Partner Therapeutics’ Bizengri (bispecific antibody) has received FDA approval for advanced cholangiocarcinoma driven by NRG1 gene fusions, marking the first approved therapy for this ultra-rare oncogenic subset. The approval expands the options for patients whose tumors carry NRG1 fusions and who have progressed beyond available treatments. The company previously acquired U.S. rights to the asset from Merus in 2024. Partner’s approval highlights how fusion-driven tumor biology continues to translate into label-defining therapies, with regulatory review increasingly shaped by biomarker-defined patient populations. For developers, the decision underscores the importance of tight companion diagnostic strategies and enrollment pipelines aimed at low-prevalence molecular drivers where data can be decisive. Overall, the FDA greenlight adds to a growing set of precision oncology approvals built around actionable genomic events rather than tumor histology alone.