Ratio Therapeutics
Ratio Therapeutics designs small molecules that carry a radioactive particle to a protein found in the supporting tissue of many tumours, so radiation is delivered from inside the body. Its lead treatment is in early human trials for sarcoma.
Overview
Ratio Therapeutics is a clinical-stage Boston radiopharmaceutical company whose Trillium targeting scaffold combines pharmacokinetic modulation with chelation chemistry to create small-molecule radioligands that can be paired with imaging or therapeutic isotopes (theranostics). The lead programme [Ac-225]RTX-2358 is a fibroblast activation protein (FAP)-targeted actinium-225 therapeutic in the ATLAS phase 1/2 trial in advanced sarcomas; the pipeline also includes a next-generation GRPR programme and additional mono- and bispecific radioligands, with a fifth IND filing in preparation. In July 2026 Ratio closed a USD 70 million Series C with Duquesne Family Office, Bristol Myers Squibb, Catalio Capital, Eli Lilly and Wasatch Group, taking total capital raised above USD 240 million. It has manufacturing collaborations with PharmaLogic, an actinium-225 supply agreement with PanTera (June 2026) and, in September 2026, a research collaboration and licence agreement with RayzeBio.
Funding
All startupsInvestors not recorded; see the round sources.
| Round | Year | Amount | Source |
|---|---|---|---|
| Series C · Brings total capital raised to over USD 240 million | 2026 | $70M | ratiotx.com |
Amounts only where the cited source states them. Rounds without a public source are not listed.
Notes
top- Earlier rounds (Series A and B) not fetched and omitted.
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