Clinical trial of gefitinib for advanced lung cancer closes early

Researchers have closed a randomized clinical trial comparing gefitinib (IressaTM) vs. placebo following chemotherapy and radiation for patients with non-small cell lung cancer (NSCLC) that had spread only to nearby tissues or lymph nodes. Review of interim data indicated that gefitinib would not improve survival.

The clinical trial was sponsored by the National Cancer Institute (NCI), part of the National Institutes of Health in Bethesda, Md., and was conducted by a network of researchers led by the Southwest Oncology Group (SWOG), Ann Arbor, Mich. AstraZeneca Pharmaceuticals LP, Wilmington, Del., which manufactures gefitinib, provided the agent for the trial under the Clinical Trials Agreement with NCI for the development of gefitinib. Iressa is a drug that inhibits an enzyme (tyrosine kinase) present in lung cancer cells, as well as other cancers and normal tissues, that appears to be important to the growth of cancer cells.

Based on a review of the limited data available from the Phase III clinical trial, the Data Monitoring Committee overseeing the trial (known as S0023*) recommended the closure, as the trial would not meet its primary endpoint of improved survival. Detailed results from the study will be presented at the American Society of Clinical Oncology Annual Meeting (ASCO) on May 14, 2005.

The study was designed to assess whether maintenance therapy with gefitinib — gefitinib given to help keep cancer in control — would improve overall survival and progression-free survival as compared to placebo in patients with stable or responding disease. These patients had inoperable stage III NSCLC and already had completed the combined chemotherapy regimen of cisplatin and etoposide with radiation, followed by docetaxel. A total of 672 patients in this study were to be randomized to one of two treatment arms following chemotherapy and radiation: one arm would receive gefitinib daily and the other arm would receive a placebo daily. As of March 10, 2005, 611 patients were entered and 276 were randomized to one of the two arms.

“The interim analysis indicates that even with accrual of more patients or with longer follow-up, the gefitinib arm would not improve survival,” said Laurence Baker, D.O., chairman of SWOG and professor of internal medicine and pharmacology at the University of Michigan in Ann Arbor. This analysis did confirm, however, the favorable survival seen with the chemotherapy and radiation regimen previously reported by SWOG**, and thus patients currently entered in the trial are being advised to complete this part of their treatment.

“Based on the analysis, the use of gefitinib following chemotherapy and radiation should not be prescribed for this group of patients,” said Scott Saxman, M.D., who oversees lung cancer clinical trials for NCI.

An estimated 172,570 people will be diagnosed with lung cancer in the United States in 2005. Lung cancer is the second most commonly diagnosed cancer and the leading cause of cancer-related death in both men and women in this country. An estimated 163,510 deaths from lung cancer will occur in 2005 in the United States, accounting for about 29 percent of all cancer-related deaths in the nation.