RespiteMatch.com Health Blog

July 23 (Bloomberg) — Novartis AG’s Gleevec cancer drug may harm patients’ hearts, researchers said after studying the product in mice and a small group of humans.

Gleevec, which can keep a form of the blood cancer leukemia in check, may cause congestive heart failure, the researchers said. Still, the scientists didn’t say patients should stop taking the treatment.

“The message is that patients need to stay on Gleevec,'’ said Thomas Force, the lead researcher and a doctor at Jefferson Medical College in Philadelphia, in a telephone interview.

Gleevec, which brought in $2.2 billion last year for Basel, Switzerland-based Novartis, is a type of targeted cancer medicine that’s thought to have fewer side effects than conventional chemotherapy. The toxicity found in Gleevec may be present in other similar drugs, Force said.

Force said he plans to monitor around 100 patients for signs of cardiological complications. He said doctors should monitor patients and perhaps find ways to keep them on the medicine if possible cardiac problems can be kept in check with other drugs.

The protein that is targeted by Gleevec to fight leukemia also appears to play an important role in the health and maintenance of cardiac muscle cells, the researchers said.

The scientists collected clinical data from 10 patients who suffered heart failure while on Gleevec and looked at heart tissue from two of the patients. They concluded Gleevec is harmful to the heart after a comparison with data gathered after feeding the drug to mice and investigating the effect on heart cells. The research was published in the medical journal Nature Medicine today.

Side Effects

“Just because a drug is targeted and has fewer obvious side effects, it does not mean it is devoid of side effects,'’ John Stevens of the American Cancer Society said in an interview.

Experience with the drug has shown that heart failures among patients taking Gleevec are rare, Novartis spokesman Chris Lewis said in an e-mailed statement.

Last month, a study found Gleevec helps leukemia patients keep their disease in check for five years, suggesting that long-term use increases survival. The product is sold as Glivec in some markets.

The study found that 89 percent of 523 patients started on Gleevec early in their diagnosis were still alive after five years, and just 7 percent had moved on to the most advanced phase of the disease. The research was presented June 3 at the meeting of the American Society of Clinical Oncology in Atlanta.

4,600 Patients

The five-year data are from the largest study to date evaluating Gleevec in patients with chronic myeloid leukemia, a form of blood cancer that is diagnosed in about 4,600 Americans each year, according to the Leukemia and Lymphoma Society. Approved in 2001, the once-a-day pill was the first drug to show effectiveness against the previously untreatable disease.

“Data are limited, and 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,'’ Novartis’s Lewis said.

Jefferson Medical’s Force said other targeted cancer drugs may have similar problems, especially those that work by blocking the same signals inside cells as Gleevec, such as dasatinib, which is sold as Sprycel by Bristol-Myers Squibb Co. Sprycel was approved by U.S. regulators in June for patients who no longer respond to Gleevec.