Xilio Therapeutics, Inc.
Xilio Therapeutics, Inc. (NASDAQ: XTXI) is a clinical-stage biotechnology company focused on discovering and developing masked immuno-oncology therapies designed to improve outcomes for patients with cancer. The company's website is www.xiliotx.com. From the company’s description.
Margins and return on equity change in ; everything else in percent. Fewer shares and less debt are shown plainly, not as bad news — it depends what you make of buybacks. Dotted labels explain each measure. is shown separately from the annual figures.
What Xilio Therapeutics, Inc. does
In the company’s own words
Xilio Therapeutics, Inc. (NASDAQ: XTXI) is a clinical-stage biotechnology company focused on discovering and developing masked immuno-oncology therapies designed to improve outcomes for patients with cancer. The company's website is www.xiliotx.com.
Xilio's core business centers on leveraging proprietary masking technology and protein engineering capabilities to create immunotherapies that selectively activate within the tumor microenvironment. The company's approach involves designing highly potent masked biologics that remain inactive until reaching tumors, where tumor-specific proteases activate them to generate localized anti-tumor immune responses while minimizing systemic toxicity associated with conventional immunotherapy agents.
The company's pipeline includes multiple programs at various development stages. XTX501, a bispecific PD-1/masked IL-2 antibody fusion protein, represents the lead program with plans to submit an investigational new drug application in mid-2026 and initiate Phase 1 trials in the second half of 2026. The company is also advancing wholly-owned masked T cell engager programs targeting PSMA and STEAP1 with co-stimulatory signaling, as well as a program targeting CLDN18.2. Efarindodekin alfa, a masked IL-12 therapy, is currently in Phase 2 clinical trials for advanced solid tumors. Vilastobart, a masked anti-CTLA-4 antibody, is being evaluated in combination with atezolizumab in a Phase 1/2 trial.
Xilio has established strategic partnerships with major pharmaceutical companies to advance its technology platform. In February 2025, the company's subsidiary entered into a collaboration with AbbVie covering up to three masked T cell engager programs and a masked antibody program. Additionally, in March 2024, Xilio Development entered into an exclusive license agreement with Gilead Sciences related to efarindodekin alfa.
The company's intellectual property portfolio includes 18 patent application families covering various aspects of its masking platform, specific product candidates, and manufacturing processes, with patent expiration dates ranging from 2037 to 2046. Xilio operates as a smaller reporting company and emerging growth company under SEC definitions.
Company details
- Sector
- Healthcare
- Industry
- Pharmaceutical Preparations
- Headquarters
- WALTHAM, MA
- Fiscal year end
- December
- CIK
- 1840233
- SIC
- 2834
Financial performance, year by year
Fiscal 2021–2025 · USDThe full income statement, balance sheet and cash flow for each of these years — every figure traceable to its filing — is on the Financials tab with a free account.
Who owns Xilio Therapeutics, Inc. — and what changed
Funds as of 2026Q2 · superinvestors as of 2026-06-30
Largest fund holders · Xilio Therapeutics, Inc.’s weight in each
Fund ownership is a floor, not a census — pensions, insurers and people holding shares directly are not visible here.
Fund ownership counts N-PORT filers only, so it is a floor rather than a census — pensions, insurers and direct holders are not visible here, and the remainder is not “held by individuals”.
Could not be determined for this company: bond issues.
Every fund and institutional holder, quarter by quarter, is on the Ownership tab with a free account.
Recent filings
All filings →Each filing opens into its own statements and disclosures here.
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