Perspective Therapeutics, Inc. announced on October 8, 2026, that the U.S. Food and Drug Administration (FDA) has granted Fast Track Designation for PSV359. The designation applies to the development of the drug for adult patients with locally advanced unresectable and/or metastatic fibroblast activation protein-positive solitary fibrous tumors (SFTs).
Solitary fibrous tumors are a rare cancer type. The company noted that patients with locally advanced unresectable or metastatic disease currently have limited treatment options. The PSV359 program is an investigational FAP-targeted alpha-particle therapy.
The therapy is being evaluated in an ongoing Phase 1/2a study. This study is a multi-center, open-label trial in patients with advanced FAP-positive solid tumors. The primary objective of the dose-finding phase is to assess the safety and tolerability of various doses of [212Pb]PSV359 to determine the recommended Phase 2 dose.
Early human imaging data for PSV359 reportedly support strong tumor uptake and fast renal clearance. The FDA Fast Track program is intended to facilitate development and expedite the review of therapies for serious conditions with unmet medical needs. Programs that receive this designation may benefit from more frequent interactions with the FDA and may qualify for rolling review, Accelerated Approval, or Priority Review if applicable requirements are met.
PSV359 is designed to target and deliver 212 Pb to tumor sites expressing FAP. The company is also developing complementary imaging techniques, such as PSV377, which uses 203 Pb or 68 Ga to detect FAP expression in individual patients.
