male contraceptive

Male contraceptive jab almost 100 per cent effective… and it can increase libido

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A contraceptive injection for men has been shown to be almost 100 per cent effective, and may also increase libido.

The hormone-based jab is designed to lower sperm counts by acting on the brain’s pituitary gland.

Over a year-long trial, nearly 96 per cent of couples relying on the injection to prevent unplanned pregnancies found it to be effective. During this time, only four pregnancies occurred among the men’s partners.

 However, researchers said more work was needed to address the treatment’s reported side effects, which included depression and other mood disorders, muscle pain and acne. However it did also increase libido.

Dr Mario Festin, from the World Health Organisation in Geneva, Switzerland, said: “The study found it is possible to have a hormonal contraceptive for men that reduces the risk of unplanned pregnancies in the partners of men who use it.

“Our findings confirmed the efficacy of this contraceptive method previously seen in small studies.”

The contraceptive was found to be 96 per cent effective during 12 month trials 
The contraceptive was found to be 96 per cent effective during 12 month trials 

The injections contained a long-acting form of progestogen, a hormone that has the effect of blocking sperm production controlled by the pituitary gland.

Nearly 300 men were given injections every two months, which reduced sperm count to one million per millilitre or fewer within 24 weeks. At the end of the trial, three-quarters of the men said they would be willing to continue using the contraceptive jab.

Prof Allan Pacey at the University of Sheffield said: “There is certainly an unmet need for an effective reversible contraceptive for men, along the lines of the hormonal contraceptive for women.

“However, none of the preparations that have been developed and tested to date have managed to become a commercial reality for one reason or another.

“In this latest study, the authors used a combination of hormones (progesterone and testosterone) to try and take the science forward. Using long-acting injectable forms of these hormones they were able to suppress the production of sperm to a remarkable degree. As such, this contraceptive was extremely effective and therefore certainly has promise.

“However, the fact that so many side effects were observed in the men who were taking part in the trial is of concern. For a male contraceptive to be accepted by men (or women) then it has to be well tolerated and not cause further problems.”

Source: Journal of Clinical Endocrinology & Metabolism

How Close Are We to a Male Contraceptive?

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Men are often portrayed as simple creatures in the media. According to contraceptive researchers, men are anything but uncomplicated. For decades, biologists have said they were ten years away from a male birth control pill. The problem in one sense is scale. While women only ovulate once a month, men produce sperm at a rate of 1,000 per second. Another consideration is the necessity of reversibility. Despite difficulties, several new options are on the horizon.

One of the most promising is what is being called as a “liquid vasectomy.” Vasalgel is a polymer that is injected into the vas deferens, two ducts which allow sperm to enter the semen before leaving the body. In an actual vasectomy these tubes are surgically snipped and tied off, or cauterized.

In this case, the polymer forms a semi-permeable barrier prohibiting sperm from getting through. Whereas with a real vasectomy, reversing the procedure is tricky and not guaranteed, all that has to happen with Vasalgel is an injection of baking soda to dissolve the polymer. This allows the sperm to enter the semen once again. The gel isn’t hormonal and is designed to last for years. It is minimally invasive, an outpatient procedure, and literally takes five minutes to complete. Two injections and it is over. There are no side effects.

This idea has been developed from a similar one known as RISUG (Reversible Inhibition of Sperm Under Guidance). RISUG is currently undergoing advanced clinical trials in India. Vasalgel has been shown to work in rabbits and lower primates, but is having some trouble in larger mammals, namely baboons. Researchers hope to overcome this sometime in 2016, and begin human trials soon after. If you are interested and cost concerns you, take heart. The executive director behind Vasalgel, Elaine Lissner, told Medical Daily, “It shouldn’t cost more than a flat screen TV.”

 

Though researchers have had decades of trouble with this issue, German inventor Clemens Bimek thought up a technique as simple as flipping a switch. 20 years ago, while watching a documentary on contraception, Bimek wondered if a simple valve might not solve the problem of male contraception. Though the many physicians he consulted didn’t take him seriously, the inventor plodded on. The result, the Bimek spermatic duct valve or Bimek SLV.

