Dienogest is as effective as intranasal buserelin acetate for the relief of pain symptoms associated with endometriosis—a randomized, double-blind, multicenter, controlled trial

ObjectiveTo compare the efficacy and safety of dienogest (DNG) with intranasal buserelin acetate (BA) in patients with endometriosis.DesignPhase III, randomized, double-blind, multicenter, controlled trial.SettingTwenty-four study centers in Japan.Patient(s)Two hundred seventy-one patients with endometriosis.Intervention(s)Dienogest (2 mg/day, orally) or BA (900 μg/day, intranasally) for 24 weeks.Main Outcome Measure(s)The pre- to posttreatment changes in the scores of five subjective symptoms during nonmenstruation (lower abdominal pain, lumbago, defecation pain, dyspareunia, and pain on internal examination) and two objective findings (induration in the pouch of Douglas and limited uterine mobility).Result(s)Dienogest reduced the scores of all symptoms and findings at the end of treatment, and the mean changes in the scores of all symptoms and findings except induration in the pouch of Douglas were comparable to those obtained with BA. Compared with BA, DNG was associated with irregular genital bleeding more frequently and with fewer hot flushes. The reduction in bone mineral density (BMD) during DNG treatment was significantly lower than that during BA treatment.Conclusion(s)DNG is as effective as intranasal BA in alleviating endometriosis, and causes less BMD loss.