[A Case of Non-Small Cell Lung Cancer Successfully Treated with Anti-PD-L1 Therapy after Exacerbation Caused by...

A 52-year-old male was diagnosed with cT4N3M1b, cStage Ⅳ adenocarcinoma of the lung, and underwent 6 courses of pemetrexed(PEM), carboplatin(CBDCA), and bevacizumab(Bev)therapy, followed by 4 courses of PEM/Bev maintenance therapy. Due to the deterioration of his condition, 4 courses of pembrolizumab(Pembro)therapy were administered as second- line therapy, but the treatment was discontinued due to disease progression. Third-line therapy with docetaxel(DTX)/ ramucirumab(Rmab)was administered, resulting in a partial response, but discontinued due to adverse events. Finally, fourth-line therapy with atezolizumab(Atezo)was initiated. After 6 courses of Atezo therapy, partial response was achieved, and the tumor continued to shrink for 3 years. The aim of the treatment strategy for both PD-1 and PD-L1 antibody drugs is to suppress T-cell exhaustion, and if either drug fails, the other drug may theoretically fail. However, in this case, the PD-L1 antibody drug was effective against non-small cell lung cancer that had shown resistance to PD-1 antibody drugs, suggesting that even if a patient becomes resistant to PD-1 antibody drugs, PD-L1 antibody drugs may result in effective outcomes.