Context: Lenvatinib improved the progression-free survival (PFS) and overall response rate of patients with radioiodine-refractory differentiated thyroid cancer vs placebo in the Phase 3 Study of (E7080) Lenvatinib in Differentiated Cancer of the Thyroid (SELECT). Objective: The objective of the study was to characterize tumor size changes with lenvatinib treatment. Design: SELECT was a phase 3, randomized, double-blind, multicenter study. Setting: In this clinical trial,tumorassessments of lenvatinib (n=261)andplacebo-treated (n=131) patients were performed by independent radiological review per Response Evaluation Criteria in Solid Tumors version, 1.1 at 8-week intervals. Patients: Patients with complete or partial response were defined as responders to lenvatinib (n= 169). Of the 92 nonresponders, 76 had at least one postbaseline tumor assessment and were included in this analysis. Interventions: Lenvatinib (24mgonce daily) or placebo in 28-day cycles until unacceptable toxicity, disease progression, or death. MainOutcomeMeasures: Thiswasanexploratory analysis of keyendpoints from SELECT, including PFS, overall response rate, and tumor reduction. Results: The medianmaximumpercentage change in tumor size was-42.9%for patients receiving lenvatinib (responders,-51.9%; nonresponders,-20.2%). Tumor size reduction was most pronounced at first assessment (median,-24.7%at 8wk after randomization); thereafter, the rate of change was slower but continuous (-1.3%per mo). In a multivariate model, percentage change in tumor size at the first assessment was a marginally significant positive predictor for PFS P= .06). Conclusions: The change in tumor size conferred by lenvatinib was characterized by two phases: an initial, rapid decline, followed by slower, continuous shrinkage. (J Clin Endocrinol Metab 101: 4103-4109, 2016).
ASJC Scopus subject areas
- Endocrinology, Diabetes and Metabolism
- Clinical Biochemistry
- Biochemistry, medical