Administration of trastuzumab deruxtecan in metastatic breast cancer patients with severe hepatic impairment

Background: Trastuzumab deruxtecan (T-DXd) shows efficacy in HER2-positive and HER2-low metastatic breast cancer (MBC), but its safety in patients with hepatic impairment is unclear. Methods: We report three cases of MBC patients with significant liver dysfunction treated with dose-reduced T-DXd after multiple prior therapies. Results: Dose-reduced T-DXd led to improved bilirubin levels and tumor response, with two patients achieving durable responses and enhanced quality of life. Supportive care and tailored dosing were crucial in managing hepatotoxicity. Conclusion: Dose-reduced T-DXd may offer clinical benefit for MBC patients with liver impairment. Further studies are warranted to refine dosing strategies in this population.