When it comes to quick and easy oral birth control, women have had more and more options in the 60 years since the pill first came on the market, but scientists have yet to effectively create a comparable male pill. However, researchers from the University of Minnesota College of Pharmacy (UoMCoP) have made strides that bring this goal another step closer to reality.
A male birth control needs to meet several criteria that still pose some challenges to scientists: It must be soluble enough to take by mouth; safe to take over decades; not interfere with libido; and not impact long-term fertility if a man does want to have children. The UoMCoP team recently presented their latest findings at the 251st national meeting and exposition of the American Chemical Society.
They have been working with existing compounds developed by pharmaceutical companies in the States and Japan. “Testosterone in high doses has been studied in different combinations for decades,” Jillian Kyzer, a graduate student working in lead researcher Gunda Georg’s lab, tells mental_floss. “But ultimately, I don’t think it’s the best compound, because there’s a small percentage—between 5 and 20 percent of men—whom it doesn’t work for. It’s unclear why, but you want something that would treat every man, not just most of them.” Testosterone also has side effects that include elevated bad cholesterol, weight gain, and impacts on the liver and the heart.
Though some labs still study testosterone, Georg’s has focused on modifying compounds developed by drug companies that target the retinoic acid receptor alpha (there are also beta and gamma receptors), RAR-a. “RAR-a is involved in a lot of different processes in the body, but male mice that lack this receptor are healthy but infertile,” Kyzer says.
Retinoic acid is a metabolite of Vitamin A, which is synthesized naturally in the body and crucial to the proper development of many tissues and cells, including sperm. By interfering with this receptor, their goal is to “prevent sperm developing all the way and to keep it in the testes so it doesn’t release,” Kyzer says.
One compound, created by Bristol-Myers Squibb (BMS), tested first on cells in their lab and then sent to a researcher at Columbia who tested it in mice, “works very well” at preventing sperm from developing, Kyzer says, “but it doesn’t work when given orally, which is also not desirable. You wouldn’t want to be injecting yourself every day or once a week.”
They are also seeing “promising results” in reducing fertility in lab tests on cells and in male mice with a compound developed by Eisai, a Japanese pharmaceutical company. It suffers the same problem as the BMS compound, "so we’re trying to make it more soluble, still selective for RAR-a, and still very potent,” Kyzer says.
To do that, they change out small groups of isopropyl molecules, which Kyzer describes as “very greasy” to make it “less dense.”
So far, their tweaked version is more soluble than the parent compound, and they are testing it to see how well it works in cells so they can get the compound off to their colleagues at Columbia for testing in mice.
As for often-expressed concerns by women that men won’t want to take a birth control pill when it’s finally ready, Kyzer says she is not concerned: “Every year there are polls sent out, and somewhere between 50 to 75 percent of men say they either definitely would take a pill or would take a pill every day.”
Don't get your hopes up too soon, however. Though these developments for a male birth control pill are promising, Kyzer says that given how difficult it is to secure funding for clinical trials, “I would say even if something were perfect, it would be at least 10 years out.”