Osilodrostat

Osilodrostat is an inhibitor of 11β-hydroxylase (also referred to as CYP11B1), the enzyme that catalyzes the final step in the biosynthesis of endogenous cortisol. It is used to lower circulating cortisol levels in the treatment of Cushing's disease, a disorder in which cortisol levels are chronically and supraphysiologically elevated. Cushing's disease is often the result of ACTH hypersecretion secondary to a pituitary tumor, and surgical resection of the tumour is generally the treatment of choice. As an orally bioavailable drug therapy, osilodrostat provides a novel treatment option for patients in whom removal of the causative tumor is not an option or for whom previous pituitary surgery has not been curative. Osilodrostat is manufactured by Novartis under the brand name Isturisa. It has undergone phase II clinical trials for the treatment of solid tumours, hypertension, and heart failure, but development for these indications was discontinued by Novartis in January 2013. Osilodrostat was approved for use in the EU in January 2020 for the treatment of endogenous Cushing's syndrome (i.e. Cushing's disease), and was granted FDA approval and Orphan Drug designation in the US in March 2020 for the same indication.