Osilodrostat (LCI699) is a potent inhibitor of human 11β-hydroxylase and aldosterone synthase with IC50 values of 2.5 and 0.7 nM, respectively.
Osilodrostat and pasireotide monotherapies are associated with significant changes in the histology and mean weights of the pituitary and adrenal glands, liver, and ovary/oviduct. Osilodrostat alone is associated with adrenocortical hypertrophy and hepatocellular hypertrophy. In combination, osilodrostat/pasireotide does not exacerbate any target organ changes and ameliorated the liver and adrenal gland changes observed with monotherapy. Cmax and AUC0-24h of osilodrostat and pasireotide increase in an approximately dose-proportional manner[1]. Osilodrostat treatment reduces urinary free cortisol in patients with Cushing's disease; 78.9% has normal urinary free cortisol at week 22. Treatment with osilodrostat is generally well tolerated[2].
References:
[1]. Li L, et al. Osilodrostat (LCI699), a potent 11β-hydroxylase inhibitor, administered in combination with the multireceptor-targeted somatostatin analog pasireotide: A 13-week study in rats. Toxicol Appl Pharmacol. 2015 Aug 1;286(3):224-33.
[2]. Fleseriu M, et al. Osilodrostat, a potent oral 11β-hydroxylase inhibitor: 22-week, prospective, Phase II study in Cushing's disease. Pituitary. 2016 Apr;19(2):138-48.