LAUSR

Abstract Background Gastrointestinal stromal tumors (GISTs) patients (pts) who develop resistance to imatinib and sunitinib have few therapeutic options. Apatinib is a multiple tyrosine kinase inhibitor and targetsVEGFR2, PDGFRβ and c-Kit, which is effective in several solid tumors. We aimed to assess the efficacy and safety of apatinib in pts with advanced GISTs who failed previous standard tyrosine kinase inhibitors. Methods In this single-arm, open-label, phase II study, we enrolled pts (aged ≥18 years) with advanced GISTs resistant to imatinib and sunitinib from 3 comprehensive cancer centers or university hospitals in China and assigned them to 500 mg oral apatinib once daily in 4-week cycles. Pts were assessed for response by RECIST 1.1 every 2 cycles. The primary endpoint was investigator-assessed progression-free survival. The secondary endpoints included response rate, overall survival and advent events. Results Between September 2017 and February 2019, 10 pts were enrolled (7 evaluable for response), and pts are still being accrued to the trial. Here we present the preplanned early analysis of clinical outcomes. The median follow-up was 16.6 months. Four pts reached stable disease. The median PFS was 5.4 months (95% CI 2.0–9.8), and the 4-month PFS rate was 57.1%. Drug-related adverse events were reported in 9 (90%) pts and the most common apatinib-related adverse events of grade 3 or higher were hypertension (3 of 10, 30%), hand-foot skin reaction (4 of 10, 40%), fatigue (5 of 10, 50%) and proteinuria (2 of 10, 20%). There was no treatment-related death. Conclusions Apatinib appears to have promising anti-tumor activity and an acceptable toxicity profile in pts with advanced GISTs previously treated with imatinib and sunitinib. Apatinib warrants further investigation in GISTs. Clinical trial identification ChiCTR1800020407. Legal entity responsible for the study The authors. Funding Chinese Society of Clinical Oncology. Disclosure All authors have declared no conflicts of interest.