OmniChickens: The Next Generation Antibody Discovery Platform

Transcription

1 OmniChickens: The Next Generation Antibody Discovery Platform Antibody Engineering and Therapeutics 2017 Bill Harriman December 12, 2017

2 OmniAb Naturally optimized human antibodies

3 Three Species for Better Epitope Coverage Different immune response genes Rat SD vs BN vs LEW vs mouse B6.SJL Diverse V-genes Single framework in OmniChicken but highly outbred with diverse MHC Different immunogenicity in different species Human antigen : rat immunogen mouse immunogen chicken immnogen Functional antibodies: OmniMouse vs OmniRat vs OmniChicken Mouse Epitope coverage Chicken Rat 3

4 OmniAb Best-in-class antibody discovery technology Only technology with 4 animal platforms Three species (rat, mouse and chicken) Mono- and bi-specific antibodies Sequence diversity provided with different animals/species Highest quality antibodies for the most difficult targets reported by partners Antibodies with great specificity, affinity and manufacturability Freedom to operate for all indications worldwide Well validated technology >300 projects with >30 partners (large pharma and small biotech) 4 Phase I trials initiated 4

5 5 OmniAb Partners A Growing and Diverse List

6 OmniAb Antibody Platform Three Species One License Platform also includes OmniFlic rat designed for bispecific antibodies

7 Powered By Evolution 300 million years primordial target gene 95 million years chicken orthologue murine orthologue human orthologue Greater evolutionary distance yields greater immunogenicity and more antibody diversity 7

8 Orthologue Comparison sequence differences at protein level average Δ 2-3x Chicken orthologues are always more divergent from human than those from mammalian species 8

9 HER2 Orthologues human vs mouse (differences in pink) human vs chicken (differences in green) 9

10 Recognition of Highly Conserved Targets by Chickens Chickens have been used historically to generate antibodies to mammalian conserved targets- but only as polyclonals, not monoclonals Antigen Reference RNA polymerase II - bovine (Carroll and Stollar 1983) β2-microglobulin - human (Horton, Holden et al. 1985) Kallikrein - human (Burger, Ramus et al. 1985) IGF1-R & Insulin-R - human (Stuart, Pietrzyk et al. 1988) PCNA - bovine (Gassmann, Thommes et al. 1990) Activin A - human (Murata, Saito et al. 1996) Prion protein (PrP) peptide - bovine (Matsushita, Horiuchi et al. 1998) Mannose-6-P/IGFII-R - human (Lemamy, Roger et al. 1999) Hypoxia Inducible Factor-1α - human (Camenisch, Tini et al. 1999) Melatonin receptor - human (Williams, Drew et al. 2001) Cystatin C - human (Hansson, Flodin et al. 2008) 10

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12 Species x-reactive mabs to a GPCR: GIP Receptor Case Study Immunization: hu prot hu prot hu prot modna modna hu prot Screening: Homology comparison (human vs mouse) (human vs chicken) 80-85% no orthologue identified mogipr/cho CHO Results: Titer (prot) 12 Titer (cells) mabs (hu) mabs (pan) Antag using GIPR expressing cells in GEM assay allowed for efficient recovery of panmammalian reactive mabs

13 Biolayer Interferometry-Derived Epitope Clustering for Anti-GIPR Antibodies 13

14 Novel Antagonistic Epitopes Revealed on GIPR rodent derived mabs only recognize epitope R 14

15 Novel Antagonistic Epitopes Revealed on GIPR 15 chicken immunization led to discovery of 4 new epitope bins!

16 What are OmniChickens? OmniChickens have been genetically engineered to generate human sequence antibodies OmniChickens have normal B cell populations and respond quickly to immunological challenge Antigen recognition properties of OmniChickens mirror those of wild-type chickens: 1) wide epitope coverage 2) multi-species cross reactivity 3) response to highly conserved targets chicken V genes human V genes WT chicken Ig locus OmniChicken Ig locus chicken C genes chicken C genes 16

17 Design of engineered Ig loci gene conversion germline VH 3-23 (for H locus) VK 3-15 (for L locus) diversified B cells for animation go to: Human V genes selected for high expression level, stability, and ubiquity Pseudo-V s have high diversity in CDRs and minimal diversity in FWs 17

