Lenvatinib in the Therapy of Aggressive Thyroid Cancer: State of the Art and New Perspectives with Patents Recently Applied

BACKGROUND AND OBJECTIVE: Lenvatinib is an oral, multitargeted tyrosine kinase inhibitor (TKI) of vascular endothelial growth factor receptors (VEGFR1-VEGFR3), fibroblast growth factor receptors (FGFR1-FGFR4), platelet-derived growth factor receptor (PDGFR)α, rearranged during transfection (RET), and v-kit (KIT) signaling networks implicated in tumor angiogenesis. METHOD: Here we review the scientific literature about lenvatinib in the treatment of thyroid cancer. RESULTS: In vitro studies have shown antineoplastic activity of lenvatinib in differentiated thyroid cancer (DTC), mainly because of its antiangiogenetic effects, but a slight effect on thyroid cancer cell proliferation has been shown. In vivo phase II, and phase III studies in patients with aggressive DTC not responsive to radioiodine, have shown that lenvatinib administration was associated with an amelioration in progression-free survival (PFS) with respect to placebo (median PFS 18.2 vs. 3.6 months). However overall survival was not significantly changed. Lenvatinib is also effective in patients resistant to sorafenib as salvage therapy. Adverse effects of any grade occur in more than 40% of lenvatinib-treated patients, mainly hypertension, diarrhea, asthenia or fatigue, nausea, decreased appetite, and decreased weight. Discontinuations of the therapy because of adverse effects occur in about 14% of patients. Moreover, deaths considered to be drug-related can occur. CONCLUSION: On the base of the above mentioned considerations, it is necessary to prove the effectiveness of lenvatinib in the context of associated moderate to severe toxicities requiring frequent dose reduction and delays, and for this reason many interesting patents have been recently applied.