Agenus presents data on botensilimab/balstilimab clinical responses

Agenus presented data at the European Society for Medical Oncology Congress held in Barcelona, Spain. The data from a Phase 1 study of botensilimab, an investigational Fc-enhanced CTLA-4 inhibitor, in combination with balstilimab, an investigational PD-1 antibody, showed clinical activity in patients with refractory sarcomas, a population with limited treatment options. Study Highlights: 64 patients with relapsed/refractory sarcomas were treated with 1 or 2 mg/kg BOT + 3 mg/kg BAL. 52 patients were efficacy evaluable with at least one post-baseline 6-week imaging scan. ORR and DOR reporting will be based on the unconfirmed response in this cohort. Majority of sarcoma subtypes included angiosarcoma and leiomyosarcoma. Clinical Findings: 23% overall response rate was observed in the full sarcoma cohort, with a median duration of response of 21.7 months. 12-month overall survival was 69% and the median OS was not reached. 39% ORR achieved in the angiosarcoma subtype, with a median DOR of 21.7 months. 12-month OS was 64% and the median OS was not reached. A representative patient with visceral angiosarcoma achieved a durable response, ongoing beyond 3 years, that has been maintained off-therapy. The adverse event profile of BOT+ BAL was manageable and reversible with no new safety signals identified.