A phase II study of everolimus in patients with aggressive RAI refractory (RAIR) thyroid cancer (TC).

6023 Background: We present results of an open label phase II study of the mTOR inhibitor Everolimus in patients (pts) with RAIR TC. Methods: Pts with metastatic, incurable RAIR TC who had shown radiographic progression within 6 months prior to enrollment received Everolimus 10mg orally once daily. Responses were monitored by CT's every two months. The primary endpoint was progression free survival. Sequential biopsies were obtained in selected pts. Results: Enrollment to the differentiated TC (DTC) cohort finished in Jan 2013 and included 33 pts, among them 11 with Hurthle cell TC. Exploratory cohorts enrolled 10 pts with medullary [MTC] and 5 with anaplastic [ATC] with 2 added openings remaining for ATC. For the DTC cohort, median time on study to date is 10 months (mo) (<1-23+). 31 pts are evaluable at this time. PFS in the DTC cohort by Kaplan-Meier (K-M) analysis is 16.0 mo (95%CI 10-NR). Currently, disease stability for 6 and 12 mo or more was achieved in 18 and 10/31 pts, respectively, 11 pts remai...