Asoprisnil: An alternative treatment for fibroids?

Asoprisnil, a new selective progesterone receptor modulator, at a dosage of 25 mg daily for 12 weeks, suppressed uterine bleeding in 83% of women with uterine leiomyomata who took it and reduced leiomyoma volume by 36%, according to the results of a phase II trial.

The study involved 129 women from 28 sites in the US and one in Canada. The women were randomized to receive 5, 10, or 25 mg of oral asoprisnil or placebo daily for 3 months.

Asoprisnil suppressed uterine bleeding in 28%, 64%, and 83% of the women at 5, 10, and 25 mg, respectively. Only the 25-mg dosage, however, produced a statistically significant decrease in tumor volume at 4 and 8 weeks of treatment. The two highest dosages produced a significant reduction in bloating, and 25 mg produced a significant reduction in pelvic pressure by week 12.

Chwalisz K, Larsen L, Mattia-Goldberg C, et al. A randomized, controlled trial of asoprisnil, a novel selective progesterone receptor modulator, in women with uterine leiomyomata. Fertil Steril. 2007;87:1399-1412.