Ratio Therapeutics, a Boston-based developer of targeted radiotherapeutics, has raised $70 million in Series C funding. The company engineers radiopharmaceuticals using its Trillium and Macropa platforms to deliver actinium-225 directly to cancer cells. The capital will advance clinical development of its pipeline and expand manufacturing infrastructure.
Big Pharma Backs Independent Radiopharma Play
The round drew participation from Bristol Myers Squibb and Eli Lilly and Company alongside existing investor Duquesne Family Office and new backers Catalio Capital Management and Wasatch Group. This follows major acquisitions in the space: RayzeBio was acquired by BMS for $4.1 billion in December 2023, Mariana Oncology by Novartis for up to $1.75 billion in May 2024, and Point Biopharma by Lilly for $1.4 billion in October 2023. Ratio's independent stance with a dual-platform approach positions it differently from those acquired assets.
Supply Chain Constraints Limit Alpha Therapy Scale
Actinium-225 supply remains a bottleneck for the entire field. Ratio has secured multiple agreements including with TerraPower Isotopes, Nusano, Niowave, and PanTera to de-risk isotope access. Competitors like AdvanCell raised $427 million across recent rounds to build similar vertical integration around lead-212.
Trillium and Macropa Optimize Delivery and Manufacturing
Ratio's Trillium scaffold modulates pharmacokinetics through reversible albumin binding to improve tumor retention while clearing healthy tissue. Its Macropa chelator enables room-temperature labeling of actinium-225, avoiding degradation issues common with standard chelators. The company runs small-scale imaging trials first to validate targets before advancing to therapy trials, a capital-efficient de-risking step.
Novartis Deal and BMS Investment Signal Validation
A November 2024 license agreement with Novartis for an SSTR2 candidate worth up to $745 million provides external validation of the platforms. BMS's participation as both investor and strategic player adds another pharma relationship. Total capital raised now exceeds $240 million across prior Series A and B rounds.
Radiopharma Markets Expand on Alpha Therapy Shift
The radioligand therapy market is projected to grow from $2.65 billion in 2025 to $9.3 billion by 2035 at 13.5% CAGR per InsightAce Analytic. Targeted alpha therapy is expected to reach $4.12 billion by 2030 at 20.8% CAGR per Strategic Market Research. Actinium-225 supply itself is forecast to expand from $1.22 billion in 2025 to $5.11 billion by 2035 per Spherical Insights.
Manufacturing Buildout Positions for Later-Stage Trials
Ratio is constructing a 65,000 square foot facility in Salt Lake City slated for operation in the second half of 2027. It has also expanded its agreement with PharmaLogic to support potential registrational trials for its lead FAP-targeted candidate RTX-2358, now in Phase 1/2.
As CSO John Babich noted on a recent podcast:
"Why the Ac-225 supply picture looks far more promising than it did five years ago — thanks to scaling efforts from groups like TerraPower Isotopes, PanTera, and Niowave."
The company's approach of building end-to-end capabilities while remaining independent differentiates it in a sector dominated by recent pharma acquisitions.