Ovulation inhibition with four variations of a four-phasic estradiol valerate/dienogest combined oral contraceptive : results of two prospective, randomized, open-label studies

Abstract

Background: Attempts to improve the tolerability of combined oral contraceptives (COCs) have included the substitution of ethinylestradiol (EE) with 17beta-estradiol (E2). However, this has proved unsatisfactory, specifically in terms of cycle control. To improve upon the poor cycle control seen previously, E2 (in the form of estradiol valerate [E2V], 1 mg E2V contains 0.76 mg E2) was combined with dienogest (DNG) in a novel four-phasic regimen. In the current studies the ovulation inhibition potency of four variations of this regimen was assessed. Study design: Two randomized, open-label, phase II studies were performed. The first study compared two regimens (1A, 2A) with similar dosages of DNG but different lengths of application. Having established in Study 1 that the length of application of regimen 2A was most suitable but that the dosages of DNG were too low for effective ovulation inhibition, a second study was undertaken, which compared two regimens (2B, 2C) with similar lengths of application but increased dosages of DNG. The primary efficacy variable in both studies was the proportion of women with a Hoogland score of 5/6 during Cycle 2. Results: The full analysis set comprised 192 and 203 women in Study 1 and 2, respectively. In Study 1, 10 women (10.9%) in regimen 1A and 6 women (6.4%) in regimen 2A had a Hoogland score of 5/6. In Study 2, 3 women (3.1 %) in regimen 2B and 1 woman (1.0%) in regimen 2C had a Hoogland score of 5/6. There were no safety concerns with any of the regimens.