56(13), 3055-61 (1996).
• CDRs according to the Kabat scheme are shown in italics and underlined
• CDRs according to the IMGT scheme are shown in bold italics, therefore any overlapping IMGT and Kabat CDR sequences are shown in bold, italics and underlined.
• variable domain in italics and, where applicable, location of LALA mutation in bold and underlined.
• variable domain shown in italics. Amino acid sequence of heavy and light chain of FS22-172-003AA/E05v2 mAh 2

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