[Effectiveness of Adding Fosnetupitant to a Doublet Antiemetic Therapy Containing Palonosetron for Trastuzumab Deruxtecan-Induced Nausea and Vomiting - A Retrospective Comparative Study].

The emetic risk of trastuzumab deruxtecan (T-DXd) is classified as moderate in Japan; however, controlling nausea and vomiting is difficult with doublet therapy comprising a 5-hydroxytryptamine type 3 (5-HT3) receptor antagonist and dexamethasone. We retrospectively evaluated the effect of adding a neurokinin-1 (NK1) receptor antagonist to doublet antiemetic therapy with palonosetron and dexamethasone on T-DXd-induced nausea and vomiting. The patients were divided into those receiving triplet antiemetic therapy containing the NK1 receptor antagonist fosnetupitant (PDN group) and those receiving doublet antiemetic therapy without fosnetupitant (PD group). Adding fosnetupitant increased the complete antiemetic control rate in the PDN group by 34.9% compared with that in the PD group. Triplet antiemetic therapy with palonosetron, dexamethasone, and fosnetupitant may provide effective antiemetic prophylaxis for T-DXd-induced nausea and vo miting.