Japan regulators approved AmoyDx’s lung cancer test as a companion diagnostic for Hernexeos, extending the tool’s use in HER2-positive non-small cell lung cancer. The approval positions Hernexeos for patients with unresectable, advanced, or recurrent HER2-positive NSCLC whose disease progressed after chemotherapy. For precision oncology, the decision matters because CDx approvals directly affect patient identification pathways in routine care. It also reinforces demand for robust HER2 testing workflows as treatment selection increasingly depends on biomarker-defined subgroups. AmoyDx’s test approval in Japan adds to the growing list of companion diagnostics moving from development pipelines into regulated decision-making, with practical impacts on both lab operations and therapy access.