Bristol Myers Squibb has made a significant investment in the radiopharmaceutical space, agreeing to pay $350 million upfront to Swiss biotech Philochem for worldwide rights to OncoACP3, an experimental radiopharmaceutical designed to diagnose and treat prostate cancer. The deal, announced Tuesday, could reach $1.35 billion in total value including milestone payments and royalties.
Novel Target Offers Alternative to PSMA
OncoACP3 represents a potentially differentiated approach to prostate cancer treatment by targeting the ACP3 protein rather than PSMA, the current standard target. According to Philochem, ACP3 is highly expressed in prostate cancer but not in healthy tissue, with expression levels that match or exceed those of PSMA. The company states that "a side-by-side comparison between ACP3 and PSMA has shown that ACP3 is more abundantly expressed in prostate cancer than PSMA."
The small-molecule ligand demonstrates high affinity for the ACP3 protein and can carry both Lutetium-177 and Actinium-225, the most common radioisotope payloads currently used in radiopharmaceuticals. OncoACP3 has shown promise in Phase 1 diagnostic imaging trials for accurately targeting prostate cancer tumors, with Philochem working toward Phase 1 therapeutic testing applications.
Strategic Move in Competitive Market
RayzeBio, Bristol Myers' radiopharmaceutical subsidiary acquired for $4.1 billion in 2023, will lead development of OncoACP3. RayzeBio president Ben Hickey emphasized that the partnership "provides a differentiated entry" for Bristol Myers "into the prostate cancer arena" by potentially opening an alternative pathway to PSMA targeting.
The acquisition positions Bristol Myers to compete more effectively in the rapidly expanding radiopharmaceutical market, where Novartis currently leads with two FDA-approved therapies: Lutathera for gastroenteropancreatic neuroendocrine tumors and Pluvicto for prostate cancer. Unlike Pluvicto, which binds to prostate cancer cells expressing PSMA protein, OncoACP3's affinity for ACP3 offers RayzeBio a novel target approach.
Industry Investment Surge
The deal reflects broader industry enthusiasm for radiopharmaceuticals, with major pharmaceutical companies pursuing partnerships and acquisitions in the space. Bristol Myers beat out two other major drugmakers with its $4.1 billion RayzeBio acquisition, while Eli Lilly and AstraZeneca have also made significant investments in radiopharmaceutical companies. AstraZeneca entered the field in March 2024 with a $2.4 billion acquisition of Fusion Pharmaceuticals, gaining access to FPI-2265, an actinium-based radioconjugate targeting PSMA for prostate cancer.
Under the agreement terms, Philochem will receive up to $1 billion in additional payments for achieving development, regulatory, and commercial milestones, plus mid-single to low-double-digit royalties on global net sales if OncoACP3 receives regulatory approval. The transaction is expected to close in the third quarter pending customary clearances and approvals, with Philogen, Philochem's parent company, surging 20% following the announcement.
