Oral gonadotropin-releasing hormone antagonists for treating endometriosis-associated pain: a systematic review and network meta-analysis

OBJECTIVE: To review the use of oral gonadotropin-releasing hormone (GnRH) antagonists and synthesize their efficacy and safety parameters for the treatment of endometriosis-associated pain. DESIGN: Systematic review and network meta-analysis. SETTING: Not applicable. PATIENT(S): Premenopausal women with endometriosis who had experienced moderate or severe pain. INTERVENTION(S): The Web of Science, Embase, Scopus, and MEDLINE were searched until April 10, 2022. Only randomized controlled trials were included. The risk of bias in the included studies was assessed using the Cochrane Risk of Bias tool 2. A Bayesian random-effects network meta-analysis was used to perform indirect comparisons. I2 was used to assess the global heterogeneity. Relative treatment estimates were performed. Treatment ranking was performed through the surface under the cumulative ranking curve. The certainty of evidence was assessed using the Grading of Recommendations, Assessment, Development and Evaluation framework. MAIN OUTCOME MEASURE(S): Endometriosis-associated pain, dysmenorrhea, dyspareunia, and noncyclic pelvic pain reduction. RESULT: (s): Five studies and 6 randomized controlled trials, including a total of 2,796 women and 10 different doses of oral GnRH antagonist treatments, were eligible for inclusion. All studies were considered to have a low risk of bias. Almost all efficacy- and safety-related outcomes showed a dose-response relationship. Regarding endometriosis-associated pain, the top 3 treatments were elagolix 400 mg, linzagolix 75 mg, and linzagolix 200 mg, with mean differences of -1.26 (95% credible interval [CrI], -1.70 to -0.79), -0.98 (95% CrI, -1.84 to -0.15), and -0.98 (95% CrI, -1.90 to -0.064), respectively. The top 3 treatments to decrease dysmenorrhea were relugolix 40 mg, elagolix 400 mg, and relugolix 20 mg, with mean differences of -1.60 (95% CrI, -2.07 to -1.14), -1.25 (95% CrI, -1.56 to -0.95), and -1.10 (95% CrI, -1.59 to -0.62), respectively. However, only high-dose treatments were significantly associated with most quality of life- and adverse effect-related outcomes. Relugolix 40 and 20 mg and elagolix 400 mg, with odds ratios of 6.88 (95% CrI, 2.18-24.58), 1.60 (95% CrI, 0.62-4.13), and 1.85 (95% CrI, 1.05-3.30), had a significantly increased incidence of adverse events. CONCLUSION: (s): Oral GnRH antagonists are effective for endometriosis-associated pain and dysmenorrhea and the patient global impression. The incidence of ovarian hypoestrogenic effects in a short-term duration was significant in a dose-effect response, particularly the highest dose. CLINICAL TRIAL REGISTRATION NUMBER: International Prospective Register of Systematic Reviews registration number CRD42022332904.