Here, a switch is surgically implanted into the scrotum that controls two valves, one attached to each vas deferens tubule. A man with this implant can push the toggle switch into the upward position to “turn off” the flow of sperm. Toggle the switch down and sperm begins flowing again. Trials are set to begin with 25 participants this year. The valve, less than an inch long, and weighing only a tenth of an ounce, is made of PEEK OPTIMA, a polymer already in use in other medical implants.

Each valve must be surgically implanted, a simple procedure that takes about a half an hour. There is some concern that attaching these could cause scar tissue in the vas deferens which may prevent sperm flow, even when the switch is flipped open. Another issue is if the valve becomes clogged over time, limiting sperm flow.

 

Several options for a male birth control pill are in the works but each is in the, pun intended, seminal stages. One possibility is H2-Gamendazole. This is a medication taken orally that prevents sperm from maturing. So far animal tests have shown great results. Next up, human trials.

Another option is a form of vitamin A which prevents retinoic acid from forming, a key element in sperm production. Successful lab results at the University of Minnesota have been reported, but it has yet to be tested on animals. Eppin Pharma Inc. is developing a compound known as EP007, which prevents sperm from swimming and so reaching the egg. This would become a non-hormonal birth control pill for men. But it is too early to tell whether it is viable.

The last of is already in the works. But instead of a pill, it is a hormone-laced gel. The topical contains a combination of nestorone (a kind of progesterone) with testosterone. The gel suppresses sperm production and has been proven 91% effective. However, side effects in men included acne and weight gain. If women are exposed they may experience excessive body hair and acne. And exposing children can result in an early onset of puberty.

One final note, researchers at University of California, Berkeley have just uncovered the final mystery in human reproduction itself, how a sperm actually enters the egg. When it gets close, the egg releases a wave of progesterone which activates a receptor on the sperm’s tail. This causes it to swim vigorously. That strong whipping action allows it to reach the egg and cut through its protective covering. Biologist and researcher Melissa Miller called it the sperm’s “power kick.” If scientists could somehow find a way to block the sperm’s tail receptor, it would be unable to enter the egg. This discovery could lead to a future form of unisex birth control.

Male pill keeps sperm ‘in storage’

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Sperm

The prospect of a “male pill” that would let men enjoy a full sex life with no chance of getting a woman pregnant has moved a step closer.

Scientists in Australia have found a reversible way to stop sperm getting into the ejaculate, without affecting sexual function.

The animal tests showed the sperm could be “kept in storage” during sex.

The findings were published in the journal Proceedings of the National Academy of Sciences.

The quest for the male contraceptive pill has largely focused on getting men to produce non-functional sperm.

But some drugs used for this purpose “have intolerable side-effects,” said Dr Sabatino Ventura, one of the researchers at Monash University.

Drugs can induce infertility, but they may also affect sexual appetite or cause permanent alterations to sperm production.

Sperm stores

The team at Monash used a different approach. Normally, the sperm is moved out of the vas deferens storage area in the testes just before ejaculation.

The group produced genetically modified mice that were unable to squeeze the sperm out of the vas deferens.

Dr Ventura told the BBC: “The sperm stay in the storage site so when the mice ejaculate there’s no sperm and they are infertile.

“It is readily reversible and the sperm are unaffected, but we need to show we can do this pharmacologically, probably with two drugs.”

So far the research group has made the mice infertile by changing their DNA to stop them producing two proteins needed to move the sperm.

The researchers now need to find a pair of drugs that can produce the same effect. They believe one has already been developed and has been used for decades in patients with benign prostate enlargement.

However, they would have to work from scratch to find the second one – a process that could take a decade.

The proteins targeted also have a role in controlling blood vessels; so there could be side-effects on blood pressure and heart rate.

However, in the mice at least, the researchers detected only a “very slight” drop in blood pressure. There could also be an impact on the volume of ejaculate.

Dr Allan Pacey, senior lecturer in andrology at the University of Sheffield , told the BBC: “It’s a very good study, almost like a biological vasectomy in [that] it stops the sperm coming out.

“It’s a good idea; they need to get on with it and see what it does in people.”

The Quest for a Male Contraceptive.

