How it Works
Relugolix is an oral, once-daily, gonadotropin-releasing hormone (GnRH) receptor antagonist. By inhibiting GnRH receptors in the anterior pituitary gland, relugolix rapidly reduces the circulating gonadotropins luteinizing hormone (LH) and follicle-stimulating hormone (FSH), leading to the suppression of estrogen in women and testosterone in men. Suppression of these hormones improves the symptoms of uterine fibroids and endometriosis in women and decreases prostate-specific antigen (PSA) levels in men with advanced prostate cancer.
Relugolix Clinical Study Results for the Treatment of Uterine Fibroids
In a double-blind, placebo-controlled Phase 2 clinical trial in 216 patients with uterine fibroids, women who received relugolix experienced a statistically significant reduction in menorrhagia, or heavy menstrual bleeding.
In a double-blind non-inferiority Phase 3 study conducted by Takeda in Japan to evaluate the efficacy and safety of relugolix in women with heavy menstrual bleeding associated with uterine fibroids, relugolix was statistically non-inferior to leuprorelin (p = 0.0013) meeting the study’s primary endpoint, the proportion of patients achieving a pre-defined reduction in menstrual bleeding.
In a randomized, double-blind placebo-controlled Phase 3 study conducted in Japan to evaluate the efficacy and safety of Relugolix in the treatment of pain symptoms associated with uterine fibroids compared to placebo, Relugolix met the primary endpoint with 57.6% of women treated with Relugolix demonstrating a marked improvement in pain symptoms.
Relugolix Clinical Study Results for the Treatment of Endometriosis
In a double-blind, placebo-controlled Phase 2 clinical trial in 487 patients with endometriosis, women who received relugolix experienced statistically significant reductions in non-menstrual and menstrual pelvic pain.
Relugolix Clinical Study Results for the Treatment of Advanced Prostate Cancer
In two randomized Phase 2 studies in approximately 228 men with advanced prostate cancer, oral once-daily relugolix suppressed serum testosterone to castrate levels and decreased PSA.
Unlike GnRH agonists, Relugolix does not cause transient increases in gonadotropin secretion (flare), which can result in an initial worsening of clinical symptoms. Moreover, upon treatment discontinuation, its effects diminish quickly and hormone levels rapidly return to baseline. We believe Relugolix, when co-administered with low-dose estrogen and progesterone add-back therapy, will preserve bone mineral density in women and increase tolerability.