Efficacy of ethinylestradiol 20 μg/drospirenone 3 mg in a flexible extended regimen in women with moderate-to-severe primary dysmenorrhoea: an open-label, multicentre, randomised, controlled study.

Objectives: The aim of this Phase III, multicentre, open-label, randomised study was to compare the efficacy and safety of ethinylestradiol (EE)/drospirenone (DRSP) in a new flexible extended regimen that allowed the management of intracyclic (breakthrough) bleeding (MIB) with that of EE/DRSP in a conventional 28-day regimen in women with moderate-to-severe primary dysmenorrhoea.
Methods: Women (aged 18-40 years) with moderate-to-severe primary dysmenorrhoea-related pain received a flexible extended regimen with MIB (flexible(MIB); minimum 24, maximum 120 days of continuous tablet intake for a flexible number of cycles to reach a treatment duration of at least 140 days with 4-day breaks between cycles) or a conventional 28-day regimen (24 active and four placebo tablets for five cycles) of EE/DRSP. The primary outcome was the number of days with dysmenorrhoeic pain over 140 days. Secondary outcomes included other dysmenorrhoea-related pain outcomes, bleeding profile, satisfaction and safety.
Results: Overall, 223 patients received study medication. There were significantly fewer days with dysmenorrhoeic pain with the flexible(MIB) regimen than the conventional regimen (difference -4.2 days, 95% CI -6.5 to -2.0; p=0.0003), as well as considerably fewer days with at least moderate dysmenorrhoeic pain (difference -2.5 days, 95% CI -3.7 to -1.3), dysmenorrhoeic pain that interfered with daily activities (difference -2.2 days, 95% CI -4.2 to -0.1) and pelvic pain (difference -3.4 days, 95% CI -5.9 to -0.9). Adverse events were similar with both regimens.
Conclusions: Compared with the conventional regimen, the flexible extended regimen of EE/DRSP with MIB was associated with a significantly greater reduction in days with dysmenorrhoeic pain in women with moderate-to-severe primary dysmenorrhoea. The flexible(MIB) regimen was also associated with greater improvements in dysmenorrhea according to the Clinical Global Impression rating scale and was generally well tolerated.