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 (FlexibleMIB ) 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 FlexibleMIB , placebo, or dienogest. The FlexibleMIB 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 FlexibleMIB . 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, FlexibleMIB significantly reduced the most severe EAPP (mean difference in visual analog scale score: -26.3 mm). FlexibleMIB also improved other endometriosis-associated pain and gynecologic findings and reduced the size of endometriomas.

CONCLUSION(S): FlexibleMIB improved EAPP and was well tolerated, suggesting it may be a new alternative for managing endometriosis.

CLINICAL TRIALS REGISTRATION NUMBER: NCT01697111.