Bristol Myers, Philochem Partner on $1.35B Radiopharma Deal Targeting ACP3 in Prostate Cancer

Highlights

• Bristol Myers Squibb and Philochem have entered a $1.35 billion collaboration to develop OncoACP3, an early-stage radiotherapeutic targeting the novel ACP3 biomarker.
• The deal includes a $350 million upfront payment, with the remainder tied to future milestones and royalties.
• OncoACP3 may offer a new pathway in prostate cancer treatment, with higher expression levels of ACP3 in tumors compared to the commonly targeted PSMA.
• The partnership marks BMS’s strategic push into the radiopharmaceutical market, currently led by Novartis, with competitors including AstraZeneca and Eli Lilly.
• Philogen shares surged 20% following the announcement, reflecting strong investor confidence in the deal’s potential.

New Partnership Targets Novel Pathway in Prostate Cancer

Bristol Myers Squibb (BMS), through its radiopharmaceutical subsidiary RayzeBio, has entered a strategic collaboration with Italian-Swiss biotech Philochem to co-develop an early-stage radiotherapeutic focused on prostate cancer. Rather than following the widely adopted approach of targeting PSMA (prostate-specific membrane antigen), the two companies will pursue a novel biomarker known as ACP3.

According to the official announcement, RayzeBio has committed an upfront payment of $350 million to Philochem, with an additional $1.35 billion in potential development, regulatory, and commercial milestone payments. The agreement also includes provisions for mid-single to low-double-digit royalties on global net sales. The transaction is expected to close in the third quarter of 2025, subject to standard regulatory approvals.

Philochem’s parent company, Philogen, saw a sharp market response following the announcement, with shares surging 20% on Wednesday morning.

ACP3: A New Contender in Prostate Cancer Therapy

The centerpiece of the deal is OncoACP3, a proprietary small-molecule radiotracer developed by Philochem that targets ACP3—a biomarker highly expressed in prostate cancer cells but not in healthy tissue. “A side-by-side comparison between ACP3 and PSMA . . . has shown that ACP3 is more abundantly expressed in prostate cancer than PSMA,” the company stated on its website.

OncoACP3 is designed to bind with high affinity to the ACP3 protein and is compatible with radiotherapeutic payloads such as Lutetium-177 and Actinium-225—both widely used in current radiopharma therapies. This technological versatility could position OncoACP3 as a significant asset in the competitive prostate cancer market.

Strategic Advantage in a Crowded Radiopharma Market

Ben Hickey, president of RayzeBio, emphasized the strategic importance of this collaboration, stating that the partnership “provides a differentiated entry” for BMS “into the prostate cancer arena.” By focusing on an alternative to PSMA, BMS aims to establish a unique position in the growing radiopharmaceuticals space.

The field is currently dominated by Novartis, which markets two FDA-approved radiotherapeutics: Lutathera, for gastroenteropancreatic neuroendocrine tumors, and Pluvicto, which targets PSMA in prostate cancer. Meanwhile, AstraZeneca and Eli Lilly are actively expanding their presence. AstraZeneca recently acquired Fusion Pharmaceuticals for $2.4 billion, gaining access to the actinium-based radioconjugate FPI-2265, which also targets PSMA. Eli Lilly has invested significantly in the sector, purchasing Point Biopharma for $1.4 billion in 2023 and Aktis Oncology for $1.1 billion in 2024. Its lead asset, PNT2002, also targets PSMA.