This site is intended for healthcare professionals

Phase III SPIRIT 1 and SPIRIT 2 studies of relugolix combination therapy in endometriosis pain published in The Lancet.- Myovant Sciences and Pfizer

Read time: 1 mins
Published:18th Jun 2022

Myovant Sciences and Pfizer Inc. announced that results of the Phase III 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.></1%>

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.

See: "Once daily oral relugolix combination therapy versus placebo in patients with endometriosis-associated pain: two replicate phase 3, randomised, double-blind, studies (SPIRIT 1 and 2)." Linda C Giudice et al. The Lancet Volume 399, ISSUE 10343, P2267-2279, June 18, 2022 DOI:

Condition: Pain; Endometriosis
Type: drug

Learning Zones

The Learning Zones are an educational resource for healthcare professionals that provide medical information on the epidemiology, pathophysiology and burden of disease, as well as diagnostic techniques and treatment regimens.

Related news and insights