Clinical outcomes of second-line treatment following first-line VEGFR-TKI failure in patients with metastatic renal cell carcinoma:a comparison of axitinib alone and axitinib plus anti-PD-1 antibody

Dear editor,The prognosis of metastatic renal cell carcinoma(mRCC)has been significantly improvedwith the development and widespread use of vascular endothelial growth factor(VEGF)pathway inhibitors and mammalian target of rapamycin(mTOR)pathway inhibitors[1].For the past decade,the standard of care utilized in the first-line setting was VEGF-targeted therapies.Recently,the mRCC treatment landscape has rapidly changed with the exploration of combinations of immune checkpoint inhibitors(ICIs)and anti-VEGF agents[2,3].