Prazarelix is gonadorelin (GnRH) antagonist. It is primarily used in assisted reproduction to control ovulation. The drug works by blocking the action of GnRH upon the pituitary, thus rapidly suppressing the production and action of luteinizing hormone (LH) and follicle-stimulating hormone (FSH).

Ozarelix is a luteinizing hormone-releasing hormone (LHRH) antagonist. It is known that LHRH antagonist exerts rapid inhibition of luteinizing hormone and follicle stimulating hormone with an accompanying rapid decrease in sex hormones. Thus this inhibitor can be effective in a variety of hormonally dependent disease including prostate cancer, benign prostatic hyperplasia (BPH), and endometriosis. Ozarelix was developed for the treatment of all these diseases including Alzheimer's disease. However, in January 2010 Spectrum Pharmaceuticals announced that it was discontinuing development of ozarelix in BPH. Because the low-dose intermittent therapy was disappointing in the treatment of lower urinary tract symptoms in men with BPH. The development of the drug for Alzheimer's disease was also discontinued. Ozarelix completed phase II trials for the treatment of prostate cancer and is in preclinical trials for the treatment of endometriosis and ovarian cancer.

Detirelix is a synthetic decapeptide containing five D-amino acids. It is a very potent Gonadotropin-releasing hormone (GnHR) antagonist. The acute effects of detirelix were consistent with peripheral vasodilation. Subchronic effects were associated with inhibition of pituitary gonadotropic and gonadal hormone secretion. As long-acting GnRH antagonist detirelix can rapidly suppress gonadotropin secretion, inhibit follicular development, and prevent ovulation. It can be used as luteolytic agent. A projected use is for the treatment of sex hormone-releasing diseases, as part of anticancer hormone therapy of sex-hormone-dependent tumors.

Kintor Pharma is developing proxalutamide (developmental code GT-0918), an androgen receptor antagonist, for the treatment of metastatic castrate-resistant prostate cancer and AR-positive triple-negative breast cancer. Proxalutamide is involved in phase III clinical trials in China and in phase II in the USA for patients with metastatic castrate-resistant prostate cancer. In addition, the drug participates in phase I clinical trials for the treatment of AR-positive triple-negative breast cancer. Proxalutamide is expected to become a more effective, less toxic second-generation AR antagonist, which will have a bright prospect once it receives approval for coming on the market.

Ribuvaptan (BAY 868050) is a vasopressin receptor antagonist that has been developed for treatment of heart failure. No information on current use is available.

Seviteronel (VT-464) is a 17,20-lyase selective inhibitor of CYP17A1, which plays key roles in adrenal and intratumoral de novo biosynthesis of androgens. The inhibition of 17,20-lyase activity by seviteronel (VT-464) is enough to reduce androgen levels, and its preserving of 17alpha-hydroxylase activity largely avoids interference with the production of other steroidal hormones. Seviteronel (VT-464) also has shown AR-antagonist activity independent of CYP17 enzyme inhibition. It is currently in phase 2 clinical trials as a therapeutic for castration-resistant prostate cancer patients.

Vilaprisan, a small molecule progesterone receptor antagonist is being developed by Bayer HealthCare Pharmaceuticals (formerly Bayer Schering Pharma) for the treatment of endometriosis and uterine leiomyoma. Hormonal imbalance observed in women with endometriosis is a potential target for treating endometriosis. Vilaprisan is a highly selective steroidal progesterone receptor modulator (SPRM). It is a partial agonist of progesterone receptor, which means that the drug activates progesterone receptors to a certain degree upon binding. This triggers a cascade of biochemical reactions that result in the suppression of prostaglandin production. This, in turn, relieves symptoms such as pain and bleeding. Modulating progesterone by taking vilaprisan might help in treating endometriosis over the long term. Phase I and II studies give encouraging results on the efficacy of vilaprisan at different doses. Like other SPRMs, vilaprisan induces benign changes of endometrium (PR modulator-associated endometrial changes, PAECs). These disappear as treatment is discontinued. Unlike GnRHa treatment, neither UPA nor vilaprisan induce hypoestrogenism and associated symptoms. Phase III studies are ongoing to confirm efficacy and safety of vilaprisan in long-term treatment of symptomatic fibroids.

Lixivaptan is an orally-active, vasopressin 2 receptor antagonist. It is indicated for the treatment of symptomatic hypervolemic and euvolemic hyponatremia, associated with heart failure (HF) and syndrome of inappropriate antidiuretic hormone (SIADH). Adverse events likely to be result of the pharmacologic action of lixivaptan are: constipation, dry mouth, dizziness, insomnia. Grapefruit juice significantly increased the extent of lixivaptan absorption as compared to lixivaptan administered under fasted conditions but not under fed conditions. Lixivaptan Cmax and AUC∞ increased by 2.4-fold and 3.2-fold, respectively, when lixivaptan was administered with ketoconazole (the same in case of Simvastatin).