Myovant Sciences  and Pfizer Inc. today announced that the Phase 3 SPIRIT long-term extension study of the investigational once-daily relugolix combination therapy (relugolix 40 mg plus estradiol 1.0 mg and norethindrone acetate 0.5 mg) in women with endometriosis reported clinically meaningful reductions in dysmenorrhea (menstrual pain) and non-menstrual pelvic pain over one year (52 weeks) with minimal and stable bone mineral density loss.