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 that it will present a late-breaking poster presentation for vilastobart, a tumor-activated, Fc-enhanced anti-CTLA-4, at the Society for Immunotherapy of Cancer (SITC) 40th Annual Meeting, taking place from November 5-9, 2025 in National Harbor, Maryland. The Phase 2 data will highlight response rate for vilastobart in combination with atezolizumab in patients with microsatellite stable (MSS) metastatic colorectal cancer (mCRC) and high plasma tumor mutational burden.

Poster presentation details are as follows:

Abstract Title: Plasma Tumor Mutational Burden (pTMB) Enriched for Response to Vilastobart in Combination with Atezolizumab in Patients with Microsatellite Stable (MSS) Metastatic Colorectal Cancer (mCRC)

Late-Breaking Abstract Number: 1315

Presentation Date: Friday, Nov. 7, 2025

Poster Hall Hours: 9:00 a.m.-7:00 p.m. EST

Location: Prince George ABC Exhibit Halls Gaylord National Resort and Convention Center Gaylord