Good and Bad News About Cancer Drug
Dec. 7, 2001 -- The cancer drug Gleevec made a big splash earlier this year when it came onto the scene as the first drug that gets right to the core of the cancer. New studies show that it continues to offer hope for people fighting a difficult-to-treat type of leukemia, but researchers are starting to see problems.
Gleevec was approved in May of this year for treatment of chronic myeloid leukemia (CML). In CML, white blood cells grow out of control, eventually driving out oxygen-carrying red blood cells. The person then develops chronic anemia and wastes away. About 4,500 Americans per year develop this malignancy, which is often untreatable in its later stage.
CML is caused by a genetic abnormality and Gleevec stops this mutation in its tracks. Previous research has shown that Gleevec can dramatically reduce the number of cancer cells in the blood.
In a new study presented at a meeting of cancer specialists, Hagop M. Kantarjian, MD, looked at more than 500 people with CML. They had not responded to or were unable to tolerate previous treatment, so they were put on Gleevec. Kantarjian is with M.D. Anderson Cancer Center in Houston.
With Gleevec, more than 90% of the study participants had their blood counts return to normal. The drug also dramatically decreased the number of cancer cells in more than half of these people, and 35% had a complete response. Severe side effects occurred in about 5% of people who took it.
The study was funded by Novartis pharmaceuticals, Gleevec's manufacturer.
But researchers are beginning to see that over time, some become resistant to Gleevec's effects. After one year, this happened in 8%, and 3% died.
But this death rate is much less than for people who do not respond to traditional treatment. Typically, up to 20% of these people would die each year.
In a second presentation at the meeting, Andreas Hockhaus, of the University of Heidelberg, Germany, reported that Gleevec can, in fact, lead to genetic changes that make the drug not work.
Gleevec continues to show great promise for the treatment of CML. And we will likely see a flurry of research into drugs that get to the core of the genetic mutations that cause the cancer. Treatments like this will hopefully one day lead to more use of the word "cure" when talking about cancer.