A Phase 1 Study of [225Ac]-FPI-1434 Injection

This study consists of a Phase 1 portion and a Phase 2 portion. Phase 1 includes the following cohorts: Single dose-ascending cohorts and Multi- dose ascending cohorts of \[225Ac\]-FPI-1434 and Multi- dose ascending cohorts evaluating administration of FPI-1175 (cold antibody), followed by, \[225Ac\]-FPI-1434 (cold + hot), with cycles repeating every 42 days. And Cold Antibody Sub-study evaluating administration of ascending doses of FPI-1175 followed by \[111In\]-FPI-1547. The Phase 2 will evaluate \[111In\]-FPI-1547 and \[225Ac\]-FPI-1434 with or without FPI-1175 in tumour-specific cohorts. The decision to utilize FPI-1175 in the Phase 2 portion of the study will be determined based on Phase 1 data, including safety, tolerability, pharmacokinetic and dosimetry results.