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
- 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.