A Randomized, Phase III Study of Lenvatinib in Chinese Patients with Radioiodine-Refractory Differentiated Thyroid Cancer.

PURPOSE Lenvatinib has shown efficacy in treating radioiodine-refractory differentiated thyroid cancer (RR-DTC) in the multinational phase III SELECT study; however, it has not been tested in Chinese patients with RR-DTC. EXPERIMENTAL DESIGN Chinese patients with confirmed RR-DTC (n = 151) were randomly assigned 2:1 to receive lenvatinib 24 mg/day or placebo in 28-day cycles. The primary endpoint was progression-free survival, and key secondary endpoints included objective response rate and safety. Analyses for progression-free survival and objective response rate were conducted using Response Evaluation Criteria in Solid Tumors v1.1 and confirmed by independent imaging review. All adverse events were assessed and monitored. RESULTS Progression-free survival was significantly longer with lenvatinib treatment [n = 103; median 23.9 months; 95% confidence interval (CI), 12.9-not estimable] versus placebo (n = 48; median 3.7 months; 95% CI, 1.9-5.6; hazard ratio = 0.16; 95% CI, 0.10-0.26; P < 0.0001). The objective response rate was 69.9% (95% CI, 61.0-78.8) in the lenvatinib arm and 0% (95% CI, 0-0) in the placebo arm. At data cutoff, 60.2% of patients receiving lenvatinib remained on treatment; treatment-emergent adverse events led to lenvatinib discontinuation in 8.7% of patients. Overall, treatment-emergent adverse events of grade ≥3 occurred in 87.4% of patients in the lenvatinib arm, the most common being hypertension (62.1%) and proteinuria (23.3%). CONCLUSIONS Lenvatinib at a starting dose of 24 mg/day significantly improved progression-free survival and objective response rate in Chinese patients with RR-DTC versus placebo. There were no new or unexpected toxicities. Results are consistent with those from SELECT involving patients with RR-DTC.