CD134 Costimulation Couples the CD137 Pathway to Induce Production
CTX-471, a novel agonistic antibody targeting CD137, eradicates … · 2019. 8. 26. · Compass...
1
Compass Therapeutics, Cambridge, MA, USA Discovery of CTX-471: Best in Class CD137 Agonist Unique Ability to Eradicate Very Large Tumors CTX-471 Shows Differentiated Activity in Human Assays Dramatic Immune Reprogramming within the TME & MoA CTX-471, a novel agonistic antibody targeting CD137, eradicates very large tumors by selectively reprogramming the tumor microenvironment without causing hepatic toxicity Ugur Eskiocak 1 , Wilson Guzman 1 , Nora Zizlsperger 1 , Benjamin Wolf 1 , Christine Cummings 1 , Thomas Daly 1 , Puru Nanjappa 1 , Lauren Milling 1,2 , Michael Ophir 1 , Pearl Bakhru 1 , Xianzhe Wang 1 , Lucy Liu 1 , Samantha Ottinger 1 , Jason Lajoie 1 , Michael Schmidt 1 , Robert Tighe 1 1 Compass Therapeutics, Cambridge, MA, USA 2 Massachusetts Institute of Technology, Cambridge, MA, USA CT26 model efficacy CT26 model survival and rechallenge 88 days off treatment Vehicle Control 10 20 40 80 10 20 40 80 10 80 CTX-471 mg/kg CTX-471-AF mg/kg 3H3 mg/kg Control CTX-471 CTX-471-AF 3H3 H&E CD8 F4/80 ➢ CD137 (a.k.a. 4-1BB and TNFSR9) is a member of the TNFR superfamily that provides costimulatory signals to activated cytotoxic lymphocytes. ➢ Agonistic antibodies against CD137 have shown promising therapeutic activity in mouse tumor models. However, current clinical-stage molecules have shown limited clinical activity for different reasons: ➢ A strong agonist (urelumab) leads to hepatic toxicity in humans and in animal models (3H3) ➢ A weak agonist (utomilumab) spares toxicity, but likely provides suboptimal activation ➢ Here we describe the discovery and characterization of CTX-471: ➢ A fully human, IgG4 agonist antibody of CD137 ➢ Optimized signaling via a unique epitope ➢ Human/cyno/mouse cross-reactive ➢ Curative efficacy in syngeneic models ➢ Well-tolerated in mice & cynomolgus monkeys Conclusions To our knowledge, CTX-471’s level of monotherapy efficacy against very large tumors is unprecedented for an IO antibody. CTX-471 displays a favorable and well-differentiated efficacy-safety profile that is attributed to a unique epitope, optimized affinity, and FcγR-dependent activity. IND-enabling toxicology studies are underway, and a Phase 1 trial is planned for the first-half of 2019. Affinity (nM) against: Human Cyno Mouse CTX-471 47 52 748 CTX-471-AF 3.3 5.8 87 Clinical lead Mouse affinity- matched version ➢ In a primary human T cell costimulation assay in which CD8+ T cells were stimulated with anti-CD3 in co-culture with CHO cells engineered to express FcyRIIb (CHO-CD32), CTX-471 displayed an intermediate level of activity that fell between urelumab and utomilumab. ➢ The activity of both urelumab and CTX-471 is driven by FcγR-mediated cross-linking; CTX-471 activity is completely FcγR-dependent. ➢ In the presence of CD137L, NFκB signaling (measured using an engineered HEK293 line) by CTX-471 is potentiated, whereas urelumab signaling remains unchanged and utomilumab signaling is attenuated. Curative Monotherapy Activity in Mouse Models A20 model efficacy ➢ CTX-471 & CTX-471-AF showed highly potent anti-tumor activity over a wide dose range. ➢ High rate of complete cures in established syngeneic models (CT26, A20, EMT-6 and MC38 OVA ) observed. ➢ All cured mice showed long-term protection from tumor growth upon rechallenge, indicating potent induction of immune memory. ➢ CT26 s.c. tumors were on average 450 mm 3 at treatment start. Treating extremely large tumors of this size is generally considered futile. ➢ Mice received either CD137 agonists (CTX-471 or 3H3; 25 mg/ms on days 0, 7, 14), checkpoint inhibitors (Avelumab, RMP-14, or 9H10; 200 mg/ms on days 0, 3, 6) or an OX40 agonist (OX-86; 200 mg/ms on days 0, 3, 6). ➢ Compared to a panel of well-validated IO antibodies, CTX-471 showed a unique ability to cure mice of large, established tumors. ➢ Histological analysis revealed the mass destruction of CT26 tumors caused by CTX-471-AF treatment of the mice. CD45 Side scatter 18 ± 1 % 62 ± 25 % Gated from live cells Control CTX-471-AF Increased Infiltration of Immune Cells Protection/Reversion of T cell Exhaustion TIGIT PD-1 Gated from CD8+ TILs; Similar