On October 8, 2026 Perspective Therapeutics, Inc. ("Perspective," the "Company," "we," "us," and "our") (NYSE AMERICAN: CATX), a radiopharmaceutical development company pioneering advanced treatments for cancers throughout the body, reported that the U.S. Food and Drug Administration (the "FDA") granted Fast Track Designation for the development of PSV359 for adult patients with locally advanced unresectable and/or metastatic fibroblast activation protein (FAP)-positive solitary fibrous tumors (SFTs).
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SFT is a rare cancer for which patients with locally advanced unresectable or metastatic disease have limited treatment options. [²¹²Pb]PSV359 is an investigational FAP-targeted alpha-particle therapy being evaluated in an ongoing Phase 1/2a study in patients with advanced FAP-positive solid tumors. Published clinical imaging research has demonstrated FAP-targeted tracer uptake in SFTs, supporting the biological rationale for evaluating a FAP-directed therapy in this disease.1 Early human imaging data for PSV359 support strong tumor uptake and fast renal clearance.
The FDA’s Fast Track program is intended to facilitate development and expedite the review of therapies for serious conditions with unmet medical needs.2 Programs that receive Fast Track Designation may benefit from more frequent interactions with the FDA regarding the development program. A Fast Track-designated product may also qualify for rolling review, Accelerated Approval, or Priority Review if the applicable requirements for those programs are met.2 FDA treats these as distinct expedited programs with separate qualifying criteria.
"FAP-α is a particularly compelling target because of its broad expression across solid tumors and within the tumor microenvironment, creating the potential for PSV359 to address a substantial patient population across multiple cancer types," said Markus Puhlmann, Perspective’s Chief Medical Officer. "There are currently no approved therapies specifically targeting FAP-α, despite its association with aggressive cancers and tumor environments that can limit drug penetration and suppress immune activity. Imaging FAP-α expression before treatment allows us to pair patient selection with targeted alpha radiopharmaceutical therapy and pursue that broad opportunity with precision."
"Fast Track designation for FAP-positive solitary fibrous tumors is an important step in advancing the broader PSV359 program and our strategy of engineering targeted radiopharmaceutical therapy based on the alpha-generating isotope 212Pb to optimize the therapeutic window in oncology," said Thijs Spoor, Perspective’s Chief Executive Officer. "We look forward to working with the FDA and the medical community to define an efficient development path for PSV359 in this rare and serious disease."
About FAP
FAP is a cell-surface protein expressed predominantly by cancer-associated fibroblasts (CAFs) in the stroma, an important component of the tumor microenvironment (TME) in many epithelial cancers. FAP may also be expressed directly by certain cancer cells, including sarcomas and mesotheliomas.3,4,5,6 Higher FAP-α expression has been found to be associated with poor prognosis in a number of solid tumors such as non-small cell lung cancer, colorectal cancer, pancreatic cancer, stomach cancer, mesothelioma, head and neck cancer, esophageal cancer, and ovarian cancer.7,8,9,10,11,12 FAP-α expression is generally limited in healthy tissues.5,6
About PSV359
PSV359 was designed to target and deliver 212Pb to tumor sites expressing FAP-α, associated with multiple highly prevalent solid tumors, with patients in need of additional treatment options. The targeting moiety may also be radiolabeled with 203Pb or 68Ga (known as PSV377) to detect FAP-α expression in individual patients. Preclinical imaging and therapy, as well as early human imaging results, have demonstrated that Perspective’s proprietary targeting ligand improves target engagement and uptake in tumors and reduces retention in healthy tissues, which may result in a desirable therapeutic index.
Perspective is conducting a multi-center, open-label, dose-finding and dose-expansion study (clinicaltrials.gov identifier NCT06710756) of [212Pb]PSV359 in patients with advanced solid tumors that express FAP-α as determined by imaging with [203Pb]PSV359. The primary objective of the dose-finding phase of the study is to assess the safety and tolerability of various doses of [212Pb]PSV359 in order to inform selection of the recommended Phase 2 dose for use in the expansion phase. Antitumor activity may be evaluated as an additional primary outcome in the expansion portion of the study.
(Press release, Perspective Therapeutics, OCT 8, 2026, View Source [SID1234673300])