Response To Lenvatinib Treatment In Patients With Radioiodine-Refractory Differentiated Thyroid Cancer (Rr-Dtc): Updated Results From Select.

6089Background: Lenvatinib (LEN) significantly prolonged median progression-free survival (PFS) vs placebo (PBO) in the primary analysis of the phase 3 SELECT study of RR-DTC (18.3 vs 3.6 mos; HR 0.21; 99% CI 0.14–0.31; Pu003c 0.001). Median duration of overall response (DOR; per RECIST 1.1) to LEN was not reached at the time of the primary analysis. Here we present new efficacy data with a focus on DOR. Methods: The data cutoff was 31 Aug 2015 (LEN: n = 261, PBO: n = 131); primary endpoint was PFS. DOR was examined for patients (pts) who had partial (PR) or complete responses (CR) and by subgroup (age, sex, tumor subtype, baseline disease burden, baseline Eastern Cooperative Oncology Group score, metastasis site, prior vascular endothelial growth factor [VEGF] therapy). For this analysis, tumor assessments were per investigator. We also report clinical features of 2 pts with RR-DTC with prolonged responses to LEN. Results: At cutoff, median PFS was 19.4 mos (95% CI 14.8–29.3) for LEN and 3.7 mos (95% CI 3.5–...