GLAXO’s ONDANSETRON: SUPERIOR EFFICACY TO METOCLOPRAMIDE

GLAXO's ONDANSETRON: SUPERIOR EFFICACY TO METOCLOPRAMIDE in controlling cisplatin-induced nausea and vomiting is shown in a study published in the March 22 New England Journal of Medicine. "The superior efficacy observed in our trial may reflect its greater potency as a competitive 5-hydroxytryptamine (serotonin) antagonist, as compared with metoclopramide," Michel Marty, MD, Institut Curie, et al., said. A total of 97 cancer patients scheduled to receive cisplatin therapy for the first time were enrolled in the double-blind, crossover study. Patients were randomly assigned to receive either ondansetron or metoclopramide with the first course of chemotherapy, and then be crossed over to the other drug during the second course three to four weeks later. Ondansetron was given intravenously in an 8 mg loading dose before cisplatin administration and then in a continuous, 1 mg/hr infusion over 24 hours. Metoclopramide was also administered intravenously, in a 3 mg/kg loading dose before cisplatin, and then infused at 0.5 mg/kg for eight hours, with placebo infused over the next 16 hours. Of the 76 patients who completed both parts of the study, complete or nearly complete control of vomiting was achieved in 57, or 75% of treatments with ondansetron, compared to 32, or 42% of treatments with metoclopramide. "Complete" or "nearly complete" control was defined as no episodes of emesis, or only one or two. The researchers also reported that ondansetron was more effective in controlling acute nausea, as assessed by a visual-analogue scale or graded scale. In addition, patient preference for ondansetron was higher at 55% versus 26% for metoclopramide. Glaxo filed an NDA for the intravenous formulation of ondansetron in October 1989, and is currently in the final stages of preparing FDA submission for an oral formulation. Glaxo is also in early clinicals with the serotonin receptor antagonist as a treatment for schizophrenia. SmithKline Beecham is developing a similar anti-emetic product, granisetron, for which the company is finalizing its U.K. regulatory submission. SmithKline Beecham recently announced that it would drop development of the 5-HT3-receptor antagonist as a treatment for migraine when long-term dosing studies in rodents showed an increase in the risk of liver tumors. In the NEJM study, the researchers observed increases in aspartate or alanine aminotransferase levels with both ondansetron and metoclopramide. They suggested that since similar elevations in liver aminotransferase have been seen with cisplatin, the changes may be related to chemotherapy. Metoclopramide is marketed by Robins (now part of American Home Products) under the Reglan brand and is widely available generically.