Xilio gets FDA clearance for XTX501 IND, reports Q2 2026 results

Xilio Therapeutics said the FDA cleared its investigational new drug application for XTX501, described as a novel bispecific PD-1 / masked IL-2 that has the potential to be a foundational backbone therapy for solid tumors, including in combination with other agents¹. The company said it expects to begin dosing patients in the Phase 1 portion of a trial covering metastatic non-small cell lung cancer and select advanced solid tumors during the second half of 2026¹, with initial Phase 1 data in metastatic NSCLC patients planned for the second half of 2027¹.

On the T cell engager side, Xilio said it is advancing IND-enabling studies for a masked TCE program aimed at CLDN18.2 and a multi-specific masked TCE program targeting PSMA and STEAP1 that includes built-in co-stimulatory signaling¹, with CLDN18.2 expressed in gastrointestinal cancers such as gastric, pancreatic and esophageal tumors, while PSMA and STEAP1 are expressed in prostate cancer¹. The company said it plans to file INDs for both the CLDN18.2 and PSMA+STEAP1 programs in the second half of 2027¹.

For its IL-12 program, Xilio said efarindodekin alfa is being tested as a monotherapy in an ongoing Phase 2 trial in advanced solid tumors, with an option data package expected to go to Gilead Sciences in the first half of 2027¹.

Turning to finances, Xilio reported cash and cash equivalents of $136.0 million as of June 30, 2026, versus $137.5 million at the end of 2025¹. The company said based on its current operating plans, existing cash is expected to fund operations and capital expenditures into the first quarter of 2028¹. That estimate excludes up to $36.2 million in additional gross proceeds if all outstanding Series C warrants are exercised in the second half of 2026, and does not include potential milestone or option-related payments under its AbbVie and Gilead agreements, including up to $31.0 million in near-term milestones and extension fees possible through the first half of 2027¹.