APhase 2 trial into the efficacy of a male contraceptive gel is aboutto get underway bringing modern medicine closer than it ever hasbefore to finally developing a male birth control drug, decades afterthe female contraceptive pill hit the market.
Finding a simple male contraceptive compound that is safe,effective and reversible has been relatively elusive for scientists.Outside of condoms and vasectomies, birth control has remained welland truly in hands of women. A male contraceptive agent, some haveargued, is simply a much more difficult pharmacological challenge: stopping the production of an egg or two a month seems to be much easierthan limiting the efficacy of millions of constantlyregenerating sperm.
However, several exciting innovations are rapidly being developed –from an injectable compound acing its early animal trials to a more traditional "pill" passing the first phase of human safety trialsearlier this year. The most advanced male contraceptive prospectthough is a novel gel, designed to be used once a day, and now movinginto a serious phase 2b trial set to establish whether it actuallystops unwanted pregnancies or not.
The gel is called NES/T and contains two hormonal compounds. The primary compound is called Nesterone, a progestin hormoneformulated to lower sperm production by blocking testosteroneproduction in the testes. The second compound is aconcentration of testosterone designed to maintain blood levels ofthe hormone, important for general health and mood, but low enough tonot kick-start sperm production.
Prior human trials into the gel, rubbed onto a man's arms andshoulders once a day, have found the contraceptive agent to be low inharmful side effects, and effective in reducing overall concentrationsof sperm. This new trial is set to encompass over 400 couplesworldwide and will follow use for well over a year to clearly find out ifthe gel actively prevents pregnancies.
The trial will run through several stages, first the men will usethe gel daily for up to 16 weeks while being monitored for unexpectedside effects. By that point tests should reveal whether sperm levelshave declined to levels below recommended conception thresh-holds.
Atthis point the second phase is for the men to use the gel as theironly form of birth control for 52 weeks. All men enrolled into thestudy must be part of a committed, monogamous couple, with bothmembers signing onto the trial. After a year of using the gel as theonly form of birth control, the men will discontinue the treatment and beobserved for 24 weeks to examine any after effects and to make suresperm levels return to normal.
"The success of a reversible contraceptive for men requires anapproach that reduces the production of sperm without impacting aman's testosterone levels or ability to produce sperm at a laterdate," says Christina Wang, lead researcher and a study principalinvestigator. "The challenge is achieving the right combination ofNestorone and testosterone at the right time."
This is the first serious, real-world test into a malecontraceptive for some time, and all members signing up for the trialmust be aware and willing to enter into a pregnancy if the gel provesineffective. The results from this trial won't be known untilaround 2022, and if positive, the treatment will move into an evenlarger, final phase 3 trial before it can ultimately reach the market.So all up, despite this being the most advanced malecontraceptive currently in development, it still may be close to ten years before itreaches the general public – and that is if all goes to plan.
"Expanding male contraceptive options could help make familyplanning more of a shared responsibility between women and men,"says Regine Sitruk-Ware, co-director of the trial, explaining theurgent need to develop an effective male contraceptive treatment."Safe, effective, and reversible tools for men to control their ownfertility gives new meaning and significance to the term 'familyplanning.' No matter the challenge, we must continue to innovateand develop new products to improve lives."
The trial is currently recruiting subjects in California, Kansasand Washington, before expanding to a number of other locationsworldwide. Interested participants can look at the selection criteria here.
Source: UW Medicine
