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Nomegestrol-estradiol OC effective with good cycle control

Reuters Health • The Doctor's Channel Daily Newscast

NEW YORK (Reuters Health) – A combined oral contraceptive containing nomegestrol acetate and 17beta-estradiol (E2) taken in a 24–4-day regimen is somewhat more effective in preventing pregnancy than an OC containing drospirenone and ethinyl E2 in a 21–7-day regimen, investigators report in the May issue of Obstetrics & Gynecology.

“The high contraceptive efficacy of nomegestrol acetate and 17beta-E2 is consistent with the ovarian suppression previously observed and also may be related to the shorter hormone-free interval,” the authors comment.

Dr. Carolyn Westhoff, at Columbia University in New York, New York, and colleages explain that the nomegestrol/17beta-E2 OC was approved as Zoely by the European Medicines Agency in 2011.

The current study reports results of a trial conducted in the Americas — specifically in the USA, Canada, Argentina, Brazil, Chile, and Mexico — with 2281 women at risk for pregnancy. They were randomized to receive the nomegestrol/17beta-E2 investigational agent or the comparator drospirenone/ethinyl E2 OC for 13 cycles.

Among women 18-35 years old, the cumulative 1-year pregnancy rate in the two arms was 1.22% versus 1.82%, the investigators report, although the difference was not statistically significant.

Furthermore, the mean number of bleeding days continuously decreased in women who received nomegestrol/17beta-E2, while it increased in the drospirenone/ethinyl E2 group, the report indicates.

Discontinuation rates were 3.8% and 1.8% in the two groups respectively. This may have been a result of the unanticipated higher rate of irregular or absent withdrawal bleeding (9% vs 0.5%), which some participants may have equated with unintended pregnancy, Dr. Westhoff and colleagues explain.

Overall, they conclude, “This comparative trial found that nomegestrol acetate and 17beta-E2 provides good contraceptive effectiveness over 1 year and has a bleeding profile characteristic of combined oral contraceptives with a 24-4 dosing regimen.”

The study was funded by Merck & Co, Inc. In response to a request to update the status of the product, a spokesperson noted that Merck received a Complete Response Letter from the US Food and Drug Administration in November 2011. “The company is planning to conduct an additional clinical study requested by the FDA and update the application in the future.”

SOURCE:

Obstet Gynecol 2012;119:989–999.