Irosustat

Irosustat (also known as STX64 and MIN-116) is a potent and selective inhibitor of the enzyme steroid sulfatase (STS). STS, also known as estrogen sulfatase, is an enzyme responsible for hydrolyzing sulfated steroids, such as estrone sulfate and dehydroepiandrosterone sulfate (DHEAS), to their active, non-sulfated forms, estrone (E1) and dehydroepiandrosterone (DHEA) respectively. By inhibiting STS, irosustat reduces the levels of active estrogens and androgens in tissues, particularly within hormone-dependent tumors.

Irosustat has been investigated as a potential treatment for hormone-sensitive cancers, including breast cancer, prostate cancer, and endometrial cancer. Its mechanism of action targets the local production of steroid hormones within the tumor microenvironment, potentially circumventing resistance mechanisms that may develop with other endocrine therapies like aromatase inhibitors or anti-androgens, which primarily target systemic hormone production or receptor binding.

Clinical trials have explored irosustat both as a monotherapy and in combination with other anticancer agents. Research has focused on assessing its efficacy, safety, and pharmacokinetic profile in different patient populations with hormone-dependent malignancies. While some promising results have been observed, the drug is not currently approved for clinical use and is still under investigation.