Efficacy and Tolerability of Elagolix in Adolescents and Young Adults with Endometriosis: A Small, Single-Center Retrospective Cohort Study

STUDY OBJECTIVE: To evaluate the efficacy and tolerability of the gonadotropin-releasing hormone antagonist elagolix for endometriosis-associated pain symptoms in adolescents and young adults (AYAs) METHODS: We performed a retrospective cohort study of AYAs with laparoscopically confirmed endometriosis prescribed elagolix between November 2018 and December 2024 at a pediatric tertiary care center. Data from the electronic medical record included demographic and clinical characteristics, previous hormonal therapies, elagolix dose and use of add-back therapy, symptom response, and adverse effects. Primary outcomes were patient-reported symptom improvement and treatment discontinuation. The study was deemed IRB exempt. RESULTS: Nineteen patients began taking elagolix, median age 18 years (IQR = 16-21). Endometriosis stage was I in 8 patients (42%), II in 10 (52%), and III in 1 (5%). All patients had previously tried 2 or more hormonal therapies, most commonly the levonorgestrel intrauterine device and norethindrone acetate (68% each). Of patients treated with elagolix, add-back therapy was used in 58%, primarily norethindrone acetate. Overall, 53% reported some improvement; dysmenorrhea and pelvic pain improved in 42% and 53%, respectively. Adverse events included persistent pelvic pain (37%), unpredictable bleeding (26%), and mood changes (16%). No serious adverse events occurred. Discontinuation occurred in 95% of patients, most commonly due to persistent pain and mood changes. The median treatment duration was 5.5 months (IQR = 3-12). CONCLUSION: In this small cohort, elagolix was associated with modest symptom improvement but high discontinuation rates in AYAs with endometriosis. Larger prospective studies are needed to define its role in the long-term management of adolescent endometriosis.