Perspective Therapeutics, Inc. announced on September 14, 2026, a clinical collaboration and supply agreement with Merck (NYSE: MRK). Under the terms of the agreement, Perspective will evaluate its targeted alpha-particle therapy [212Pb]PSV359 in combination with Keytruda (pembrolizumab), Merck’s anti-PD-1 therapy.
The collaboration will utilize an amendment to Perspective’s ongoing Phase 1/2a study of [212Pb]PSV359. The study, which has already completed enrollment in the first three monotherapy dose cohorts, focuses on patients with non-small cell lung cancer and colorectal cancer that express fibroblast activation protein alpha (FAP-α). The clinical trial identifier for this study is NCT06710756.
Merck is providing the pembrolizumab at no cost to Perspective. The primary objective of the study’s dose-finding phase is to assess the safety and tolerability of various doses of [212Pb]PSV359 to determine the recommended Phase 2 dose for the expansion phase.
PSV359 is designed to target and deliver the alpha-generating isotope 212Pb to tumor sites expressing FAP-α. The company notes that FAP-α is abundantly expressed on the surface of cancer-associated fibroblasts in the majority of epithelial cancers, including non-small cell lung cancer, colorectal cancer, pancreatic cancer, and mesothelioma.
