Pfizer: Myovant Sciences and Pfizer Announce Publication in The Lancet of Phase 3 SPIRIT 1 and SPIRIT 2 Studies of Once-Daily Relugolix Combination Therapy in Women With Endometriosis-Associated Pain

Myovant Sciences (NYSE: MYOV) and Pfizer Inc. (NYSE: PFE) today announced that results of the Phase 3 SPIRIT 1 and SPIRIT 2 studies of investigational once-daily relugolix combination therapy (relugolix 40 mg plus estradiol 1.0 mg and norethindrone acetate 0.5 mg) in over 1,200 women with moderate to severe pain associated with endometriosis were published in The Lancet.

As previously reported, both studies achieved their co-primary endpoints by demonstrating clinically meaningful reductions in dysmenorrhea (menstrual pain) and non-menstrual pelvic pain in women with endometriosis. SPIRIT 1 and 2 each met their co-primary endpoints with 75% of women in the relugolix combination therapy 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, relugolix combination therapy achieved a clinically meaningful reduction in 59% and 66% of women, compared with 40% and 43% of women in the placebo groups (p < 0.0001). In SPIRIT 1, seven key secondary endpoints, and in SPIRIT 2, six key secondary endpoints comparing relugolix combination therapy with placebo at Week 24 achieved statistical significance, including reductions in dyspareunia and opioid use. In addition, more women treated with relugolix combination therapy groups were opioid free at Week 24 compared with placebo (86% and 82% vs 76% and 66%, respectively). In both studies, relugolix combination therapy was associated with a generally well-tolerated safety profile, including bone mineral density loss of <1% over 24 weeks.

“Approximately 7.5 million premenopausal women in the United States have endometriosis and 75-80 percent of them are symptomatic,” said Juan Camilo Arjona Ferreira, M.D., Chief Medical Officer of Myovant Sciences, Inc.1,2,3,4 “The data published in The Lancet underscore the value relugolix combination therapy may provide as a potential new treatment option for women with endometriosis-associated pain.”

“We are excited to see this data published in The Lancet,” said James Rusnak, M.D., Ph.D., Senior Vice President, Chief Development Officer, Internal Medicine and Hospital, Global Product Development at Pfizer. “We continue to look forward to bringing this potential new treatment option to women with endometriosis-associated pain.”

Seven key secondary endpoints in SPIRIT 1 and six key secondary endpoints in SPIRIT 2 comparing relugolix combination therapy with placebo at Week 24 also achieved statistical significance. These endpoints include changes in mean dysmenorrhea, non-menstrual pelvic pain, overall pelvic pain, impact of pain on daily activities as measured by the Endometriosis Health Profile-30 (EHP-30) pain domain, the proportion of women not using opioids, the proportion of women not using analgesics, and change in mean dyspareunia (painful intercourse). While the seventh endpoint for the SPIRIT 2 study – reduction in analgesic use (based on pill count) – did not achieve statistical significance, possibly due to the low number of average pills per day and variability in day-to-day pill consumption, a post-hoc analysis of SPIRIT 2 showed that the percentage of patients who were analgesic-free at end of treatment was greater among women in the combination therapy group than the placebo group.

The most frequently reported adverse events in both relugolix combination treatment and placebo groups were headache, nasopharyngitis, and hot flushes.

In the U.S., relugolix combination tablet (relugolix 40 mg, estradiol 1.0 mg, and norethindrone acetate 0.5 mg) is currently available as MYFEMBREE® for the management of heavy menstrual bleeding associated with uterine fibroids in premenopausal women, with a treatment duration of up to 24 months. Data from SPIRIT 1 and SPIRIT 2, in addition to data from an open-label extension study, were included in a supplemental New Drug Application for MYFEMBREE for the management of moderate to severe pain associated with endometriosis, which has a target Prescription Drug User Fee Act (PDUFA) action date of August 6, 2022.

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