Efficacy of oral ondansetron in the prevention of emesis in outpatients receiving cyclophosphamide-based chemotherapy

Objective: To evaluate the efficacy and safety of oral ondansetron (Zofran) as an antiemetic in patients receiving cyclophosphamide-based chemotherapy. Design: A multicenter, randomized, double-blind, stratified, placebo-controlled trial conducted between March 1989 and January 1990. Setting: Twenty-seven oncology centers including university hospitals, community cancer centers, and private medical oncology practices. Patients: A total of 349 chemotherapy-naive patients having their first cycle of cyclophosphamide (≥ 450 mg/m²-based chemotherapy. Patients also received methotrexate (≥ 30 mg/m²) or doxorubicin (≥ 35 mg/ m²). All patients were evaluated for safety and 318 (91%) were evaluated for efficacy. Interventions: Patients were randomly assigned to one of four treatment groups: placebo, 1 mg, 4 mg, or 8 mg of ondansetron. Assigned study medication was taken three times per day for 3 consecutive days. Measurements: Time and number of emetic episodes as well as degree of nausea were recorded by patients for each of the 3 study days. Results: Compared with placebo, all three doses of ondansetron were superior (P < 0.001) in preventing vomiting and controlling nausea. A complete response (no emetic episodes) was observed in 19%, 57%, 65%, and 66% of patients in the placebo, 1-mg, 4-mg, and 8-mg ondansetron groups, respectively. For patients who received higher-dose cyclophosphamide and doxorubicin, a dose-related trend in antiemetic efficacy of ondansetron was observed. Mild headache and constipation were the most frequently reported adverse events. No extrapyramidal reactions were observed. Conclusion: Oral ondansetron is a safe and effective antiemetic that is more efficacious than placebo for patients receiving cyclophosphamide-based chemotherapy.