According to a recent article published in the Journal of Clinical Oncology, patients with non-small cell lung cancer who have increased mutations of the epidermal growth factor receptor (EGFR) appear to experience significant improvements in survival when treated with Iressa® (gefinitib) compared to patients with normal EGFR.
Lung cancer remains the leading cause of cancer-related death in the world. In fact, lung cancer is responsible for more deaths annually in the United States than breast cancer, colon cancer and prostate cancer combined. Non-small cell lung cancer (NSCLC) refers to the type of cell within the lung that the cancer originated and accounts for approximately 75%-80% of all lung cancers.
A significant proportion of lung cancer expresses epithelial growth factor receptors (EGFR). EGFR is a protein that is involved in the growth and replication of a cell. In some cancers, the EGFR may not be working properly, leading to excessive replication of the cancer cell.
Several novel compounds, called EGFR inhibitors, are targeted against the receptor. Iressa is a small, oral agent that binds to a portion of EGFR and blocks part of the biochemical pathway initiated by EGFR that induces cancer cells to grow.
Previous results have demonstrated that Iressa produces anti-cancer responses in some patients with NSCLC that have stopped responding to standard therapies. However, results from other trials have failed to demonstrate that Iressa produces an improvement in survival overall in these patients. This has resulted in a restriction in the ability for all patients with NSCLC to obtain Iressa for treatment.
Results from more recent trials have demonstrated that specific subgroups of patients with NSCLC, specifically those with mutations within the EGRR, may obtain significant benefit from treatment with Iressa, while patients who do not have these mutations do not appear to achieve this benefit.
Researchers from Japan have recently conducted a clinical study to evaluate outcomes related to EGFR mutations in patients with NSCLC who were treated with Iressa.
This trial included 66 patients with NSCLC who experienced a cancer recurrence following prior treatment. All patients were of Japanese ethnicity; some patients had received previous chemotherapy, and some had only undergone surgery. The researchers studied their cancer specimens for specific EGFR mutations, or excess copies of the EGFR.
Overall, EGFR mutations or excess copies of EGFR were associated with significantly improved survival following treatment with Iressa:
• Thirty-nine patients (59%) had EGFR mutations
• Anti-cancer responses to Iressa were achieved in 82% of patients with EGFR mutations compared to only 11% of patients without EGFR mutations
• The median time to cancer progression was 12.6 months in patients with EGFR mutations and only 1.7 months in patients without EGFR mutations
• The median overall survival was 20.4 months in patients with EGFR mutations, compared with only 6.9 months in those without mutations
• 29 patients (44%) had excess EGFR copies
• Anti-cancer responses to Iressa were achieved in 72% of patients with excess copies of EGFR and only in 38% of patients with normal EGFR copies
• The median time to cancer progression was 9.4 months in patients with excess copies of EGFR and only 2.6 months in patients with normal EGFR copies
The researchers concluded that EGFR mutations and/or excess copies of EGFR appear to play a significant role in outcomes of patients with NSCLC. Patients with mutations or excess copies of EGFR experienced significantly improved anti-cancer response rates, improved time to cancer progression and improved overall survival compared to patients with normal EGFR following treatment with Iressa.
Patients with recurrent NSLC may wish to speak with their physician regarding their individual risks and benefits of treatment with Iressa or other EGFR inhibitors.
Reference: Takano T, Ohe Y, Sakamoto H, et al. Epidermal Growth Factor Receptor Gene Mutations and Increased Copy Numbers Predict Gefitinib Sensitivity in Patients With Recurrent Non–Small-Cell Lung Cancer. Journal of Clinical Oncology. 2005; 23: 6829-6837.
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