results obtained from CD4+ TILs 43 ± 5 % 8 ± 5 % Control CTX-471-AF 31 ± 9 % 7 ± 3 % Control CTX-471-AF FOXP-3 CD25 Gated from CD4+ TILs Treg Reduction 44 ± 4 % 24 ± 11 % Control CTX-471-AF CD11b F4/80 Tumor Associated Macrophage (TAM) Reduction Gated from CD45+ TILs; Remaining macrophages are M1 polarized Isotype Control CTX-471-AF Day 10: 10% necrosis Day 10: Few tumor cells Day 14: 40% necrosis Day 14: 80% necrosis T cell depletion NK cell depletion ➢ Immunophenotypic analysis of CT26 tumors by flow cytometry revealed increased infiltration of CD45 + cells, protection/reversal of T cell exhaustion, & depletion of suppressive Tregs and TAMs. These effects are seen across a wide dose range (12.5 to 200 μg) and with various dosing schedules. ➢ In order to further delineate the mechanisms of action, a series of immune subset depletion and isotype switch experiments were conducted in the CT26 tumor model. The data suggest cooperative involvement of both innate (NK cells) and adaptive immunity (CD4 + and CD8 + T cells) in the anti-tumor activity of CTX-471. Potent anti-tumor efficacy was observed with CTX-471 as hIgG4 (binds FcgRs, induces ADCP) and rat IgG2a (binds FcgRs, cannot induce ADCP) but not with aglycosylated IgG4 (no FcgR binding, cannot induce ADCP). Differentiated Safety Profile ➢Four-week repeated dose (up to 80 mg/kg/week) toxicity studies were conducted in mice. ➢Urelumab-like anti-mouse CD137 Ab, clone 3H3, induced hepatic toxicity in mice and formation of inflammatory foci in livers. ➢CTX-471 did not induce T cell or macrophage foci, and spared cytokine induction and transaminase elevations. ➢ In contrast to 3H3, the anti-tumor efficacy of CTX-471 is achieved at dose levels that are completely sparing of hepatic toxicity. Fc dependent efficacy Treg depletion not required Intratumoral Treg levels Human T cell Costimulation Assay FcγR-Dependent Activity NFκB Signaling in Presence of CD137L CTX-471 Urelumab Utomilumab
Transcript of CTX-471, a novel agonistic antibody targeting CD137, eradicates … · 2019. 8. 26. · Compass...
Compass Therapeutics, Cambridge, MA, USA
Discovery of CTX-471: Best in Class CD137 Agonist Unique Ability to Eradicate Very Large Tumors
CTX-471 Shows Differentiated Activity in Human Assays
Dramatic Immune Reprogramming within the TME & MoA
CTX-471, a novel agonistic antibody targeting CD137, eradicates very large tumors by selectively reprogramming the tumor microenvironment without causing hepatic toxicityUgur Eskiocak1, Wilson Guzman1, Nora Zizlsperger1, Benjamin Wolf1, Christine Cummings1, Thomas Daly1, Puru Nanjappa1, Lauren Milling1,2, Michael Ophir1, Pearl Bakhru1, Xianzhe Wang1, Lucy Liu1, Samantha Ottinger1, Jason Lajoie1, Michael Schmidt1, Robert Tighe1
1Compass Therapeutics, Cambridge, MA, USA 2Massachusetts Institute of Technology, Cambridge, MA, USA
CT26 model efficacy
CT26 model survival and rechallenge
88 days off
treatment
CTX-471PBS
CTX-471CTX-471CTX-471
3H33H3
Vehicle Control10204080102040801080
CTX-471 mg/kg
CTX-471-AFmg/kg3H3 mg/kg
Control CTX-471 CTX-471-AF 3H3
H&
EC
D8
F4/8
0
➢ CD137 (a.k.a. 4-1BB and TNFSR9) is a member of the TNFR superfamily that provides costimulatory signals to
activated cytotoxic lymphocytes.
➢ Agonistic antibodies against CD137 have shown promising therapeutic activity in mouse tumor models. However,
current clinical-stage molecules have shown limited clinical activity for different reasons:
➢ A strong agonist (urelumab) leads to hepatic toxicity in humans and in animal models (3H3)
➢ A weak agonist (utomilumab) spares toxicity, but likely provides suboptimal activation
➢ Here we describe the discovery and characterization of CTX-471:
➢ A fully human, IgG4 agonist antibody of CD137
➢ Optimized signaling via a unique epitope
➢ Human/cyno/mouse cross-reactive
➢ Curative efficacy in syngeneic models
➢ Well-tolerated in mice & cynomolgus monkeys
ConclusionsTo our knowledge, CTX-471’s level of monotherapy efficacy against very large tumors is unprecedented for an IO antibody. CTX-471 displays a favorable and well-differentiated efficacy-safety profile that is attributed to a unique epitope, optimized affinity, and FcγR-dependent activity. IND-enabling toxicology studies are underway, and a Phase 1 trial is planned for the first-half of 2019.
