Epidermal growth factor receptor expression analysis in chemotherapy-naive patients with advanced non-small-cell lung cancer treated with gefitinib or placebo in combination with platinum-based chemotherapy

PURPOSE

Two large, randomized, placebo-controlled trials (IRESSA NSCLC Trial Assessing Combination Therapy; INTACT 1 and 2) in non-small-cell lung cancer (NSCLC) failed to show survival benefit for gefitinib (IRESSA) in combination with first-line platinum-based chemotherapy. Epidermal growth factor receptor (EGFR) staining was assessed retrospectively in relation to survival response to gefitinib in combination with chemotherapy.

METHODS

Tumor biopsies obtained prior to start of therapy were assessed by immunohistochemistry for EGFR using the Dako EGFR pharmDx assay (Dako, Denmark). Analyses were stratified by trial and performed independently for patients randomized to placebo and gefitinib as well as for both treatment groups combined. A restricted backwards elimination Cox regression analysis was conducted to identify independent EGFR factors that were statistically significant (P < 0.10), and these were also tested for treatment interaction to assess if they served as predictive factors.

RESULTS

Analyses found two statistically significant EGFR-based prognostic factors representing growth pattern and percent membrane staining in patients treated with gefitinib (P = 0.0023), placebo (P = 0.0128), and both combined (P < 0.0001). The prognostic effect was independent of other known prognostic factors. There was no predictive effect of either the growth pattern or membrane staining variable.

CONCLUSIONS

While some previous studies indicate that higher EGFR expression correlates with poor survival, our analyses provide statistically significant evidence that the combination of EGFR expression and growth pattern is a strong prognostic indicator for improved survival within this setting. The effects of membrane staining and growth pattern are still significant when adjusting for mutation.

The role of gefitinib in the management of Asian patients with non-small cell lung cancer

BACKGROUND

Lung cancer is the most common cause of death in cancer patients worldwide. Non-small cell lung cancer (NSCLC) accounts for approximately 85% of lung cancer cases. The prognosis of NSCLC is still poor, albeit slow and steady improvement achieved in the past three decades by chemotherapy. Recently, the importance of epidermal growth factor receptor (EGFR) in the pathogenesis and progression in NSCLC was identified particularly in those cancer cells with EGFR mutation and/or increased gene copy number. Gefitinib was the first EGFR tyrosine kinase inhibitor approved for treating advanced NSCLC [corrected] It has become a popular choice in treating Asian patients after a higher response rate was reported in Japanese patients than in non-Japanese patients in the first Phase II trial.

OBJECTIVE

To evaluate the role of gefitinib in the treatment of Asian patients with NSCLC.

METHODS

A review of published papers in PubMed and Embase (2000-2007) and meeting reports of the American Society of Clinical Oncology and World Conference on Lung Cancer (2000-2007) was carried out.

RESULTS/CONCLUSIONS

In general, gefitinib is well tolerated. As the second- or third-line treatment, gefitinib has proven survival benefits in Asian patients with advanced NSCLC, when compared with placebo. It has equivalent efficacy to docetaxel with less toxicity as the second-line therapy. As the first-line therapy, it yielded encouraging results but its final role is pending on the results of the ongoing randomised Phase III trial. Gefitinib should be considered as the treatment of choice for second- or third-line therapy in advanced NSCLC in Asian patients after progression from previous chemotherapy. Its role as the first-line, adjuvant or neoadjuvant therapy remains to be determined.