Relugolix, sold under the brand names Orgovyx and Relumina and as one component of Myfembree, is a gonadotropin-releasing hormone antagonist (GnRH receptor antagonist) medication which is used in the treatment of prostate cancer in men and uterine fibroids in women. It is also under development for use in the treatment of endometriosis. It is taken by mouth once per day.Side effects of relugolix include menstrual abnormalities, hot flashes, excessive sweating, headache, and decreased bone mineral density. Relugolix is a GnRH antagonist, or an antagonist of the gonadotropin-releasing hormone receptor. Unlike most other GnRH modulators, but similarly to elagolix (brand name Orilissa), relugolix is a non-peptide, small-molecule compound and is orally active. It suppresses sex hormone levels to the postmenopausal or castrate range in both women and men with administration once per day.As of February 2019, relugolix is in phase III clinical trials for endometriosis. It was approved for use for the treatment of uterine fibroids in Japan in January 2019, and for the treatment of prostate cancer in the United States in December 2020. Medical uses
Relugolix is approved in the United States for the treatment of prostate cancer in men and in Japan for the treatment of uterine fibroids (uterine leiomyoma) in women. It is used at a dosage of 120 mg once daily by mouth in the treatment of prostate cancer (after a single 360 mg loading dose on the first day of therapy) and at a dosage of 40 mg once daily in the treatment of uterine fibroids.
Available forms
Relugolix is available in the form of 40 and 120 mg oral tablets. Side effects
The main side effects of relugolix for uterine fibroids include abnormal uterine bleeding (24.6–48.6% vs. 6.3% for placebo), hot flashes (42.8–45.5% vs. 0% for placebo), heavy menstrual bleeding (12.1–49.3% vs. 9.4% for placebo), headache (12.3–15.2%), and excessive sweating (9.4–15.2% vs. 0% for placebo). In addition, decreased bone mineral density occurs with relugolix (21.7% decrease by week 12, 24.4% decrease by week 24). Pharmacology
Pharmacodynamics
Relugolix is a selective antagonist of the gonadotropin-releasing hormone receptor (GnRHR), with a half-maximal inhibitory concentration (IC50) of 0.12 nM.A dosage of relugolix of 40 mg once per day has been found to suppress estradiol levels to postmenopausal levels (<20 pg/mL) within 24 hours in premenopausal women. In the control group of women, estradiol levels fluctuated between 50 and 250 pg/mL. Estradiol levels have been found to return to normal concentrations within 4 weeks of discontinuation of relugolix in premenopausal women. The medication additionally suppresses levels of progesterone, luteinizing hormone, and follicle-stimulating hormone in premenopausal women. Relugolix at a dosage of 40 mg or more once per day has been found to reduce testosterone levels to sustained castrate levels (<20 ng/dL) in men. It additionally suppresses luteinizing hormone and follicle-stimulating hormone levels in men.Lower doses of relugolix (<40 mg/day) are under investigation for achieving partial sex hormone suppression in the treatment of endometriosis and uterine fibroids.