(297) Pregnancy and Pain Outcomes When Elagolix and Hormonal Contraceptives are Used Concomitantly: A Prospective Cohort Study Using a Health Insurance Claims Database

Background: Women prescribed elagolix for endometriosis-related pain are advised to use non-hormonal contraceptives (HC), due to a lack of clinical trial data for elagolix in combination with HCs.

Objectives: To assess (1) the impact of elagolix on effectiveness of HCs in preventing pregnancy and (2) the impact of HCs on effectiveness of elagolix in reducing pain in the real-world setting, where co-prescribing may occur.

Methods: This cohort study included women aged 18 to 53 years who initiated elagolix or a variety of HCs from July 2018 through December 2021 in a U.S. health insurance claims database (Optum Research Database). Women were classified into 3 cohorts according to their initiation medication: elagolix only, HC only, and elagolix and HC in combination. The occurrence of pregnancy (identified by claims for pregnancy-related services) among the elagolix and HC combination cohort compared to HC only cohort was used to assess the impact of elagolix on the effectiveness of HCs. The impact of HCs on the effectiveness of elagolix was assessed using the outcome of “endometriosis-related pain” by comparing the occurrence of claims related to pain or pain management among the elagolix and HC combination cohort relative to the elagolix only cohort. Propensity score matching was used to balance the compared cohorts with respect to baseline characteristics. Patients were followed from cohort entry date until occurrence of pregnancy, endometriosis-related pain, or end of follow-up.

Results: There were 1,061 women who entered the elagolix and HC combination cohort, 354,282 who entered the HC only cohort, and 1,274 who entered the elagolix only cohort. The matched cohorts included 1,047 women receiving combination elagolix and HC matched to 3,660 HC only women, and 516 combination elagolix and HC women matched to 516 elagolix only women. The hazard ratio (95% confidence interval [CI]) for pregnancy among women receiving combination elagolix and HC was 0.25 (0.08, 0.79) compared to the HC only cohort. The relative risk (95% CI) for endometriosis-related pain comparing the elagolix and HC combination cohort to the elagolix only cohort was 1.01 (0.84, 1.20).

Conclusions: Among women with commercial health insurance who initiated HCs, elagolix did not increase the rate of pregnancy and, among women who used elagolix, there was no difference in pain indicators between those who were on concomitant HC and those who were not. This study provides real-world evidence of the impact of elagolix on the effectiveness of HCs with respect to pregnancy rates and the effectiveness of elagolix with respect to endometriosis-related pain.