DOSE-RANGING EVALUATION OF THE SEROTONIN ANTAGONIST DOLASETRON MESYLATE IN PATIENTS RECEIVING HIGH-DOSE CISPLATIN

Purpose: This dose-ranging trial of intravenous dolasetron mesylate (MDL73, 147EF) was performed to determine its adverse and antiemetic effects in patients receiving cisplatin at doses ≥ 100 mg/m2. Patients and Methods: Eighty-nine patients treated with initial cisplatin received a single intravenous dose of dolasetron mesylate administered over 20 minutes beginning 30 minutes before chemotherapy. The following four dose levels were studied: 1.8, 2.4, 3.0, and 5.0 mg/kg. Emesis and adverse effects were measured for 24 hours after cisplatin. Results: All adverse effects were mild and transient including loose stools, headache, serum AST/ALT elevations, and asymptomatic prolongation of ECG intervals. Among the dose levels, no-emesis rates from 24% to 52% were observed, and the percentage of patients having zero, one, or two emetic episodes ranged from 48% to 82%. Complete control of vomiting increased as the dose was escalated to 2.4 mg/kg, but did not improve further with higher doses. Conclusion: Dolasetron mesylate can be administered safely at doses up to 5.0 mg/kg, with comparable complete protection rates and increased adverse effects at doses greater than 2.4 mg/kg. Antiemetic activity was seen after cisplatin. Trials comparing single infusions of dolasetron mesylate and ondansetron are under way.