ABSTRACT
Sequential therapy using tyrosine kinase inhibitors (TKIs) and mammalian target of rapamycin inhibitors is the mainstay of treatment for metastatic renal cell carcinoma. Recently, anti-programmed death-1 (PD-1) antibody, a type of immune checkpoint inhibitor, was approved for use against metastatic renal cell carcinoma. In the present report, two cases of TKI-refractory metastatic renal cell carcinoma which regained sensitivity to TKI after immunotherapy with nivolumab were described. In one case, a third challenge with axitinib after nivolumab treatment resulted in tumor shrinkage, although the second challenge with axitinib immediately before nivolumab treatment had no effect. In another case, a second challenge with pazopanib after nivolumab slightly reduced lung metastasis, which was refractory to pazopanib before nivolumab treatment. These cases suggest that nivolumab can influence the response to subsequent TKI treatment.
