Associations Between Plasma Concentrations of Lenvatinib and Angiopoietin and Clinical Responses to Lenvatinib Therapy in Japanese Patients With Thyroid Cancer

Purpose: The purpose of this study was to investigate the relationships among plasma concentrations of lenvatinib, angiopoietin (Ang)-1 and Ang-2, and clinical responses to lenvatinib therapy in Japanese patients with thyroid cancer. Methods: Plasma concentrations of lenvatinib (C0) and Ang-1 and -2 were measured by HPLC and ELISA, respectively.Results: The median change rates of Ang-1 and Ang-2 at 1 month after treatment from baseline in 36 patients were -15.3% and -48.4%, respectively. However, the change of Ang-1 and Ang-2 at 1 month from baseline did not correlate with lenvatinib C0. In patients with partial response (PR) and stable disease to lenvatinib, Ang-2 at 1 month were significantly lower than Ang-2 at baseline (P < 0.001 and P < 0.05, respectively), but were not significantly lower in patients with progressive disease. 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 the change rate of Ang-2 of -49.83%. A one year overall survival for patients having the change rate of Ang-2 of at least -49.83% and less than -49.83% were 62.5% and 40%, respectively. In patients who continued treatment with lenvatinib for 1 year, Ang-2 at 1 month and 1 year after treatment were significantly lower than those at baseline (each P < 0.001).Conclusion: The change of Ang-2 at 1 month after treatment from baseline rather than simply the Ang-2 level at baseline may be important as a biomarker of the inhibitory effect of angiogenesis by lenvatinib.