Male Contraceptives

Studies from the last decade (1, 2) show that men want to share the responsibility for contraceptives and family planning. Additionally, women are not satisfied with their current choices of contraceptives (3) and they have suffered from various side effects since the pill was introduced in the 1960ies.

Today, no oral male contraceptives are available. Existing choices of male contraception includes condoms, withdrawal and vasectomy (sterilization). While condoms and withdrawal have a high rate of user failure, vasectomy, though most effective, is a permanent procedure with little chance of reversal. As a consequence, there is a high demand for developing an oral male contraceptive which gives temporary infertility, is easy to use and possess no side effects.

Of all the potential male contraceptives, male hormonal contraceptives have been closest to the market in the US and Europe. Promising projects involving the male hormone testosterone have reached clinical trials. Unfortunately, these trials revealed several limitations. These include inconvenient route of administration (implants and injections), substantial side effects (acnes, weight gain and mood changes), slow reversibility and incidents of non-responders.

The lack of success with hormonal contraceptives has made scientists look for alternatives. During the last few years the focus has shifted from hormonal to non-hormonal strategies. This emerging research comes from the realization that the human sperm cell contains several sperm specific proteins essential for male fertility. These proteins can be ideal targets for pharmaceutical drugs. Since these proteins (drug- targets) exist nowhere else in the body, a male birth control pill attacking one of them could potentially give 100 % infertility without side effects. Spermatech’s technology takes advantage of this fact, and we have found small drug-like molecules that interfere with proteins important for male fertility.

1) Heinemann, K, F Saad, M Wiesemes, S White and L Heinemann (2005) “Attitudes toward male fertility control: results of a multinational survey on four continents.” Human Reproduction 20(2): 549-56.

2) Brooks, M (1998) “Men’s views on male hormonal contraception: A survey of the views of attendees at a fitness centre in Bristol, UK.” British Journal of Family Planning 24: 7-17.

3) Rosenfeld, JA, PM Zahorik, W Saint and G Murphy (1993) “Women’s satisfaction with birth control.” Journal of Family Practice 36(2): 169-73.