Emerging drugs for chemotherapy-induced emesis.

Chemotherapy-induced nausea and vomiting (CINV) is associated with a significant deterioration in quality of life. The emetogenicity of the chemotherapeutic agents, repeated chemotherapy cycles and patient risk factors (female gender, younger age, no alcohol consumption, history of motion sickness) are the major risk factors for CINV. The use of 5-hydroxytryptamine-3 (5-HT3) receptor antagonists plus dexamethasone has significantly improved the control of acute CINV, but delayed nausea and vomiting remains a significant clinical problem. Two new agents, palonosetron and aprepitant, have recently been approved for the prevention of both acute and delayed CINV. Palonosetron is a 5-HT3 receptor antagonist with a longer half-life and a higher binding affinity than first-generation 5-HT3 receptor antagonists. Aprepitant is the first agent available in the new drug class of neurokinin-1 receptor (NK-1) antagonists. There are a number of 5-HT3 receptor antagonists and NK-1 receptor antagonists currently in Phase II and III clinical trials. Revised antiemetic guidelines for the prevention of CINV are reviewed. Future studies may consider the use of palonosetron and aprepitant with current and other new agents (olanzapine, gabapentin) in moderately and highly emetogenic chemotherapy, as well as in the clinical settings of multiple-day chemotherapy and bone marrow transplantation.