Comparison of gefitinib and erlotinib efficacies as third-line therapy for advanced non-small-cell lung cancer☆

https://doi.org/10.1016/j.ejca.2012.07.014Get rights and content

Abstract

Purpose

The epidermal growth factor receptor inhibitors, gefitinib and erlotinib, are used as standard salvage therapy for advanced non-small-cell lung cancer (NSCLC). The aim of the present study was to compare their efficacies in this population.

Patients and methods

The Taiwan Cancer Registry and the National Health Insurance claim databases were searched for newly diagnosed patients with NSCLC from 2004 to 2007 who received gefitinib or erlotinib as third-line therapy. Overall survival (OS) and time to treatment failure (TTF) were determined from registered parameters. Treatment efficacies were compared by the log-rank test in total population and subsets with different clinical characteristics. The Cox’s proportion hazard model was used to estimate the adjusted hazard ratios in multivariate analyses.

Results

A total of 984 patients who received gefitinib (67%) or erlotinib (33%) were included. Patients receiving gefitinib or erlotinib had similar OS (median, 10.2 versus 9.9 months, p = 0.524) and TTF (median, 5.5 versus 3.4 months, p = 0.103). In multivariate analyses, both treatment groups had similar risk of overall mortality (adjusted hazard ratio [HR] = 1.04, p = 0.629) and treatment failure (adjusted HR = 0.94, p = 0.417). Comparing the treatments in subgroups based on age, tumour histology and gender also revealed no differences in OS and TTF. For patients who received gefitinib or erlotinib for more than 3 or 6 months, there was no difference in TTF but patients who received erlotinib had longer OS.

Conclusions

Gefitinib and erlotinib had similar efficacies as salvage therapy for advanced NSCLC in Taiwan.

Introduction

The epidermal growth factor receptor (EGFR) tyrosine kinase inhibitors (TKI), gefitinib and erlotinib, are used for the treatment of advanced non-small cell lung cancer (NSCLC) worldwide. In East Asia, both gefitinib and erlotinib are used as standard salvage therapy for patients with NSCLC refractory to cytotoxic chemotherapy.1, 2, 3 For patients with tumours harbouring activating EGFR mutations, randomised studies demonstrated that the use of gefitinib and erlotinib as first-line therapy could prolong progression-free survival (PFS) compared to cytotoxic chemotherapy.4, 5, 6

Although the mechanism by which gefitinib and erlotinib inhibit EGFR function is similar,7 whether they possess comparative efficacy as salvage therapy for NSCLC remains controversial.8 A series of case studies showed that an objective response or stable disease can be observed in some patients who received erlotinib after treatment failure using gefitinib for advanced NSCLC.9, 10, 11, 12 However, two phase II studies using erlotinib in such patients showed overall response rates of only 4–10%.13, 14

One randomised phase II study compared the efficacies of gefitinib and erlotinib as salvage therapy for NSCLC.15 The study enrolled 96 patients with advanced NSCLC who had failed or were intolerable to first-line chemotherapy. Patients receiving gefitinib and erlotinib had no statistically significant difference in overall response rates (48% versus 40%) and PFS (median 4.9 versus 3.1 months). The limited patient number greatly reduced the statistical power to detect efficacy differences between the two drugs.

Two single-institution retrospective studies compared the efficacies between gefitinib and erlotinib. Neither of the studies restricted the lines of previously failed chemotherapy.16, 17 Although response rates of EGFR TKIs may be similar when used as first-line and second-line treatments,18 the imbalance of previous lines of chemotherapy may have impact on the interpretation of survival outcomes. Furthermore, single-institution studies are inherent to selection bias.

The claim database of Taiwan’s National Health Insurance (NHI), a mandatory single-player health insurance system in Taiwan, provides an opportunity to examine such an issue. Physicians have to apply for the use of gefitinib or erlotinib with initial pathology diagnosis and image studies confirming disease progression after prior chemotherapy. Gefitinib or erlotinib has to be reapplied every 3 months with imaging evidence (e.g. the report of the chest computed tomography) showing no disease progression, which had to be peer-reviewed. No more than 14 d of gefitinib or erlotinib can be prescribed in one visit. Such a strict regulation enabled us to estimate the time to treatment failure (TTF) and ensured that the use of gefitinib and erlotinib followed the approved indications. We thus designed this study to examine the comparative efficacies of gefitinib or erlotinib as the third-line therapy for advanced NSCLC, combining items in the databases of Taiwan Cancer Registry (TCR), NHI and the National Death Registry (NDR).

Section snippets

Data source

A population-based retrospective cohort was established by linking two national databases, the TCR, which is managed by the Bureau of Health Promotion (BHP), Department of Health, Taiwan,19, 20 and the claim database of Taiwan’s NHI. All major cancer care providers in Taiwan are obligated to input data into the TCR, which covers approximately 78% of the newly diagnosed cancer patients.19 The TCR database provided information regarding patient demographics, initial tumour stages and histology.

Results

A total of 984 patients (median age, 61.5 years) were included in this study (Fig. 1). As shown in Table 1 and 47% of the patients were female, and 80% had adenocarcinoma. The most frequently used first-line chemotherapeutic agent other than platinum was gemcitabine (63%). More than 60% of patients received docetaxel as the second-line therapy. Among the study population, 655 (67%) patients received gefitinib, and 329 (33%) patients received erlotinib as the third-line therapy for NSCLC.

Discussion

In the present study, similar OS and TTF were observed between the gefitinib and erlotinib treatment groups as salvage therapy for advanced NSCLC. The comparative efficacies were shown in most subgroups analysed, including those grouped by histology (adenocarcinoma or squamous cell carcinoma) and gender, which is compatible to a small randomised study and two single-institution retrospective studies.15, 16, 17 The present study is the largest to address the efficacy difference between gefitinib

Conflict of interest statement

None declared.

Acknowledgement

The data used in this study were provided by the Bureau of Health Promotion, Department of Health, Taiwan (Taiwan Cancer Registry Project).

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    ☆

    Grant support: This study was supported by grants from the Bureau of National Health Insurance, Department of Health, Taiwan (DOH96-NH-1003) and the Science and Technology Unit, Department of Health, Taiwan (DOH99-TD-B-111-001 and DOH100-TD-B-111-001), and by the grant from National Center of Excellence for General Clinical Trial and Research at the National Taiwan University Hospital (NCTRC200847).

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