Mifepristone for Treatment of Uterine Leiomyoma: A Prospective Randomized Placebo Controlled Trial

A hysterectomy is the primary therapeutic option for women with uterine leiomyomas. To avoid surgical intervention, several medical options have been explored. Because the growth of uterine leiomyomas is promoted by estrogen and progesterone, a number of studies have investigated the effect of treatment with the antiprogesterone drug mifepristone and other progesterone receptor modulators in these patients. The results of these studies have been promising. Daily oral doses of mifepristone treatment reduced bleeding in women with uterine leiomyomas in several studies. This prospective, randomized, placebo-controlled study investigated the effect of 3 months of mifepristone on leiomyoma volume, endometrium, and bleeding. This was a proof of concept study. About 30 women with leiomyoma-related problems indicating the need for surgical intervention were randomized to receive either mifepristone or a placebo for 3 months on alternate days before scheduled surgery. Until surgery, both uterine blood flow and leiomyoma volume were measured once a month. At baseline and at the end of treatment, endometrial biopsies were examined and pertinent biochemistry, symptoms, and bleeding were recorded. Reduction in uterine leiomyoma size was the primary study outcome. Compared to the control, there was a significant decrease in the percent of total leiomyoma delta volume after 3 months of treatment with mifepristone: the values for the mean within 95% confidence interval were −28 (−48% to −28%) in the mifepristone-treated-group compared to −6% (−13% to +25%) in the control group. At 3 months, a significant reduction in bleeding days was noted within the mifepristone group compared with the placebo group (P = 0.001) and there was a significant increase in blood hemoglobin values in the mifepristone group (P = 0.046). No change occurred in serum cortisol levels during the 3 months of treatment with mifepristone, and a small increase in serum androgens was found. None of the biopsies in the mifepristone-treated women revealed any evidence of hyperplasia or malignancy. The findings of this proof-of-concept study suggest that mifepristone may be an effective medical treatment option for leiomyomata, and may achieve rapid control of the associated marked uterine bleeding.