Affinity (nM) against:
Human Cyno Mouse
CTX-471 47 52 748
CTX-471-AF 3.3 5.8 87
Clinical lead
Mouse affinity-matched version
➢ In a primary human T cell costimulation assay in which CD8+ T cells were stimulated with anti-CD3 in co-culture with CHO cells engineered to express FcyRIIb (CHO-CD32), CTX-471 displayed an intermediate level of activity that fell between urelumab and utomilumab.
➢ The activity of both urelumab and CTX-471 is driven by FcγR-mediated cross-linking; CTX-471 activity is completely FcγR-dependent.
➢ In the presence of CD137L, NFκB signaling (measured using an engineered HEK293 line) by CTX-471 is potentiated, whereas urelumabsignaling remains unchanged and utomilumab signaling is attenuated.
Curative Monotherapy Activity in Mouse Models
A20 model efficacy
➢ CTX-471 & CTX-471-AF showed highly potent anti-tumor activity over a wide dose range.
➢ High rate of complete cures in established syngeneic models (CT26, A20, EMT-6 and MC38OVA) observed.
➢ All cured mice showed long-term protection from tumor growth upon rechallenge, indicating potent induction of immune memory.
➢ CT26 s.c. tumors were on average 450 mm3 at treatment start. Treating extremely large tumors of this size is generally considered futile.
➢ Mice received either CD137 agonists (CTX-471 or 3H3; 25 mg/ms on days 0, 7, 14), checkpoint inhibitors (Avelumab, RMP-14, or 9H10; 200 mg/ms on days 0, 3, 6) or an OX40 agonist (OX-86; 200 mg/ms on days 0, 3, 6).
➢ Compared to a panel of well-validated IO antibodies, CTX-471 showed a unique ability to cure mice of large, established tumors.
➢ Histological analysis revealed the mass destruction of CT26 tumors caused by CTX-471-AF treatment of the mice.
CD45
Sid
e sc
atte
r
18 ± 1 % 62 ± 25 %
Gated from live cells
Control CTX-471-AF
Increased Infiltration of Immune Cells Protection/Reversion of T cell Exhaustion
TIGIT
PD
-1
Gated from CD8+ TILs; Similar results obtained from CD4+ TILs
43 ± 5 % 8 ± 5 %
Control CTX-471-AF
31 ± 9 % 7 ± 3 %
Control CTX-471-AF
FOXP-3
CD
25
Gated from CD4+ TILs
Treg Reduction
44 ± 4 % 24 ± 11 %
Control CTX-471-AF
CD11b
F4/8
0
Tumor Associated Macrophage (TAM) Reduction
Gated from CD45+ TILs; Remaining macrophages are M1 polarized
Isotype Control
CTX-471-AF
Day 10: 10% necrosis
Day 10: Few tumor cells
Day 14: 40% necrosis
Day 14: 80% necrosis
T cell depletion NK cell depletion
➢ Immunophenotypic analysis of CT26 tumors by flow cytometry revealed increased infiltration of CD45+ cells, protection/reversal of T cell exhaustion, & depletion of suppressive Tregs and TAMs. These effects are seen across a wide dose range (12.5 to 200 µg) and with various dosing schedules.
➢ In order to further delineate the mechanisms of action, a series of immune subset depletion and isotype switch experiments wereconducted in the CT26 tumor model. The data suggest cooperative involvement of both innate (NK cells) and adaptive immunity (CD4+
and CD8+ T cells) in the anti-tumor activity of CTX-471. Potent anti-tumor efficacy was observed with CTX-471 as hIgG4 (binds FcgRs, induces ADCP) and rat IgG2a (binds FcgRs, cannot induce ADCP) but not with aglycosylated IgG4 (no FcgR binding, cannot induce ADCP).
Differentiated Safety Profile
➢Four-week repeated dose (up to 80 mg/kg/week) toxicity studies were conducted in mice.
➢Urelumab-like anti-mouse CD137 Ab, clone 3H3, induced hepatic toxicity in mice and formation of inflammatory foci in livers.
➢CTX-471 did not induce T cell or macrophage foci, and spared cytokine induction and transaminase elevations.
➢ In contrast to 3H3, the anti-tumor efficacy of CTX-471 is achieved at dose levels that are completely sparing of hepatic toxicity.
Fc dependent efficacy Treg depletion not required
IntratumoralTreg levels
Human T cell Costimulation Assay FcγR-Dependent Activity NFκB Signaling in Presence of CD137L
CTX-471 Urelumab
Utomilumab
