First-line treatment with Iressa® (gefitinib) improves progression-free survival over combination treatment with Paraplatin® (carboplatin) and Taxol® (paclitaxel) in advanced non–small cell lung cancer (NSCLC) among nonsmokers and former light smokers in East Asia, according to the results of a study published in the New England Journal of Medicine.

Non–small cell lung cancer (NSCLC) accounts for roughly 85% of all lung cancers; non–small cell refers to the type of cell within the lung where the cancer originated. In advanced NSCLC cancer has spread outside the lung; standard therapy for this stage of disease includes chemotherapy. However, chemotherapy is often difficult to tolerate. Another approach to treatment utilizes agents targeted specifically against cancer cells; these targeted agents may have fewer side effects.

Iressa is an oral agent that is targeted specifically against the human epidermal growth factor receptor (EGFR). EGFR is a protein that is found on the surface of cells and is involved in cellular growth, spread, and replication. Cancerous cells often overexpress EGFR or have mutations within EGFR, leading to uncontrolled growth or spread of the cancer cells. Iressa binds to EGFR and halts or reduces its effects on cancer cells.

This Phase III multicenter study involved 1,217 patients from East Asia who were nonsmokers or former light smokers and had previously untreated advanced (Stage IIIB or IV) NSCLC. The patients were randomly assigned to receive Iressa or Paraplatin/Taxol. The median progression-free survival was 5.7 months in the Iressa group and 5.8 months in the Paraplatin/Taxol group. The 12-month rate of progression-free survival was 24.9% with Iressa and 6.7% with Paraplatin/Taxol. The objective response rate was 43% in the Iressa group compared with 32.2% in the Paraplatin/Taxol group.

Out of the total study group of 1,217 patients, EGFR data was evaluated for 437 patients; 261 patients tested positive for an EFGR mutation. In this subgroup of 261 patients, progression-free survival was significantly longer among those receiving Iressa compared with those receiving Paraplatin/Taxol. Conversely, in the 176 patients who were EGFR-negative, progression-free survival was significantly longer in the group of patients receiving Paraplatin/Taxol compared with those receiving Iressa. In the mutation-positive subgroup, the objective response rate was 71.2% with Iressa and 47.3% with Paraplatin/Taxol. In the mutation-negative subgroup, the objective response rate was 1.1% with Iressa and 23.5% with Paraplatin/Taxol.

Iressa was associated with less severe side effects, and patients receiving it reported a better quality of life than those receiving Paraplatin/Taxol. The most common side effects in the Iressa group were rash, acne, and diarrhea, whereas the most common side effects in the Paraplatin/Taxol group were neurotoxicity, low blood counts, and hair loss.

The researchers concluded that Iressa is superior to Paraplatin/Taxol as first-line treatment for advanced NSCLC in this population. An EGFR-positive tumor is a strong predictor for a better outcome with Iressa.

Reference: Mok TS, Wu YL, Thongprasert S, et al. Gefitinib or carboplatin-paclitaxel in pulmonary adenocarcinoma. New England Journal of Medicine [early online publication]. August 19, 2009.

Copyright © CancerConsultants. All Rights Reserved.