Osilodrostat Gets FDA Go-Ahead for Cushing's Disease in Adults

Renee Matthews


March 09, 2020

The Food and Drug Administration has approved the oral cortisol synthesis inhibitor osilodrostat (Isturisa) for the nonsurgical treatment of adults with Cushing's disease who either are not good candidates for pituitary gland surgery ― the recommended first-line therapy ― or in whom the disease persists after surgery.

Cushing's disease is a rare condition caused when a pituitary tumor releases too much of the hormone adrenocorticotropin, which in turn, triggers the adrenal gland to overproduce cortisol. The condition is associated with serious health complications, including high blood pressure, obesity, type 2 diabetes, and compromised immunity.

Osilodrostat is the first therapy approved by the FDA to tackle the overproduction of cortisol, which it does by blocking the 11-beta-hydroxylase enzyme and thus preventing cortisol synthesis, the agency said in a press release.

In November 2019, the European Medicines Agency recommended the granting of a marketing authorization for osilodrostat, also for treating adults with Cushing's disease.

The U.S. approval was based on outcomes from a study that evaluated the drug's safety and efficacy in 137 adults with Cushing's disease who had undergone pituitary surgery but were not cured, or who were not surgical candidates, according the release. About three-quarters of the patients were women, and the mean age was 41 years.

All of the patients started a 24-week, single-arm, open-label period at a dose of 2 mg of osilodrostat twice daily that could be increased every 2 weeks to 30 mg twice daily.

By week 24, cortisol levels in roughly half the patients were within the normal range, and 71 patients who did not need any more dose increases and who tolerated the drug were randomized to either osilodrostat or placebo for an 8-week withdrawal study. At the end of that time, 86% of the osilodrostat patients maintained their normal-range cortisol levels, compared with 30% of those taking placebo.

Osilodrostat is taken as an oral tablet twice a day, in the morning and evening. Among the common side effects reported in the study were adrenal insufficiency, headache, vomiting, nausea, fatigue, and edema, although hypocortisolism, QTc prolongation, and elevations in adrenal hormone precursors, and androgens may also occur, according to the release.

The drug had been given an Orphan Drug Designation in recognition of its intended use in the treatment of a rare disease. The approval was granted to Novartis.

This story originally appeared on MDedge.com.


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