Endocrine Abstracts

The pharmaceutical armamentarium available for contraception is remarkable and extraordinary progress has been achieved since 1960, when the first hormonal contraceptive, Enovid, was approved in the USA. However, the demand for new methods, for improvement of existing methods, and easier availability, remains extraordinary. Indeed, the number of unintended pregnancies is still too high, averaging 40% of all pregnancies. In addition, 50% of these pregnancies are followed by abortion, many of those being unsafe. The situation is further complicated by the decreased interest of the Pharma industry. Improvement of existing methods includes OCs given non stop with bleed free regimens. There is also a need for improvement of the choice offered to women, and the multiplication of methods among which women can choose the method they like best: intrauterine devices which blocks menstruation without systemic exposure, vaginal contraceptive rings with 17 beta estradiol, and patches/transdermal hormonal contraception containing friendly steroids. Although the state of reproductive research has not permitted to target oocyte fertilization or implantation as a contraceptive method, several leads show great future: (1) the replacement of ethinyl estradiol by estradiol, which will allow the reduction VTE events, and tolerance, (2) the development of new estrogens such as estetrol, and (3) the development of the progesterone receptor modulators (PRMs). This class of product is remarkable since it is devoid of metabolic and coagulation side effects. PRMs block the LH surge and prevent implantation without suppressing endogenous estradiol production. The end result of their administration is a bleed free method available as a daily continuous regimen. Other regimens include emergency contraception, where better results have been achieved in comparison with levonorgestrel. The development of this method will allow the introduction of the first product on the market next year. Even though long term efficacy as well as endometrial safety will have to be assessed, this class of compounds looks very promising, because of their safety and efficacy but also because in animal models, PRMs prevent the development of breast cancer. Finally, the most difficult task will be to develop, in parallel, or in association, a contraceptive method, which at the same time, will protect against sexually transmitted infections.