In DESTINY-Breast06, the safety profile of ENHERTU was consistent with previous clinical trials with no new safety concerns identified. Grade 3 or grade 4 treatment-related adverse events from a pooled safety analysis of patients treated with ENHERTU (5.4 mg/kg) across multiple tumor types in clinical studies included neutropenia (18.0%), anemia (10.5%), fatigue (7.8%), leukopenia (6.0%), thrombocytopenia (5.4%), nausea (4.9%), lymphopenia (3.9%), hypokalemia (3.8%), transaminases increased (3.5%), diarrhea (2.5%), vomiting (2.4%), decreased appetite (1.8%), pneumonia (1.3%), and ejection fraction decreased (1.0%). Grade 5 adverse reactions occurred in 1.4% of patients, including interstitial lung disease (1.1%).