Xilio is focused on developing cytokines with exemplary clinical activity and tolerability. We are developing efarindodekin alfa (XTX301), a tumor-activated, engineered IL-12, for the treatment of advanced solid tumors.

About IL-12

IL-12, or Interleukin-12, has emerged as one of the most potent cytokine mediators of antitumor activity because of its multiple effects on different immune cells in the tumor microenvironment (TME). IL-12 has the ability to activate and bridge both innate (natural killer or NK cell) and adaptive (cytotoxic CD8+ T and CD4+ T cells) immunity for tumor cell killing while further coordinating additional anti-cancer defenses such as regulatory T-cell suppression and anti-angiogenic effects. Despite research across the field suggesting that IL-12 can significantly benefit patients in fighting cancer, there are currently no approved IL-12 agents due to severe systemic toxicity with unmodified IL-12.

Efarindodekin Alfa (XTX301), a Tumor-activated, Engineered IL-12

About the Phase 1/2 Trial for Efarindodekin Alfa (XTX301)

Efarindodekin alfa (XTX301) is an investigational masked IL-12 designed to potently stimulate anti-tumor immunity and reprogram the tumor microenvironment (TME) of poorly immunogenic “cold” tumors towards an inflamed or “hot” state. In March 2024, Xilio entered into an exclusive license agreement with Gilead Sciences, Inc. for Xilio’s tumor-activated IL-12 program, including efarindodekin alfa. Xilio is currently evaluating the safety and tolerability of efarindodekin alfa as a monotherapy in patients with advanced solid tumors in the Phase 1 portion of a first-in-human, multi-center, open-label Phase 1/2 clinical trial and the safety and efficacy of efarindodekin alfa as a monotherapy in the Phase 2 portion in patients with advanced solid tumors. The Phase 2 portion of the trial is anticipated to enroll approximately 40 patients in specific tumor types at multiple sites in the United States. Please refer to NCT05684965 on www.clinicaltrials.gov for additional details.