A Study of [225Ac]-FPI-1966 in Participants With Advanced Solid Tumours

\[225Ac\]-FPI-1966 is a targeted alpha therapeutic that consists of vofatamab, a bifunctional chelate, and actinium-225, an alpha particle emitting radionuclide. In Phase 1, the dose depends on cohort assignment. In Phase 2, the RP2D regimen will be administered.

\[111In\]-FPI-1967 is an imaging agent that consists of vofatamab, a bifunctional chelate and indium-111 radionuclide. Participants will receive \[111In\]-FPI-1967 Injection of 185 MBq for imaging.

Vofatamab is a Fibroblast Growth Factor Receptor 3 (FGFR3)-targeting human monoclonal antibody without a radioisotope. In Phase 1, the dose depends on cohort assignment. In Phase 2, if pre-dosing with vofatamab is indicated, the RP2D regimen will be administered.