Objective: To evaluate the efficacy of cabergoline therapy in patients with Cushing disease who remained uncured (had persistent or recurrent disease) after a pituitary surgical procedure with or without radiotherapy.
Methods: We undertook a prospective, open-label, single-arm study, with short-term (5 months) and longterm (1 year) evaluations. In 20 patients with uncured Cushing disease, treatment was initiated with cabergoline at a dosage of 1 mg/wk, with a monthly increment of 1 mg, until midnight serum cortisol (MNSC) or low-dose dexamethasone suppression serum cortisol (LDSC) (or both) normalized or a maximal dosage of 5 mg/wk was reached.
Results: Overall, 5 of 18 patients (28%) responded in terms of LDSC or MNSC (or both) at a mean dosage of 3.6 mg/wk (range, 2 to 5). When the response was defined with use of either LDSC or MNSC level as an isolated criterion, it was achieved in 4 of 16 patients (25%) and 3 of 18 patients (17%), respectively. Four patients were treated for 1 year, and the response was persistent in 2 and 3 patients on the basis of MNSC and LDSC levels, respectively. Lower baseline serum cortisol (basal, MNSC, and LDSC) values were predictive of a therapeutic response.
Conclusion: Cabergoline was an effective therapy in 28%, 25%, and 17% of patients with uncured Cushing disease in terms of LDSC or MNSC (or both), LDSC alone, and MNSC alone, respectively. Further studies are needed to address the persistence of the drug response and the effects on the dynamics of the hypothalamic-pituitary-adrenal axis.