0001), regardless of clinical characteristics [8]. With regards to the co-primary endpoint, namely PFS in patients with high EGFR protein expression as assessed by immunohistochemistry (IHC), PFS was significantly longer in patients with EGFR IHC-positive tumors who received erlotinib versus placebo (p < 0.0001). EGFR IHC-positive disease was defined in SATURN as any

membrane staining in ≥10% of tumor cells. A prospective biomarker analysis from this study found that the interaction between treatment and EGFR IHC status was not significant for PFS (p = 0.63) or overall survival (OS; p = 0.52), suggesting no differential effect of erlotinib between IHC-positive and IHC-negative groups [9]. Cetuximab, a chimeric monoclonal antibody Staurosporine purchase targeting EGFR, has also been investigated in advanced NSCLC. In a major phase III clinical trial, the FLEX study, the investigators Trichostatin A datasheet demonstrated that the addition

of first-line cetuximab to cisplatin and vinorelbine significantly improved OS (p = 0.044) compared with chemotherapy alone in patients with stage IV NSCLC [6]. In an attempt to increase the clinical benefit–risk ratio of this combination, the investigators examined the expression of EGFR by IHC as a potential predictive factor [10]. They used the H-score method with magnification rule, as previously proposed by Hirsch et al. [11] to define staining intensity across different categories [12]. A score was assigned to each patient on a continuous scale of 0–300 with an outcome-based discriminatory threshold calculated at 200. Based on this categorization, EGFR IHC-positive status (H-score ≥ 200) was associated Dynein with improved OS for patients who received cetuximab, whereas patients with EGFR IHC-negative status (H-score < 200) had no OS benefit with cetuximab [10]. We hypothesized that this scoring system with magnification rule might help to predict outcomes in patients treated with EGFR TKIs as maintenance therapy. We therefore re-examined existing available samples from the SATURN study using this alternative EGFR IHC reading and scoring method, to determine whether the

new classification would lead to any correlation between EGFR IHC status and survival outcomes with erlotinib in this setting. Between December 2005 and May 2008, 1949 patients were screened and received platinum-doublet chemotherapy. A total of 889 patients had non-progressive disease after chemotherapy and were suitable for randomization into the SATURN study. Following stratification (according to EGFR IHC status, disease stage, Eastern Cooperative Oncology Group [ECOG] performance status [PS], chemotherapy regimen, smoking status and region), patients were randomized to receive either erlotinib (150 mg/day) or placebo until disease progression or unacceptable toxicity. The SATURN inclusion/exclusion criteria and methodology are further detailed in the original manuscript [8]. The study was carried out in accordance with the Declaration of Helsinki and Good Clinical Practice guidelines.