Fig. 1. Kaplan-Meier plot of the fraction of patients in the dose-ranging studies who remained free of emetic symptoms during the first 24 h after surgery. Because the study was performed sequentially at doses of 100 mg (vs.  placebo) followed by 200 mg (vs.  placebo), four separate curves are shown for placebo (vs.  100 mg), placebo (vs.  200 mg), CP-122,721 100 mg, and CP-122,721 200 mg. The delay in time to emesis and the proportion of patients with emesis were significantly different (P < 0.01) in patients receiving 200 mg versus  placebo.