Fusion Pharmaceuticals Inc. (Nasdaq: FUSN), a Canada-based clinical-stage oncology company, announced on Monday that it has dosed its first patient in the phase one study assessing [225Ac]-FPI-2059 (FPI-2059).

FPI-2059 is a small molecule targeted alpha therapy (TAT) designed to deliver actinium-225 to tumour sites expressing neurotensin receptor 1 (NTSR1), a protein that is overexpressed in gastrointestinal, prostate, pancreatic ductal adenocarcinoma (PDAC) and multiple other cancers.

The Phase 1, multi-centre, open-label clinical trial is designed to investigate the safety, tolerability, dosimetry, biodistribution, and pharmacokinetics of FPI-2059, as well as preliminary anti-tumour activity in participants with neurotensin receptor 1 (NTSR1) expressing advanced metastatic solid tumours. The study will employ a 3+3 dose escalation design to identify the recommended Phase 2 dose (RP2D) of FPI-2059 administered intravenously every 56 days for up to four cycles.

Fusion Pharmaceuticals' chief executive officer, John Valliant, PhD, said, 'Tremendous opportunity exists in the radiopharmaceutical field to look beyond the few established targets, particularly when using a potent payload like actinium-225. The initiation of the Phase 1 study of FPI-2059 marks an important milestone in this regard, bringing us a step closer to providing a differentiated therapy for patients. FPI-2059 is our fourth clinical program and the second small molecule-based TAT in our pipeline of radiopharmaceuticals, showcasing the potential for our platform technology to create TATs that treat a broad array of solid tumour types with high unmet need.'