People with advanced gastrointestinal stromal tumors (GIST) who take Gleevec (imatinib) for prolonged periods continue to benefit from the drug, according to a five-year study by Oregon Health & Science University Cancer Institute researchers.
The study was led by Charles Blanke, M.D., leader of the OHSU Cancer Institute Solid Tumors Program, with colleagues at OHSU, Dana-Farber Cancer Institute, the Fox Chase Cancer Center, and the University of Helsinki. The study was presented at the recent 2006 annual meeting of the American Society of Clinical Oncology.
It represents the long-term analysis of a randomized clinical trial begun in 2000. More than half of study participants saw their GIST go into remission on Gleevec. Those promising early results prompted the U.S. Food and Drug Administration to approve Gleevec as a treatment for GIST on Feb. 1, 2002.
The long-term analysis, completed in 2005, continues to demonstrate promising results. Eighty-four percent of the 147 GIST study participants on Gleevec showed clinical improvement during the study period, meaning that their disease stabilized or went into remission. Two of those experienced complete remission. However, some subjects developed resistance to the drug and some experienced a relapse of their cancer.
It typically took 13 weeks before a study participant responded to the drug, and the typical positive response lasted 118 weeks (2.3 years).
"This study shows that the response to Gleevec among GIST patients is durable," Blanke said. "Molecularly targeted therapy helps extend their lives."