The FDA rejected RP1, an engineered oncolytic herpesvirus therapy by Replimune Group, despite earlier “breakthrough therapy” designation tied to promising melanoma trial results. The agency has twice declined approval as regulators pressed for additional evidence, adding friction for developers aiming to bring a second-line option to patients with limited treatment choices. Separately, Rigel Pharmaceuticals published final Phase 1/2 ARROW data for pralsetinib (GAVRETO) in RET fusion-positive metastatic NSCLC in the Journal of Clinical Oncology. The updated follow-up reinforces durable, once-daily responses and a manageable safety profile, including efficacy signals in patients with measurable baseline CNS metastases. Together, the two stories highlight how regulatory decisions can still diverge from early promise, while longer-term datasets continue to strengthen the clinical case for targeted targeted therapies.