The study, published Sunday in the online edition of the journal Nature Medicine, followed by reports that 10 patients taking Gleevec for chronic myelogenous leukemia developed severe congestive heart failure. However, the researchers didn't say patients should stop taking the treatment.

    "Gleevec is a wonderful drug and patients with these diseases need to be on it. It's a lifesaving drug for sure," said Dr. Thomas Force, the lead researcher and a doctor at Jefferson Medical College in Philadelphia.

    "We're trying to call attention to the fact that Gleevec and other similar drugs coming along could have significant side effects on the heart and clinicians need to be aware of this. It's a potential problem because the number of targeted agents is growing rapidly."

    Gleevec, sold under the Glivec in some countries, had worldwide sales of 1.2 billion dollars in the first six months of this year, according to Novartis Pharmaceuticals Corp. 

    Novartis said the cases of heart failure in Gleevec patients were extremely rare and said those few patients were successfully treated with two drugs that can help heart failure -- ACE inhibitors and carvedilol.

    "Further study is necessary to better understand the relationship between these preclinical studies and their potential impact on the clinical management of patients taking Glivec," the company said in a statement. Enditem

    (Agencies)