Xilio Therapeutics announces new data on Phase 2 trial of vilastobart

Xilio Therapeutics (XLO) announced new data from its ongoing Phase 2 clinical trial evaluating vilastobart, a tumor-activated, Fc-enhanced anti-CTLA-4, in combination with atezolizumab in patients with microsatellite stable metastatic colorectal cancer. A 40% objective response rate was demonstrated in heavily pre-treated patients with MSS mCRC without liver metastases and with high plasma TMB, 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 at the Society for Immunotherapy of Cancer, SITC, 40th Annual Meeting, taking place from November 5-9, 2025, in National Harbor, Maryland. Key Findings: % ORR in heavily pre-treated patients with MSS mCRC without liver metastases and with high plasma tumor mutational burden; Estimate 55% of patients with MSS CRC have high plasma TMB, representing a meaningful population with high unmet need