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Emerging and Ongoing Medication Research for Endometriosis

Scientists are studying several potential new drugs for the treatment of endometriosis-related symptoms.

Relugolix

Relugolix is a Gn-RH antagonist in development. It works in a similar way to the drug elagolix (Orlissa). It quickly lowers the two most common hormones circulating in women: luteinizing hormone (LH) and follicle-stimulating hormone (FSH). In turn, this lowers estrogen in women.

Relugolix is a pill taken once a day. Current Gn-RH antagonists often result in a temporary increase in hormone levels including estrogen.

Gn-RH antagonists make the Gn-RH receptors in the pituitary gland less effective. This happens when a receptor gets activated so many times that it eventually stops working. So, at first, Gn-RH antagonists create a surge in these Gn-RH receptor-related hormones. Then, as the drug is overloads the receptors, the receptors begin to shut off and hormone levels drop dramatically. After that initial surge, the symptoms that the drug is supposed to control, such as pelvic pain, may increase. Scientists hope that relugolix could decrease that first increase in estrogen levels.

The SPIRIT 2 clinical trials of relugolix by Myovant Sciences continue. Relugolix is also being studied as a treatment for uterine fibroids and prostate cancer.1-4

Linzagolix

Linzagolix is an experimental oral drug made manufactured by ObsEva. Scientists believe that it eases the pain of endometriosis and uterine fibroids.

Like Orlissa and relugolix, it is a Gn-RH antagonist. It works by stopping GnRH in the pituitary gland from binding to its receptors. This lowers estrogen levels. Its creators also hope that linzagolix will lower the initial hormonal surge other treatments cause, which also cause more pain.

Researchers are studying how well linzagolix works at low and high doses. If results are good, dosing will be tailored to individual needs. This could reduce the chances of side effects, and reduce the need for another drug to counter side effects such as bone loss or high cholesterol.

Linzagolix is being studied in two Phase 3 clinical trials.5-6

Aromatase inhibitors

Aromatase inhibitors decrease levels of estrogen in the bod. These drugs are used by post-menopausal women with some forms of breast cancer. It is not FDA-approved for endometriosis, but some doctors have begun prescribing it for the condition. Data on its effectiveness in relieving endometriosis symptoms is not strong at this time. More studies are underway to see if endometriosis should be added to the list of uses for aromatase inhibitors. Clinical trials are required to get FDA approval for additional uses.7-8

This is not an exhaustive list of all the drug research for endometriosis. Ask your healthcare team about any new medications as well as any clinical trials available in your area that might be right for you.

Written by: Casey Hribar | Last reviewed: July 2019
  1. SPIRIT 2: Efficacy and Safety of Relugolix in Women with Endometriosis-Associated Pain. National Institutes of Health: U.S. National Library of Medicine. ClinicalTrials.gov. https://clinicaltrials.gov/ct2/show/NCT03204331?recrs=ad&cond=endometriosis&phase=2&rank=5. Updated April 3, 2018. Accessed May 1, 2018.
  2. Relugolix. Available at: https://endometriosisnews.com/relugolix/. Accessed 2.26.19
  3. SPIRIT 2: Efficacy and Safety Study of Relugolix in Women With Endometriosis-Associated Pain. Available at: https://www.centerwatch.com/clinical-trials/listings/121654/endometriosis-related-pain-spirit-2-efficacy-safety/. Accessed 2.27.19
  4. How It Works. Available at: http://myovant.com/relugolix. Accessed 2.27.19
  5. Linzagolix. Available at: http://www.obseva.com/pipeline/obe2109. Acccessed 2.26.19
  6. Linzagolix (OBE2109). Available at: https://endometriosisnews.com/obe2109/. Accessed 2.27.19
  7. Endometriosis: Should I Use Hormone Therapy? Michigan Medicine: University of Michigan. https://www.uofmhealth.org/health-library/tv7240. Published October 6, 2017. Accessed May 1, 2018.
  8. Bulun S, Wood R. Aromatase in Endometriosis. Endometriosis.org. http://endometriosis.org/resources/articles/aromatase/. Accessed May 1, 2018.