Agenus announces results from cohort in study of botensilimab with balstilimab

Agenus announced results from a cohort of 24 evaluable patients in an expansion of the Company’s Phase 1b study of botensilimab in combination with balstilimab in patients with recurrent platinum resistant/refractory ovarian cancer. These findings, presented in an oral plenary session at the Society of Gynecologic Oncology 2023 Annual Meeting on Women’s Cancer, showed a 33% overall response rate. The ovarian cancer cohort is part of a large study evaluating the safety, efficacy, and dose optimization of botensilimab alone and in combination with balstilimab in multiple solid tumors. Agenus is currently enrolling in Global Phase 2 ACTIVATE trial programs in metastatic microsatellite stable colorectal cancer, melanoma and pancreatic cancers. Based on recent positive findings presented at SITC, Agenus is also expanding enrollment of its anti-PD-(L)1 relapsed/refractory non-small cell lung cancer cohort of the Phase 1b study and planning additional NSCLC studies. A total of 24 evaluable patients with recurrent platinum resistant/refractory ovarian cancer received either 1 or 2 mg/kg botensilimab every 6 weeks and 3 mg/kg balstilimab every 2 weeks. Patient Demographics: 79% were high grade serous, which has a poor prognosis; Patients were heavily pre-treated, with a median of 4 prior lines of therapy including 21% with prior immunotherapy; Majority of patients had biomarkers associated with poor response to immunotherapy: 90% had a low tumor mutation burden; Over half of patients were PD-L1 negative by IHC. Clinical Findings: 33% overall response rate; Other PD-(L)1 + CTLA-4 combinations in other trials reported 3-10% response rates in a comparable patient population.67% disease control rate; Median duration of response not reached; Manageable tolerability profile.