Ovarian function during and after treatment with the new progestagen Org 30659

Objective: To evaluate ovarian function during 21 days of oral administration of different doses of Org 30659, a novel selective progestagenic steroid.

Design: Randomized, double-blind, dose-finding study.

Settings: Three centers in Austria, Sweden, and the United Kingdom.

Participants: Eighty-one healthy women 19-40 years of age with regular ovulatory cycles.

Intervention: Daily oral administration of 0.060, 0.120, 0.180, or 0.240 mg of Org 30659, or 0.075 mg desogestrel (reference group), for 21 days.

Main outcome measure(s): Once-daily measurements of follicular diameter and 17-beta estradiol, progesterone, FSH, and LH levels.

Result(s): Daily treatment with Org 30659 for 21 days caused dose-dependent suppression of ovarian activity. No ovulation was observed in any study group. On average, ovulation returned 16.5 to 22.1 days after treatment. The effects of desogestrel, 0.075 mg, were similar to those of 0.060 and 0.120 mg of Org 30659. All doses were well tolerated, as shown by the type of side effects that occurred, the absence of an effect on physical and laboratory findings, and the low rate of study discontinuation.

Conclusion(s): Daily oral administration of 0.060-0.240 mg of Org 30659 suppresses ovarian function to a level sufficient to inhibit ovulation. This effect is dose-dependent, and the suppressive effect is readily reversible at all doses tested. Org 30659 can thus be safely administered orally for 21 days to healthy female volunteers in a dosage of 0.060 mg/d to 0.240 mg/d.