Transcript anti-G mAb
Larry Kauvar, PhD Founder and VP Chief Scientific Officer 4th World Congress on Virology San Antonio, TX 8 October 2014 Trellis Clones Native Human mAbs from Blood Process is fast enough to address emerging disease threats CellSpotTM Platform Native Human Antibody (mAb) 2 Advantages of Native Human mAbs Superb efficacy and safety compared to any other drug class Natural immunogen and exposure route Target relevant epitopes High Affinity Picomolar Kd mAbs Immune Response Native Antibody Screened against human proteome Excellent safety profile Affinity Maturation Therapeutic Relevance Correlate mAb properties with clinical outcomes Risk reduction for IND candidate 3 CellSpot: Merger of Biotech With High Tech Isolate antibodies from single B-cells, after screening millions Miniaturization (without liquid handling) Millions of B-cells screened from 25-50 donors to provide comprehensive survey of the human repertoire footprint is ~150 µm diameter ~100 fg mAb per spot Multiplexing Fluorescent beads Antigen a B-cells as rare as 1 in 100,000 are readily identified, and the mAb is then cloned by single cell cDNA PCR Antigen b Antigen c Antigen d Antigen e (9 types via patented combinatorial coloring) Antibodies from 3 sibling B-cells bind Antigen e 4 CellSpot: Exploit the Mature Immune Response • Interrogate circulating memory B-cells from donor blood • Bias search for mAbs with high affinity to targets (Kd <10 nM) B-Cell Culture 5 days 2 million PBMCs (per plate) Master Plates 200 memory B-cells (per well) CellSpot 40x mag Replicate Plates Single Cell Footprint gigabytes SURVEY Single Cell Profile kilobytes CLONING • Limiting dilution cell cloning • cDNA cloning of mAb H+L mRNA Native Human mAb 5 Infectious Disease Programs Trellis mAbs Address Major Unmet Medical Needs RSV (respiratory syncytial virus) Bacterial biofilms • Superior efficacy vs Synagis (>$1B sales) • Superior in post-infection treatment, for which Synagis has not been approved • Implicated in 60-85% of infections (CDC data) • Major cause of antibiotic drug failure • Novel target enables disruption of biofilm • Trellis mAb binds target homologs from both Gram-positive and Gram-negative bacteria CMV (cytomegalovirus) • Leading cause of transplant failures • Only current drug is Valcyte™: $700M/yr • Too toxic for bone marrow transplant • Also leading cause of maternal infection that contributes to stillbirth and birth defects Influenza Bacterial surface target • Iron Transporters are essential for viability • Conserved domains found in Staph and Strep • Efficacy in murine post-infection treatment model for Trellis mAb against Strep homolog • Existing drug Tamiflu™: ~$1B/year • Limited efficacy and drug resistance is emerging globally • Trellis program licensed to ContraFect Q1 2014 6 Human mAb against RSV Direct Antiviral AND Prevents Viral Disruption of Immune Response RSV: 11 genes, 2 Major Coat Proteins (F and G) Respiratory Syncytial Virus RSV Viral Particle F-protein membrane G-protein Synagis Target Trellis mAb Targets Both soluble G-protein Target F-Protein G-Protein Function • Virus entry into host epithelial cells (fusion protein) • Virus attachment to respiratory epithelium • Modifies host immune response to favor virus persistence 8 Conserved Motif Within Variable G-Protein High conservation and low immunogenicity suggests a vital function RSV G protein • Central conserved motif • CX3C homolog • Motif is invariant across 75 strains • Key epitope has low immunogenicity • Pepscan array probed with sera from vaccinated subjects Pepscan immune repertoire data Hole in human repertoire even in vaccinated people Plotnicky et al. 2002 Virology 