Xilio Therapeutics Announces Phase 2 Data For Vilastobart In Combination With Atezolizumab Continues To Demonstrate Differentiated And Generally Well-Tolerated Safety Profile

40% ORR in heavily pre-treated patients with MSS mCRC without liver metastases and with high plasma tumor mutational burden (TMB)

Estimate 55% of patients with MSS CRC have high plasma TMB, representing a meaningful population with high unmet need

Company to host conference call and webcast on Monday, November 10, 2025, at 4:30 p.m. ET with leading cancer experts to review the data

WALTHAM, Mass., Nov. 07, 2025 (GLOBE NEWSWIRE) -- Xilio Therapeutics, Inc. (NASDAQ:XLO), a clinical-stage biotechnology company discovering and developing tumor-activated immuno-oncology therapies for people living with cancer, today announced new data from its ongoing Phase 2 clinical trial evaluating vilastobart, a tumor-activated, Fc-enhanced anti-CTLA-4, in combination with atezolizumab (Tecentriq®) in patients with microsatellite stable (MSS) metastatic colorectal cancer (mCRC). A 40% objective response rate (ORR) was demonstrated in heavily pre-treated patients with MSS mCRC without liver metastases and with high plasma TMB (≥10 mutations/Mb), as well as a statistically significant correlation between plasma TMB status and response. These new clinical data are being presented in a late-breaking poster presentation (Abstract # 1315) today at the Society for Immunotherapy of Cancer (SITC) 40th Annual Meeting, taking place from November 5-9, 2025, in National Harbor, Maryland.