Male Birth Control: More Options Soon?
There’s an old joke among
contraceptive researchers: "Twenty years ago, the male contraceptive
pill was just 10 years away.''
Despite many attempts over the years at developing a contraceptive for men, condoms
-- or permanent vasectomy -- remain the only choices. But that may be
changing, as researchers are studying a number of options for male birth
control. Although none will be on the market right away, one or two
might be available by 2018, some experts think.
What's Taking So Long?
Making a male contraceptive is challenging, experts agree.
Men's anatomy is complicated. Women ovulate once a month, but guy's sperm
production is constant. "Men produce 1,000 sperm [or more] a second,"
says Mara Roth, MD, an endocrinologist and assistant professor of
medicine at the University of Washington, Seattle, who researches male
birth control.
And preventing the sperm from meeting an egg isn't
easy. But "you don't need zero [sperm] to be effective,'' Roth says of
male contraceptives. They only need to reduce a man’s sperm count low
enough to prevent pregnancy.
Another challenge: They need to be reversible, just like women’s.
Side effects are another concern. Researchers in
2011 halted a test of hormonal contraceptive shots for men when side
effects, including depression and other mood changes and increased libido, were higher than expected.
Funding is another obstacle. That’s true for many drugs.
What's in the Pipeline?
The methods being studied include options that use hormones and others that don't. They include:
Nestorone and testosterone gel: This treatment combines the
hormone nestorone (a kind of progestin) with testosterone in a gel that
men rub on their arms. "It suppresses the sperm output to very low,"
says Christina Wang, MD, professor of medicine at Harbor-UCLA Medical
Center and the L.A. Biomedical Research Institute.
In a 6-month test on men, the combination suppressed sperm enough to prevent pregnancy
in nearly 90% of them. That’s comparable to the pill for women, which
is 91% effective at preventing pregnancy, according to the CDC.
The side effects are short term and few for the men,
Wang says, ''because it is applied to the skin." Some men said they had
acne or weight gain.
Wang is hopeful that final tests to confirm
its effectiveness and check for side effects will begin by the end of
2016. She had no information on what it might cost.
Men
using this gel will need to take precautions not to expose women and
children to it. That can trigger early puberty in children, and excess
body hair and acne in women, Wang says.
Vasalgel: This is a type of gel that doesn't use hormones
and is made to last for many years. It "is injected into the vas
deferens, the tube the sperm swim through, and basically blocks or
filters them out," says Elaine Lissner, executive director of the
Parsemus Foundation, a nonprofit organization behind Vasalgel. The
technique will involve a 5-minute outpatient procedure, she says,
similar to the time it takes to do a vasectomy.
To restore fertility, researchers use a baking
soda solution to flush the gel out, Lissner says. While the procedure
was successfully reversed in some animal studies, Lissner says
researchers are ''having a harder time in large animals."
She hopes to get approval to start testing it on men by the end of 2016.
The technique was inspired by a similar
contraceptive, RISUG (Reversible Inhibition of Sperm Under Guidance),
which is undergoing testing in India. Some men there have used it for
more than 20 years, she says. Whether RISUG can be reversed has not been
formally studied in men.
Lissner predicts the costs for Vasalgel should be less than the costs of other long-acting birth control methods for women, such as IUDs, which can be up to $900.
H2-Gamendazole: This compound taken by mouth “prevents
mature sperm from being produced," says Joseph Tash, PhD, professor of
molecular and integrative physiology at the University of Kansas Medical
Center, Kansas City. The premature sperm are then reabsorbed into the
body.
In tests on animals, ''we can get not only 100%
infertility, but full recovery of fertility," Tash says. Even though the
research looks promising, it needs to be tested on men to show it can
be reversed, he says.
Retinoic Acid Pill: This compound works by preventing
retinoic acid, a form of vitamin A, from doing its job in the process of
sperm production, says Gunda Georg, PhD, professor and head of
medicinal chemistry at the University of Minnesota. She presented the
results of the latest research on the compound at the annual meeting of
the American Chemical Society in San Diego recently.
With
this compound, sperm production ''is halted in the middle," says Jill
Kyzer, a graduate student at the university also involved in the
research.
It has only been tested in the lab and needs to be tested in animals and in people.
EP007: This compound, a non-hormone birth control pill
for men, stops sperm from swimming, says Michael O'Rand, PhD, president
of Eppin Pharma Inc., the developer. The research is early, he says, and
he can't predict when it might become a viable option.
Would Men Be on Board?
Once the male pill or other effective contraceptive gets to market, would guys actually use it?
Lissner of Vasalgel says she has 31,000 on the waiting list to participate in a trial for the method.
"That's an easy yes," says Aaron Hamlin, MPH,
executive director of the Male Contraception Initiative, an organization
devoted to the development of non-hormonal contraception. He cites
interest from men who've contacted his web site. "We’ve had a number of
supporters reach out indicating how beneficial a male contraceptive
would be for them and their partner."
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