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Cancer Treat Rev. 2018 Apr;65:65-77. doi: 10.1016/j.ctrv.2018.02.005. Epub 2018 Feb 22.

Breaking the biomarker code: PD-L1 expression and checkpoint inhibition in advanced NSCLC.

Author information

Medical Oncology, BCCA - Vancouver Centre, Vancouver, BC, Canada. Electronic address:
Cross Cancer Institute and University of Alberta, Edmonton, AB, Canada.
McMaster University, Juravinski Cancer Centre, Hamilton, ON, Canada.
Princess Margaret Hospital and University of Toronto, Toronto, ON, Canada.
BCCA and The University of British Columbia, Vancouver, BC, Canada.
Princess Margaret Cancer Centre, University Health Network, University of Toronto, Toronto, ON, Canada.
Kaleidoscope Strategic Inc., Toronto, ON, Canada.
Montreal General Hospital, Royal Victoria Hospital and McGill University, Montreal, QC, Canada.



Lung cancer is the most common cause of cancer-related death among males and the second leading cause among females globally. Checkpoint inhibitors re-engage the immune system to fight cancer. This review evaluates phase III data on the use of checkpoint inhibitors in the treatment of advanced NSCLC and addresses PD-L1 expression in predicting efficacy.


Six phase III clinical trials investigating checkpoint inhibitors for NSCLC were identified through a search of PubMed (to November 15, 2016) and conference databases, with findings updated from a directed search of eligible studies conducted in January 2018.


Significant reductions in the risk of death ranging from 27% to 41% and were observed second-line and beyond. A relationship between PD-L1 expression and survival was apparent in most trials with optimal benefit for the highest expression levels (≥50%). Benefit was also observed at low or no PD-L1 expression levels and in third-line in some studies. Significantly improved PFS was observed for pembrolizumab at high PD-L1 expression levels (≥50%) first-line. Immune-related adverse events associated with checkpoint inhibitors are tolerable and rates of pneumonitis may be lower among PD-L1 inhibitors. Use of checkpoint inhibitors for tumors with driver mutations should only be considered after all appropriate targeted therapy and chemotherapy have been exhausted. PD-L1 testing presents a valuable tool to guide treatment sequencing and we recommend use of agent-specific PD-L1 tests and respective scoring systems until a standardized, convenient and broadly applicable test is identified.


Checkpoint inhibitors represent a major advance in the treatment of advanced NSCLC and PD-L1 status can inform treatment decisions.


Biomarkers; Checkpoint inhibitors; Lung cancer; NSCLC; PD-L1

[Indexed for MEDLINE]

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