On June 3, 2023, Arcus Biosciences, Inc. issued a press release announcing updated results from an interim analysis of ARC-7, its randomized, 150-patient Phase 2 trial in first-line metastatic PD-L1=50% non-small cell lung cancer in which the Company is studying domvanalimab in combination with zimberelimab both with and without etrumadenant vs. zimberelimab monotherapy. This interim analysis was conducted at the clinical data cutoff date of February 7, 2023 (the “DCO”).

With a median follow-up time of approximately 18 months, both domvanalimab-containing study arms demonstrated sustained, clinically meaningful improvements in progression free survival (“PFS”) compared to zimberelimab monotherapy, with a 33% reduction in risk of disease progression or death for the doublet and 28% for the triplet. The preliminary duration of response (DoR) analyses favor domvanalimab-containing arms, with median DoR (range, ‘+': censored) as follows: Z: 13.2mo (+1.4-+19.4); DZ: not reached (2.8-+26.6); and EDZ: 23.7mo (2.6-23.7). As of the DCO, approximately twice as many participants remain in the ongoing study treatment in the domvanalimab-containing arms (DZ: (n=17), EDZ: (n=20)) compared to zimberelimab monotherapy (Z: (n=9)).

Consistent ORR and PFS improvements were shown for the domvanalimab-containing arms in a post-hoc analysis of centrally confirmed PD-L1-high patients. No unexpected safety signals were observed across the three study arms at the time of DCO. The domvanalimab-containing study arms appeared to be generally well tolerated and showed an overall safety profile consistent with the known safety profiles of each individual molecule to date.

Incidence of infusion-related reactions was low across all treatment arms: 4%, 4% and 12% for zimberelimab monotherapy and the domvanalimab-doublet and -triplet arms, respectively. The addition of domvanalimab to zimberelimab did not increase the incidence of infusion-related reactions, consistent with the Fc-silent design of domvanalimab.