Mifepristone Okayed for Adults With Cushing's Syndrome

Robert Lowes

February 17, 2012

February 17, 2012 — Mifepristone, already indicated for medical abortions, received approval today from the US Food and Drug Administration (FDA) to control hyperglycemia in adults with endogenous Cushing's syndrome, the agency announced.

Mifepristone (Korlym, Corcept Therapeutics) is the first FDA-approved medical therapy for this syndrome, caused by the body's overproduction of the steroid hormone cortisol. In 2007, the FDA designated mifepristone an orphan drug, meaning that it treats a rare disease affecting fewer than 200,000 patients in the United States. Orphan-drug status confers economic benefits that make commercializing a drug for a small number of patients more feasible.

The FDA said that roughly 5,000 patients will be eligible for mifepristone therapy.

The drug reduces the effects of excess cortisol, such as hyperglycemia, by preventing the hormone from binding to its receptor.

The drug is specifically indicated for 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. It is contraindicated for pregnant women. The drug label will bear a boxed warning stating that the drug will terminate a pregnancy.

The FDA cited research showing that patients who received mifepristone experienced improved control of hyperglycemia, and some needed markedly less insulin. Some patients reported improvements in clinical signs and symptoms.

The most common adverse events were nausea, fatigue, headache, arthralgia, vomiting, swelling of the extremities, dizziness, and decreased appetite. Other adverse events include adrenal insufficiency, low potassium levels, vaginal bleeding, and the possibility of abnormal heart conduction.

The FDA said that certain drugs administered in combination with mifepristone may increase its drug level. Accordingly, the agency cautions clinicians to consider the potential for drug-drug interactions and avoid using certain drugs with mifepristone or else adjust dosing.

Corcept Therapeutics voluntarily proposed to use a central pharmacy to distribute mifepristone to patients with endogenous Cushing's syndrome or medical institutions where they are treated. "Most retail pharmacies are unlikely to keep adequate supplies of the drug for this rare condition and central distribution will give patients...better access to Korlym," the FDA stated.

More information on today's FDA decision is available on the agency's Web site.