Outcomes of axitinib versus sunitinib as first-line therapy to patients with metastatic renal cell carcinoma in the immune-oncology era

Although combination immune checkpoint inhibitor (immuno-oncology [IO]) therapy is the first-line treatment for metastatic renal cell carcinoma (mRCC), it mostly causes resistance and tumor regrowth. Therefore, an optimal second-line therapy is necessary. Such therapy typically comprises vascular endothelial growth factor receptor-tyrosine kinase inhibitors (VEGFR-TKIs). This study was aimed at comparing the efficacy of two TKIs-axitinib and sunitinib-in mRCC patients. From January 2008 to October 2018, we registered 703 mRCC patients from 8 Japanese institutes. Of these, 408 patients received axitinib or sunitinib as the first-line treatment. Thereafter, efficacy and survival rate were compared between the axitinib and sunitinib groups. To reduce the effects of selection bias and potential confounders, propensity score matching analysis was performed. Axitinib and sunitinib were administered in 274 and 134 patients, respectively. More than 25% of the patients received nivolumab sequence therapy. To calculate the propensity scores for each patient, we performed multivariate logistic regression analysis. The objective response rate, progression-free survival (PFS), cause-specific survival, and overall survival (OS) were significantly better in the axitinib group than in the sunitinib group. Furthermore, the OS was better in the nivolumab-treated patients in the axitinib group. Axitinib showed higher efficacy and afforded greater survival benefits than did sunitinib when administered as first-line therapy in mRCC patients. Thus, from among VEGFR-TKIs, axitinib might be a possible option for application in the middle of IO drug-based treatment sequences.