Apatinib Monotherapy For Chemotherapy-Refractory Metastatic Colorectal Cancer: A Multicenter, Single Arm, Prospective Study.

3527 Background: Apatinib is an oral highly-selective tyrosine kinase inhibitor (TKI) that blocks vascular endothelial growth factor receptor 2 (VEGFR-2). This exploratory study evaluated the efficacy and safety of apatinib monotherapy in patients with chemotherapy-refractory metastatic colorectal cancer. Methods: In this multicenter, single-arm, prospective study, 48 patients with metastatic colorectal cancer who had failed at least two lines standard chemotherapies including fluorouracil, oxaliplatin and irinotecan were recruited from 14 centers in Guangdong, China. Apatinib at a 500mg dose was administered daily continuously. Each cycle was 4 weeks (28 days). The primary endpoint was progression free survival (PFS). Secondary end points included overall survival (OS), objective response rate (ORR), disease control rate (DCR), quality of life (QoL) and toxicity. Results: A total of 48 patients was enrolled in the study from September 3, 2015 to June9, 2017. Four patients achieved a partial response, and 22 achieved stable disease, representing a response rate of 8.3% and a disease control rate of 60.4%. Median follow-up time was 10.3 months. Median progression-free survival (PFS) and overall survival (OS) of evaluable patients (n=41) were 4.7 months (95% confidence interval [CI] 3.7-5.9) and 9.7 months (95% CI 5.9-13.6). The most common grade 3 or 4 adverse events (AE) were hypertension (12.5%), hand-foot syndrome (10.4%), thrombocytopenia (10.4%), proteinuria (8.3%) and mucositis oral (6.3%). Conclusions: Apatinib monotherapy shows promising efficacy and manageable toxicities in patients with chemotherapy-refractory metastatic colorectal cancer. Further phase 3 trial is warranted. Clinical trial information: ChiCTR1900020503.