Evaluation of epidermal growth factor receptor (EGFR) as a predictive marker in patients with non-small-cell lung cancer (NSCLC) receiving first-line gefitinib combined with platinum-based chemotherapy

7013 Background: In two Phase III trials (INTACT 1 & 2), gefitinib (‘Iressa’, ZD1839) in combination with first-line platinum-based chemotherapy regimens failed to show benefit in terms of survival when compared with chemotherapy alone in patients (pts) with NSCLC. The primary objective of this analysis was to evaluate if EGFR staining was predictive of survival. Methods: Pretreatment tumor biopsies were assessed by immunohistochemistry for EGFR using the DakoCytomation pharmDx assay™. The percentage of tumor cells was assessed using 4 levels of intensity: no staining, 0; weak, 1+; moderate, 2+; strong, 3+; as well as the presence of complete membrane staining. 516 pts (INTACT 1/2, 219/297) with tumor samples fully evaluable for EGFR were analyzed in the per protocol population of the combined trials. The analysis was stratified by trial and performed independently for pts randomized to placebo or gefitinib. A restricted backwards elimination Cox regression analysis was conducted to identify independent E...