The U.S. Food and Drug Administration has announced the approval of the first drug that directly turns off the signal of a protein known to cause cancer. 

The drug, called Gleevec, was discovered and developed by Novartis Oncology as a treatment for chronic myelogenous leukemia (CML).

CML is a disease in which too many white blood cells are made in the bone marrow. In the first stages of CML, most people do not have any symptoms of cancer, and the disease progresses slowly. Bone marrow transplantation in the initial phase is the only known cure, but many patients are not young or healthy enough to tolerate transplantation or do not have a suitable donor. The procedure can also cause serious side effects or death.

Treatment with the drug interferon alfa may produce remission, restoring a normal blood count in up to 70% of patients with CML. If interferon alfa is ineffective , the prognosis is generally bleak. But Gleevec has produced higher remission rates, restoring normal blood counts in 53 out of 54 interferon-resistant patients.

While other drugs may interfere with proteins associated with certain cancers, Gleevec is the first to interfere with a protein that directly causes the disease.