Osilodrostat (INN, USAN) (developmental code name LCI-699) is an orally active, non-steroidal corticosteroid biosynthesis inhibitor which is under development by Novartis for the treatment of Cushing's syndrome and pituitary ACTH hypersecretion (a specific subtype of Cushing's syndrome). Osilodrostat specifically acts as a potent and selective inhibitor of aldosterone synthase (CYP11B2) and at higher dosages of 11β-hydroxylase (CYP11B1). Osilodrostat decreases plasma and urinary aldosterone levels and rapidly corrects hypokalemia, in patients with primary aldosteronism and hypertension. At doses ≥1 mg o.d. Osilodrostat markedly increases 11-deoxycortisol plasma levels and blunts ACTH-stimulated cortisol release in ≈20% of patients, consistent with the inhibition of CYP11B1. In patients with resistant hypertension, Osilodrostat produces a non-significant reduction in blood pressure, possibly due to the increase in 11-deoxycortisol levels and the stimulation of the hypothalamic-pituitary-adrenal feedback axis. Because of the lack of selectivity, poor antihypertensive effect, and short half-life, the development of Osilodrostat as antihypertensive was halted. As of 2017, Osilodrostat is in phase III and phase II clinical trials for the treatment of pituitary ACTH hypersecretion and Cushing's syndrome, respectively.

Pasireotide is a synthetic long-acting cyclic hexapeptide with somatostatin-like activity. It is marketed as a diaspartate salt called Signifor, indicated for the treatment of adult patients with Cushing’s disease for whom pituitary surgery is not an option or has not been curative. SIGNIFOR is an injectable cyclohexapeptide somatostatin analogue. Pasireotide exerts its pharmacological activity via binding to somatostatin receptors (ssts). Pasireotide binds and activates the hsst receptors resulting in inhibition of ACTH secretion, which leads to decreased cortisol secretion.

Ketoconazole is an azole antifungal. Ketoconazole was the first broad-spectrum oral antifungal agent available to treat systemic and superficial mycoses. Evidence of hepatotoxicity associated with its use emerged within the first few years of its approval. Due to its hepatotoxic side effects, oral ketoconazole was withdrawn from the European and Australian markets in 2013. The United States imposed strict relabeling requirements and restrictions for prescription, with Canada issuing a risk communication echoing these concerns. Today, oral ketoconazole is only indicated for endemic mycoses, where alternatives are not available or feasible. Meanwhile, topical ketoconazole is effective, safe, and widely prescribed for superficial mycoses, particularly as the first-line treatment for tinea versicolor. Topically administered ketoconazole is usually prescribed for fungal infections of the skin and mucous membranes, such as athlete's foot, ringworm, candidiasis (yeast infection or thrush), jock itch, and tinea versicolor. Topical ketoconazole is also used as a treatment for dandruff (seborrheic dermatitis of the scalp) and for seborrheic dermatitis on other areas of the body, perhaps acting in these conditions by suppressing levels of the fungus Malassezia furfur on the skin. Ketoconazole interacts with 14-α demethylase, a cytochrome P-450 enzyme necessary for the conversion of lanosterol to ergosterol. This results in inhibition of ergosterol synthesis and increased fungal cellular permeability. Other mechanisms may involve the inhibition of endogenous respiration, interaction with membrane phospholipids, inhibition of yeast transformation to mycelial forms, inhibition of purine uptake, and impairment of triglyceride and/or phospholipid biosynthesis. Ketoconazole can also inhibit the synthesis of thromboxane and sterols such as aldosterone, cortisol, and testosterone. Ketoconazole is active against clinical infections with Blastomyces dermatitidis, Coccidioides immitis, Histoplasma capsulatum, Paracoccidioides brasiliensis.

Seliciclib (CYC202, R-roscovitine) is a second-generation orally available cyclin-dependent kinases (CDKs) inhibitor that competes for ATP binding sites on these kinases. It is a direct inhibitor of cyclin CDK2/E, CDK2/A and it has inhibitory effects on cyclin H/CDK7, CDK5, and CDK9. CDKs are enzymes that are central to the process of cell division and cell cycle control and play pivotal roles in cancer cell growth and DNA damage repair. Seliciclib exerts an anti-proliferative effect via several key mechanisms: selective downregulation of proliferative and survival proteins and upregulation of p53, leading to growth arrest or apoptosis. The second one is decreasing phosphorylation of Rb and modulating E2F transcriptional activity leading to growth arrest or apoptosis. Seliciclib is currently in phase II clinical trial as a drug candidate for the treatment of Cushing's disease and as a potential therapeutic agent for the treatment of cystic fibrosis (CF). In addition, it is in Phase II trials for non-small cell lung cancer and nasopharyngeal carcinoma.

Ritanserin (INN, USAN, BAN) is a serotonin receptor antagonist which was never marketed for clinical use but has been used in scientific research. In humans, ritanserin increases deep slow-wave sleep, improved liveliness in a variety of psychiatric disorders and facilitated participation in behaviour therapy. During clinical trials, unexpected observations indicated that ritanserin may be of value in treating obsessive-compulsive disorder, acute mania, negative symptoms of schizophrenia, drug addicts, etc. Clinical observations confirmed the efficacy of ritanserin in the chronic withdrawal phase after detoxification from ethanol. Ritanserin had been in phase III clinical trials by Janssen L.P. for the treatment of anxiety disorder and major depressive disorder. However, the clinical development of ritanserin was discontinued.

