Background: The 5HT3 receptor antagonist Granisetron (GRA) is available on the market as a 1 mg vial in USA and as a 3 mg vial in Europe. This study aimed to compare the two i.v. doses of GRA (3 mg vs 1 mg), both of which combined with Dexamethasone (DEX) (20 mg) in the prevention of acute Cisplatinum (CP)-induced emesis.
Patients and methods: One hundred and ninety-eight consecutive chemotherapy-naive cancer patients, mainly suffering from lung and bladder cancer, were randomized at their first cycle to receive either GRA 1 mg + DEX or GRA 3 mg + DEX as i.v. bolus prior to chemotherapy and crossed-over to another GRA dose at the second cycle. The cytotoxic treatment included different multi-drug regimens containing CP (median dose 60 mg/m2, range 50-70) administered on day 1 and repeated every 21-28 days.
Results: Of the 192 evaluable patients complete protection from acute emesis with GRA 1 and GRA 3, was observed after the 1st + 2nd cycles as follows: nausea 70% and 74%, vomiting 90% and 94%, nausea and vomiting 67% and 74% respectively (no statistically significant difference). No carry-over effect was observed on the complete protection from emesis. The crossover analysis comprising 156 patients confirmed there were no differences between the two antiemetic treatments. Twenty-seven per cent of patients preferred GRA 1, 31% preferred GRA 3, while 42% expressed no preference (P = 0.75). Nor was any difference observed for tolerability, the only reported side-effects being mild headache (16% vs 17%) and constipation (18% vs 25%).
Conclusion: This study shows that, under the above conditions, the 1 mg and 3 mg i.v. GRA doses are comparably effective when combined with DEX 20 mg in the prevention of acute CP-induced emesis.