OBJECTIVE: To describe programmed cell death ligand-1 (PD-L1) testing patterns and results among patients with metastatic non-small cell lung cancer (NSCLC) in the United States (US), United Kingdom (UK), Germany, Spain, and Canada.
METHODS: Physicians provided a retrospective medical record review of patients diagnosed with metastatic NSCLC from January 2011 to March 2016. Patient characteristics and PD-L1 testing at initial diagnosis were descriptively assessed.
RESULTS: Data were abstracted from 204 US, 206 UK, 212 German, 205 Spanish, and 55 Canadian patients. The majority of patients were male (US, 63.2%; UK, 60.7%; Germany, 69.3%; Spain, 75.1%; Canada, 65.5%). Most were initially diagnosed with stage IV disease (US, 74.5%; UK, 82.0%; Germany, 88.7%; Spain, 83.4%; Canada, 43.6%); the remaining presented initially with earlier stage disease and subsequently developed metastases. Distant lymph node metastases were observed in 32.6% (US), 33.3% (UK), 21.9% (Germany), 30.3% (Spain), and 36.4% (Canada) of patients. In each country, approximately 90% of patients were current or former smokers. PD-L1 testing at initial diagnosis occurred in 34.3% (US), 27.2% (UK), 31.6% (Germany), 17.1% (Spain), and 34.6% (Canada) of patients. Among these patients, 55.7% (US), 62.5% (UK), 37.3% (Germany), 48.6% (Spain), and 26.3% (Canada) tested positive. The mean (SD) percent of tumor cells staining for PD-L1 was 33.9% (34.3) in the US, 31.1% (31.1) in the UK, 16.7% (24.0) in Germany, 17.2% (23.5) in Spain, and 33.1% (21.7) in Canada. The Dako assay was used most often in the UK, while “other/not specified” was most frequently reported in the US and Canada. Physicians in Germany and Spain did not report which assay they used most often.
CONCLUSIONS: Despite similar distributions of risk factors (e.g., smoking history, nodal disease, stage IV disease) for elevated PD-L1 expression across countries and the recent introduction of highly effective anti-PD-L1 agents, PD-L1 testing rates remain low.
