A feasibility study of lenvatinib plus pembrolizumab in Japanese patients with advanced solid tumors

Purpose Combination treatment using lenvatinib (a multikinase inhibitor) plus pembrolizumab (a programmed death-1 immune checkpoint inhibitor) has shown efficacy in the treatment of endometrial and renal cell cancers. This phase 1b study investigated the tolerability and safety of lenvatinib plus pembrolizumab in Japanese patients with metastatic selected solid tumors. Methods Patients received a starting dose of 20 mg oral lenvatinib per day plus 200 mg intravenous pembrolizumab every 3 weeks in 21-day cycles. Dose-limiting toxicities were evaluated during the first cycle. Tumor assessments were performed by investigators based on modified RECIST v1.1. Pharmacokinetic parameters and serum biomarkers were assessed. Results Among enrolled patients (N = 6), 3 had non-small cell lung cancer, and 3 had urothelial cancer. No patients experienced a dose-limiting toxicity. All patients experienced at least 1 treatment-related treatment-emergent adverse event. The objective response rate was 33.3% (95% confidence interval 4.3-77.7); both responses (1 complete, 1 partial) were observed in patients with urothelial cancer. Pharmacokinetics were consistent with previous studies. Serum angiopoietin-2 levels tended to decrease, and serum fibroblast growth factor-23 levels tended to increase from baseline to Cycle 2 Day 1. Conclusions This study supports the tolerability of 20 mg lenvatinib/day plus 200 mg pembrolizumab every 3 weeks in Japanese patients, consistent with the results from a global study of lenvatinib plus pembrolizumab combination therapy in patients with selected solid tumors. Favorable antitumor activity was observed and there were no new safety signals identified.