Once-a-Month Birth Control Pill Seems to Have Worked in Pigs. Are People Next?

Scientists used a device that sits in the stomach and slowly releases hormones into the body

Diagram of pill release
The capsule dissolves into a star-shaped device that slowly releases the hormone levonorgestrel over the course of a month. Lyndra Therapeutics

When it comes to birth control, taking a daily pill is kind of a pain. Missing a dose, or even delaying it by just a few hours, can seriously raise the risk of unintended pregnancy.

For women who prefer oral contraceptives, but want to ditch the inflexible schedule of traditional pills, an alternative is in the works. Researchers have created a once-a-month capsule that, after swallowing, will gradually deliver hormones into the body for up to 29 days, according to a study published yesterday in Science Translational Medicine.

The catch? So far, it’s only been tested in pigs.

Testing the drugs in an animal model is one step closer to bringing the pills to humans, which is the ultimate goal, of course, reports Megan Molteni for Wired. While a team of researchers led by MIT gastroenterologist Giovanni Traverso recently received $13 million from the Bill and Melinda Gates Foundation to advance the monthly pill to human trials, that's a long way off; additional safety and efficacy testing needs to happen before those experiments can begin.

Eventually, the timed-release drug could offer another appealing option for women seeking long-term contraception, joining a list that already includes vaginal rings, injections and IUDs, which last weeks, months and years, respectively. The team has announced its intention to focus on making its pill available in low- and middle-income countries with limited access to other family planning methods.

“Birth control is not one-size-fits-all,” Beatrice Chen, a family planning specialist at the University of Pittsburgh who wasn’t involved in the new research, tells Lauran Neergard at Associated Press. And the new technology, she says, “has a lot of potential.”

The biggest innovation in the team’s capsule is the staying power of the star-shaped device contained within it. Once the pill is swallowed, digestive acids dissolve its gelatinous coating, liberating a six-armed, silicone-based structure full of the hormone levonorgestrel­, the main ingredient in Plan B, as well as some IUDs.

At two inches wide—too big to enter the intestines—the flexible, body-friendly star-shaped device camps out in the stomach, releasing hormones out through little pores that adorn each of its limbs. Over the course of a month, the device is designed to slowly disintegrate, eventually passing through the rest of the digestive tract.

The team had previously used a similar approach to deliver treatments for malaria, tuberculosis and HIV, reports Molteni. But pairing the device with contraceptives is a first—and the researchers are optimistic about their early results.

Fed to several pigs, the device settled comfortably in their stomachs and gradually broke down over the course of about three to four weeks, the team’s X-rays showed. When the researchers took blood samples from their porcine participants, they found the amount of hormone circulating through their bodies was comparable to what daily tablets deliver. Based on the team’s results, it doesn’t seem that the device impedes the passage of other stuff—like food or fluids—through the digestive tract, as first author Ameya Kirtrane tells Yasemin Saplakoglu at Live Science.

But there are plenty of other open questions that need addressing. The researchers didn’t actually test whether the pigs could still get pregnant, for instance. And even though pigs share a lot of digestive architecture with humans, their reproductive cycles are shorter, and they menstruate differently, as Christine Metz, a medicinal biochemist at the Feinstein Institutes for Medical Research at Northwell Health who was not involved in the study, tells Saplakoglu. (There’s also not a straightforward way to measure the discomfort experienced by a pig swallowing a pill that unfolds into a medical device.)

Just as daily pills may slip the mind, taking a tablet once a month can be easy to forget, as Erica Pasciullo Cahill, an obstetrician-gynecologist at Stanford University who wasn’t involved in the study, points out to Molteni. But Traverso says that the team is planning to hone their device to release hormones for three weeks, then taper off to allow for menstruation, reports Neergaard. Like many daily contraceptives, this could signal to women that the contraceptive’s cycle is up, cuing them to take another monthly dose.

Some of these concerns and more will be tackled by Lynda Therapeutics, a company co-founded by Traverso and MIT bioengineer Robert Langer in 2015. The researchers will also be tinkering with dosing and different materials as they gear up to take the pill from pigs to people—perhaps sometime in 2021 or later, reports Molteni.

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