Researchers have found a potential new female contraceptive that could prevent pregnancy without affecting hormones. New research shows the benefits of using monoclonal antibodies to trap and block human sperm.1
The goal is to produce a water-soluble, 2 × 2-inch film that could be folded and inserted in the vagina before intercourse, where it would dissolve within 30 minutes to two hours, says Bhawana Shrestha, PhD, post-doctoral researcher at the University of North Carolina (UNC) School of Pharmacy in Chapel Hill.
Researchers engineered a panel of sperm-binding immunoglobulin G (IgG) with antigen-binding fragments, isolated from immune-infertile women, creating highly multivalent IgGs (HM-IgGs) that are more potent and faster at agglutinating sperm than the IgG.
The benefits of this on-demand contraception would be its ease of use and lack of hormones. Eventually, this type of contraceptive could be developed into an intravaginal ring that works for the entire month of a woman’s ovulation cycle.
“I believe it would appeal to almost all women,” Shrestha says. “There are women who avoid contraception because of the lack of choices. If this product is developed and safe and effective, I think this would appeal to women who avoid using hormonal contraceptives and also to women who reluctantly use hormonal contraceptives.”
A monoclonal antibody contraceptive is noninvasive and provides users with the freedom of using it only if and when they desire.
While women in the United States appear to have a wide range of contraceptive options, most of these use hormones. This is problematic for women’s choices and access.
“Despite so many options, many women don’t use those options because of side effects that go from minor to severe,” Shrestha says. “This leaves women with very little choice for nonhormonal contraceptives.”
Side effects include disrupted or different menstrual bleeding, acne, weight gain, mood swings, increased blood pressure, headache, breast tenderness or pain, depression, and bloating.2
Condoms and the copper intrauterine device are their chief options for nonhormonal contraception. “There should be a newer form of contraceptive, and I think our product will appeal to a lot of women,” Shrestha says.
The potential contraceptive still is years away from availability.
“Most of the data we have is in vitro data and animal data,” Shrestha explains. “We have not been able to test safety and efficacy in humans yet.”
There are human trials of a contraceptive that uses the traditional format of IgG to neutralize sperm, but the target of Shrestha’s project is a few years from being studied in clinical trials.
“I believe clinical trials could happen within five years,” Shrestha adds. “Product finalizing and being in the market will be after five years.”
The ideal contraceptive solution may be a nonhormonal product that also neutralizes sexually transmitted infections (STIs). This approach holds promise for an eventual contraceptive that also prevents STIs.
“At the moment, there is no anti-STI component, but we’re making antibodies that bind the sperm and also neutralize gonorrhea and HIV,” Shrestha says.
One type would target sperm and HIV and another would target sperm and gonorrhea.
A multipurpose product for contraception and a range of STIs would be the end goal. “I would love to have this product used by all women globally,” Shrestha says. “But I believe antibody production has become cheaper over time, but it’s not that cheap to be inexpensive for all global use.”
REFERENCES
- Shrestha B, Schaefer A, Zhu Y, et al. Engineering sperm-binding IgG antibodies for the development of an effective nonhormonal female contraception. Sci Transl Med 2021 Aug 11;13:eabd5219. doi: 10.1126/scitranslmed.abd5219.
- Gotter A, Ernst H. What are the side effects of birth control pills? Healthline. Updated Aug. 3, 2018.
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