Ondansetron plus dexamethasone is superior to ondansetron alone in the prevention of emesis in chemotherapy-naive and previously treated patients

BACKGROUND: This prospective, randomized, double-blind study assessed whetherthe addition of dexamethasone to ondansetron leads to improvedcontrol of chemotherapy - induced emesis, both in patients undergoingtheir first course of highly emetogenic chemotherapy and inchemotherapypretreated patients refractory to standard anti-emetics. PATIENTS AND METHODS: Patients were randomized to receive either 20 mg dexamethasoneas an intravenous infusion or placebo plus ondansetron 8 mg15 minutes prior to and 4 and 8 hours after the administrationof chemotherapy. According to the randomisation code patientsreceived from day 2 to day 5 either ondansetron 8 mg p.o. +placebo p.o., three times daily, or ondansetron 8 mg p.o. +dexamethasone 4 mg p.o., three times daily. Patients undergoingmultiple-day treatment received intravenous study treatmenton the days of chemotherapy and thereafter oral treatment asoutlined above. RESULTS: A total of 215 patients were entered into the study. Of these,207 were evaluable (111 previously-untreated and 96 previously-treatedpatients). In the chemotherapynaive patients the combinationof ondansetron plus dexamethasone was significantly superiorto ondansetron plus placebo in protecting the patients completelyfrom emesis (retching and vomiting) (81% versus 64%, p –0.04). The mean number of vomiting episodes was significantlylower in the ondansetron-plus-dexamethasone-treated patientsthan in those receiving ondansetron plus placebo (0.8 versus2.1, p – 0.03). In this group of patients there was significantlysuperior protection from emesis on the second day (pvalue –0.04), and a trend towards a better protection on the thirdand fourth days. On each day the active combination offeredbetter protection from nausea with an approximately 20% differencein favor of ondansetron plus dexamethasone. In the group ofestablished vomiters the combination of ondansetron plus dexamethansonewas superior to ondansetron plus placebo in protecting the patientsfrom acute emesis, with 70% versus 48% of the patients beingcompletely protected (p = 0.03). The mean number of vomitingepisodes was significantly lower in the ondansetron-plusdexamethasone-treated-patientsthan in those receiving ondansetron plus placebo (0.9 versus2.1, p = 0.02). In the ondansetron-plus-dexamethasone arm 55%of the patients had complete protection from nausea, retchingand vomiting compared to 35% in the ondansetron-plus-placebo-treatedgroup (p = 0.05). Overall 22% of the patients (20% in the ondansetronplus-placeboand 25% in the ondansetron-plus-dexamethasone arm) experiencedat least one, usually mild, adverse event. More patients inthe ondansetron-plus-dexamethasone arm complained of epigastricpain or burning (8/101 versus 4/112, p-value = 0.16). The differencein patients reporting constipation (6/101 versus 0/112) washighly significant at a p-value of 0.008. CONCLUSIONS: The combination of dexamethasone plus ondansetron is more effectivein protecting chemotherapynaive patients undergoing their firstcourse of highly emetogenic chemotherapy with cisplatin andchemotherapy-pretreated patients refractory to standard antiemeticsfrom chemotherapy-induced nausea and vomiting compared to ondansetronplus placebo. nausea, vomiting, chemotherapy, ondansetron, dexamethasone, delayed emesis