What’s the status of the single-rod implant?
What’s the status of the single-rod implant?
Rewind to November 2004. Netherlands-based Akzo Nobel’s pharmaceutical business Organon announces that the Food and Drug Administration (FDA) has granted approvable status for its etonogestrel subdermal contraceptive implant Implanon. Fast forward to today. Do you see the method added to the U.S. contraceptive mix?
Not yet. The implant continues to be reviewed by the FDA. Organon received an action letter from the regulatory agency in June 2005, which maintains the implant’s approvable status. According to a press statement issued by Organon, the company is in the process of reviewing the FDA’s response and is meeting with the agency to address outstanding issues. According to the FDA, an approvable letter signals that the agency is prepared to approve the product dependent on the company meeting specified conditions. Organon is confident it will be able to provide the FDA with the appropriate information to expedite their review, according to the statement.1
Implanon is a safe, highly effective, and rapidly reversible new method of contraception, according to just-published research from the U.S. clinical trial.2 The study included 330 women with normal menstrual cycles who used the implant for up to two years. Women recorded bleeding and/or spotting in a daily diary. Safety was assessed through adverse experiences, laboratory tests, and physical and gynecologic examinations.
No pregnancies occurred in the trial, which recorded total exposure of 474 woman-years (6,186 cycles); 68% of subjects had at least one year of exposure. The most common bleeding pattern observed throughout the study was infrequent bleeding, defined as less than three episodes of bleeding in a reference period (excluding amenorrhea). Infrequent, prolonged, and frequent bleeding patterns were most common early in the study and declined thereafter.
Forty-three women (13%) withdrew from the study because of bleeding pattern changes, and 76 subjects (23%) discontinued because of other adverse experiences such as emotional lability (6.1%), weight increase (3.3%), depression (2.4%), and acne (1.5%). The return to normal menstrual cycles and fertility was rapid after removal.
Implanon does not impact bone mineral density; in a separate study, researchers detected no decrease in levels during three years of single-rod implant use.3
The single-rod implant, which provides up to three years of contraceptive efficacy, is available in more than 30 countries, including the United Kingdom, Chile, Egypt, Finland, and the Slovak Republic.4 Measuring 40 mm long and 2 mm wide, Implanon consists of a flexible ethylene vinyl acetate rod filled with 68 mg etonogestrel, the same drug used in the contraceptive vaginal ring (NuvaRing, Organon). The rod releases an average dose of 40 mcg etonogestrel every day, which inhibits ovulation and thickens cervical mucus. Implanon typically is inserted in the inside portion of the upper arm during a brief office procedure.4
"It is a relatively easy insertion and removal, given that it is a single capsule," says Mitchell Creinin, MD, professor and director of family planning, and director of gynecologic specialties in the Department of Obstetrics, Gynecology, and Reproductive Services at the University of Pittsburgh. Implanon is implanted just under the skin using a preloaded insertion device. Clinicians should verify the presence of the implant by palpation directly after insertion.4 Even though insertion and removal of the device is relatively simple, health care providers will require proper training, states Creinin.
Counsel on bleeding
Implanon represents a good contraceptive choice for those women who cannot take estrogen contraceptives and who desire long-term protection and rapid return to fertility. Women who are breast-feeding can safely use the method, as research indicates it does not affect milk production or infant growth.5
Successful use of the method does call for effective counseling on management of irregular vaginal bleeding, experienced by most women who use the method. During the first three months of use, 30% to 40% of women become amenorrheic, while about 50% of women bleed infrequently. About 30% of women experience prolonged bleeding during the first three months of use, which declines to 10% to 20% thereafter.6
"It is just more of a counseling issue, telling patients to be patient with it and to realize that the bleeding does not mean anything bad," says Creinin. "If anything, it is all just part of using highly effective contraception."
References
- Organon. Organon receives approvable from FDA for contraceptive implant. Press release. Roseland, NJ; June 22, 2005. Accessed at: www.organon-usa.com/news/2005_06_22_organon_receives_approvable_from_fda.asp.
- Funk S, Miller MM, Mishell DR Jr, et al. Safety and efficacy of Implanon, a single-rod implantable contraceptive containing etonogestrel. Contraception. 2005; 71:319-326.
- Beerthuizen R, van Beek A, Massai R, et al. Bone mineral density during long-term use of the progestogen contraceptive implant Implanon compared to a non-hormonal method of contraception. Hum Reprod 2000; 15:118-122.
- Creinin MD, Clark B. The latest contraceptive option: The single-rod implant. Contemporary OB/GYN 2005; accessed at: www.contemporaryobgyn.net/obgyn/article/articleDetail.jsp?id=178617&pageID=4.
- Reinprayoon D, Taneepanichskul S, Bunyavejchevin S, et al. Effects of the etonogestrel-realizing contraceptive implant (Implanon) on parameters of breast-feeding compared to those of an intrauterine device. Contraception 2000; 62:239-246.
- Edwards JE, Moore A. Implanon. A review of clinical studies. Br J Fam Plann 1999; 24(4 suppl):3-16.
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