Partner Therapeutics’ Bizengri (bispecific antibody) became the first FDA-approved therapy for advanced cholangiocarcinoma driven by NRG1 gene fusions, marking a regulatory milestone for a narrowly defined molecular subgroup. The approval follows Partner’s acquisition of U.S. rights from Merus in 2024, positioning the company to pursue further label expansion in a fusion-defined segment. The decision underscores how fusion-driven oncology continues to produce first-in-class approvals where patient selection is tied directly to a specific genomic driver. For clinicians and developers, it also highlights the commercial value of partnering models that secure geography-specific rights in advance of pivotal readouts. Bizengri’s approval also adds urgency for companies building next-generation NRG1-pathway assets, including those targeting resistance mechanisms or pairing with existing standards in cholangiocarcinoma.