Difference in persistence of efficacy of two antiemetic regimens on acute emesis during cisplatin chemotherapy

Purpose and Methods: We conducted a prospective, double-blind, multicenter study of 287 cancer patients treated for the first time with high-dose cisplatin chemotherapy who were randomly assigned to receive three consecutive cycles of the same antiemetic treatment consisting of ondansetron plus dexamethasone, or metoclopramide plus dexamethasone and diphenhydramine. Results: Patients who received the ondansetron combination achieved significantly greater complete protection from vomiting, but not from nausea, in all three cycles of chemotherapy than did patients treated with metoclopramide (78.7% v 59.6%, P < .002 during the first cycle; 73.4% v 51.0%, P < .002 during the second cycle; 73.7% v 47.5%, P < .001 during the third cycle). The ability of ondansetron treatment to protect patients from vomiting during the first cycle did not change in subsequent cycles, but decreased significantly as far as complete protection from nausea and from both nausea and vomiting are concerned. With the metoclopramide combination, a significantly greater reduction of complete protection from vomiting, nausea, and both nausea and vomiting was detected. Protection obtained in previous cycles of chemotherapy was the most important prognostic factor. Adverse events were significantly less frequent with ondansetron treatment during the three cycles of chemotherapy and no cumulative toxic effects were found with either treatment. Conclusion: Ondansetron plus dexamethasone was significantly more efficacious and better tolerated than metoclopramide plus dexamethasone and diphenhydramine during three cycles of chemotherapy and, in contrast to the metoclopramide regimen, the efficacy of ondansetron plus dexamethasone, at least for vomiting, is maintained in subsequent cycles.