On January 8, 2026 Xilio Therapeutics, Inc. (Nasdaq: XLO), a clinical-stage biotechnology company discovering and developing masked immuno-oncology therapies for people living with cancer, reported upcoming milestones and recent corporate updates.
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"2025 was marked by robust execution at Xilio as we delivered on key priorities across our deep portfolio of differentiated I-O therapies, demonstrated additional clinical validation of our masking technology and further strengthened our financial position through strategic partnerships and our recent equity financing," said René Russo, Pharm.D., president and chief executive officer of Xilio. "In the year ahead, we have a strong foundation to advance our potential best-in-class bispecific PD-1/IL-2 and T cell engager programs toward the clinic and maximize the value of our vilastobart and efarindodekin alfa programs through strategic partnerships."
Xilio also announced the appointment of Sara Bonstein as chair of the board of directors, following the retirement of Paul Clancy. Dr. Russo continued, "Sara has been an invaluable member of our board since 2021 and brings more than two decades of executive leadership in finance, corporate strategy and business operations in the biotechnology industry, as well as extensive experience advancing novel therapies from discovery through commercialization. I look forward to continuing to partner with Sara as we advance our pipeline of masked immuno-oncology therapies through development. On behalf of the entire board, I’d also like to express my gratitude to Paul for his leadership and contributions as chair, which have been instrumental in helping shape Xilio over the past five years."
Ms. Bonstein added, "During my tenure, Xilio has made significant progress demonstrating validation for its novel masking technology through strategic partnerships with Gilead and AbbVie as well as promising clinical data for its most advanced programs. I am excited to chair the board and look forward to working closely with the management team to advance the company’s deep portfolio of differentiated I-O therapies."
Corporate Updates
In January 2026, Xilio announced the receipt of $35.8 million in gross proceeds from the exercise of Series B warrants, before deducting underwriting discounts and commissions and any offering expenses, including the full exercise of Series B warrants held by Coastlands Capital, Frazier Life Sciences and Gilead Sciences, Inc. The Series B warrants were issued in connection with a follow-on public offering in June 2025.
Xilio today announced:
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The achievement of a development milestone related to the masked antibody-based immunotherapy program under the company’s collaboration, license and option agreement with AbbVie.
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The nomination of a development candidate for its masked T cell engager program targeting the tumor-associated antigen for CLDN18.2, which has broad potential as a target for gastric, pancreatic, esophageal and lung cancers.
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The appointment of Sara M. Bonstein as chair of the board of directors of Xilio. Ms. Bonstein has served as a member of Xilio’s board of directors since August 2021 and succeeds Paul Clancy, who retired from the board of directors on January 6, 2026. Ms. Bonstein has more than 10 years of experience as a chief financial officer for public biotechnology companies, and she currently serves as chief financial officer of Insmed, Inc. where she oversees key financial functions including capital raising, investor relations, accounting, treasury, financial planning and analysis and procurement. Earlier in her career, Ms. Bonstein held finance roles of increasing responsibility at Eli Lilly & Company and Johnson & Johnson. Ms. Bonstein holds a B.S. in finance from The College of New Jersey and an M.B.A. from Rider University.
Anticipated Milestones
Xilio’s anticipated upcoming milestones include:
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Submit an investigational new drug (IND) application for XTX501 in the middle of 2026
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Report initial Phase 1 data for XTX501 in the second half of 2027, subject to clearance of the IND by the U.S. Food and Drug Administration
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Nominate a development candidate for the STEAP1 program (masked T cell engager with co-stimulation) in the first half of 2026
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Advance at least two masked T cell engager programs into IND-enabling studies and submit IND applications for those programs in 2027
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Deliver the Phase 1/2 option data package to Gilead for the efarindodekin alfa program in the first half of 2027
Financial Guidance
As of December 31, 2025, Xilio estimates that it had cash and cash equivalents of $137.5 million, including $35.8 million in gross proceeds received in the fourth quarter of 2025 from the exercise of Series B warrants.
Based on its current operating plans, Xilio anticipates that its cash and cash equivalents as of December 31, 2025 will be sufficient to enable it to fund its operating expenses and capital expenditure requirements into the second quarter of 2027.
The cash and cash equivalents information provided above is based on preliminary unaudited information and management estimates for the year ended December 31, 2025, is not a comprehensive statement of the company’s financial results as of and for the fiscal year ended December 31, 2025 and may change. Xilio’s independent registered public accounting firm has not conducted an audit or review of, and does not express an opinion or any other form of assurance with respect to, this preliminary estimate.
(Press release, Xilio Therapeutics, JAN 8, 2026, View Source [SID1234661857])