Apatinib in patients with recurrent or metastatic thymic epithelial tumor: a single-arm, multicenter, open-label, phase II trial

BACKGROUND: Thymic epithelial tumors (TETs) are rare malignancies and the treatment options are limited. We aimed to evaluate the efficacy and safety of apatinib, an angiogenesis inhibitor, in advanced TETs. METHODS: This was an open-label, single-arm, phase II trial at three centers in China. Patients with TET who had progressed after failure of at least one line of platinum-based chemotherapy were enrolled. Patients received apatinib 500 mg orally per day. The primary endpoint was objective response rate (ORR). Secondary endpoints were progression-free survival (PFS), overall survival (OS), disease control rate (DCR), and safety. RESULTS: From June 29, 2017, to April 18, 2019, 25 patients were enrolled. At data cut off (September 30, 2021), one patient achieved complete response, nine achieved partial response, and 11 achieved stable disease, with an ORR of 40% (95% CI 21-61%) and DCR of 84% (95% CI 64-95%). The median PFS was 9.0 (95% CI 5.4-12.6) months. The median OS was 24.0 (95% CI 8.2-39.8) months. All patients reported treatment-related adverse events (TRAEs). Grade 3 TRAEs occurred 26 times in 15 patients. No grade 4 or 5 toxicities occurred. CONCLUSIONS: This is the first trial of apatinib for the treatment of TETs. Apatinib showed promising antitumor activity and the toxicities were tolerable and manageable.