A retrospective study of treatment outcomes and safety in patients receiving long-term relugolix administration

Objective Relugolix, an oral gonadotropin-releasing hormone (GnRH) antagonist, is effective for uterine fibroids, but its recommended use is limited to 180 days. Data on the long-term efficacy and safety of relugolix monotherapy are scarce. This study aimed to evaluate the treatment outcomes and safety of long-term relugolix administration in a real-world clinical setting. Methods We conducted a retrospective study of patients prescribed relugolix at a single institution between 2013 and 2024. Patients who received relugolix for more than 180 days were included in the analysis. Key outcomes included changes in uterine fibroid volume and diameter, symptom improvement, bone mineral density (BMD), and the rate of subsequent surgical intervention. Multivariate imputation was used for missing data, and multiple linear regression analysis was performed to identify factors correlated with treatment response. Results Eighty-three patients were analyzed, with a mean relugolix administration duration of 357.1 ± 158.4 days. The mean age was 41.7 ± 6.8 years. A reduction in uterine volume (-10.1% ± 209.4%) and maximum fibroid diameter (1.5% ± 40.1%) was observed. Multiple regression analysis revealed that a larger initial fibroid diameter (p = 0.01) and older age (p < 0.01) were significantly correlated with a greater percentage reduction in fibroid size. Symptomatic improvement was reported by 60.2% of patients, and 36.1% no longer desired surgery. No significant decrease in BMD was observed. Ultimately, 44.5% of patients underwent surgery, while 8.4% successfully transitioned into menopause on therapy. No serious adverse events were reported during long-term administration. Conclusion Long-term administration of relugolix monotherapy was well-tolerated and effective in reducing uterine fibroid volume and improving symptoms. It allowed a substantial number of patients to improve their quality of life and avoid or delay surgery, suggesting it is a viable option for the long-term management of symptomatic uterine fibroids.