Boston-based Ratio Therapeutics, Inc., a clinical-stage radiopharmaceutical company, has closed a USD 70 million Series C financing round, bringing total capital raised to over USD 240 million. The round draws in Eli Lilly and Company as a new strategic investor alongside existing backers, signalling continued large-cap pharmaceutical interest in the company's alpha-particle radioligand therapy platform.
Existing investors Duquesne Family Office and Bristol Myers Squibb participated in the round, joined by new entrants Catalio Capital Management, Eli Lilly, and Wasatch Group. The company said proceeds will advance the ongoing ATLAS Phase I/II trial of its lead asset, the fibroblast activation protein (FAP)-targeted alpha-emitting radioligand [Ac-225]RTX-2358, in advanced sarcomas, and fund a fifth investigational new drug filing expected to cover its next-generation gastrin-releasing peptide receptor (GRPR)-targeted program. Ratio also plans to expand its discovery pipeline into additional oncology targets and scale its hybrid manufacturing infrastructure, anchored by a vertically integrated site in Utah. The Series C follows a USD 50 million Series B closed in January 2024, which first brought Bristol Myers Squibb into the investor syndicate.
Ratio's platform rests on two proprietary technologies developed from academic research at Weill Cornell Medicine and Cornell University. The Trillium scaffold — originating from the laboratory of Dr. John Babich at Weill Cornell — is a trifunctional construct combining a tumor-targeting moiety, a reversible albumin-binding moiety to tune blood half-life and tumor exposure, and a chelator. The Macropa chelator, invented by Professor Justin J. Wilson at Cornell and licensed through Cornell's Center for Technology Licensing, provides stable chelation of Actinium-225 under mild conditions, reducing the risk of in vivo isotope release that can cause off-target bone toxicity. Cornell's Center for Technology Licensing participated as an investor in the Series B, reflecting the university's continued institutional stake.