Abstract
BACKGROUND/AIM: The purpose of this study was to investigate the relationships between the plasma concentration of Lenvatinib (C0), the levels of angiopoietin (Ang)-1 and Ang-2, and clinical responses to lenvatinib therapy in patients with thyroid cancer. PATIENTS AND METHODS: Lenvatinib C (0) and Ang were measured by high-performance liquid chromatography and enzyme-linked immunosorbent assay, respectively. RESULTS: The median decrease rates of Ang-1 and Ang-2 at 1 month after treatment from baseline were -15.3% and -48.4%, respectively. However, the decrease in the levels of Ang-1 and Ang-2 at 1 month from baseline did not correlate with C0. In patients with partial response (PR) and stable disease, Ang-2 at 1 month was significantly lower than Ang-2 at baseline. The area under the ROC for PR prediction was 0.667, giving the best sensitivity (69.2%) and specificity (73.9%) at a threshold of decrease rate of Ang-2 of -49.83%. CONCLUSION: The decrease in Ang-2 at 1 month of treatment from baseline may be important as a biomarker of the inhibitory effect of lenvatinib on angiogenesis.