Gleevec has been found effective in treating yet another rare and fatal blood disorder and, at the same time, has opened another pathway in cancer discovery and research.
Researchers from Brigham and Women's Hospital and Harvard Medical School, intrigued by reports of Gleevec's effectiveness in patients with hypereosinophilic syndrome (HES), decided a gene inhibited by Gleevec may be the cause of the disease. HES is a proliferation of certain white blood cells, known as eosinophils, that specialize in attacking worms and other parasites.
"Usually researchers first have to understand a disease to find a treatment," said Brian Druker, M.D., JELD-WEN Chair of Leukemia Research at Oregon Health & Science University Cancer Institute and a Howard Hughes Medical Investigator. "But in this case, understanding Gleevec helped lead to the discovery of a cancer-causing gene."
While traditional chemotherapy attacks all cells, both cancerous and normal, Gleevec works by stopping action of an enzyme known to drive the growth of chronic myelogenous leukemia (CML). This mechanism of action offered clues to the gene causing HES -- a gene connected to the same enzyme Gleevec inhibits.
The current study, published in the March 27, 2003, issue of the New England Journal of Medicine, treated 11 HES patients with Gleevec and identified the molecular cause of their response. All but one have remained free of the disease, some for as long as 18 months.
Druker, in collaboration with scientists at Novartis, helped develop Gleevec to target the molecular cause of CML. In 2001 the FDA broke a record for cancer therapy approval by fast-tracking Gleevec and approving it in less than three months for patients who failed interferon treatment. In 2002, the FDA also approved Gleevec as an effective treatment for gastrointestinal stromal tumors, a deadly form of intestinal cancer that, until then, had been difficult to treat.