AlphaBreak is a Phase 2/3 registrational program for FPI-2265 in patients with metastatic castration-resistant prostate cancer

HAMILTON, Canada and BOSTON, MA, USA I May 9, 2024 I Fusion Pharmaceuticals Inc. (Nasdaq: FUSN), a clinical-stage oncology company focused on developing next-generation radioconjugates (RCs) as precision medicines, today announced that the first patient has been dosed in the Phase 2 portion of the AlphaBreak trial evaluating FPI-2265 (225Ac-PSMA I&T) in patients with metastatic castration-resistant prostate cancer (mCRPC).

“Actinium-based PSMA targeting RCs have demonstrated compelling safety and clinical activity, which is supported by Fusion’s encouraging data from the Phase 2 TATCIST trial reported recently at the AACR Annual Meeting. We believe FPI-2265 represents an important potential new treatment option for patients with mCRPC, and with the initiation of the AlphaBreak trial we are pleased to move forward,” said Chief Medical Officer Dmitri Bobilev, M.D.

“Despite recent advances in the field, we see many patients with mCRPC still in need of additional treatment options, especially after progressing on lutetium-based radiotherapy. It is encouraging to see the promising clinical activity and good safety profile demonstrated by FPI-2265. The initiation of the AlphaBreak trial brings us a step closer to addressing the gap for patients and providing this needed treatment option,” said investigator Luke Nordquist, M.D., FACP, XCancer Chief Executive Officer.

The AlphaBreak trial is a Phase 2/3, randomized, open-label, multicenter study to evaluate the safety and efficacy of FPI-2265 in patients with mCRPC previously treated with 177Lu-PSMA radiotherapy. The Phase 2 dose optimization portion is designed to evaluate whether there are added safety and/or efficacy benefits of two alternative dosing regimens in comparison to the previously studied regimen of 100 kBq/kg every eight weeks. The Phase 2 portion of the AlphaBreak trial is expected to complete enrollment of approximately 60 patients by the end of 2024. Following analysis of the Phase 2 data and an end of Phase 2 meeting to determine the recommended Phase 3 dosing regimen with the U.S. Food and Drug Administration (FDA), the Phase 3 global registration portion of the AlphaBreak trial will enroll approximately 550 patients and is expected to begin in 2025.

About FPI-2265

 FPI-2265 is an actinium-225 based PSMA targeting RC, for mCRPC, currently in a Phase 2 trial. Actinium-225 emits alpha particles and holds the promise of being a next-generation radioisotope in cancer treatment. By delivering a greater radiation dose over a shorter distance, alpha particles such as actinium-225 have the potential for more potent cancer cell killing, and targeted delivery, thereby minimizing damage to surrounding healthy tissue.

About Fusion 

Fusion Pharmaceuticals is a clinical-stage oncology company focused on developing next-generation RCs. Fusion conjugates alpha particle emitting isotopes to various targeting molecules in order to selectively deliver the alpha emitting payloads to tumors. Fusion’s clinical-stage development portfolio includes lead program, FPI-2265, targeting PSMA for mCRPC and novel RCs targeting solid tumors. Fusion has a fully operational Good Manufacturing Practice compliant state-of-the-art radiopharmaceutical manufacturing facility to meet supply demand for the Company’s growing pipeline of RCs. The Company has strategic actinium supply agreements with Niowave, Inc. and BWXT Medical.

SOURCE: Fusion Pharmaceuticals