Fusion Pharmaceuticals Announces First Patient Dosed in the Phase 2 Portion of the AlphaBreak Trial Evaluating FPI-2265 in Metastatic Castration-Resistant Prostate Cancer

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

HAMILTON, ON and BOSTON, May 9, 2024 /PRNewswire/ -- 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.

Forward-Looking Statements

This press release contains "forward-looking statements" for purposes of the safe harbor provisions of The Private Securities Litigation Reform Act of 1995, including but not limited to the statements regarding the future business and financial performance of Fusion Pharmaceuticals Inc. (the "Company"). For this purpose, any statements contained herein that are not statements of historical fact may be deemed forward-looking statements. Without limiting the foregoing, the words "expect," "plans," "anticipates," "intends," "will," and similar expressions are also intended to identify forward-looking statements, as are expressed or implied statements with respect to the Company's financial condition, liquidity, and potential drug candidates, including any expressed or implied statements regarding the successful development of FPI-2265. Actual results may differ materially from those indicated by such forward-looking statements as a result of risks and uncertainties, including but not limited to the following: there can be no guarantees that the Company will advance FPI-2265 in the clinic, to the regulatory process or to commercialization; management's expectations could be affected by unexpected patient recruitment delays or regulatory actions or delays; uncertainties relating to, or unsuccessful results of, clinical trials, including additional data relating to the ongoing clinical trial evaluating FPI-2265; the Company's ability to obtain additional funding required to conduct its research, development and commercialization activities; changes in the Company's business plan or objectives; competition in general; the Company's ability to obtain, maintain and enforce patent and other intellectual property protection for its product candidates and its discoveries; and the Company partners' ability to advance any technology relating to actinium-225 to development. Such forward-looking statements involve known and unknown risks, uncertainties and other factors that may cause actual results to be materially different from any future results, performance or achievements expressed or implied by such statements. These and other risks which may impact management's expectations are described in greater detail under the heading "Risk Factors" in the Company's quarterly report on Form 10-Q for the period ended March 31, 2024, as filed with the Securities and Exchange Commission (the "SEC") and in any subsequent periodic or current report that the Company files with the SEC. All forward-looking statements reflect the Company's estimates only as of the date of this release (unless another date is indicated) and should not be relied upon as reflecting the Company's views, expectations, or beliefs at any date subsequent to the date of this release. While Fusion may elect to update these forward-looking statements at some point in the future, it specifically disclaims any obligation to do so, even if the Company's estimates change.

Investors and others should note that Fusion communicates with its investors and the public using the Fusion website, www.fusionpharma.com, including, but not limited to, company disclosures, investor presentations, SEC filings, and press releases. The information that Fusion posts on this website could be deemed to be material information. As a result, Fusion encourages investors, media and others interested to review the information that Fusion posts there on a regular basis.

Contact:
Amanda Cray
Senior Director of Investor Relations & Corporate Communications
(617) 967-0207
[email protected] 

SOURCE Fusion Pharmaceuticals