Casopitant and ondansetron for postoperative nausea and vomiting prevention in women at high risk for emesis: a phase 3 study.

HYPOTHESIS Postoperative nausea and vomiting (PONV) are associated with a variety of complications. Neurokinin subtype 1 receptor antagonists have antiemetic activity in the postoperative setting, and the neurokinin subtype 1 receptor antagonist casopitant mesylate (GW679769) was well tolerated and effective at reducing the incidence of PONV in phase 1 and phase 2 trials. DESIGN A multicenter, randomized, double-blind, parallel-group, phase 3 analysis was designed to evaluate the safety and efficacy of casopitant in combination with a single intravenous dose of the serotonin subtype 3 receptor antagonist ondansetron hydrochloride for the prevention of PONV in the perioperative setting. SETTING Forty-three centers in 11 countries. PATIENTS We studied 484 women at high risk for developing PONV scheduled to undergo operations associated with high emetogenic risk. INTERVENTIONS The women were randomized to receive a single dose of intravenous ondansetron, 4 mg, or oral casopitant, 50 mg, in combination with intravenous ondansetron, 4 mg. MAIN OUTCOME MEASURES The primary end point was the proportion of patients who achieved a complete response, defined as no vomiting, retching, or rescue therapy. Patients received a balanced anesthetic regimen. RESULTS Between March 20 and August 31, 2006, 484 patients were enrolled in the study. Patients in the casopitant plus ondansetron group had a 68.7% rate of complete response during the first 24 hours after surgery compared with 58.7% in the ondansetron-only group (P = .03). The difference between groups in complete response from 24 to 48 hours (63.4% with ondansetron only vs 70.0% with ondansetron plus casopitant) was not significant. No vomiting for 0 to 24 hours was observed in 89.7% of the casopitant plus ondansetron group compared with 74.9% of the ondansetron-only group (P < .001). Oral casopitant administered in combination with ondansetron was well tolerated. CONCLUSIONS The results of this pivotal phase 3 study demonstrate that the combination of casopitant and ondansetron was superior to ondansetron only in patients at high risk for PONV. Trial Registration clinicaltrials.gov Identifier: NCT00326248.