FDA Approval Summary: Lenvatinib for Progressive, Radio-iodine-Refractory Differentiated Thyroid Cancer.

The FDA approved lenvatinib (Lenvima, Eisai Inc.) for the treatment of patients with locally recurrent or metastatic, progressive, radioactive iodine-refractory (RAI-refractory) differentiated thyroid cancer (DTC). In an international, multicenter, double-blinded, placebo-controlled trial (E7080-G000-303), 392 patients with locally recurrent or metastatic RAI-refractory DTC and radiographic evidence of disease progression within 12 months prior to randomization were randomly allocated (2:1) to receive either lenvatinib 24 mg orally per day (n = 261) or matching placebo (n = 131) with the option for patients on the placebo arm to receive lenvatinib following independent radiologic confirmation of disease progression. A statistically significant prolongation of progression-free survival (PFS) as determined by independent radiology review was demonstrated [HR, 0.21; 95% confidence interval (CI), 0.16-0.28; P < 0.001, stratified log-rank test], with an estimated median PFS of 18.3 months (95% CI, 15.1, NR) in the lenvatinib arm and 3.6 months (95% CI, 2.2-3.7) in the placebo arm. The most common adverse reactions, in order of decreasing frequency, observed in the lenvatinib-treated patients were hypertension, fatigue, diarrhea, arthralgia/myalgia, decreased appetite, decreased weight, nausea, stomatitis, headache, vomiting, proteinuria, palmar-plantar erythrodysesthesia syndrome, abdominal pain, and dysphonia. Adverse reactions led to dose reductions in 68% of patients receiving lenvatinib at the 24 mg dose and 18% of patients discontinued lenvatinib for adverse reactions leading to residual uncertainty regarding the optimal dose of lenvatinib.