Salivary cortisol is a useful tool to assess the early response to pasireotide in patients with Cushing's disease.

Purpose: Late night salivary cortisol (LNSC) is useful for diagnosing hypercortisolism and monitoring patients with Cushing's disease (CD) following pituitary surgery. It may also be a better index of cortisol secretion than serum cortisol or urinary free cortisol (UFC). No data regarding the role of LNSC in the early monitoring of patients with CD receiving drug therapy has been published. We investigated the value of LNSC in monitoring the short-term efficacy of pasireotide. Methods: Seven patients who were enrolled in a phase II study investigating the efficacy of pasireotide in CD (CSOM230B2208) were included in this analysis. Patients self-administered subcutaneous pasireotide 600 μg bid for 15 days. LNSC and UFC levels were assessed at baseline and day 15. Results: At baseline, all patients had elevated LNSC which was correlated significantly with UFC levels (r = 0.97, P = .0002). At day 15, LNSC was reduced in six patients. LNSC decreases were observed from day 1 (-20 %) and persisted until day 15 (overall mean reduction from baseline -51 %), with the greatest decrease on day 5 (-58 %). At day 15, UFC levels were decreased in all patients and normalized in one that restored also salivary cortisol rhythm. Conclusions: In patients with CD, pasireotide rapidly reduced and normalized both UFC and LNSC levels. LNSC may be a simple, non-invasive biomarker to assess the early response to pasireotide, particularly in determining whether cortisol rhythm is normalized in patients with normalized UFC levels.