Randomized phase II trial comparing two versus three doses of ondansetron when used in combination with dexamethasone in patients receiving cisplatin > or = 100 mg/m2.
Ondansetron controls cisplatin-induced emesis when given in three 0.15 mg/kg doses, and preliminary data suggest that control may be maintained when fewer doses are employed. Prior trials have further shown improved antiemetic effects and fewer adverse effects of cisplatin treatment when neurotransmitter receptor blockers are combined with dexamethasone. This trial was undertaken to determine the effectiveness of the combination of dexamethasone and ondansetron and to see if equivalent results could be obtained with only two doses of ondansetron. There were 44 patients receiving initial cisplatin at a dose > or = 100 mg/m2, each given dexamethasone 20 mg and randomized to receive either two or three 0.15 mg/kg doses of ondansetron. Vomiting prevention was identical (35%) whether two or three doses were given. No new adverse effects were noted and cisplatin-induced diarrhea, usually seen in up to 60% of patients given this dose of cisplatin, was noted in only 5%. Although this trial did not demonstrate enhanced antiemetic effects with the combination, other investigators have done so and all agree that the regimen is safe and reduces adverse effects. Further exploration and use of the combination of ondansetron and dexamethasone, and studies testing fewer doses of ondansetron in this regimen are warranted.