A multi-laboratory research team has been investigating heart damage caused by Gleevec, a cancer drug that specifically treats CML, chronic myelogenous leukemia. Lawyer Jeff Rasansky advises patients using Gleevec to be extremely careful and consult with their cardiologist as soon as possible.

The research was published in the August issue of Nature Medicine. The study, lead by Thomas Force, examined 10 Gleevec patients who subsequently developed heart failure -- the worst result of heart damage. The study entailed treating mice with the drug, which appeared to be toxic to cardiac cells.

Mice treated with Gleevec developed left ventricular dysfunction, one of the key symptoms of heart failure in which the heart fails to pump out blood completely. Patients taking Gleevec should be followed closely for symptoms of heart damage, Force's team advised, but that they should not necessarily discontinue use of the widely successful leukemia drug.

The FDA approved Gleevec in 2001, enthusiastic about its proven success against the rare cancer, CML. At the time of the approval, there was no reason to believe that the drug could potentially damage the heart, but the FDA?s acting commissioner, Bernard A. Schwetz, D.V.M., Ph.D. noted that future research may find additional Gleevec side effects.

When drug maker Novartis began to sell Gleevec in 2001, awareness about the drug spiked because it successfully stopped chronic myeloid leukemia in most patients. Some studies show Gleevec keeps between 80 and 90 percent of CML patients free of cancer for a minimum of five years. Before the Nature Medicine study, there was no evidence that Gleevec caused heart damage.

Novartis has been raking in profits from Gleevec, ("Glivec" in Europe,) recording global sales of $1.2 billion in the first six months of 2006.

Currently, doctors are concerned that Gleevec may be connected to more incidences of heart damage, and Novartis is also concerned about Gleevec causing heart problems.