Lead-212 PSV359 Therapy for Patients With Solid Tumors

This is a prospective, multi-center open label dose finding, dose expansion study of \[212Pb\]Pb-PSV359 in subjects with a positive Fibroblast Activation Protein (FAP) imaging scan with imaging agent. FAP is specifically expressed on the surface of cancer-associated fibroblasts in some tumor tissues and therefore is an attractive target in the diagnosis and treatment of various cancers. Lead-212 (\[212Pb\]Pb-) based peptide-radiopharmaceuticals are an emerging class of targeted alpha-particle cancer therapies that have potential to improve delivery of a highly effective form of radiation. This study will be conducted in 2 parts: Part 1: Dose-escalation: \[212Pb\]Pb-PSV359 is administered in escalating doses to determine the Maximum Tolerated radioactivity (MTD) Dose and potential recommended Phase 2 dose (RP2D). Part 2: Dose-expansion: This part will enroll subjects in expansion cohorts based on the identified MTD and RP2D for the selection of \[212Pb\]Pb-PSV359 doses for further clinical development. A Dosimetry sub-set utilizing an imaging surrogate, \[203Pb\]Pb-PSV359, has been incorporated into the study in order to assess organ biodistribution and tumor uptake of the investigational products. This sub study will also estimate radiation dosimetry and correlate uptake of the investigation products with observed toxicities and efficacy.