Clinical data | |
---|---|
Other names | Oristusane; STX-64; 667-Coumate; BN-83495; STX-64PC |
Routes of administration | By mouth [1] |
Pharmacokinetic data | |
Elimination half-life | 24 hours [1] |
Identifiers | |
| |
CAS Number | |
PubChem CID | |
DrugBank | |
ChemSpider | |
UNII | |
KEGG | |
CompTox Dashboard (EPA) | |
Chemical and physical data | |
Formula | C14H15NO5S |
Molar mass | 309.34 g·mol−1 |
3D model (JSmol) | |
| |
|
Irosustat (INN , USAN ; developmental code names STX-64, 667-coumate, BN-83495; also known as oristusane) is an orally active, irreversible, nonsteroidal inhibitor of steroid sulfatase (STS) and member of the aryl sulfamate ester class of drugs [2] that was under development by Sterix Ltd and Ipsen for the treatment of hormone-sensitive cancers such as breast cancer, prostate cancer, and endometrial cancer but has not yet been marketed. [3] [1] The drug [4] [5] was first designed and synthesized in the group of Professor Barry V L Potter at the Department of Pharmacy & Pharmacology, University of Bath, working together with Professor Michael J. Reed at Imperial College, London and its initial development was undertaken through the university spin-out company Sterix Ltd and overseen by Cancer Research UK (CRUK). Results of the "first-in-class" clinical trial in breast cancer of an STS inhibitor in humans were published in 2006 [6] and dose optimisation studies and further clinical data have been reported. [7]
By inhibiting STS, irosustat prevents the conversion of hormonally inactive steroid sulfates such as DHEA sulfate (DHEA-S) and estrone sulfate (E1S) into their respective active forms, DHEA and estrone (which, in turn, can be transformed into more potent androgens and estrogens, respectively). [1]
The X-ray crystal structure of the drug bound to CAII has been determined. [8]
Despite Irosustat being quickly degraded in plasma ex vivo, this is prevented in vivo by its sequestration almost completely inside red blood cells after oral administration, being bound to carbonic anhydrase II (CA II) like its parent steroidal sulfamate ester E2MATE and thus avoiding first pass metabolism. [9]
In 2004 Sterix Ltd was acquired by Ipsen and Irosustat continued in development through formal academic-industry partnerships by Ipsen with the University of Bath and Imperial College. The drug reached phase II clinical trials in women with hormone-dependent breast cancer and endometrial cancer prior to the discontinuation of its initial development by Ipsen as a monotherapy for endometrial cancer in women with advanced/metastatic or recurrent estrogen-receptor positive endometrial cancer after a futility analysis of trial data. [3] [10] Results published in 2017 showed clinical activity and a good safety profile for Irosustat, with 36% of patients on Irosustat alive without progression at 6 months; 11% showed responses and there was more stable disease noted (47%) compared to the current therapy (32%), the progestin megestrol acetate (MA). [11] However, overall there were no statistically significant differences between Irosustat and the current standard of care MA in response and survival rates. It also reached a phase I trial in the US for prostate cancer, being safe and well tolerated in male patients with castration-resistant prostate cancer and ongoing androgen deprivation therapy. Pharmacodynamic proof of concept was demonstrated with Irosustat effecting nearly complete STS inhibition at three doses, and in all patients there was notable suppression of endocrine parameters. [12] The development of Irosustat has continued with clinical trials overseen by CRUK designed to explore its activity in early breast cancer (IPET trial) [13] and also in combination with an aromatase inhibitor (AI) (IRIS trial). [14] The multicentre IRIS trial, an open-label phase II clinical study, explored the clinical value of adding an STS inhibitor in addition to a first-line AI in patients with advanced breast cancer and enrolled postmenopausal women with ER+ locally advanced or metastatic breast cancer who had benefited from a first-line AI but were subsequently progressing. The IPET trial was a pre-surgical window-of-opportunity study, assessing Irosustat for the first time in ER+ early breast cancer and recruiting postmenopausal women with untreated early disease. Importantly, these data are the first to demonstrate clinical activity of Irosustat in early breast cancer, albeit in a small patient population. The results of both trials were published in 2017, showing evidence of clinical benefit and underpinning the scientific concept of STS inhibition. Larger studies are now required. Irosustat was also evaluated as a combination therapy with an oral epidermal growth factor receptor tyrosine kinase inhibitor for the treatment of Non-Small Cell Lung Cancer Patients. [15] Clinical development continues and the current status was reviewed in 2018. [16]
Administration of 5 mg/day irosustat to women with breast cancer for 5 days inhibited STS activity by 98 to 99% in breast tumor tissue and significantly decreased serum levels of estrone (by 76%), estradiol (by 39%), DHEA (by 41%), androstenediol (by 70%), androstenedione (by 62%), and testosterone (by 30%), whereas levels of DHEA-S and E1S increased slightly (by 1.1% and 7.4%, respectively). [1]
Importantly, it was demonstrated [17] that oral treatment with Irosustat alleviates the symptoms of Alzheimer’s Disease in a murine model, indicating that the drug passes the blood–brain barrier. STS inhibitors could therefore potentially be employed to treat aging and aging-associated diseases.[ citation needed ]
in patients.
