Ratio Therapeutics has announced a USD 70 million Series C round with participation from existing investors Duquesne Family Office and Bristol Myers Squibb (BMS), alongside new investors Catalio Capital Management, Eli Lilly, and Wasatch Group, bringing cumulative financing to over USD 160 million since the company's 2022 inception.

Proceeds will fund the ATLAS study (NCT07156565), a Phase I/II trial of lead candidate [Ac-225]RTX-2358 in advanced sarcoma, push next-generation radioligand therapies into the clinic, expand novel tumour targets, and scale proprietary manufacturing. RTX-2358 is a FAP-targeted actinium-225 conjugate currently in early clinical evaluation, with additional programmes against GRPR and SSTR2, the latter paired with a global licence and collaboration agreement with Novartis.

Ratio's differentiated position rests on two platforms: Trillium, a trifunctional delivery system enabling pharmacokinetic tuning across payloads and targets, and Macropa, a proprietary chelator that simplifies actinium-225 conjugation and improves in vivo stability.

The raise aligns with renewed investor appetite for alpha-particle radiotherapeutics, following AdvanCell's USD 315 million Series D for its lead-212 PSMA agent ADVC001 in Phase II. With BMS and Eli Lilly on the cap table, Ratio gains both strategic validation and potential commercialisation pathways as the actinium-225 supply chain and targeting chemistry mature into registrable assets.