Heart-damaging side effects of cancer drugs under-reported in studies, Stanford researchers say

Public release date: 26-Mar-2012 [ | E-mail | Share ]

Contact: Tracie White traciew@stanford.edu 650-723-7628 Stanford University Medical Center

STANFORD, Calif. The under-reporting of the possible side effects of heart damage from cancer drugs puts patients at an increased risk for heart failure, according to two researchers at the Stanford University School of Medicine.

In a commentary that will be published online March 26 in the Journal of Clinical Oncology, the Stanford researchers say urgent reforms are needed to standardize measurements of the potential toxicity of cancer drugs during clinical trials in order to prevent the publication of misleading results, as have appeared in such prestigious scientific journals as the Lancet and the New England Journal of Medicine.

"It's a major issue when adverse events aren't being counted in clinical trials, and this has led to a profound underappreciation of the risk for heart failure and other adverse cardiac events," said Ronald Witteles, MD, assistant professor of cardiovascular medicine and the first author of the commentary.

The two researchers Witteles, a cardiologist at Stanford Hospital & Clinics, and co-author Melinda Telli, MD, assistant professor of oncology and a member of the Stanford Cancer Institute became concerned when they started seeing a surprising numbers of patients with heart failure who were being treated with the cancer treatment sunitinib.

"That's what first raised our eyebrows," Witteles said.

The U.S. Food & Drug Administration approved sunitinib, which is marketed by Pfizer Inc. under the trade name Sutent, for the treatment of kidney cancer and certain types of pancreatic and gastrointestinal cancers over the past five years.

What the two authors found was a complete disconnect between reported incidences of cardiac toxicities in journal articles on the one hand, and the FDA's drug labeling on the other. The labeling raised red flags, indicating that clinicians should be aware of the possible side effects of cardiac damage in patients using the drug a very different picture than what had been presented in the journal articles.

"It didn't make any sense," Witteles said. "The labeling warned of a high incidence of heart failure during the clinical trials that was not even mentioned in the journal articles."

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Heart-damaging side effects of cancer drugs under-reported in studies, Stanford researchers say