Agenus presents data on clinical responses to botensilimab/balstilimab

Agenus presented data at the European Society for Medical Oncology Congress in Barcelona, ​​Spain. Data from a Phase 1 study of botensilimab, an experimental Fc-boosted CTLA-4 inhibitor, in combination with balstilimab, an experimental PD-1 antibody, demonstrated 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. In 52 patients, efficacy could be assessed with at least one imaging scan after baseline for 6 weeks. Reporting of ORR and DOR is based on the unconfirmed response in this cohort. The majority of sarcoma subtypes included angiosarcoma and leiomyosarcoma. Clinical findings: Across the sarcoma cohort, an overall response rate of 23% was observed, with a median duration of response of 21.7 months. 12-month overall survival was 69% and median OS was not reached. In the angiosarcoma subtype, an ORR of 39% was achieved, with a median DOR of 21.7 months. 12-month OS was 64% and median OS was not reached. One representative patient with visceral angiosarcoma achieved a durable response lasting over 3 years, which was maintained without therapy. The side effect profile of BOT+ BAL was manageable and reversible, with no new safety signals identified.