Male contraception: Obstacles to research and development, "Beyond the Abstract," by Erwin Goldberg, PhD

BERKELEY, CA (UroToday.com) - As we pointed out in this review, there are two main obstacles to research on a male contraceptive technology. The first is the lack of interest by “big pharma” in going forward with research or research funding in the development of a useful product. The second is that women might not embrace the technology because they have the most to lose, i.e., having an unwanted pregnancy. There’s not much that can be done to increase the interest of the pharmaceutical industry except the completion of basic research showing an immediately proven, reliable product. Of course, it’s always possible that a forward-looking pharma executive could decide to embark on product development, but unlikely. Profit motives get in the way. A stable relationship is the strongest reason for women to accept a man’s willingness to be the contraceptor. Of course, some women suffer unwelcome side effects from hormonal contraception and therefore are more amenable to the partner being the responsible party.

Current options available to men include withdrawal, condoms, and vasectomy, each of which has its own drawbacks. Methods in development of a contraceptive technology fall into two categories: hormonal and non-hormonal. Development of a male hormonal contraceptive has been pursued for many years as the most approachable method that would be successful. The challenges to this approach have involved the need for an injectable formulation, unacceptable side effects, and failure to adequately suppress spermatogenesis in 5-10% of men. Hormonal treatment that suppresses gonadotropins is associated with, but does not ensure, adequate suppression of spermatogenesis. As noted in our review, there is a clinical trial underway involving combined delivery of testosterone (T) and nestorone (a nonandrogenic progestin), by transdermal gels, for the suppression of spermatogenesis. Transdermal gels are a more acceptable method of delivery, and efficacy across diverse ethnic groups was achieved with 88–89% of treated men achieving sperm concentrations below 1 million/ml. This information may be utilized to allow for rapid identification of non-responders in male hormonal contraceptive trials.

Non-hormonal methods involve searching for specific and reversible targets in testes or spermatozoa, or more recently in the ejaculatory process. Targets include structural components in the testes and enzymes and other proteins and ion channels specific to spermatozoa. It is almost essential that there be a biological basis for validating a target. Targeted disruption of a gene, or identification of a gene mutation that shows an infertility phenotype, has identified several candidates. The next steps, screening libraries of potential inhibitors, involve collaborations between medicinal chemists and reproductive biologists to demonstrate feasibility of target disruption and reversible inhibition of fertility. This is time-consuming, expensive, and is considered risky by study sections. Funding is limited and progress is slow. Since contracepting doesn’t involve a life threatening disease, it is unlikely that this research will attract the resources necessary for success in developing a male product. The fact that world-population increases cry out for control is not sufficiently viewed as something that will be life threatening. This attitude overlooks the effect of over-population on quality of life.

Written by:
Erwin Goldberg, PhD as part of Beyond the Abstract on UroToday.com. This initiative offers a method of publishing for the professional urology community. Authors are given an opportunity to expand on the circumstances, limitations etc... of their research by referencing the published abstract.

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Male contraception: Another holy grail - Abstract

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