ONDANSETRON SUPPOSITORY - A RANDOMIZED, DOUBLE-BLIND, DOUBLE-DUMMY, PARALLEL-GROUP COMPARISON WITH ORAL ONDANSETRON FOR THE PREVENTION OF CYCLOPHOSPHAMIDE-INDUCED EMESIS AND NAUSEA

This multinational, multicentre, randomised, parallel-group study comp ared the safety, tolerability and efficacy of ondansetron 8 mg orally twice a day with ondansetron suppository 16 mg once daily in patients receiving cyclophosphamide-containing chemotherapy. A total of 406 pat ients were randomised to receive ondansetron 8 mg p.o. (198 patients) or ondansetron suppository (208 patients) medication in a double-blind , double-dummy trial. The primary efficacy analysis revealed that onda nsetron provided good anti-emetic control with 81% of patients in the 8 mg p.o. b.d. group and 73% of patients in the 16 mg ondansetron supp ository o.d. group experiencing complete or major control of emesis (l ess than or equal to 2 emetic episodes) on the worst day of days 1-3. The 90% confidence interval for the difference between the two treatme nts for complete or major control (1.4, 15.0%) showed that the treatme nts could be regarded as equivalent. A difference in favour of oral on dansetron treatment was noted for the complete control (0 emetic episo des) rates over days 1-3, but no differences were found on day 1. Ther e were no significant differences in the distribution of nausea grades between the treatment groups on the worst day of days 1-3 or on day 1 . The incidence of adverse events was similar for the two treatment gr oups, the most frequently reported events were headache and constipati on. There were no significant laboratory findings in either treatment group. In conclusion this study showed that the ondansetron treatments could be regarded as equivalent for the primary efficacy endpoint and that ondansetron suppository was well tolerated and effective in the prevention of cyclophosphamide-induced emesis.