What are the next steps for male contraceptive research?

A concerted research effort in the following eight areas would ensure that a new male contraceptive is available sooner rather than later:

1. Tripterygium wilfordii (TW) and Tripterygium hypoglaucum (TH) are readily available and known to have contraceptive effect; since they have been used for millennia, their side effects are well understood. In conjunction with Chinese researchers, the World Health Organization conducted research to successfully purify extracts of TW in the 1980s and 1990s. Rather than allowing this research to go to waste, systematic studies must clarify the optimal contraceptive dose.
2. Dr. Christina Wang and Dr. Ronald Swerdloff ’s studies on the effect of heat as a booster for hormonal methods should be encouraged and expanded, and Dr. Roger Mieusset and Dr. Louis Bujan ’s proposed study on artificial cryptorchidism should be funded. Additional knowledge on how heat affects the testes and DNA (and whether it has any impact on hormones) might allow us to feel more confident in using artificial cryptorchidism, a method that is free and already available to men everywhere in the world.
3. The lack of studies on ultrasound is an egregious omission. Respected scientists should be engaged to duplicate Dr. Fahim ’s animal studies in order to confirm or disprove effectiveness. Any study should also monitor hormone levels and the structural health of the testes. A simple, cheap contraceptive that can be either medium-term or permanent would be an incredible boon.
4. The IVD plug showed excellent results in its latest test. The NIH has shown courage in making a grant to support a larger clinical trial on the IVD plug, and the results are eagerly awaited. The NIH should be thanked for its decision and encouraged to follow through with this method.
5. Though miglustat (Zavesca®) is systemic in its effects, and though it is a patented medication with a price barrier, it still merits study because the drug is already approved for other uses in both Europe and the United States . Clinical trials will determine whether the contraceptive dose is small enough, as hoped, to eliminate side effects. The National Institutes of Health is now funding a seven-man study in Seattle (ClinicalTrials.gov, 2005). This research should be applauded and encouraged.
6. Only a single study would be needed to determine whether nifedipine truly has a reliable contraceptive effect. Nifedipine is usually used as a blood pressure medication, but high blood pressure can reduce fertility, confounding the results. However, nifedipine is also used as a migraine treatment. Dr. Susan Benoff has proposed collaborating with a colleague who runs a headache clinic to test nifedipine’s effect on fertility. A simple set of before-and-after sperm tests could determine whether this widely-used drug is also a contraceptive. Such a study should be funded immediately.
7. Funding should be made available to publish the results of the World Health Organization’s large study of no-scalpel vasectomy (NSV) versus medical polyurethane plug (MPU) versus chemical vas occlusion. Publishing the study results would prevent the work done so far from going to waste and provide definitive data on these methods.
8. Finally, only when RISUG studies are initiated outside India can we say that we are truly making an effort to develop a practical male contraceptive. This method has been shown to provide years of contraception for men with a single ten-minute procedure. It is reversible in animals (including nonhuman primates) and is also likely to be reversible in humans. U.S. and international government agencies must support and encourage India in its long-term follow-up and reversibility trials, while simultaneously beginning toxicology studies of their own. Approval under the new harmonized U.S./European Union/Japanese regulations would open the door to approval in most of the rest of the world.

What about intriguing early leads such as CatSper? Adding new methods to the pipeline is also important. However, our current research environment makes it easier to spend money on dozens of early leads than to finish clinical trials on the methods already known to work. Though it is tempting to pursue the next great discovery around the corner, it is not acceptable to spend money doing so if we do not plan to finish the jobs already started.

Universities, government agencies, and research organizations each tend to specialize in a particular stage of research. All too often, no one agency keeps track of the big picture. Ongoing projects can thus run out of money at the halfway point at the same time as new projects are being funded.

Further basic contraceptive research cannot be justified until we show that we have a fully functioning, integrated system by taking the above contraceptives as far as they can go — which will, hopefully, be to market and to end users. Only then can we justify spending limited funds on basic research or on looking for nontoxic variants of additional plant compounds. Only then will we know that it is not destined to be research in a vacuum. And only then will we know that this new research will not also be abandoned halfway.

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