NEW YORK – Fusion Pharmaceuticals on Wednesday said that the US Food and Drug Administration has cleared its investigational new drug applications (INDs) for its targeted alpha therapy FPI-1966 and imaging agent FPI-1967, allowing it to begin studying the radiopharmaceutical in FGFR3-expressing cancers.
FPI-1966 uses Fusion's Fast-Clear linker to connect vofatamab, an FGFR3-targeting monoclonal antibody, with actinium-225, an alpha-particle emitting radionuclide. The FDA's acceptance of Fusion's INDs will allow the Hamilton, Ontario-headquartered firm to start a Phase I trial of the radiopharmaceutical involving patients with FGFR3-expressing solid tumors.
In the Phase I trial, researchers will first explore different doses of a non-radiolabeled vofatamab and screen patients for the trial using the imaging analogue FPI-1967. Only patients who meet the predefined tumor uptake and safety criteria in this portion of the trial will advance to receive the radiopharmaceutical FPI-1966. In the study, Fusion hopes to establish the safety, tolerability, and pharmacokinetics of FPI-1966 and the recommended dose to take into Phase II studies.
In 2019, the US Food and Drug Administration approved erdafitinib (Janssen Pharmaceutical's Balversa) for advanced bladder cancer patients who have progressed on platinum chemotherapy and who harbor tumor alterations in FGFR3 or FGFR2 genes. By targeting FGFR3 overexpression, which occurs in various solid tumors, especially head and neck cancer, Fusion is hoping to expand the proportion of patients eligible for its drug.
"We have an opportunity to selectively deliver alpha particles to these tumors and use precision radiation therapy as a new treatment paradigm," said Fusion CEO John Valliant. "While the currently approved pan-FGFR inhibitor for bladder cancer requires the presence of a specific mutation, our approach requires only overexpression of FGFR3. If successful, this could provide an opportunity to treat a larger population of patients."
In addition to starting human trials of FPI-1966, earlier this year Fusion inked a deal with AstraZeneca to develop up to three targeted alpha therapies and evaluate combination approaches with AstraZenca's DNA damage response inhibitors.