HX630 is a synthetic RXR pan-agonist. HX-630 has bein shown to exert anti-proliferative and pro-apoptotic effects in murine pituitary corticotroph tumor AtT20 cells, making HX-630 a new therapeutic candidate for Cushing’s disease. It might also serve as potential pharmacological tool for treating retina degenerative diseases and Alzheimer's disease.

Trilostane is a synthetic steroid, which interferes with the formation of both cortisol and aldosterone. It is an inhibitor of 3 beta-hydroxysteroid dehydrogenase. This drug under trade name MODRASTANE was withdrawn from human use in the United States market. But marketed under the trade names Modrenal and is already approved in the United Kingdom for the treatment of advanced post-menopausal breast cancer and Cushing 's disease. In addition, this drug has been successfully developed and marketed for veterinary use in the United Kingdom under the trade name Vetoryl.

Aminoglutethimide, marketing as Cytadren has been used in the treatment of advanced breast and prostate cancer. It was formerly used for its weak anticonvulsant properties. Cytadren is indicated for the suppression of adrenal function in selected patients with Cushing’s syndrome. Morning levels of plasma cortisol in patients with adrenal carcinoma and ectopic ACTH producing tumors were reduced on the average to about one half of the pretreatment levels, and in patients with adrenal hyperplasia to about two thirds of the pretreatment levels, during 1-3 months of therapy with Cytadren. Data available from the few patients with adrenal adenoma suggest similar reductions in plasma cortisol levels. Measurements of plasma cortisol showed reductions to at least 50% of baseline or to normal levels in one third or more of the patients studied, depending on diagnostic groups and time of measurement. Because Cytadren does not affect the underlying disease process, it is used primarily as an interim measure until more definitive therapy such as surgery can be undertaken or in cases where such therapy is not appropriate. Only small numbers of patients have been treated for longer than 3 months. A decreased effect or “escape phenomenon” seems to occur more frequently in patients with pituitary dependent Cushing’s syndrome, probably because of increasing ACTH levels in response to decreasing glucocorticoid levels. Cytadren blocks several other steps in steroid synthesis, including the C-11, C-18, and C-21 hydroxylations and the hydroxylations required for the aromatization of androgens to estrogens, mediated through the binding of Cytadren to cytochrome P-450 complexes. A decrease in adrenal secretion of cortisol is followed by an increased secretion of pituitary adrenocorticotropic hormone (ACTH), which will overcome the blockade of adrenocortical steroid synthesis by Cytadren. The compensatory increase in ACTH secretion can be suppressed by the simultaneous administration of hydrocortisone. Since Cytadren increases the rate of metabolism of dexamethasone but not that of hydrocortisone, the latter is preferred as the adrenal glucocorticoid replacement. Although Cytadren inhibits the synthesis of thyroxine by the thyroid gland, the compensatory increase in thyroid-stimulating hormone (TSH) is frequently of sufficient magnitude to overcome the inhibition of thyroid synthesis due to Cytadren. In spite of an increase in TSH, Cytadren has not been associated with increased prolactin secretion. At low doses, aminogluthethimide is only an effective inhibitor of aromatase (Cytochrome P450 11A1), but at higher doses, it effectively blocks Cytochrome P450 11A1 (P450scc) as well. Citadel was marketed previously as an anticonvulsant but was withdrawn from marketing for that indication in 1966 because of the effects on the adrenal gland.

Osilodrostat (INN, USAN) (developmental code name LCI-699) is an orally active, non-steroidal corticosteroid biosynthesis inhibitor which is under development by Novartis for the treatment of Cushing's syndrome and pituitary ACTH hypersecretion (a specific subtype of Cushing's syndrome). Osilodrostat specifically acts as a potent and selective inhibitor of aldosterone synthase (CYP11B2) and at higher dosages of 11β-hydroxylase (CYP11B1). Osilodrostat decreases plasma and urinary aldosterone levels and rapidly corrects hypokalemia, in patients with primary aldosteronism and hypertension. At doses ≥1 mg o.d. Osilodrostat markedly increases 11-deoxycortisol plasma levels and blunts ACTH-stimulated cortisol release in ≈20% of patients, consistent with the inhibition of CYP11B1. In patients with resistant hypertension, Osilodrostat produces a non-significant reduction in blood pressure, possibly due to the increase in 11-deoxycortisol levels and the stimulation of the hypothalamic-pituitary-adrenal feedback axis. Because of the lack of selectivity, poor antihypertensive effect, and short half-life, the development of Osilodrostat as antihypertensive was halted. As of 2017, Osilodrostat is in phase III and phase II clinical trials for the treatment of pituitary ACTH hypersecretion and Cushing's syndrome, respectively.

Pasireotide is a synthetic long-acting cyclic hexapeptide with somatostatin-like activity. It is marketed as a diaspartate salt called Signifor, indicated for the treatment of adult patients with Cushing’s disease for whom pituitary surgery is not an option or has not been curative. SIGNIFOR is an injectable cyclohexapeptide somatostatin analogue. Pasireotide exerts its pharmacological activity via binding to somatostatin receptors (ssts). Pasireotide binds and activates the hsst receptors resulting in inhibition of ACTH secretion, which leads to decreased cortisol secretion.