Estrone (E1), also spelled oestrone, is a steroid, a weak estrogen, and a minor female sex hormone. It is one of three major endogenous estrogens, the others being estradiol and estriol. Estrone, as well as the other estrogens, are synthesized from cholesterol and secreted mainly from the gonads, though they can also be formed from adrenal androgens in adipose tissue. Relative to estradiol, both estrone and estriol have far weaker activity as estrogens. Estrone can be converted into estradiol, and serves mainly as a precursor or metabolic intermediate of estradiol. It is both a precursor and metabolite of estradiol.
2-Methoxyestradiol is a natural metabolite of estradiol and 2-hydroxyestradiol (2-OHE2). It is specifically the 2-methyl ether of 2-hydroxyestradiol. 2-Methoxyestradiol prevents the formation of new blood vessels that tumors need in order to grow (angiogenesis), hence it is an angiogenesis inhibitor. It also acts as a vasodilator and induces apoptosis in some cancer cell lines. 2-Methoxyestradiol is derived from estradiol, although it interacts poorly with the estrogen receptors. However, it retains activity as a high-affinity agonist of the G protein-coupled estrogen receptor (GPER).
Danazol, sold as Danocrine and other brand names, is a medication used in the treatment of endometriosis, fibrocystic breast disease, hereditary angioedema and other conditions. It is taken by mouth.
Tibolone, sold under the brand name Livial among others, is a medication which is used in menopausal hormone therapy and in the treatment of postmenopausal osteoporosis and endometriosis. The medication is available alone and is not formulated or used in combination with other medications. It is taken by mouth.
Steroid sulfatase (STS), or steryl-sulfatase, formerly known as arylsulfatase C, is a sulfatase enzyme involved in the metabolism of steroids. It is encoded by the STS gene.
Megestrol acetate (MGA), sold under the brand name Megace among others, is a progestin medication which is used mainly as an appetite stimulant to treat wasting syndromes such as cachexia. It is also used to treat breast cancer and endometrial cancer, and has been used in birth control. Megestrol acetate is generally formulated alone, although it has been combined with estrogens in birth control formulations. It is usually taken by mouth.
Dienogest, sold under the brand name Visanne among others, is a progestin medication which is used in birth control pills and in the treatment of endometriosis. It is also used in menopausal hormone therapy and to treat heavy periods. Dienogest is available both alone and in combination with estrogens. It is taken by mouth.
Estrone sulfate, also known as E1S, E1SO4 and estrone 3-sulfate, is a natural, endogenous steroid and an estrogen ester and conjugate.
Hormone replacement therapy (HRT), also known as menopausal hormone therapy or postmenopausal hormone therapy, is a form of hormone therapy used to treat symptoms associated with female menopause. Effects of menopause can include symptoms such as hot flashes, accelerated skin aging, vaginal dryness, decreased muscle mass, and complications such as osteoporosis, sexual dysfunction, and vaginal atrophy. They are mostly caused by low levels of female sex hormones that occur during menopause.
