Randomized comparison of the antiemetic efficacy of a serotonin type 3 receptor antagonist (MDL 72,222) with a high-dose metoclopramide regimen.

This pilot randomized study compared MDL 72,222, a highly selective 5-HT3 receptor antagonist, with a high-dose metoclopramide regimen (HDM) for chemotherapy-induced nausea and vomiting. MDL 72,222 was given in 20 mg intravenous doses 30 minutes before chemotherapy, as well as 2, 6, and 12 hours after chemotherapy infusion. The HDM was composed of diphenhydramine 50 mg i.v., metoclopramide 2 mg/kg i.v., and lorazepam 0.04 mg/kg i.v. administered 30 minutes before chemotherapy and 2, 4, 6, and 8 hours after chemotherapy. Patients were randomized to either MDL 72,222 (n = 12) or the HDM (n = 12) and were matched for age, weight, Karnofsky performance status, and chemotherapy. More patients in the MDL 72,222 group had received prior cisplatin. The MDL 72,222 group and the HDM group received a mean cisplatin dose of 66 mg/m2 and 62 mg/m2, respectively. Patients were observed for retching and/or emesis for 24 hours and completed a visual analog scale (VAS) for nausea. Six MDL 72,222 and five HDM patients had no vomiting. One MDL 72,222 and two HDM patients had one episode of emesis within 24 hours of chemotherapy. The median number of emetic episodes in the first 24 hours was 0.5 for MDL 72,222 and 1.0 for HDM patients. HDM patients were frequently asleep and were not awakened for evaluation of nausea with the VAS; 58% (70 of 120) of the HDM (mean score: 19.1 mm) and 14% (17 of 119) of the MDL 72,222 (mean score: 17.1) patients could not have VAS scores obtained (X2 = 50.74, p < 0.001). MDL 72,222 had similar efficacy with less sedation, and further trials are warranted.