[Long-term treatment of Cushing's disease using ketoconazole. Possibility of therapeutic escape].

Five women suffering from Cushing's disease were treated with ketoconazole 800 mg per day for 2 to 28 months (mean 12.4 months). Four of them had full clinical and biochemical regression. However, after 8 months of therapy the disease failed to respond in three of these four women. Increasing the ketoconazole dosage up to 1,200 mg per day was ineffective in two patients. Such an escape phenomenon, not described until now, will restrict the use of ketoconazole in the treatment of Cushing's disease, although the drug is easy to administer and well tolerated globally and by the liver in most cases.