Characterizing the ALK-positive NSCLC population in Europe

Following on from the positive data reported by Dr Alice Shaw on the Phase 3 trial of crizotinib as second-line therapy for patients with anaplastic lymphoma kinase (ALK)-positive non-small-cell lung cancer (NSCLC), findings from the European Thoracic Oncology Platform Lungscape Project, which is evaluating the prevalence of ALK positivity in resected stage I-III lung adenocarcinomas in Europe, were met with great interest.

In the Proffered Papers Session (Sunday Sep. 30th, ESMO, 2012 Vienna) on Biomarkers in Lung Cancer, Dr Fiona Blackhall from the Christie Hospital NHS Foundation Trust, Manchester, UK, explained that the prevalence of ALK-positive patients with NSCLC in Europe is unknown. As such, the Lungscape Project is providing a platform for evaluating the expression and clinical significance of ALK in a large cohort of patients with resected NSCLC (www.etop-eu.org).

At the time of her presentation, Dr Blackhall said that 15 European sites are currently participating in the study. These sites have retrospectively identified cases of NSCLC with clinical demographic and outcome data, and available tissue for research according to predefined protocol criteria. Accepted cases on the basis of completeness of clinical data were assessed for ALK expression using immunohistochemistry (IHC) and fluorescence in situ hybridization (FISH) was performed on ALKpositive cases and matched ALK-negative controls.

Dr Blackwell advised that 1099 patient cases have been included in the database so far, 69 (6.3%) of which were ALK-positive by IHC. There was a high level of concordance between ALK IHC0+ and FISH+ (90.5% sensitivity and 97.7% specificity between ALK IHC 3+ and ALK FISH+). ALK IHC+ and ALK FISH+ also appear to provide prognostic information in patients with early-stage, resected adenocarcinoma, Dr Blackwell noted.

Dr Blackwell said that these findings represent the first large European dataset evaluating prevalence and outcome of ALK positivity in patients with stage I-III, resected lung adenocarcinoma, using IHC and FISH confirmation.