Iressa® Benefits Selected Patients with Refractory Non-Small Cell Lung Cancer
According to a study published in the Lancet and previously presented at the 2005 World Conference on Lung Cancer, treatment of refractory non-small cell lung cancer with Iressa® (gefitinib) does not produce an overall survival benefit, but may benefit patients of Asian ancestry and those who have never smoked.
Lung cancer remains the leading cause of cancer death in the U.S. Non-small cell lung cancer (NSCLC) is the most common type of lung cancer, accounting for 75%-80% of all lung cancers. In most circumstances, NSCLC is not curable unless the disease is treated surgically before it has spread.
Iressa is an anticancer agent that selectively blocks the epidermal growth factor receptor (EGFR). EGFR is a protein involved in the growth and replication of a cell. In some cancers, the EGFR may not be working properly; this leads to excessive replication of the cancer cell. Iressa is taken orally and binds to a portion of EGFR to inhibit cancer cell growth.
In order to evaluate whether treatment with Iressa improves survival among patients with NSCLC that has stopped responding to chemotherapy (refractory NSCLC), researchers conducted a phase III clinical trial. A total of 1692 patients were enrolled from 28 countries across Europe, Asia, Central and South America, and Canada. Patients were randomly assigned to receive either Iressa (1129 patients) or a placebo (563 patients).
After roughly 7 months of follow-up, survival did not differ significantly between study groups: Median survival among patients treated with Iressa was 5.6 months, compared to 5.1 months among patients treated with placebo. Analyses of particular groups of patients, however, identified some who might benefit from treatment with Iressa:
- Among patients of Asian ancestry, survival was longer after treatment with Iressa (9.5 months) than after treatment with placebo (5.5 months).
- Never-smokers also appeared to derive a benefit from treatment with Iressa. Never-smokers treated with Iressa survived for a median of 8.9 months, while never-smokers treated with placebo survived for a median of 6.1 months.
Adverse effects that occurred more commonly among patients receiving Iressa included rash and diarrhea. There was no significant difference between treatment groups in the frequency of serious adverse events.
The researchers conclude that in the overall study population of patients with refractory NSCLC, treatment with Iressa did not improve survival. It’s possible, however, that certain patient subgroups, such as patients of Asian ancestry and never-smokers, may derive a survival benefit from treatment with Iressa.
Reference: Thatcher N, Chang A, Parikh P et al. Gefitinib plus best supportive care in previously treated patients with refractory advanced non-small-cell lung cancer: results from a randomized, placebo-controlled, multicentre study (Iressa Survival Evaluation in Lung Cancer). Lancet. 2005;366:1527-37.
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