What is the role of gefitinib in the treatment of non-small cell lung cancer (NSCLC)?

Updated: Aug 21, 2019
  • Author: Maurie Markman, MD, MS; Chief Editor: Keith K Vaux, MD  more...
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Answer

Answer

Gefitinib was the first EGFR-TKI evaluated in a phase III trial. In July 2015, gefitinib was approved by the FDA as first-line treatment of patients with metastatic NSCLC whose tumors have EGFR exon 19 deletions or exon 21 (L858R) substitution mutations, as detected by an FDA-approved test. Approval as first-line treatment for metastatic NSCLC is based on data from the IFUM (IRESSA Follow-Up Measure) clinical trial, which showed an overall response rate (ORR) of about 50%, with a median duration of response of 6 months. [15]

The IFUM results were supported by the most recent analysis of the IPASS (IRESSA Pan-ASia Study) study, which assessed gefitinib versus carboplatin/paclitaxel as a first-line treatment in these patients. The subset population consisted of 186 of 1217 patients (15%) determined to be EGFR positive by the same clinical trial assay used in IFUM, and they had radiographic scans available for a retrospective assessment. IPASS showed an ORR of 67% and a median duration of response of 9.6 months in gefitinib-treated patients, versus a 41% ORR with a median duration of response of 5.5 months for the carboplatin/paclitaxel group. Mean progression-free survival (PFS) was 10.8 months in the gefitinib group versus 5.4 months for the carboplatin/paclitaxel patients. [16]

Data from a phase III study of gefitinib conducted in Asia more clearly indicated that EGFR mutation status could influence the choice of first-line treatment options. [17, 18] In this study, known as the Iressa Pan-Asia Study, or IPASS, previously untreated never-smokers and light ex-smokers with advanced NSCLC adenocarcinomas were randomized to gefitinib versus carboplatin/paclitaxel. Patients who were positive for an activating EGFR mutation demonstrated significantly longer progression-free survival when treated with gefitinib than with carboplatin-paclitaxel, whereas patients who were negative for the mutation had significantly longer progression-free survival with carboplatin-paclitaxel; overall survival rates did not differ between the groups.


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