Efficacy and Safety of Osilodrostat in Paraneoplastic Cushing Syndrome: A Real-World Multicenter Study in France

Context: Prospective studies have demonstrated the efficacy of osilodrostat in Cushing disease. No study has evaluated osilodrostat in a series of patients with paraneoplastic Cushing syndrome/ectopic adrenocorticotropin syndrome (PNCS/EAS). Objective: This work aimed to evaluate in France the real-world efficacy and safety of osilodrostat in patients with PNCS/EAS. Methods: A total of 33 patients with PNCS/EAS with intense/severe hypercortisolism were involved in this retrospective, multicenter, real-world study. Patients received osilodrostat between May 2019 and March 2022 at a median initial dose (range) of 4 mg/day (1-60) and maximum dose, 20 mg/day (4-100), first under patient then cohort temporary authorizations and after marketing authorization. Regimens used titration (n = 6), block and replace (n = 16), or titration followed by block and replace (n = 11). Results: In 11 patients receiving osilodrostat as first-line monotherapy, median 24-hour urinary free cortisol (24h-UFC) decreased dramatically (from 26 × upper limit of normal [ULN; 2.9-659] to 0.11 × ULN [0.08-14.9]; P < .001). In 9 of them, 24h-UFC normalization was achieved in 2 weeks (median). Thirteen additional patients were previously treated with classic steroidogenesis inhibitors but 10 of these 13 were not controlled. In these patients, osilodrostat monotherapy, used as second line, induced a significantly decreased of 24h-UFC (from 2.6 × ULN [1.1-144] to 0.22 × ULN [0.12-0.66]; P < .01). Nine additional patients received osilodrostat in combination with another anticortisolic drug, decreasing 24h-UFC from 11.8 × ULN (0.3-247) to 0.43 × ULN (0.33-2.4) (P < .01). In parallel, major clinical symptoms/comorbidities improved dramatically with improvement in blood pressure, hyperglycemia, and hypokalemia, allowing the discontinuation or dose reduction of patient treatments. Adrenal insufficiency (grade 3-4) was reported in 8 of 33 patients. Conclusion: Osilodrostat is a rapidly efficient therapy for PNCS/EAS with severe/intense hypercortisolism. Osilodrostat was generally well tolerated; adrenal insufficiency was the main side effect.