Xilio Therapeutics Announces Multiple Masked T Cell Engager Programs
Also entered into collaboration and option agreement with AbbVie to develop novel tumor-activated
immunotherapies, including masked T cell engagers, with $52.0 million in upfront payments
Extended anticipated cash runway into the first quarter of 2026
Company to host investor conference call and webcast today at 8:30 am ET
WALTHAM, Mass., February 12, 2025 – 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 three wholly-owned preclinical programs for masked T cell engagers targeting prostate-specific membrane antigen (PSMA), claudin 18.2 (CLDN18.2) and six-transmembrane epithelial antigen of prostate 1 (STEAP1). In addition, as announced earlier today, Xilio entered into a collaboration, license and option agreement with AbbVie leveraging Xilio’s proprietary tumor-activation technology and platform to discover and develop novel tumor-activated immunotherapies, including masked T cell engagers. Under the collaboration, Xilio will receive $52.0 million in upfront payments and be eligible for additional option-related fees and milestones, as well as tiered royalties.
“Today, we are excited to announce the next phase of Xilio’s tumor-activation platform with multiple internal masked T cell engager programs, as well as a multi-program collaboration with AbbVie,” said René Russo, Pharm.D., president and chief executive officer of Xilio. “T cell engagers have demonstrated meaningful clinical activity, yet many promising targets for solid tumors remain out of reach due to toxicity limitations. Leveraging our clinically-validated masking technology, we aim to lead the next wave of innovation in cancer immunotherapy by developing masked T cell engagers designed to improve tolerability through tumor-selective activation. In addition, we are able to incorporate co-stimulatory signaling into our T cell engager designs with the goal of further enhancing T cell activation, persistence and anti-tumor activity. We look forward to collaborating with AbbVie as we advance our pipeline of novel tumor-activated immunotherapies.”
Masked T Cell Engager Programs
T cell engagers are designed to redirect immune effector cells against cancer cells by simultaneously binding to a specific tumor-associated antigen expressed on the cancer cells and the T cell receptor complex on T cells, resulting in T cell-mediated killing of tumor cells. To date, T cell engagers have demonstrated significant promise as cancer immunotherapies in a variety of advanced solid tumors, but their potential has been limited by toxicity.
Xilio is leveraging its proprietary, clinically-validated tumor-activation platform to advance a pipeline of wholly-owned, novel masked T cell engager molecules with conditional half-life modulation designed to enable potent, localized T cell activation and tumor cell destruction together with an improved therapeutic index. These programs include bispecific molecules designed using Xilio’s advanced tumor-activated cell engager (ATACR) format, which consists of a T cell engager with a masked CD3 targeting domain, and tri-specific molecules designed using Xilio’s selective effector-enhanced cell engager (SEECR) format. The SEECR format builds upon the ATACR format by adding co-stimulatory signaling designed to further enhance potency and T cell activation.
Xilio is currently advancing three wholly-owned preclinical programs for masked T cell engager molecules targeting the following tumor-associated antigens: PSMA, CLDN18.2 and STEAP1.