Xilio Therapeutics Inc. (NASDAQ: XLO) reported fourth quarter and full year 2025 financial results, announcing plans to submit an investigational new drug application for XTX501 in mid-2026 and initiate Phase 1 trials in the second half of 2026.

The clinical-stage biotechnology company reported cash and cash equivalents of $137.5 million as of December 31, 2025, compared to $55.3 million a year earlier. The company stated its existing cash will fund operations through the end of 2027.

Collaboration and license revenue increased to $43.8 million for 2025 from $6.3 million in 2024, primarily due to agreements with AbbVie entered in February 2025 and a $17.5 million development milestone payment from Gilead Sciences achieved in the third quarter.

Research and development expenses rose to $56.0 million in 2025 from $41.2 million in 2024, driven by manufacturing activities for XTX501 IND-enabling studies and increased clinical development activities for efarindodekin alfa. The company reported a net loss of $35.0 million for 2025, compared to $58.2 million in 2024.

XTX501 is a bispecific PD-1/masked IL-2 designed to selectively stimulate PD-1 positive T cells. The company plans to initially evaluate the therapy in patients with metastatic non-small cell lung cancer before expanding to other solid tumor types.

Xilio is advancing two masked T cell engager programs targeting CLDN18.2 and a multi-specific program targeting PSMA and STEAP1 for prostate cancer. The company plans to submit IND applications for these programs in 2027.

In January 2026, the company received $35.8 million in gross proceeds from Series B warrant exercises and appointed Sara Bonstein as board chair. In February, Xilio completed a follow-on offering of prefunded warrants for $40.0 million in gross proceeds.