Michael J. Reed was a British chemist who held the position of professor of steroid biochemistry at Imperial College, London.
A steroidogenesis inhibitor, also known as a steroid biosynthesis inhibitor, is a type of drug which inhibits one or more of the enzymes that are involved in the process of steroidogenesis, the biosynthesis of endogenous steroids and steroid hormones. They may inhibit the production of cholesterol and other sterols, sex steroids such as androgens, estrogens, and progestogens, corticosteroids such as glucocorticoids and mineralocorticoids, and neurosteroids. They are used in the treatment of a variety of medical conditions that depend on endogenous steroids.
Estradiol sulfamate, or estradiol-3-O-sulfamate, is a steroid sulfatase (STS) inhibitor which is under development for the treatment of endometriosis. It is the C3 sulfamate ester of estradiol, and was originally thought to be a prodrug of estradiol.
Estrone sulfamate, or estrone-3-O-sulfamate, is a steroid sulfatase (STS) inhibitor which has not yet been marketed. It is the C3 sulfamate ester of the estrogen estrone. Unlike other estrogen esters however, EMATE is not an effective prodrug of estrogens. A closely related compound is estradiol sulfamate (E2MATE), which is extensively metabolized into EMATE and has similar properties to it.
EC508, also known as estradiol 17β-(1- -L-proline), is an estrogen which is under development by Evestra for use in menopausal hormone therapy and as a hormonal contraceptive for the prevention of pregnancy in women. It is an orally active estrogen ester – specifically, a C17β sulfonamide–proline ester of the natural and bioidentical estrogen estradiol – and acts as a prodrug of estradiol in the body. However, unlike oral estradiol and conventional oral estradiol esters such as estradiol valerate, EC508 undergoes little or no first-pass metabolism, has high oral bioavailability, and does not have disproportionate estrogenic effects in the liver. As such, it has a variety of desirable advantages over oral estradiol, similarly to parenteral estradiol, but with the convenience of oral administration. EC508 is a candidate with the potential to replace not only oral estradiol in clinical practice, but also ethinylestradiol in oral contraceptives. Evestra intends to seek Investigational New Drug status for EC508 in the second quarter of 2018.
Estriol sulfamate, or estriol 3-O-sulfamate, is a synthetic estrogen and estrogen ester which was never marketed. It is the C3 sulfamate ester of estriol. The drug shows substantially improved oral estrogenic potency relative to estriol in rats but without an increase in hepatic estrogenic potency. However, the closely related compound estradiol sulfamate (E2MATE) failed to show estrogenic activity in humans, which is due to the fact that it is additionally a highly potent inhibitor of steroid sulfatase which regulates the estrogenicity of such compounds and thus it prevents its own bioactivation into estradiol.
The pharmacology of estradiol, an estrogen medication and naturally occurring steroid hormone, concerns its pharmacodynamics, pharmacokinetics, and various routes of administration.
Barry Victor Lloyd Potter MAE FMedSci is a British chemist, who is Professor of Medicinal & Biological Chemistry at the University of Oxford, Wellcome Trust Senior Investigator and a Fellow of University College, Oxford.
2-Methoxyestradiol disulfamate is a synthetic, oral active anti-cancer medication which was previously under development for potential clinical use. It has improved potency, low metabolism, and good pharmacokinetic properties relative to 2-methoxyestradiol (2-MeO-E2). It is also a potent inhibitor of steroid sulfatase, the enzyme that catalyzes the desulfation of steroids such as estrone sulfate and dehydroepiandrosterone sulfate (DHEA-S).
Linustedastat is a 17β-hydroxysteroid dehydrogenase 1 inhibitor which is under development for the treatment of endometriosis. It is a steroidal compound derived from estrone and works by preventing the formation of the more potent estrogen estradiol from the minimally active precursor estrone. This in turn results in antiestrogenic effects that may be useful in the treatment of estrogen-dependent conditions. As of November 2023, the drug is in phase 2 clinical trials for endometriosis. It is also under preclinical investigation for treatment of breast cancer and endometrial cancer.