Elagolix Suppresses Ovulation in a Dose-Dependent Manner: Results From a 3-Month, Randomized Study in Ovulatory Women

David F. Archer, Juki Ng*, Kristof Chwalisz, Yi Lin Chiu, Eve C. Feinberg, Charles E. Miller, Robert A. Feldman, Cheri E. Klein

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

15 Scopus citations


Context: Elagolix is an oral gonadotropin-releasing hormone (GnRH) antagonist recently approved for the treatment of endometriosis-associated pain and being developed for heavy menstrual bleeding associated with uterine fibroids. Objective: The objective was to evaluate the effects of elagolix on ovulation and ovarian sex hormones. Design and Setting: This was a randomized, open-label, multicenter study. Participants: Participants were healthy ovulatory women aged 18 to 40 years. Interventions: Elagolix was administered orally for 3 continuous 28-day dosing intervals at 100 to 200 mg once daily (QD), 100 to 300 mg twice daily (BID), and 300 mg BID plus estradiol/norethindrone acetate (E2/NETA) 1/0.5 mg QD. Main Outcome Measures: The main outcomes measures were ovulation rates measured by transvaginal ultrasound, progesterone concentrations, and hormone suppression. Results: Elagolix suppressed ovulation in a dose-dependent manner. The percentage of women who ovulated was highest at 100 mg QD (78%), intermediate at 150 and 200 mg QD and 100 mg BID (47%-57%), and lowest at 200 and 300 mg BID (32% and 27%, respectively). Addition of E2/NETA to elagolix 300 mg BID further suppressed the ovulation rate to 10%. Elagolix also suppressed luteinizing hormone and follicle stimulating hormone in a dose-dependent manner, leading to dose-dependent suppression of estradiol and progesterone. Elagolix had no effect on serum biomarker of ovarian reserve, and reduced endometrial thickness compared to the screening cycle. Conclusion: Women being treated with elagolix may ovulate and should use effective methods of contraception. The rate of ovulation was lowest with elagolix 300 mg BID plus E2/NETA 1/0.5 mg QD.

Original languageEnglish (US)
Article numberdgz086
JournalJournal of Clinical Endocrinology and Metabolism
Issue number3
StatePublished - Jan 8 2020


  • GnRH antagonist
  • elagolix
  • endometrial thickness
  • ovarian reserve
  • ovulation
  • sex hormones

ASJC Scopus subject areas

  • Endocrinology, Diabetes and Metabolism
  • Biochemistry
  • Endocrinology
  • Clinical Biochemistry
  • Biochemistry, medical


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