A two-centre, open-label, randomised study of ovulation inhibition with three transdermal contraceptive patches, each containing different amounts of ethinyl estradiol and gestodene in healthy, young women.

Here we report the findings of a two-centre, open-label, randomised, Phase IIa study designed to investigate whether an ethinyl estradiol (EE)/gestodene (GSD) patch that has been developed (referred to herein as the 'EE/GSD patch') reliably inhibits ovulation in comparison with patches delivering lower doses of these hormones. The study rationale was to provide justification of the doses of EE and GSD selected for the EE/GSD patch. Healthy women, aged 18-35 years, were randomised to receive treatment with either the EE/GSD patch, a 'reduced-GSD patch' (delivering similar amounts of EE and approximately half the amount of GSD) or a 'reduced-EE/GSD patch' (delivering half the amount of EE and GSD). Treatment was administered for three 28-day cycles (three × 7 patch-wearing days, plus a 7-day patch-free interval). The primary pharmacodynamic variable was the percentage of women with ovulation in at least one of Cycles 2 and/or 3, as indicated by Hoogland score. Pharmacokinetic parameters for EE and GSD were also measured. Results indicated that the EE/GSD patch effectively suppressed ovulation, while patches delivering lower doses of EE and GSD were less effective for this purpose. All three patches showed comparable tolerability.