Breakthrough Data on Botensilimab/Balstilimab in MSS CRC Presented at the 2024 ASCO Annual Meeting

Agenus Inc. (“Agenus”) (Nasdaq: AGEN), a leader in developing novel immunological agents to treat various cancers, today announced a novel analysis from the Phase 1b trial of botensilimab in combination with balstilimab (BOT/BAL) in relapsed/refractory microsatellite stable colorectal cancer (r/r MSS CRC) with no active liver metastases (NLM) will be presented at the upcoming 2024 American Society of Clinical Oncology (ASCO) Annual Meeting on June 1, 2024. The analysis shows that BOT/BAL is active in metastatic sites beyond the lungs and lymph nodes, including the peritoneum, soft tissue, and brain, which have historically been unresponsive to treatment.

“The findings observed in this analysis are notable in that they are seen within challenging and historically unresponsive metastatic sites of disease,” said Dr. Steven O'Day, Chief Medical Officer at Agenus. “Seeing broad activity beyond the lungs and lymph nodes is rare for immunotherapy in MSS mCRC, making BOT/BAL stand out from other treatments. We are committed to advancing BOT/BAL for those living with cancer, with the intent to provide durable long-term benefits.”

Patient Demographics

• A total of 77 patients with NLM MSS mCRC were treated with 1 or 2 mg/kg BOT every 6 weeks plus 3 mg/kg BAL every 2 weeks.
• Patients were heavily pre-treated, with a median of four prior lines of therapy, including 21% who received prior PD-(L)1/CTLA-4 therapy.
• Location of NLM sites: 62 patients (81%) had lung involvement, 33 patients (43%) had peritoneal involvement, 32 (42%) patients had lymph node involvement, 15 patients (19%) had soft tissue involvement, and 18 patients (23%) had other sites including the bone and brain.

Clinical Findings

• Across different NLM sites, overall response rates (ORR) ranged from 18-33% and disease control rates (DCR) ranged from 67-82%. Overall survival (OS) remained consistent and ranged from 20.7 months to not reached (NR).
• No new safety signals were observed.

Presentation Details:

Abstract Title: Botensilimab plus balstilimab in microsatellite stable metastatic colorectal cancer: Assessing efficacy in non-liver metastatic sites.
Abstract Number: 3556
Presenting Author: Marwan Fakih, MD, Division Head, GI Medical Oncology, City of Hope Comprehensive Cancer Center
Session: Poster Session – Gastrointestinal Cancer – Colorectal and Anal
Session Date and Time: June 1, 2024, at 1:30 p.m. – 4:30 p.m. CT

About Botensilimab

Botensilimab is a human Fc enhanced CTLA-4 blocking antibody designed to boost both innate and adaptive anti-tumor immune responses. Its novel design leverages mechanisms of action to extend immunotherapy benefits to "cold" tumors which generally respond poorly to standard of care or are refractory to conventional PD-1/CTLA-4 therapies and investigational therapies. Botensilimab augments immune responses across a wide range of tumor types by priming and activating T cells, downregulating intratumoral regulatory T cells, activating myeloid cells and inducing long-term memory responses.