Fusion Pharmaceuticals to Acquire Phase 2 Program for 225Ac-PSMA I&T, a Radiopharmaceutical Targeting Metastatic Castrate Resistant Prostate Cancer

Fusion Pharmaceuticals, a clinical-stage oncology company focused on developing next-generation targeted alpha therapies as precision medicines, has announced the acquisition from RadioMedix of the investigational new drug application for an ongoing Phase 2 clinical trial (the “TATCIST” trial) evaluating 225Ac-PSMA I&T, a small molecule targeting prostate specific membrane antigen (“PSMA”) expressed on prostate cancers. Following the closing, the alpha-emitting radiopharmaceutical being evaluated in the TATCIST trial will be known as FPI-2265.

“We are pleased to announce this acquisition, which adds an ongoing Phase 2 program for a validated cancer target to our pipeline of innovative TATs,” commented Fusion Chief Executive Officer John Valliant, Ph.D. “From our inception, Fusion has recognized the potential opportunity for actinium-based therapies to address unmet needs in cancer given the power and potency of alpha radiation. We believe that with Fusion’s TAT development expertise, and early investments that provide us with our actinium supply advantage, we are uniquely positioned to be first-to-market with an actinium-based PSMA agent.”

“A growing body of clinical data demonstrates the power of targeted alpha therapies in prostate cancer, including for patients who progress on or after lutetium-based PSMA therapies,” said Oliver Sartor, M.D, Laborde Professor for Cancer Research and Medical Director at Tulane Cancer Center. “With more than 250 patients treated with actinium-based radiopharmaceuticals targeting PSMA in investigator sponsored studies, this class of therapy has both the efficacy data and safety profile that supports continued development. I believe 225Ac-PSMA I&T will have the potential to target a growing patient population with significant unmet need. In addition, it has the potential to move into earlier lines of therapy as monotherapy as well as in combination with other agents.”

The TATCIST trial is designed to evaluate patients with metastatic castration-resistant prostate cancer (“mCRPC”) with progressive disease, including patients who are naïve to PSMA targeted radiopharmaceuticals and those who have been pre-treated with 177Lu-based PSMA radiopharmaceuticals such as PLUVICTO™. The trial is expected to evaluate approximately 100 patients with four treatment cycles per patient occurring every eight weeks. Patients are initially dosed at 100 kBq/kg with dose de-escalation possible based on biochemical response. Efficacy will be assessed using change in PSA levels and radiographic response. Fusion plans to expand the Phase 2 program to additional sites and expects to report data on 20 to 30 patients in the first quarter of 2024.

“Having treated mCRPC patients for many years, I initiated the TATCIST trial to address the unmet needs for the many patients who are not adequately addressed with currently available therapies,” said Ebrahim Delpassand, M.D., Chairman and CEO of RadioMedix and Medical Director of Excel Diagnostics & Nuclear Oncology Center. “Given Fusion’s radiopharmaceutical development capabilities, leadership in Actinium supply and established infrastructure, we look forward to this preeminent partnership to advance FPI-2265 through the Phase 2 program for the benefit of our patients.”

Dr. Valliant continued, “With one Phase 2 program, three ongoing Phase 1 programs, and an IND submission through our collaboration with AstraZeneca expected in the first quarter of 2023, Fusion continues to extend its leadership in targeted alpha therapy development. Following the encouraging data we reported from the cold antibody sub-study of the FPI-1434 trial in June, we continue to dose escalate and we look forward to reporting the preliminary Phase 1 data in the second quarter of this year. The FPI-1434 data will be the first in what we expect will be multiple clinical updates generated from our pipeline over the next 24 months.”