FDA Approves Myfembree as First Once-Daily Therapy to Significantly Reduce Heavy Menstrual Bleeding in Premenopausal Women with Uterine Fibroids

Today, Myovant Sciences and Pfizer announced that the U.S. FDA has approved Myfembree (relugolix 40 mg, estradiol 1 mg, and norethindrone acetate 0.5 mg). The press release noted that this is the first once-daily medication for the treatment of heavy menstrual bleeding associated with uterine fibroids in premenopausal women, with a treatment duration of up to 24 months. This approval is supported by efficacy and safety data from the Phase 3 clinical trials LIBERTY 1 and LIBERTY 2, published in The New England Journal of Medicine.

Both Phase 3 LIBERTY studies met their primary endpoints. At Week 24, 72.1% and 71.2% of women in the Myfembree groups met the response criteria, respectively, compared with 16.8% and 14.7% in the placebo groups (p<0.0001). Symptom response was defined as menstrual blood loss of less than 80 mL during the last 35 days of treatment and a reduction in menstrual blood loss of at least 50% from baseline. Adverse events with a higher incidence in women treated with Myfembree compared with the placebo group included hot flashes, abnormal uterine bleeding, alopecia, and decreased libido.

Uterine fibroids are benign tumors that grow in the inner lining or wall of the uterus, and they are among the most common tumors of the female reproductive system. In addition to genetic factors, estrogen levels are a key regulator of fibroid growth. Uterine fibroids can cause debilitating symptoms, including abnormal uterine bleeding, heavy menstrual bleeding, anemia, and abdominal pain, and may lead to infertility. These symptoms can result in reduced work productivity and limitations in daily activities. Statistics indicate that approximately 5 million women in the United States are affected by symptomatic uterine fibroids, of whom approximately 3 million have inadequately controlled symptoms.

Each tablet of the relugolix combination therapy contains relugolix (40 mg), estradiol (1.0 mg), and norethindrone acetate (0.5 mg). As a gonadotropin-releasing hormone (GnRH) receptor antagonist, relugolix reduces ovarian estrogen production, thereby alleviating a range of symptoms associated with uterine fibroids.

▲Molecular Structure of Relugolix (Image source: Meodipt [Public domain])

Note: The original text has been abridged.

References:

[1] Myovant Sciences and Pfizer Receive FDA Approval for MYFEMBREE®, the First Once-Daily Treatment for Heavy Menstrual Bleeding Associated With Uterine Fibroids. Retrieved May 26, 2021, from https://www.globenewswire.com/news-release/2021/05/26/2236871/0/en/Myovant-Sciences-and-Pfizer-Receive-FDA-Approval-for-MYFEMBREE-the-First-Once-Daily-Treatment-for-Heavy-Menstrual-Bleeding-Associated-With-Uterine-Fibroids.html

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