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John Amory, a doctor at the University of Washington, has been developing a male contraceptive for 15 years. Turns out, it’s harder than it sounds. We spoke with him to find out why.

PopSci: Why is it taking so long to produce a birth-control pill for men?

John Amory: Women make one egg a month, but men make 1,000 sperm every second of every day, from puberty until the day they die. Turning that off is difficult.

PS: How does hormone contraception work?

JA: If you give a man enough testosterone, the brain will shut down the secretion of gonadotropins, which are the hormones that signal the testes to make sperm. This is why most bodybuilders are infertile, by the way. But it doesn’t work in all men.

PS: How many men does testosterone work for?

JA: We have never been able to get more than 95 percent effectiveness. It’s possible to identify who testosterone won’t work for, but it involves getting a lot of sperm counts. It would be much nicer if you could just say, “Take this and it will work.” Women don’t have to undergo ovulation detections and testing to see if the Pill is going to work for them.

PS: The World Health Organization funded a study across eight countries for hormone-based contraception, but last year, it shut down the study early. What happened?

JA: There were side effects, including severe depression. Some men don’t take hormonal shifts very well.

PS: What other approaches might work?

JA: Sperm have a pretty daunting mission. There’s a lot that can go wrong. Researchers have injected monkeys with eppin, a protein that coats sperm so they can’t swim. There’s also the process by which sperm make energy. If you can block that, you’d get tired sperm. Also, the testes need vitamin A to produce sperm, and there’s an enzyme that converts vitamin A to its active metabolite, retinoic acid. No retinoic acid, no sperm. I’m developing drug inhibitors that stop retinoic-acid production in the testes. I’m hopeful that we’ll have something approved in five years.

PS: Do you expect much demand for the male pill?

JA: Yes. Men are interested in having sex. Most of the time they’re not as interested in fathering a pregnancy.

http://www.popsci.com

Gel combo showed promise as male contraceptive.

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When combined and applied to the skin, testosterone and a synthetic progestin provided a successful method for suppressing sperm concentration, with minimal adverse effects.

In the past, combinations of testosterone and progestin injections with pills; implants with injections; or two different injections or implants enhanced the suppression of sperm production as a method of contraception. Injections and implants require a provider to administer the hormones.

“Our purpose was to develop a user friendly male contraceptive,” Christina Wang, MD, researcher and professor at the Los Angeles Biomedical Research Institute at Harbor-UCLA Medical Center, said during a presentation. “We showed the [synthetic progestin] gel was very effective in suppressing spermatogenesis in combination with testosterone gel.”

Wang and colleagues at LA BioMed and the University of Washington aimed to determine the effectiveness of testosterone gel alone or combined with Nestorone (NES) — a non-androgenic and non-estrogenic progestin in gel form being developed by the Population Council — through a randomized, double blind, comparator clinical trial completed at two academic medical centers.

“Nestorone was chosen because it’s a pure progestin,” Wang said.

The patient population was composed of 99 healthy men who were randomly assigned to one of three treatment groups applying daily transdermal gels: testosterone 10 g plus placebo (n=32); testosterone 10 g plus NES 8 mg (n=33); testosterone 10 g plus NES 12 mg (n=34).

Researchers analyzed 56 patients who completed at least 20 weeks of treatment. The percentage of men with sperm concentration of less than 1 million/mL was significantly higher for testosterone plus NES 8 mg (89%, P<.0001) and testosterone plus NES 12 mg (88%, P<.0002) vs. the testosterone plus placebo group (23%).

Additionally, data conveyed that significantly more patients became azoospermic in the testosterone plus NES 8 mg (78%, P<.001) and testosterone plus NES 12 mg (69%, P<.008) groups vs. testosterone plus placebo (23%).

All participants recovered to a sperm concentration of more than 15 million/mL during the recovery period. Adverse effects were minimal in all groups, with acne being the most common (21%).

“We can achieve effective suppression of sperm concentration, and after we test the combination of testosterone and Nestorone formulated into one gel and show efficacy, we will proceed to a phase 3 contraceptive efficacy study supported by the National Institute of Child Health and Human Development,” Wang said.

Source: Endocrine Today.