April 23, 2007

Gleevec Helps Prevent Return of Type of Gastrointestinal Tumor

Photo of Gleevec tablets next to pharmaceutical bottle Daily Gleevec tablets helped to prevent the return of cancer in patients with a rare form of gastrointestinal cancer. GIST Support International

Preliminary findings from a large clinical trial expand the potential use for Gleevec, one of a new class of cancer drugs specifically designed to block abnormal proteins that lead to tumor growth. After surgical removal of a rare type of gastrointestinal tumor, patients who took daily Gleevec tablets were significantly less likely to have the cancer return than patients who didn't take the drug. The results were announced because the study had met its main goal of boosting survival without cancer recurrence.

Gleevec, or imatinib mesylate, has already been approved by the U.S. Food and Drug Administration (FDA) to treat two types of cancer, including rare stomach or intestinal cancers known as gastrointestinal stromal tumors (GIST). By some estimates, up to 6,000 patients are newly diagnosed with GIST each year in the U.S. FDA approval, however, addresses only specific forms of GIST that are inoperable or that have metastasized, spreading to other parts of the body.

This new clinical study provides evidence that the drug may also help to reduce the risk of cancer recurrence in patients after surgical removal of their primary GIST. The study was sponsored by the NIH National Cancer Institute (NCI) and conducted by a network of researchers led by the American College of Surgeons Oncology Group. Gleevec tablets were provided by Novartis Pharmaceutical Corporation.

The study included more than 600 patients whose primary GIST had been completely removed. Within 10 weeks after surgery, patients were randomly assigned to take daily pills containing either an inactive substance (placebo) or 400 milligrams of imatinib. Neither patients nor their physicians knew which type of pills had been received.

After a year of treatment, only about 3% of patients taking imatinib had a recurrence of their cancer, compared to 17% of patients who had received placebo. In addition, the imatinib treatments were well-tolerated in most patients. Side effects included nausea, diarrhea and swelling. Although the drug reduced cancer recurrence, there was no difference in overall survival for patients in the two treatment arms of the trial.

"Gleevec was one of the first targeted therapies that showed remarkable efficacy in clinical trials,” said NCI Director Dr. John E. Niederhuber. “These current results emphasize the need to continue to investigate all possible uses of these cutting-edge drugs and to make them available to as many patients as possible.”

Ongoing clinical trials funded by NCI are exploring the potential of imatinib and related targeted therapies for treating a wide variety of cancers, including melanoma, breast cancer, brain tumors and certain types of leukemia.