Isturisa (osilodrostat) oral tablets have been approved in the US for adults with Cushing’s disease who either cannot undergo pituitary gland surgery or have undergone the surgery but still have the disease.
Cushing’s disease is a rare disease in which the adrenal glands make too much of the cortisol hormone.
Made by Novartis, Isturisa is the first FDA-approved drug to directly address this cortisol overproduction by blocking the enzyme known as 11-beta-hydroxylase and preventing cortisol synthesis.
Isturisa’s safety and effectiveness for treating Cushing’s disease among adults was evaluated in a study of 137 adult patients (about three-quarters women) with a mean age of 41 years.
The majority of patients either had undergone pituitary surgery that did not cure Cushing’s disease or were not surgical candidates.
In the 24-week, single-arm, open-label period, all patients received a starting dose of 2 mg of Isturisa twice a day that could be increased every two weeks up to 30 mg twice a day. At the end of this 24-week period, about half of patients had cortisol levels within normal limits.
After this point, 71 patients who did not need further dose increases and tolerated the drug for the last 12 weeks entered an eight-week, double-blind, randomized withdrawal study where they either received Isturisa or a placebo (inactive treatment).
At the end of this withdrawal period, 86% of patients receiving Isturisa maintained cortisol levels within normal limits compared to 30% of patients taking the placebo.
Made by Novartis, Isturisa received Orphan Drug Designation.