US clears Pfizer, Myovant's Myfembree for fibroid-associated menstrual bleeding

Pfizer and Myovant Sciences announced Wednesday that the FDA has approved Myfembree, which combines the GnRH antagonist relugolix with hormones estradiol and norethindrone, to manage heavy menstrual bleeding in premenopausal women who have uterine fibroids. Nick Lagunowich, global president for internal medicine at Pfizer, said "this new treatment option…will help provide much needed symptom relief with the convenience of an oral, once-daily tablet."

Under the terms of their collaboration, Pfizer and Myovant will jointly commercialise Myfembree in the US, where the product is slated for launch next month. The drug, whose approval was capped with a treatment duration of up to two years, will cost about $975 a month.

The filing was based on data from the Phase III LIBERTY 1 and LIBERTY 2 studies. Each met the primary endpoint, with Myfembree demonstrating respective response rates of 72.1% and 71.2% in menstrual blood loss (MBL) at week 24, with MBL reductions of 82% and 84.3% from baseline. Responses were defined as an MBL volume of less than 80 mL, and a reduction of 50% or more from baseline in MBL volume during the last 35 days of treatment.

The European Medicines Agency's Committee for Medicinal Products for Human Use (CHMP) last week adopted a positive opinion for the treatment to alleviate moderate-to-severe symptoms of uterine fibroids in adult women of reproductive age. If approved in the EU, the combination tablet will be marketed under the name Ryeqo by Gedeon Richter.

Triggers $100-million milestone

Pfizer struck a deal with Myovant last December potentially worth up to $4.2 billion to develop and commercialise relugolix in oncology and women's health in the US and Canada. Wednesday's FDA approval triggers a $100-million milestone payment to Myovant from Pfizer. Relugolix was first cleared late last year in the US as a once-daily treatment for men with advanced prostate cancer under the brand name Orgovyx.

Meanwhile, in May last year, the FDA approved AbbVie's Oriahnn capsules, consisting of the GnRH antagonist elagolix, estradiol and norethindrone, co-packaged for oral use, also to manage heavy menstrual bleeding associated with uterine fibroids in premenopausal women.