Phase III, randomized, double-blind study of clarithromycin extended-release and immediate-release formulations in the treatment of adult patients with acute maxillary sinusitis

Background: Clarithromycin has an established bacteriologic efficacy and safety profile in the treatment of respiratory tract infections. Objective: This study compares the efficacy and tolerability of extended-release and immediate-release formulations of clarithromycin in patients with acute maxillary sinusitis. Methods: Fourteen days' treatment with once-daily clarithromycin was compared with the immediate-release, twice-daily formulation in a phase III, randomized, double-blind, parallel-group, multicenter study. Patients aged greater than or equal to 12 years with signs, symptoms, and a radiologically confirmed diagnosis of acute maxillary sinusitis were eligible. Patients were assessed before treatment, within 48 hours after treatment, on study days 16 to 18, and at the test-of-cure visit on study days 24 to 31. Patients who received greater than or equal to1 dose of study drug were included in the safety analysis. Results: Of 283 patients treated, 245 were included in the efficacy analysis (122 in the extended-release group, 123 in the immediate-release group). Treatment groups were well matched with respect to demographic characteristics and medical condition and history. At the test-of-cure visit, 85% of patients in the clarithromycin extended-release group and 79% in the immediate-release group were deemed clinical cures; 89% and 91% in the extended-release and immediate-release groups, respectively, demonstrated radiographic success. Overall incidences of study drug-related adverse events were similar in the 2 treatment groups (32% in the extended-release group and 28% in the immediate-release group); however, significantly fewer patients receiving extended-release clarithromycin (2/142 [1%]), compared with those receiving the immediate-release formulation (10/141 [7%]; P = 0.02) discontinued therapy because of drug-related gastrointestinal symptoms or abnormal taste. No clinically meaningful changes in laboratory values or vital signs were observed during the study. Conclusion: Although the efficacy of the 2 formulations was comparable, once-daily clarithromycin extended-release was better tolerated than the twice-daily immediate-release formulation by patients with acute maxillary sinusitis.