The U.S. Food and Drug Administration (FDA) has approved Myovant Sciences and Pfizer’s MYFEMBREE (relugolix 40 mg, estradiol 1 mg, and norethindrone acetate 0.5 mg) as a one-pill, once-a-day therapy for the management of moderate to severe pain associated with endometriosis in pre-menopausal women, with a treatment duration of up to 24 months.
The approval is supported by one-year efficacy and safety data, including 24-week data from the Phase 3 SPIRIT 1 and SPIRIT 2 trials, which were published in The Lancet, and the first 28 weeks of an open-label extension study for eligible women who completed either SPIRIT 1 or SPIRIT 2. MYFEMBREE also is approved for heavy menstrual bleeding associated with uterine fibroids in pre-menopausal women. Myovant and Pfizer will continue to jointly commercialize MYFEMBREE in the U.S. and product is available immediately.
“Endometriosis is a painful, chronic disease with limited therapies to manage symptoms,” said Juan Camilo Arjona Ferreira, M.D., chief medical officer of Myovant Sciences, Inc. “The new MYFEMBREE indication helps advance our mission to redefine care for women by helping address a disease with high unmet need, giving women and physicians a new meaningful treatment option to manage moderate to severe pain associated with endometriosis.”
“This approval is an important milestone reflecting Pfizer and Myovant’s commitment to women’s health in areas of significant unmet need,” said James Rusnak, M.D., Ph.D., senior vice president, chief development officer, Internal Medicine and Hospital, Global Product Development at Pfizer. “We look forward to making MYFEMBREE available to women with endometriosis and broadening their options in managing this complex disorder.”
MYFEMBREE offers an effective, once-daily treatment option for the management of moderate to severe pain associated with endometriosis, with a treatment duration of up to 24 months. Endometriosis is a serious chronic condition that requires long-term interventions. Optimization of medical therapies is the recommended treatment paradigm. MYFEMBREE introduces an option for up to two years of pharmacological management of moderate to severe pain associated with endometriosis in pre-menopausal women.
“The data from the SPIRIT studies showed the clinical benefit that relugolix combination therapy can have on moderate to severe pain associated with endometriosis and how it can impact patients,” said Linda Giudice, M.D., Ph.D., distinguished professor at the University of California, San Francisco (UCSF), and chair, SPIRIT Program Steering Committee. “This newly approved option for patients with pain from endometriosis offers the convenience of one pill taken once daily with a mean change in bone mineral density of <1% that did not appear to worsen at 12 months of treatment; however, monitoring is recommended.”
This approval is supported by one-year data from the Phase 3 SPIRIT program, which included two 24-week multi-national clinical studies (SPIRIT 1 and SPIRIT 2) in more than 1,200 women with pain associated with endometriosis, as well as the first 28 weeks of an open-label extension study to assess its longer-term use. Overall, these studies showed MYFEMBREE reduced menstrual pain and non-menstrual pelvic pain with a loss of mean bone mineral density of less than 1% from baseline through one year of treatment.
SPIRIT 1 and 2 each met their co-primary endpoints with 75% of women in the MYFEMBREE group in both studies achieving a clinically meaningful reduction in dysmenorrhea compared with 27% and 30% of women in the placebo groups at Week 24, respectively (both p <0.0001). For non-menstrual pelvic pain, treatment with MYFEMBREE demonstrated a clinically meaningful reduction in pain in 59% and 66% of women, compared with 40% and 43% of women in the placebo groups (p < 0.0001). Adverse reactions occurring in at least 3% of women treated with MYFEMBREE and greater than placebo were: headache, vasomotor symptoms, mood disorders, abnormal uterine bleeding, nausea, toothache, back pain, decreased sexual desire and arousal, arthralgia, fatigue, and dizziness.
The open-label extension study for eligible women who completed either SPIRIT 1 or SPIRIT 2 showed mean bone mineral density loss of less than 1% from baseline through one year of treatment; some patients (19.7%) had losses >3%. Annual bone density measurement is recommended while treating women for endometriosis.
