FDA approves mifepristone for patients with endogenous Cushing’s syndrome

The FDA today approved mifepristone to control hyperglycemia in adults with endogenous Cushing’s syndrome who have type 2 diabetes or glucose intolerance and are not candidates for surgery or who have not responded to prior surgery.

Researchers evaluated the safety and efficacy of mifepristone (Korlym, Corcept Therapeutics) in patients with endogenous Cushing’s syndrome in a clinical trial involving 50 patients. A separate open-label extension of this trial is ongoing. Additional evidence supporting the agency’s approval included several safety pharmacology studies, drug-drug interaction studies and published scientific literature. Data showed patients experienced significant improvement in blood sugar control during treatment, including some patients who had marked reductions in their insulin requirements. Improvements in clinical signs and symptoms were reported by some patients, according to a press release.

The most common side effects reported in the clinical trials were nausea, fatigue, headache, arthralgia, vomiting, swelling of the extremities, dizziness and decreased appetite. Other side effects of mifepristone include adrenal insufficiency, low potassium levels, vaginal bleeding and a potential for heart conduction abnormalities. When used in combination with mifepristone, certain drugs may increase its drug level. Additionally, the drug should never be used by pregnant women.

The FDA determined that a Risk Evaluation and Mitigation Strategy (REMS) is unnecessary for mifepristone to ensure that the benefits outweigh the risks for patients with endogenous Cushing’s syndrome. Several factors were considered:

There are no other approved medical therapies for this form of Cushing’s syndrome and patients would suffer if impediments to access were imposed.
The number of Cushing’s syndrome patients who will require treatment with mifepristone is small, with an estimated 5,000 patients being eligible for treatment.
The number of health care professionals in the United States who would potentially prescribe the drug is very small and highly specialized and they are familiar with the risks of treatment in this population.
The risks of treatment in the intended population can be managed through physician and patient labeling, as the drug’s risks will be outlined in a medication guide.

The manufacturer has voluntarily proposed distributing mifepristone through a central pharmacy to ensure the timely, convenient and appropriate delivery of the drug to patients with Cushing’s syndrome or to the health care institutions where this therapy may be initiated.

Follow EndocrineToday.com on Twitter.