When it comes to birth control options for women, little has changed in the past two decades. In fact, according to Planned Parenthood, there are only three methods of birth control that are more than 95 percent effective in preventing an unwanted pregnancy: the birth control implant, the intrauterine device (IUD), and the birth control shot. All of them require time in a doctor’s office, and none of them protect against getting or spreading sexually transmitted infections. The “newest” of the trio, the Depo-Provera shot, became available to women in the 1990s.
“There is a need for good non-hormonal contraceptives on demand,” says Deborah Anderson, a professor of medicine at Boston University Chobanian & Avedisian School of Medicine. Anderson, an expert in immunology and reproductive health, directs BU’s Contraceptive Research Center, which is one of only three federally-mandated contraceptive laboratories in the country. This year, the center received a $7.2 million grant from the National Institute of Child Health and Human Development of the National Institutes of Health to continue developing a new generation of contraceptives and STI prevention products. The four-year award will support Anderson’s work on the use of monoclonal antibodies (laboratory-made proteins that act like the body’s natural antibody defense system) as a means of protection. She calls the antibodies made from her “plantibodies” because they are grown on tobacco plants.
The contraceptive and STI prevention antibodies created in his team’s lab, while far from hitting the shelves at your local pharmacy, have been in development for more than a decade, with promising results coming from early phases of clinical trials. last year.
“Our ultimate goal is to have a contraceptive that also protects women against sexually transmitted infections,” Anderson says.
The Divided State of Birth Control
The center’s products are administered as topical films, almost like a Listerine strip, which are inserted into the vagina, dissolve, and rapidly release monoclonal antibodies. The contraceptive film releases antibodies that target the sperm, rendering them immobile before they can reach the ovaries. An STI prevention film contains antibodies against the herpes simplex virus (HSV) and the human immunodeficiency virus (HIV), two viruses that, once contracted, remain in a person for life.
The two lines of monoclonal antibodies are being tested separately, with the goal of combining them to make effective reversible birth control that also provides protection against HIV and HSV. The research team is also working to make birth control applicable to people without a vagina.
“There is a huge gender disparity in contraceptive use and adherence,” says Matt Geib, a doctoral student in the department of engineering and materials science in BU’s College of Engineering. He is working with Anderson on optimizing the material for his soluble contraceptive film and is also investigating how to use the antibodies in personal lubricants that can be marketed to men. “The burden most often falls squarely on people who might get pregnant,” he says.
The lab’s increased funding, which will also support more clinical trials, comes at a time when abortion has become highly restricted in the United States; some policymakers have also proposed limiting access to reproductive health care, including birth control. The race to create non-hormonal, non-invasive, reversible contraceptives has become even more urgent, Anderson says.
“Unwanted pregnancies have so many adverse effects on women physically, financially, and psychologically,” Anderson says. “Many young women find themselves without protection.” It has been estimated that about 48 percent of pregnancies worldwide are unintended, she notes.
“There is a huge gap both in the accessibility of contraception and in fertility management education,” says Emilie Mausser, a PhD candidate in the BU School of Medicine’s molecular and translational medicine program, who is focuses on better understanding how monoclonal antibodies interact with immune cells in the vagina, and how to make them more effective. “People should be able to access many birth control options and choose the one that is best for them,” she says.
Making the contraception of the future
The idea of using monoclonal antibodies as a method of birth control may seem revolutionary, but these sperm-attacking proteins have a surprisingly long history. Anderson was part of a team of scientists in the 1980s that tested more than 200 monoclonal antibodies against sperm. The group narrowed the list down to the two most effective, Anderson says, and the one he uses in his work today is one of those original two.
Anderson partners with a small company in San Diego, California, ZabBio, to grow antibodies using tobacco plants, dubbing them “plantibodies.” The leaves of the plant act almost like a petri dish: the plant cells receive the human antibody genes, and the leaves produce the antibodies. Anderson and ZabBio used this technique to make the anti-HIV and anti-HSV plantibodies first, and then the contraceptive plantibodies.
Data from the first clinical trial using plantibodies against HIV and HSV showed it to be safe, offering protection for 24 hours and possibly longer. They also tested the participants’ blood to make sure the antibodies were localized to the vagina and found no trace of them anywhere else in the body.
The team recently completed a second clinical trial with the contraceptive antibody film. One of the methods used to test the effectiveness of a contraceptive is a postcoital test, Anderson says. Her lab partnered with the Eastern Virginia Medical School, where eight heterosexual couples were tested, given an ovulation kit, and returned to the clinic for three consecutive months at their peak of fertility. All of the women in the study were ligated (commonly called “tubal tied”), so there was no risk of accidental pregnancy; all the men involved were fertile. The women would insert the contraceptive film, have intercourse, and then return to the clinic within two hours. They found that in the month the women applied the product, there were virtually no motile (or moving) sperm in their cervical mucus, compared to about 50 per microscope field when it was not used in the first and third month of the trial. . .
“It was as clear as possible,” Anderson says. The document with those results is expected to be published soon.
She estimates that it will be another 5 to 10 years before her work is available to the public. By the end of the latest round of funding from the NIH, the team hopes to be ready to conduct a large clinical efficacy trial, when the products are administered to hundreds of women for real-life use, with close follow-up.
In the meantime, Anderson and the team plan to work on combining their contraceptive antibody with the antibodies that prevent STIs and create more birth control options for men, with the goal of easing the burden on women and making the on-demand birth control more accessible to everyone. .
“I hope the future holds a host of new contraceptive options, not just male contraceptives,” Geib says. “We should always strive to give everyone a choice. I hope that the future of contraceptives has less invasive, more effective and more equitable options.”
