A new Phase I trial of a male birth control pill led by researchers at the University of Washington School of Medicine along with UCLA in the US has revealed successful results.
The pill, 11-beta-methyl-19-nortestosterone dodecylcarbonate (11-beta-MNTDC), mimics testosterone that has the combined actions of a male hormone (androgen) and progesterone.
When used by healthy men once daily for a month, the birth control pill passed tests of safety and tolerability.
Researchers testing the drug said that it produced hormone responses consistent with effective contraception.
For the Phase I trial, 40 healthy men across UW Medical Center in Seattle and the Los Angeles Biomedical Research Institute in Torrance, California were included.
Out of the total study participants, ten of them were randomly given a placebo capsule. 14 men received 200mg of 11-beta-MNTDC and 16 got the 400mg dose.
Subjects were given the drug or placebo once daily for a period of 28 days.
In the study cohort, levels of two hormones required for sperm production dropped greatly, compared with those taking the placebo, researchers reported.
Only a few mild side effects including fatigue, acne and headache were reported among men receiving 11-beta-MNTDC in each dosage level.
As the drug would take at least 60 to 90 days to affect sperm production its effects were reversible after stopping treatment.
The researchers plan longer clinical trials if they find the drug to be effective and will move to larger studies and then testing in sexually active couples.
University of Washington School of Medicine professor Stephanie Page said: “The goal is to find the compound that has the fewest side effects and is the most effective.
“We are developing two oral drugs in parallel in an attempt to move the (contraceptive medicine) field forward.”
The researchers also tested another potential male birth control pill, dimethandrolone undecanoate (DMAU).
Findings from the study of DMAU in March last year demonstrated that the experimental contraceptive could be effectively used as a birth control pill for men.
The latest study was funded by Eunice Kennedy Shriver National Institute of Child Health and Human Development, which is developing 11-beta-MNTDC and other male contraceptives.