Ethinylestradiol 20 μg/drospirenone 3 mg in a flexible extended regimen for the management of endometriosis-associated pelvic pain: a randomized controlled trial

Objective To investigate the efficacy and safety of ethinylestradiol 20 μg/drospirenone 3 mg in a flexible extended regimen (Flexible MIB ) compared with placebo to treat endometriosis-associated pelvic pain (EAPP). Design A phase 3, randomized, double-blind, placebo-controlled, parallel-group study, consisting of a 24-week double-blind treatment phase followed by a 28-week open-label extension phase with an unblinded reference arm. Setting Thirty-two centers. Patient(s) A total of 312 patients with endometriosis. Intervention(s) Patients were randomized to Flexible MIB , placebo, or dienogest. The Flexible MIB and placebo arms received 1 tablet per day continuously for 120 days, with a 4-day tablet-free interval either after 120 days or after ≥3 consecutive days of spotting and/or bleeding on days 25–120. After 24 weeks, placebo recipients were changed to Flexible MIB . Patients randomized to dienogest received 2 mg/d for 52 weeks in an unblinded reference arm. Main Outcome Measure(s) Absolute change in the most severe EAPP based on visual analog scale scores from the baseline observation phase to the end of the double-blind treatment phase. Result(s) Compared with placebo, Flexible MIB significantly reduced the most severe EAPP (mean difference in visual analog scale score: −26.3 mm). Flexible MIB also improved other endometriosis-associated pain and gynecologic findings and reduced the size of endometriomas. Conclusion(s) Flexible MIB improved EAPP and was well tolerated, suggesting it may be a new alternative for managing endometriosis. Clinical Trials Registration Number NCT01697111.