Objective: The aim of this study was to assess the non-inferiority of 1 mg to 3 mg granisetron (GRN) injection for the treatment of acute chemotherapy-induced nausea and vomiting (CINV) and to evaluate the tolerability of GRN given at 1 mg in Japanese cancer patients.
Methods: Patients with cancer receiving highly emetogenic chemotherapy were enrolled in this single-blind randomized controlled study. Patients were randomly assigned to receive GRN at a single dose of 1 or 3 mg. The primary endpoint was the rate of complete protection from emetic events (no vomiting, no retching and no need for rescue medication) during the first 24 h following the initiation of chemotherapy.
Results: There were 89 patients in the 1 mg group and 90 patients in the 3 mg group. Complete protection was achieved in 70 patients (78.7%) in the 1 mg group and 73 (81.1%) patients in the 3 mg group. The one-sided test did not reveal non-inferiority of either dose of GRN to the other at a 5% significance level.
Conclusions: Our data failed to show the non-inferiority of 1 mg of GRN to 3 mg of GRN administered as a single dose. However, the rate of complete protection from nausea and vomiting was similar in the two groups. Given the recommended dosage in the guidelines and the economic need for reduction of medical care expenses in Japan, prophylactic administration of GRN at 1 mg may be an appropriate, alternative treatment for acute CINV in cancer patients.