With the exception of condoms, most forms of non-permanent contraception are under women's control. There's the pill, the patch, the implant, the IUD (hormonal or non-hormonal) and, less popular nowadays, the diaphragm. Now scientists are closer than ever to developing new techniques for male birth control ready for clinical trial.
Yet some pharmaceutical companies are concerned a new birth control method for men has the potential to win as much as half the $10 billion market for female contraceptives worldwide and cut into the $3.2 billion of annual condom sales — businesses dominated by pharmaceutical giants Bayer AG, Pfizer and Merck.
Nevertheless, scientists are pushing ahead — and the momentum and buzz in the field is reflecting fresh optimism.
In the next year or so, researchers hope to start trials in humans using a technique called reversible inhibition of sperm under guidance, which has been under development in India for decades. RISUG works by wedging a thick substance into the vas deferens to prevent sperm from making their way through the pathway to be ejaculated. A few years ago the researchers behind it licensed their technology to an American foundation that used the knowledge to create Vasalgel. Thus far, it has been promising in trials done in rabbits and primates.
Another compound, called gendarussa, which is derived from an Indonesian shrub, interrupts the way sperm enter an egg to fertilize it. Clinical trials in Indonesia have found that the compound is highly effective, with few side effects, though larger studies would be needed before the drug could be submitted for approval by the FDA.
Throughout the past two decades, researchers have faced some major hurdles; primary among them are side effects and funding. Late last year, researchers published the results of a phase II clinical trial, commissioned by the World Health Organization, that evaluated a two-hormone drug designed to lower sperm count in men. The drug was effective, but the trial ended early because there were too many side effects and the hormone combination didn't work effectively in everyone.
In 2012, researchers from the National Institutes of Health tested an injectable contraceptive of two hormones; their results were promising, and they will soon begin testing it in a larger population
Other compounds also disrupt the production of sperm, but without hormones. CatSper, for example, can alter the function of sperm so they won't fertilize an egg without disrupting the rest of the man's reproductive system, though this is still in the research stage.
JQ1, a compound initially used to block a protein implicated in various forms of cancer, was found to disrupt the production and motility of sperm; an article published last year in MIT Tech Review notes that it has not yet been tested in humans.
A researcher at the University of Washington is testing a version of a compound called WIN 18,446, which interferes with the vitamin absorption necessary to make sperm. It was first tried in humans in the 1950s but was found to cause harmful side effects when combined with alcohol, according to Bloomberg Businessweek.
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Another compound, called H2-gamendazole, prevents sperm from reaching their mature (and thus virile) form. In 2015 the compound was still being tested in animals; the U.S. Food and Drug Administration had previously determined that more research was needed to make sure the compound didn't have any additional effects on women's bodies, Wired reports.
But to some experts these sorts of chemical interventions are less than ideal. They take a long time to kick in and have more side effects than those that physically block the passage of sperm or interfere with how it fertilizes an egg, says Aaron Hamlin, the executive director of the Male Contraception Initiative, a nonprofit organization working to bring new male contraceptives to market. "Our organization is not a fan of approaches that stop sperm production. We would rather not take that route because of the inherent delays," he says.
Despite decades of development, few techniques have moved past initial phases of testing. Pharmaceutical companies have not been interested in developing a male contraceptive beyond what is already on the market. Efforts in the early 2000s from small pharmaceutical companies, such as Organon and Schering, have stalled.
A spokesperson from Merck, which acquired Organon's parent company in 2009, says this is not an active area of research or interest. Bayer, which acquired Schering in 2007, reached a similar conclusion: "Ultimately, the decision was made to halt male contraceptive research, and we currently do not have plans to pursue in the future," a spokesperson said via email.
Experts have some ideas as to why big pharmaceutical companies might not be interested. According to Kenneth Kaitin, professor and director of the Tufts Center for the Study of Drug Development, marketing a male contraceptive might be harder than some might think — it would only appeal to men in long-term heterosexual relationships with partners of reproductive age. And since the drug wouldn't be combating a rare, life-threatening illness but would rather serve patients who are already well, pharmaceutical companies would have to make it affordable to the average consumer. All in all, Kaitin says, they probably don't think they would make much money off this kind of drug.
"Getting women to stop taking her drug for a man to start taking his drug, that would take a lot of selling," Kaitin says.
"Ultimately, it comes down to capitalism," says Allan Pacey, a fertility expert at the University of Sheffield. And so far that has meant that male contraceptives don't make financial sense.
It's also risky. A male contraceptive would serve a population that's already healthy with the goal of preventing pregnancy, for which men don't carry the physical risk. That would mean that regulators would have a very low bar for side effects. And for the intervention to work, it couldn't let even one viable sperm through—it just takes one to get a woman pregnant.
But the argument that there's no market for male birth control is deeply flawed. Research has discovered that men, in fact, want more contraceptive options. "A key aspect is that it gives men the opportunity to be involved in family planning. At the moment, they are excluded from being able to shoulder the burden," says Richard Anderson, a professor of clinical reproductive science at the University of Edinburgh. That especially makes sense for heterosexual couples in which the woman can't take birth control for medical reasons, such as a high risk of blood clots.
Survey data reflects this openness to male contraceptives. Anderson, along with some collaborators, conducted a survey back in 2000 and found that 83 percent of men from various countries would take a contraceptive. A separate survey found that most women agreed that a male contraceptive was a good idea. The overall market for contraceptives is expected to balloon to $33 billion by 2013, according to another Bloomberg story. Giving consumers more options might not be a bad idea, after all.
Smaller companies developing new products and techniques have a big, expensive hurdle between them and the market they hope to serve: clinical trials. No matter how promising these interventions may seem in the lab, clinical trials are needed to test their safety and efficacy before they can be submitted for regulatory approval (indeed, some of the techniques mentioned here are already going through clinical trials, though nothing has made it past the first few stages).
But clinical trials are expensive and risky. The later-stage trials, which can involve hundreds or thousands of participants, are often outside the means of small pharmaceutical start-ups. To fund their development and testing, and without backing from big pharma, some small companies are receiving grants from large public health organizations such as the Bill and Melinda Gates Foundation (in 2016 the organization doled out $600,000 for development of male contraceptives, according to MIT Tech Review) and the World Health Organization, which has funded several trials for hormonal interventions over the past few decades. Others partner with nonprofits to develop their drugs — the Parsemus Foundation, a nonprofit investigating a number of different drugs, is backing the trials for Vasalgel.
As the companies push interventions through the early phase clinical trials, big pharma may get involved, after all. "Pharmaceutical companies are looking to minimize risk while opening themselves up to large profits," Hamlin says. "[In phase 2 and 3], most of the safety issues have already been parsed out and you can see how these things are working. The level of risk is lower. So pharmaceutical companies may look more seriously [into licensing the technology or acquiring the company]."
Experts were reluctant to predict which intervention would hit the shelves first. "It's very hard to predict what is going to be the winner that gets to market first," Hamlin says. "So long as we strategically put resources behind good approaches, this is something we can make happen," he says.
— By Alexandra Ossola, special to CNBC.com