The following article features coverage from the European Society of Medical Oncology (ESMO) 2017 Congress in Madrid, Spain. Click here to read more of Cancer Therapy Advisor’s conference coverage.

Patients with PD-L1 negative non-small cell lung cancer (NSCLC) treated with atezolizumab may experience an overall survival (OS) benefit regardless of the PD-L1 IHC assay utilized, according to a study presented at the European Society for Medical Oncology (ESMO) 2017 Congress.1

The phase 3 OAK trial ( Identifier: NCT02008227) demonstrated that previously treated patients with advanced NSCLC experienced prolonged OS with atezolizumab compared to docetaxel regardless of PD-L1 status. Researchers investigated whether these results would be consistent across patients who were confirmed to be PD-L1 negative by varying assays.

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In this study, researchers determined PD-L1 expression in patients with NSCLC prospectively using the SP142 assay and then retrospectively with the Dako 22C3 pharmDx PD-L1 assay.

Of the 850 patients in the primary population, 400 patients were evaluable by the 22C3 assay. Seventy-seven percent of patients found to be PD-L1 negative by the SP142 were confirmed to not express PD-L1 by the 22C3 assay.

Patients who were PD-L1 negative in both arms experienced a comparable OS benefit once treated with atezolizumab. Patients with the highest levels of PD-L1 expressions also experienced an improved clinical benefit.

The authors of the study concluded that “These data provide evidence of [atezolizumab] OS benefit in [patients] with PD-L1–negative tumors irrespective of the PD-L1 IHC assay used.”

RELATED: Similar Survival Benefit Observed in Both Simple and Extensive NSCLC Follow-up

Read more of Cancer Therapy Advisor‘s coverage of the European Society of Medical Oncology (ESMO) 2017 Congress by visiting the conference page.


  1. Gadjeel S, Kowanetz M, Zou W, et al. Clinical efficacy of atezolizumab (Atezo) in PD-L1 subgroups defined by SP142 and 22C3 IHC assays in 2L+ NSCLC: results from the randomized OAK study. Presented at: ESMO 2017 Congress; Madrid, Spain: September 8-12, 2017. Abstract 1296O.