Relugolix (TAK-385) is an orally active nonpeptide gonadotropin-releasing hormone (GnRH) that binds to human GnRH receptors with subnanomolar affinity. Relugolix was demonstrated to act as a classic competitive antagonist of GnRH binding, but the exact molecular mechanism of that antagonism remains unknown. This drug is being developed as a treatment for various sex hormone related disorders. Based on the phase III HERO trial results, relugolix (Orgovyx) received Food and Drug Administration approval for adult patients with advanced prostate cancer. An oral fixed-dose combination of relugolix/estradiol/norethisterone (also known as norethindrone) acetate (Ryeqo®; Myfembree®) has been approved for the management of heavy menstrual bleeding associated with uterine fibroids in the USA and management of moderate to severe symptoms of uterine fibroids in the EU.

Elagolix (ABT-620) is an oral gonadotropin-releasing hormone antagonist being studied for the treatment of endometriosis and uterine fibroids. The U.S. Food and Drug Administration (FDA) approved AbbVie's elagolix under the brand name Orilissa as the first and only oral gonadotropin-releasing hormone (GnRH) antagonist specifically developed for women with moderate to severe endometriosis pain.

DEGARELIX (FIRMAGON®) is a synthetic linear decapeptide amide containing seven unnatural amino acids, five of which are D-amino acids. It is a GnRH receptor antagonist. It binds reversibly to the pituitary GnRH receptors, thereby reducing the release of gonadotropins and consequently testosterone. DEGARELIX (FIRMAGON®) is effective in achieving and maintaining testosterone suppression below the castration level of 50 ng/dL and is indicated for the treatment of patients with advanced prostate cancer.

Cetrorelix is a synthetic decapeptide with gonadotropin-releasing hormone (GnRH) antagonistic activity. GnRH induces the production and release of luteinizing hormone (LH) and follicle stimulating hormone (FSH) from the gonadotrophic cells of the anterior pituitary. Due to a positive estradiol (E2) feedback at midcycle, GnRH liberation is enhanced resulting in an LH-surge. This LH-surge induces the ovulation of the dominant follicle, resumption of oocyte meiosis and subsequently luteinization as indicated by rising progesterone levels. Cetrorelix competes with natural GnRH for binding to membrane receptors on pituitary cells and thus controls the release of LH and FSH in a dose-dependent manner. Cetrorelix binds to the gonadotropin releasing hormone receptor and acts as a potent inhibitor of gonadotropin secretion. It competes with natural GnRH for binding to membrane receptors on pituitary cells and thus controls the release of LH and FSH in a dose-dependent manner. Cetrorelix is marketed primarily under the brand name Cetrotide. Cetrotide (cetrorelix acetate for injection) is indicated for the inhibition of premature LH surges in women undergoing controlled ovarian stimulation.

Ganirelix (N-acetyl-3-(2-naphthyl)-D-alanyl-4-chloro-D-phenylalanyl-3-(3-pyridyl)-D-alanyl-L-seryl-L-tyrosyl-N9 ,N10-diethyl-D-homoarginyl-L-leucylN9 ,N10-diethyl-L-homoarginyl-L-prolyl-D-acrylamide) is a synthetic decapeptide with high antagonistic activity against naturally occurring gonadotropin-releasing hormone (GnRH). Ganirelix Acetate Injection is indicated for the inhibition of premature luteinizing hormone (LH) surges in women undergoing controlled ovarian hyperstimulation. Ganirelix is administered by a subcutaneous injection of 250 µg once per day during the mid to late follicular phase of a woman’s menstrual cycle. Treatment should start on the 5th or 6th day after the start of ovarian stimulation, and the mean duration of its use is five days. Clinical studies have shown that the most common side effect is a slight reaction at the site of injection in the form of redness, and sometimes swelling. Clinical studies have shown that, one hour after injection, the incidence of at least one moderate or severe local skin reaction per treatment cycle was 12% in 4 patients treated with Ganirelix and 25% in patients treated subcutaneously with a GnRH agonist. The local reactions generally disappear within 4 hours after administration. Other reported side effects are some that are known to be associated with ovarian hyperstimulation, including gynecological abdominal pain, headache, vaginal bleeding, nausea, and gastrointestinal abdominal pain.

Histrelin is a gonadotropin releasing hormone (GnRH) agonist that acts as a potent inhibitor of gonadotropin when administered as an implant that delivers continuous therapeutic doses. Following an initial stimulatory phase with increased circulating levels of luteinizing hormone (LH) and follicle-stimulating hormone (FSH), leading to a transient increase in concentration of gonadal steroids (testosterone and dihydrotestosterone in males), continuous administration of histrelin acetate results in decreased levels of LH and FSH due to a reversible down-regulation of the GnRH receptors in the pituitary gland and desensitization of the pituitary gonadotropes. As the product Supprelin LA (FDA), histrelin is indicated for the treatment of children with central precocious puberty (CPP). As the product Vantas (FDA), histrelin is indicated for the palliative treatment of advanced prostate cancer.

Nafarelin acetate (brand name Synarel) is a synthetic agonist of gonadotrophin-releasing hormone (GnRH) [luteinising hormone-releasing hormone (LH-RH), which is indicated for management of endometriosis, including pain relief and reduction of endometriotic lesions and for the treatment of central precocious puberty (CPP). Nafarelin has also been used effectively in in vitro fertilisation programmes, and in hirsute women and those with uterine leiomyoma, particularly to induce preoperative fibroid shrinkage. Side effects are related to the low estrogen state and include hot flashes, vaginal dryness, headaches, mood changes, and decreased interest in sex.

Goserelin is a synthetic decapeptide analogue of LHRH. Goserelin acts as a potent inhibitor of pituitary gonadotropin secretion when administered in the biodegradable formulation. The result is sustained suppression of LH and serum testosterone levels. Goserelin is used to treat hormone-sensitive cancers of the breast (in pre- and peri- menopausal women) and prostate, and some benign gynaecological disorders (endometriosis, uterine fibroids and endometrial thinning). In addition, goserelin is used in assisted reproduction and in the treatment of precocious puberty. Goserelin is marketed under the brand names Zoladex, by AstraZeneca, or goserelin acetate.

Leuprolide acetate is a synthetic nonapeptide analog of naturally occurring gonadotropin-releasing hormone (GnRH or LH-RH). The analog possesses greater potency than the natural hormone. It acts primarily on the anterior pituitary, inducing a transient early rise in gonadotrophin release. With continued use, leuprorelin causes pituitary desensitisation and/or down-regulation, leading to suppressed circulating levels of gonadotrophins and sex hormones. Leuprolide acetate used to treat a wide range of sex hormone-related disorders including advanced prostatic cancer, uterine leiomyomata (fibroids), endometriosis and precocious puberty.

Sufugolix (TAK-013 or 5-(N-benzyl-N-methylaminomethyl)-1-(2,6-difluorobenzyl)-6-[4-(3-methoxyureido)phenyl]-3-phenylthieno[2,3-d]pyrimidine-2,4(1H,3H)-dione) is a highly potent and orally active non-peptide antagonist of luteinizing hormone-releasing hormone (LHRH) receptor. Sufugolix by oral administration suppresses a pituitary-ovarian axis continuously and reversibly in cynomolgus monkeys. Takeda studied Sufugolix in the trials for the treatment of endometriosis and uterine leiomyoma however development was discontinued.