Corcept Therapeutics announced it has received orphan drug designation from FDA for mifepristone 300 mg tablets indicated for the management of hyperglycemia secondary to hypercortisolism in adult patients with endogenous Cushing syndrome who have type 2 diabetes or glucose intolerance and have failed surgery or are not candidates for surgery. The active ingredient, mifepristone, is also marketed in 200 mg tablets as Mifeprex (Danco Laboratories) as an early option to terminate pregnancy.

In patients with Cushing syndrome, mifepristone works by blocking the glucocorticoid receptor type II to which cortisol normally binds. By blocking this receptor, mifepristone inhibits the effects of excess cortisol in patients with the disease. The starting dose is 300 mg once daily, titrated up to a maximum of 1,200 mg once daily.

Approval was based on data from an uncontrolled, open-label, multicenter, 24-week phase III study of 50 patients with endogenous Cushing syndrome who were either not eligible for or had relapsed from surgery and were either glucose intolerant (n = 29) or had hypertension (n =21). Within the glucose intolerant group, 60% of patients had a greater than 25% reduction from baseline in area under the curve in an oral glucose tolerance test. In addition, mean glycosylated hemoglobin was reduced from 7.4% to 6.3% in these patients.

The most common adverse reactions in patients with Cushing syndrome, occurring at an incidence of 20% or more, were nausea, fatigue, headache, decreased blood potassium, arthralgia, vomiting, peripheral edema, hypertension, dizziness, decreased appetite, endometrial hypertrophy. The tablets have a boxed warning for pregnancy, as administration of these tablets can result in termination.

The tablets will be available by May 1 through CuraScript SP, a specialty pharmacy and subsidiary of Express Scripts.