Novel Therapy For Uterine Fibroids
Fibroids are the most common tumors of women during their reproductive life. While the majority of uterine fibroids that require treatment are treated either surgically or by radiology treatments such as focused ultrasound or uterine artery ablation, there is not at the present time an effective long term medical therapy for these benign tumors. Since progesterone has been shown to enhance the growth of uterine fibroids, studies have been underway to develop anti-progestational agents, which may be useful for long term non-surgical management of symptomatic uterine fibroids. Ulipristal acetate belongs to a group of compounds referred to as selective progesterone receptor modulators (SPRMs), and has been shown to reversibly block the progesterone receptor in target tissues such as the uterus, cervix, ovaries, and hypothalamus. Several trials have been completed in Europe looking at short term use of this progesterone modulator for treatment of uterine fibroids prior to surgery. It has shown significant reduction of uterine bleeding, fibroid volume, and improved quality of life, without significant side-effects.
Randomized, double blind, placebo controlled trials have shown excellent results when Ulipristal was administered at doses of 10-20 mg/day for 3-6 months. In this study, ulipristal showed a 92% reduction in uterine bleeding versus 19% with placebo. Fibroid volume was reduced by 29% in the ulipristal group compared to 6% reduction in the placebo group. In another study in which ulipristal was used at a dosage of 10 mg/day for 13 weeks, abnormal uterine bleeding was controlled in 98% of patients. Adverse reactions to ulipristal acetate were mild and did not lead to discontinuation of the medication. Side effects included hot flushes, headache, functional ovarian cysts, vertigo, nausea, acne, sweating, muscle pain and tiredness.
At the present time, ulipristal for treatment of fibroids is only approved for use in Europe at a dose of 5 mg/day for 3 months in preparation for surgery. Further studies are needed to answer the following questions:
1) Does ulipristal result in a permanent reduction in the size of uterine fibroids following the initial 13 week treatment? If fibroids do re-grow after treatment, how quickly do they do so?
2) Will additional courses of treatment result in improved effectiveness in terms of fibroid sizes and bleeding? (Studies investigating this question are underway at this time.)
3) Will ulipristal improve pregnancy rates for women with multiple intermediate or large fibroids without surgical removal?
4) What effects might pre-treatment with ulipristal have on pregnancy outcomes if fibroids are not surgically removed?
5) Does ulipristal have any adverse effects on the lining of the uterus when used long term?
6) Are there certain types or sizes of uterine fibroids that are most likely to respond favorably to ulipristal?
Ulipristal, or a similar compound may prove to be an important option for women with symptomatic uterine fibroids, improving the quality of their lives and their fertility potential while avoiding the risks of surgery.
