We've been waiting a long time for a male contraceptive, with a variety of approaches making headlines recently. Now Australian scientists think they have hit on an approach that provides safe and effective birth control without long-term side effects.
It's focused on two proteins that trigger the transport of sperm, effectively preventing the sperm from leaving the body.
The work is building on previous research conducted at Monash University. In a paper released in 2013, scientists demonstrated that it is indeed effective - at least in mice. Now they're looking to scale it up to humans, with help from new funding from the Male Contraceptive Initiative.
In mice, the team has showed that two proteins, α1A-adrenoceptor and P2X1-purinoceptor, can be safely deleted resulting in 100 percent infertility, without affecting either sex performance or function.
"We are moving closer to developing a convenient, safe and effective, non-hormonal oral male contraceptive that can be readily reversed," said senior researcher Sab Ventura.
"We aim to do this by developing a combination of two drugs that simultaneously block sperm transport rather than disrupt sperm development or maturation."
This result could give it an edge over other exciting approaches currently being tested, such as a hormonal injection that is 96 percent effective, or Vasalgel - an injectable 'plug' that's shown huge promise in animal trials.
According to the researchers, the development of a hormonal male pill has stalled because of long-term irreversible side effects on fertility and sex drive, not to mention the potential for causing birth defects.
Other research has shown that certain kinds of hormonal contraceptive simply don't work for all men, and that men are put off by the idea of having to receive the contraception via injection, although the idea continues to have potential.
"Previous strategies have focused on hormonal targets or mechanisms that produce dysfunctional sperm incapable of fertilisation, but they also often interfere with male sexual activity and cause long-term irreversible effects on fertility," Ventura said.
"With this non-hormonal approach, sperm are unaffected so the contraception is likely to be readily reversible once the medication has been stopped."
Some of the work has already been accomplished. There's already a pill on the market that blocks the α1A-adrenoceptor as treatment for a condition called benign prostatic hyperplasia, or an enlarged prostate. The next step in the research is to develop the pill to block the second protein.
If this stage is successful, the team will be looking to start clinical trials, estimating that, if all goes well, the drug could be on the market in as soon as 5 to 10 years.
We hope they're right - even if only because it sounds more appealing than a contraceptive made from a toxic substance used on poison arrows.