James Gilmore, Steven D’Amato, Niesha Griffith, Lee Schwartzberg

To discuss new therapeutic strategies for chemotherapy-induced nausea and vomiting (CINV) involving 5-hydroxytryptamine type 3 (5HT3)-receptor antagonists (RAs). CINV remains poorly controlled in patients receiving moderately emetogenic chemotherapy (MEC) or highly emetogenic chemotherapy (HEC); nausea and delayed-phase CINV (24-120 hours after chemotherapy) are the most difficult to control. National Comprehensive Cancer Network (NCCN) and American Society of Clinical Oncology (ASCO) antiemesis-guideline recommendations for HEC include a four-drug regimen (5HT3 RA, neurokinin 1 [NK1] RA, dexamethasone, and olanzapine). For some MEC regimens, a three-drug regimen (5HT3 RA, NK1 RA, and dexamethasone) is recommended. While 5HT3 RAs have dramatically improved CINV in the acute phase (0-24 hours after chemotherapy), their efficacy declines in the delayed phase. Newer formulations have been developed to extend 5HT3-RA efficacy into the delayed phase. Granisetron extended-release subcutaneous (GERSC), the most recently approved 5HT3 RA, provides slow, controlled release of therapeutic granisetron concentrations for ≥5 days. GERSC is included in the NCCN and ASCO guidelines for MEC and HEC, with NCCN-preferred status for MEC in the absence of an NK1 RA. Efficacy and safety of 5HT3 RAs in the context of guideline-recommended antiemetic therapy are reviewed. Recent updates in antiemetic guidelines and the development of newer antiemet-ics should help mitigate CINV, this dreaded side effect of chemotherapy. GERSC, the most recently approved 5HT3-RA formulation, is indicated for use with other antiemetics to prevent acute and delayed nausea and vomiting associated with initial and repeat courses of MEC and anthracycline-cyclophosphamide combination-chemotherapy regimens.