Two new types of antiprogestins that can suppress menstruation and could end the monthly misery many women suffer have passed their first tests in animals, scientists report in Europe's leading reproductive medicine journal, Human Reproduction.*
Studies in rhesus macaque monkeys show that that one drug - ZK 137 316 - can, depending on dose, allow ovulation but block menstruation, while the other - ZK 230 211 - blocks both ovulation and menstruation. Of great importance, both the drugs block the effects of oestrogen on the lining of the uterus, thus preventing the potentially dangerous build-up of endometrial cells caused by the action of unopposed oestrogen.
The studies have been carried out in Dr Robert Brenner's laboratory in the Division of Reproductive Sciences at Oregon Regional Primate Research Centre in the USA.
Rhesus macaque monkeys were used because they are one of the only animals that regularly menstruates and the mechanism in the brain, ovary and uterus controlling their periods is identical to that of humans. According to Dr Brenner, senior scientist with the Oregon Center, the results should therefore be directly applicable to women.
He said: "A reliable means of menstrual suppression would greatly improve the quality of life for women. The modern woman is accustomed to having control over her reproductive functions and menstruation is one function that many women would like to control. It is possible to use the oral contraceptive pill without the pill-free interval for this purpose, but not all women can tolerate the Pill and there are some health conditions that proscribe its use.
"Our goal in these studies was to obtain pre-clinical data prior to clinical development, and these results are very encouraging. All the treated animals, regardless of the dose they were given, remained in good health, maintained normal follicular phase concentrations of oestradiol and returned to normal menstrual cycles withi
Contact: Margaret Willson
European Society for Human Reproduction and Embryology