18 FACS profiles of OmniChicken B-cells Comparable B cell populations in wild-type and Omni chickens WT Ig-KO OmniChicken B-cell staining in OmniChickens is comparable to wild type: As part of the characterization of the OmniChicken, peripheral blood lymphocytes were isolated and stained with a panel of B-cell markers. Briefly, samples were taken from wild type, heavy chain knockout and Omni birds, and PBLs were isolated using ficoll. Cells were stained with ms anti-bu1 (a chicken B-cell marker), anti-ch IgM (μ-specific), or anti-ch IgL (λ-specific). Shown are representative plots from each genotype. KO, Heavy chain knockout; HuMab, SynVK-CK/SynVH-A7/DKO 18

19 OmniChicken immune response to antigen cocktail polyclonal response (serum ELISA) Thrombin mabs: epitope & sequence diversity selected mab profiles AA substitution per 100 residues 19

20 Recognition of highly conserved targets that are non-immunogenic in mouse Human brain-derived neurotrophic factor (BDNF) is highly conserved in mammals; human/murine sequence identity is 97%, whereas human/chicken identity is 91% Human BDNF is non-immunogenic in mice, but both engineered and wild-type chickens have been shown to respond. BDNF mab sequence diversity AA substitution per 100 residues 20

21 Comparison of WT and HuMab responses to model antigen progranulin (PGRN) Human Progranulin (PGRN) was chosen as a model antigen for the comparison of epitope coverage between host animals. PGRN is immunogenic in both mice and chickens, and large panels of mabs from each source have been recovered. Previously published work demonstrates that wild-type chickens recognize different epitopes than mice, including those that are species cross-reactive Current data demonstrates that OmniChickens retain the epitope coverage profile of WT chickens 21

22 Omni and WT chickens share antigen recognition characteristics Abdiche et al. MAbs Dec 14:0. WT Chicken vs WT Mouse (anti-pgrn mabs) OmniChicken KD (nm) Bin msx hupgrn C+D No N.D. C+D No N.D. C+D No N.D. C+D Yes N.D. C+D No N.D. C+D No N.D. C+D Yes 17.4 C+D Yes N.D. C+D Yes N.D. C+D No N.D. G No N.D. A No N.D. A No 1.0 E No N.D. C+D No 2.6 C+D No N.D. C+D Yes 17.7 C+D Yes 3.6 B Yes 0.2 B Yes 0.5 B Yes 0.2 B Yes 0.1 B Yes 6.9 B Yes 1.1 P No 1.7 P Yes 0.5 B Yes 25.1 B Yes 38.8 B Yes 2.3 B Yes 4.9 B Yes 13.5 B Yes 6.5 B No 4.0 B No N.D. P Yes N.D. P No 0.6 P No 2.1 P No N.D. A Yes 0.5 A Yes 5.1 A Yes N.D. G No N.D. G No 1.7 A No N.D. G No 0.2 green nodes are chicken mabs purple nodes are mouse mabs species x-reactive indicated by red arrows 22

23 Sequence Diversity of PGRN mabs from OmniChicken VL VH 23 diversity is principally focused in the CDR regions of human VH and VL; a result of both transgene design and cellular selection

24 Conclusions OmniChickens have a phenotypically normal B cell compartment and can respond to a variety of antigens OmniChickens retain the antigen recognition capabilities of wild-type chickens, including response to conserved antigens, unique epitope coverage, and species cross-reactivity OmniChickens generate high affinity and high specificity antibodies through CDR focused diversification of transgenes that are designed upon a single-family human antibody scaffold (VH3/VK3) 24

25 16 OmniChicken Partner Programs in Progress Titer Achieved unique epitope x-reactive mabs advanced to animal models Partner A Target 1 Targets 2, 3, 4 Pending contract Partner B Target 1 Target 2 Target 3 Partner C Target 1 Target 2 Targets 3, 4 Pending contract Partner D Target 1 Target 2 Partner E Target 1 Partner F Target 1 In progress Target 2 In progress 25