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Biodegradable Implants: A Novel Idea Revisited

© PhotoShare /Aimee Centivany/1999
© PhotoShare /Aimee Centivany/1999
Guest contributors are Scientists Derek Owen, PhD, and Rebecca Callahan, PhD, from FHI 360’s Contraceptive Technology Innovation department.

Use of contraceptive implants has increased dramatically over the past several years. This trend is especially evident in several Family Planning 2020 (FP2020) focus countries where the addition of implants is increasing the diversity of the long-acting contraceptive method mix.  This is all good news.

Contraceptive implants are attractive because they are more than 99% effective at preventing pregnancy for three to five years, depending on product type. Once inserted, they are “forgettable,” with women only having to think about them when the period of effectiveness is about to expire. What these women cannot forget is that these implants require removal by a trained professional.  While the procedure itself is relatively easy, finding a trained provider or making arrangements to get to the implant removal clinic can present challenges—especially in low-resource settings.

How cool would it be if a contraceptive implant would simply biodegrade over time, eliminating the need for removal? Even cooler…what if, for up to a year post-insertion, it still could be removable, for example, if the user experiences unwanted side effects or decides to become pregnant? With support from the Bill & Melinda Gates Foundation, FHI 360 researchers are evaluating this concept with scientists at pH Sciences/Gesea and Yale University.

So just what is a biodegradable implant?

Imagine an implant made of a non-toxic polymer structure that gradually releases a contraceptive hormone over several months.  Meanwhile, the polymer material itself slowly degrades, absorbing into the body over time, much like resorbable sutures.  The implant we are seeking to develop would:

  • Be no bigger than the size of current implants (41mm x 2.1 mm)

  • Prevent pregnancy for between 18 and 24 months to ensure healthy child spacing

  • Provide a rapid and predictable return to fertility once the implant’s period of efficacy ends

  • Be removable by a skilled provider, if requested, up to 12 months post-insertion.

The concept of a biodegradable contraceptive implant is not new.  The first version of such a product was studied in women over 30 years ago. Development efforts stopped because the time between when the implant biodegraded and when a woman became fertile again (the tail) was unacceptably long.  With funding from the U.S. Agency for International Development, we resurrected the concept using a different product design to reduce the “tail.”  Our concept – a fused drug/ cholesterol product—is now being refined by John Baillie and his team at pH Sciences/Gesea.

Our other partner, Dr. Mark Saltzman at Yale University, is developing an implant from a novel polymer with variable drug-release properties. His design would provide a customizable profile that could release contraceptive hormones at various intervals.

Both ideas are still in the pre-clinical stage of research, with human studies still several years away. Assuming all development efforts move forward favorably, an FDA-approved biodegradable implant could be 8 to 10 years away from commercialization.

Because of its dissolving/reabsorbing characteristics, a biodegradable contraceptive implant would be unlike any method currently available. Will women be amenable to using such a product? We recently asked that question to women of reproductive age in Uganda and Burkina Faso. Simply finding the right words to describe the product in the local languages of our study participants proved challenging.  Think about it for a moment – how would you describe biodegradable?  What actually happens when something biodegrades?

Women participating in our focus group discussions raised several concerns:  Where would the method disappear to?  Would it move to a body organ and cause other health problems?  Indeed, misperceptions about how existing contraceptive implants migrate or disappear could be exacerbated by the introduction of a product that actually disappears. As part of any future clinical trial programming, we will need to draft and field test patient counseling materials to properly convey the biodegradable nature of this product to potential users. Similar attention will have to be paid in development of related market introduction messaging.

If the concept of a biodegradable implant moves successfully through clinical trials… and product communication efforts are carefully designed and implemented, this could become a game-changing addition to the method mix …with no disappearing act!

This blog series is a collaboration with K4Heatlh and also can be found on their topics page.

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