OBJECTIVE: To investigate the efficacy and safety of the oral 
gonadotropin-releasing hormone receptor antagonist, relugolix, in patients 
experiencing uterine fibroid-associated pain.
DESIGN: Phase 3, multicenter, randomized, double-blind, placebo-controlled 
study.
SETTING: Medical centers.
PATIENT(S): Premenopausal Japanese women (N = 65) experiencing 
moderate-to-severe uterine fibroid-associated pain with a maximum Numerical 
Rating Scale (NRS) score of ≥4 were randomized and completed the study.
INTERVENTION(S): Once-daily 40 mg relugolix (n = 33) or placebo (n = 32) for 
12 weeks.
MAIN OUTCOME MEASURE(S): Primary end point: proportion of patients with a 
maximum NRS score of ≤1 during the 28-day period before the final dose of study 
drug. Secondary end points: proportion of patients with no pain (NRS = 0) and 
percentage of days without pain during the 28-day period before the final dose 
of study drug; adverse events.
RESULT(S): More patients receiving relugolix versus placebo achieved a maximum 
NRS score of ≤1 during the 28-day period before the final dose of study drug 
(57.6% vs. 3.1%). Similarly, more patients receiving relugolix versus placebo 
achieved a maximum NRS score of 0 (48.5% vs. 3.1%) and experienced more days 
without pain (96.4% vs. 71.4%). More patients receiving relugolix versus placebo 
experienced treatment-emergent adverse events (TEAEs; 87.9% vs. 56.3%); however, 
the rate of treatment discontinuation was low and not different between groups. 
Most TEAEs were mild to moderate in intensity. TEAEs (≥10%) included hot flush, 
metrorrhagia, hyperhidrosis, and menorrhagia, consistent with relugolix's 
mechanism of action, and viral upper respiratory tract infection.
CONCLUSION(S): Relugolix improved uterine fibroid-associated pain and was well 
tolerated.
CLINICAL TRIAL REGISTRATION NUMBERS: NCT02655224.
JAPIC CLINICAL TRIAL INFORMATION: JapicCTI-163127.