Xilio Therapeutics, Inc.

What they do

Xilio discovers and develops masked immuno-oncology therapies designed to activate selectively within the tumor microenvironment. Its pipeline includes XTX501, a bispecific PD-1 / masked IL-2; two wholly-owned masked T cell engager programs targeting CLDN18.2 and PSMA+STEAP1; and efarindodekin alfa, a masked IL-12. The company operates under collaboration and license agreements with AbbVie and Gilead and has no approved products.

Revenue drivers

• AbbVie collaboration — Upfront payments, milestones and option-related fees under the AbbVie collaboration agreement, which also includes an additional masked T cell engager program. No further segment-level revenue breakdown was provided.
• Gilead license agreement — Payments tied to efarindodekin alfa under the Gilead license, including an option data package expected in the first half of 2027. No further segment-level revenue breakdown was provided.
• Roche collaboration — Development event payments under a co-funded clinical trial collaboration with F. Hoffmann-La Roche Ltd. No further segment-level revenue breakdown was provided.
• Equity financings — Proceeds from private placements, IPO, at-the-market offerings, prefunded warrant sales and warrant exercises, including June 2025 and February 2026 follow-on offerings. These are financing inflows rather than product revenue.

Recent performance

For the second quarter ended June 30, 2026, revenue was $18.7 million, compared with $12.6 million in the first quarter of 2026 and $19.1 million in the third quarter of 2025. Full-year 2025 revenue was $43.8 million versus $6.3 million in 2024. Net loss was $35.0 million for 2025, narrowing from $58.2 million in 2024. Cash and cash equivalents were $136.0 million as of June 30, 2026, compared with $137.5 million as of December 31, 2025, and total shareholder equity was $72.3 million.

Strategy

Xilio is advancing XTX501 into a Phase 1/2 trial after FDA clearance of its IND, with dosing expected to begin in the second half of 2026 in metastatic NSCLC and select advanced solid tumors. It is also advancing IND-enabling studies for masked T cell engager programs targeting CLDN18.2 and PSMA+STEAP1, with INDs planned for the second half of 2027. Efarindodekin alfa continues in a Phase 2 monotherapy trial, with an option data package expected to Gilead in the first half of 2027. The company states a cash runway into the first quarter of 2028.

Risks

• No product revenue — All programs are in early clinical or preclinical development, and the company does not expect product revenue for at least the next several years, if at all.
• Dependence on collaborations — Revenue depends on payments under agreements with AbbVie and Gilead, including milestones and option-related fees that may not be achieved.
• Clinical and regulatory uncertainty — XTX501, the masked TCE programs and efarindodekin alfa must successfully complete preclinical and clinical development before any potential approval.
• Additional capital needs — The company states it may need to secure additional capital, and its stated cash runway extends only into the first quarter of 2028.

Outlook

Management expects to initiate dosing in the Phase 1 portion of the XTX501 trial in the second half of 2026 and report initial Phase 1 data in metastatic NSCLC in the second half of 2027. The company plans IND submissions for its CLDN18.2 and PSMA+STEAP1 masked TCE programs in the second half of 2027. It expects to deliver an option data package for efarindodekin alfa to Gilead in the first half of 2027. Xilio states its cash runway is expected to support key milestones into the first quarter of 2028.