Metronidazole Vaginal Gel 1.3% in the Treatment of Bacterial Vaginosis: A Dose-Ranging Study

OBJECTIVE Metronidazole vaginal gel (MVG) 0.75% is a US Food and Drug Administration-approved, 5-day treatment for bacterial vaginosis (BV). This study tested the hypothesis that a shorter treatment course at a higher dose (MVG 1.3%) would yield similar efficacy to 5 days of MVG 0.75%. MATERIALS AND METHODS This phase 2, multicenter, randomized, controlled, investigator-blinded, dose-ranging study enrolled women with a clinical diagnosis of BV. Patients were assigned to MVG 1.3% once daily for 1, 3, or 5 days or MVG 0.75% once daily for 5 days. The therapeutic cure rate, requiring clinical and bacteriological cure, at the end-of-study visit was determined for the per-protocol population. A Kaplan-Meier analysis was used to estimate median time-to-symptom resolution. RESULTS In total, 255 women (mean age = 35 y) were enrolled. The per-protocol population included 189 patients. The therapeutic cure rate was higher in the 1-day (13/43, 30.2%), 3-day (12/48, 25.0%), and 5-day (16/49, 32.7%) MVG 1.3% groups versus the MVG 0.75% group (10/49, 20.4%). Median time-to-resolution of fishy odor was shorter in the 3 MVG 1.3% groups versus the MVG 0.75% group. The 5-day MVG 1.3% group had the lowest rate of symptom return. No clinically important differences were observed in adverse events across treatment groups; most events were mild or moderate in intensity and considered unrelated to treatment. Similar results were found in the modified intent-to-treat population. CONCLUSIONS Metronidazole vaginal gel 1.3% applied once daily for 1, 3, or 5 days showed similar efficacy, safety, and tolerability as MVG 0.75% once daily for 5 days.