The US Food and Drug Administration (FDA) on Friday allowed the use of Korlym as the first approved medical therapy to control high blood sugar levels in adults with endogenous Cushing's syndrome.

Endogenous Cushing's syndrome is a serious, debilitating and rare multisystem disorder. It is caused by the overproduction of cortisol (a steroid hormone that increases blood sugar levels) by the adrenal glands. This syndrome most commonly affects adults between the ages of 25 and 40.

Korlym, a lead product of pharmaceutical firm Corcept Therapeutics, blocks the binding of cortisol to its receptor. It does not decrease cortisol production but reduces the effects of excess cortisol, such as high blood sugar levels. The safety and efficacy of Korlym in patients with endogenous Cushing's syndrome was evaluated in a clinical trial with 50 patients.

According to the FDA, the most common side effects experienced by endogenous Cushing's syndrome patients treated with Korlym were nausea, fatigue, headache, arthralgia, vomiting, swelling of the extremities, dizziness and decreased appetite.