Novel contraceptive inserted as a single rod

September 4, 2006

A subdermal implantation of a single etonogestrel-containing rod can prevent pregnancy for up to three years. Does this sound too simple to be true? The manufacturer of Implanon, Organon Inc., is hoping women will be intrigued. The Food & Drug Administration approved the new 68-mg implant just last month. It contains the same component that's in the company's vaginal contraceptive, NuvaRing.

A subdermal implantation of a single etonogestrel-containing rod can prevent pregnancy for up to three years. Does this sound too simple to be true? The manufacturer of Implanon, Organon Inc., is hoping women will be intrigued. The Food & Drug Administration approved the new 68-mg implant just last month. It contains the same component that's in the company's vaginal contraceptive, NuvaRing.

At a recent FDA press telebriefing, Scott Monroe, M.D., acting director of FDA's division of reproductive and urologic products, described the product as a nonbiodegradable medical polymer designed to be implanted on the inner side of a woman's upper arm. "After insertion, etonogestrel is slowly released over a period of three years," he said.

"Many of the features introduced in the labeling and review of Implanon have been derived from our previous experience with Norplant," Monroe said, referring to the six-rod contraceptive implant that was removed from the market in 2002 by manufacturer Wyeth Pharmaceuticals. Problems with hormone-release rates, manufacturing issues, and difficulty removing the implant from patients' arms eventually led to its withdrawal.

Of the 942 reproductive-age women included in clinical trials of Implanon, 11.1% (n=105) experienced menstrual bleeding irregularities, the most common reason for stopping treatment. Pregnancy occurred in six patients, two at the end of each of the three years. According to Monroe, these data indicate no loss of efficacy over the three-year period and an incidence of less than one pregnancy per 100 women over a year of use.

Other common adverse events included headaches (24.9%), vaginitis (14.5%), weight increase (13.7%), and acne (13.5%). Postmarketing reports from other countries where Implanon has been used since 1998 include serious thromboembolic events-cases of pulmonary emboli (some fatal) and stroke. Implanon should therefore not be used by patients with current or past thrombosis or thrombolic disorder. In cases of long-term immobilization due to surgery or illness, consideration should be given to removing the implant prior to surgery.

According to Organon, Implanon requires a small surgical procedure for both implantation and removal. In general, this can be accomplished in the physician or healthcare provider's office with a local anesthetic.

"The company has designed a comprehensive training program for those who will be prescribing the product," Monroe said. "The plan is to launch Implanon slowly over the next few months and focus on physician training so the implants are inserted properly." In fact, Organon has said that only providers who undergo the training process will be able to order the contraceptive.

Physician training will begin in late August to coincide with commercial launch of the product. More information on Implanon can be accessed at 1-877-IMPLANON and on-line at http://www.implanon.com/.

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