Palonosetron improves prevention of chemotherapy-induced nausea and vomiting following moderately emetogenic chemotherapy: Results of a double-blind randomized phase III trial comparing single doses of palonosetron with ondansetron

Background: Although all first-generation 5-HT₃ receptor antagonists demonstrate efficacy in preventing acute chemotherapy-induced nausea and vomiting (CINV), effective prevention of delayed CINV has not yet been achieved. This study compared the efficacy and tolerability of palonosetron, a novel, second-generation 5-HT₃ receptor antagonist, with ondansetron. Patients and methods: In this multicenter, randomized, double-blind, stratified, phase III study, 570 adult cancer patients were randomized to receive a single i.v. dose of palonosetron 0.25 mg, palonosetron 0.75 mg or ondansetron 32 mg, each administered 30 min before initiation of moderately emetogenic chemotherapy. The primary end point was the proportion of patients with no emetic episodes and no rescue medication [complete response (CR)] during the 24 h after chemotherapy administration (acute period). Secondary end points included efficacy in treatment of delayed CINV (≤5 days post-chemotherapy) and overall tolerability. Results: 563 patients were evaluable for efficacy. CR rates were significantly higher (P <0.01) for palonosetron 0.25 mg than ondansetron during the acute (0-24 h) (81.0% versus 68.6%, respectively, delayed (24-120 h) (74.1 % versus 55.1 %) and overall (0-120 h) (69.3% versus 50.3%) periods. CR rates achieved with palonosetron 0.75 mg were numerically higher but not statistically different from ondansetron during all three time intervals. Both treatments were well tolerated. Conclusions: A single i.v. dose of palonosetron 0.25 mg was significantly superior to i.v. ondansetron 32 mg in the prevention of acute and delayed CINV.