Aug. 14, 2002 -- A promising new drug that zaps cancerous cells while leaving healthy ones unharmed is quickly finding new uses in treating previously untreatable types of cancer. New research shows the 'smart bomb' anticancer drug Gleevec can provide a valuable new treatment option for people with a rare and usually fatal form of stomach and intestinal cancer. Gleevec may also be useful in treating a rare bone marrow disease.
But researchers found Gleevec was able to shrink tumors in more than half of the 147 patients who received the drug. Although no one had a complete remission, the tumor size was reduced by 50% to 96% in those who responded to the drug.
The findings appear in the Aug. 15 issue of TheNew England Journal of Medicine. Early results from this clinical trial prompted the FDA to approve Gleevec for treating GIST earlier this year.
The study found patients began to respond after an average of 13 weeks of daily treatment with the drug. And the benefits lasted more than 6 months.
Researchers say the drug works by blocking a substance that causes GIST to grow and spread.
Study author George D. Demetri, MD, of the Dana-Farber Cancer Institute and Harvard Cancer Center in Boston, and colleagues say targeting these growth-related mechanisms "is a promising treatment for advanced gastrointestinal stromal tumors, which resist traditional chemotherapy."
But the study authors caution that more research is needed to determine if using the drug actually prolongs life for people with this aggressive form of cancer.
In addition, they say new strategies are needed for increasing response to the drug and reducing resistance. Other studies of Gleevec have suggested that its effectiveness can wear off over time in some people as their bodies become resistant to the drug.
In a second study in the journal, researchers found that Gleevec also works well for people with a cancer-like condition of bone marrow called chronic myeloproliferative disease. However, since Gleevec works specifically on one gene abnormality, the drug was tested only in people who had this gene mutation. The four participants in the study all had improvements that lasted for 9 to 12 months. More study is needed to see if the response will last longer.