There are many methods of contraception available for those of us who are interested in baby-making without making babies. For women, forms of birth control include hormones, physical barriers, and intrauterine devices. For men, the options are fewer and include barriers (condoms), semi-permanent solutions (vasectomy), and old-timey methods such as withdrawal and testicular warming.(a)
Developing reliable male birth control that is as simple as popping the female birth-control pill has been a holy grail of sorts in contraception research. Currently, there are clinical trials for hormonal male birth control in the U.S., while in India, researchers are testing a cheap, semi-permanent, reversible, injectable gel that kills sperm as it passes through the vas deferens. Adding to these approaches, a recent Cell paper out of James Bradner’s lab at the Dana Farber Cancer Center in Boston describes a drug that appears to provide efficient, reversible, non-hormonal contraception in male mice.1
The Bradner group’s main focus is cancer therapeutics, particularly the targeting of proteins that interact with DNA. It turns out that one of the compounds they developed as an anti-cancer treatment (JQ1), also inhibits a protein that has been identified through genetic studies as a key regulator of male fertility. In their latest paper, the researchers tested whether JQ1 could function as a male contraceptive. The results look very promising. Mice treated with the drug showed decreased sperm count and motility.(b) When male mice undergoing treatment with JQ1 were allowed to mate, a once daily low-dose treatment prevented pregnancy in about half of the mice. Contraception was successful in the rest of the mice following prolonged twice-daily administration.(c) An ideal contraceptive should not only be highly effective but also reversible, and JQ1 was successful in this regard. Mice that had been on JQ1 for several months successfully sired pups one to two months after they were taken off the drug.
Functionally, JQ1 seems to possess all the attributes of an excellent contraceptive for men. It is effective, reversible and does not interfere with hormone levels or mating behavior. Right now, the main drawback seems to be administration of the drug, which required twice daily injections in some of the mice. The Bradner group is working on JQ1 derivatives that have stronger selectivity and availability. Hopefully, these derivatives will be amenable to less invasive methods of administration and we will see them in clinical trials in the near future.
- M.M. Matzuk, M.R. McKeown, P. Filippakopoulos, Q. Li, L. Ma, J.E. Agno, M.E. Lemieux, S. Picaud, R.N. Yu, J. Qi, S. Knapp, J.E. Bradner (2012) “Small-Molecule Inhibition of BRDT for Male Contraception,” Cell, 150(4): 673-684.
- (a) A vasectomy involves blocking the tubes that carry sperm. It is permanent (unless intentionally reversed) and is almost 100% effective, though in rare cases (1 in 1,000) the tubes can grow back and begin working again.
- (b) Motility means movement. Sperm that can’t swim can’t reach the egg and can’t make a baby.
- (c) Although the drug was 100% effective when given twice a day, the trial was small, involving only seven mice treated over a period of 6 months. Further study would be needed to demonstrate that the treatment works consistently in all mice.