303:130 9 Desired Strain-Independent Antibodies are Rare CellSpot multiplexed screen identified mAbs x conserved motif on G-protein 20 million B cells screened from 30 RSV exposed donors CellSpot surveys patient mAb repertoires and identifies target Abs (red bars) Sample from which lead candidate was isolated desired antibodies Donors were largely healthy nurses on RSV wards; an average of 800,000 B-cells were screened from each donor 10 Anti-G is an Excellent Direct Antiviral 100x more potent than Synagis In vitro plaque reduction – RSV virus A2 complement dependent 11 Anti-G ➔ Reduced Inflammatory BAL Cell Influx Day +3 treatment with anti-G rapidly reduced BAL cell inflammation Effect was pronounced at Day +5, and sustained at Days +7, +10, +14 • Trellis 3D3 and backup 2B11 performed similarly • Synagis showed no effect vs. controls Trellis *p<0.05 Dr. Lia Haynes, CDC 12 Anti-G ➔ Improved Lung Function Breath Distension (um) • Mice infected with RSV Line 19F (known for increased airway reactivity) • Breath distension of peripheral arteries (pulse oximetry) reflects pulmonary obstruction • Day +3 treatment with murine anti-G mAb restored pulmonary function at Day +6 • No effect with murine anti-F mAb 143-6C 131-2G non-immune IgG as a control Dr. Larry Anderson, Emory University no RSV control 13 Dissect Anti-viral from Anti-inflammatory Activity Full IgG vs truncated F(ab’)2 (full IgG minus the Fc domain) mucus production Day 5 viral load •Line 19F known to induce high mucus production and airway inflammation •Prophylaxis with full length mAb suppresses viral load RSV F(ab’)2 IgG ø F(ab’)2: no activity as anti-viral agent Dr. Larry Anderson, Emory University RSV F(ab’)2 IgG ø F(ab’)2: full activity as anti-inflammatory agent 14 MOA: Anti-G mAb Restores Acute IFN-α Antiviral Response Anti-G mAb counteracts suppressive effect of G protein ➔ enhanced IFN-α Anti-F mAbs skew IFN-α response in a deleterious direction IFN-α in NHBE cells • G protein suppresses IFN-α • F protein stimulates IFN-α • Anti-G mAb restores IFN-α • Anti-F mAb suppresses IFN-α G G F F IFN-α in plasmacytoid dendritic cells • G-protein suppresses IFN-α • Mutating CX3C prevents the effect • Fab of 131-2G has comparable efficacy mock + + 3D3 Synagis Dr. Ralph Tripp, University of Georgia Dr. Larry Anderson, Emory University 15 Trellis 3D3 (anti-G mAb) vs Synagis (anti-F mAb) Synagis exacerbates airway inflammation, Trellis mAb ameliorates it fold increase over normal at 50 mg/mL MCh Airway Resistance tracheostomized mouse model Day Dr. Erwin Gelfand, MD, Chairman Pediatrics, National Jewish 16 Human mAb against CMV High Affinity AND Blocks the Virus’ Broad Cell Tropism Trellis TRL345: human mAb x Conserved gB(AD-2) 5 million B-cells screened, 30 mAbs cloned ➔ TRL345 (Kd ~50 pM) TRL 345 EPITOPE 18 Trellis mAb TRL345: High Potency anti-gB(AD-2) In vitro plaque reduction – VR1814 in ARPE-19 cells 19 TRL345: Neutralizes CMV’s Broad Cell Tropism Sharp contrast to published mAb (1F11) against CMV pentameric complex (red) 1F11 TRL345 20 Efficacy in ex vivo Placental Infection Model Most realistic model for predicting efficacy in man (HCMV does not infect animals) Placental Infection Model • Placental fragments grown ex vivo on Matrigel extend villi and mimic normal invasive growth into uterine wall • Virus strain VR1814 suppresses placental growth mimicking intra-uterine growth restriction 21 Summary: Better Screening ➔ Better mAbs RSV CMV Ralph Tripp Lenore Pereira, Takako Tabata, Matthew Petttt, Mitsuru Tsuge June-Fang Hoover Larry Anderson Stuart P. Adler, Xiaohong Cui, Michael A. McVoy Erwin Gelfand Lia Haynes F. Eun-Hyung Lee, Ed Walsh SBIR grant 1R44AI102396-01