Mifepristone in the treatment of the ectopic adrenocorticotropic hormone syndrome

OBJECTIVES: Mifepristone, a glucocorticoid receptor antagonist, can be used to manage hypercortisolism in patients with ectopic adrenocorticotropic hormone syndrome (EAS) when surgical cure is not feasible. Outcomes of EAS patients treated with mifepristone have been limited to reports of isolated cases. We aimed to determine the efficacy and limitations of mifepristone in the treatment of EAS and to compare outcomes with those of patients who underwent bilateral adrenalectomy. METHOD: A retrospective cohort study of EAS patients from the University of Michigan between 1997 and 2017 was conducted. RESULTS: Of the 55 patients with EAS, 16 were treated with mifepristone: eight neuroendocrine tumours, two carcinomas and six occult tumours. Treatment with mifepristone was most commonly prompted by psychosis, uncontrolled glucose and/or hypertension. The median maintenance dose was 600 mg/d. Amelioration of psychosis was observed within 48 hours in 3/3 patients, and the glycaemic control was improved in 14/16 patients. The median duration of treatment was 9 months, and three patients were treated for more than 24 months. The overall survival at 24 months was equivalent between patients with EAS treated with mifepristone vs bilateral adrenalectomy (N = 12) (P = 0.6). CONCLUSIONS: Mifepristone is effective in treating EAS for over 2 years, and survival was not different from that of patients treated with bilateral adrenalectomy. Aggressive concomitant therapy for hypokalaemia and hypertension is necessary.