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Study: 2 thiazolidinediones diabetes drugs raise heart risks
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By Bruce Japsen, Chicago Tribune staff reporter Bloomberg News contributed to this report
December 12, 2007
Older diabetes patients treated with Takeda Pharmaceutical North American Inc.'s Actos and GlaxoSmithKline PLC's Avandia had a "significant" increased risk of heart attack, congestive heart failure and death compared with those taking a more established treatment, according to a study in this week's Journal of the American Medical Association.
The study, published in the Wednesday issue of JAMA, is the latest to call into question the use of diabetes pills known as thiazolidinediones, or TZDs. Avandia and Actos, which generated more than $2 billion in annual sales last year for Deerfield-based Takeda, are the only two drugs in the TZD class. They work by increasing the body's sensitivity to insulin.
Compared with patients taking oral hypoglycemic drugs, people over 65 with diabetes who took TZDs had a 60 percent increased risk of heart failure, a 40 percent increased risk of a heart attack and a 29 percent increased risk of dying. The findings are similar to those in a May 21 New England Journal of Medicine report by researchers at the Cleveland Clinic, who found Avandia increased heart attack risks by 43 percent.
But the Institute for Clinical Evaluative Services in Toronto, which led the study for JAMA, said in a statement that the risks were "predominantly among those taking" Avandia. Researchers reasoned the limited risks found with Actos were because fewer people in the study received Takeda's drug.
The researchers say the study is different than highly publicized earlier studies of the drugs because it was post-marketing surveillance and not a research trial.
The latter, said Lorraine L. Lipscombe, a researcher at the institute, is "insufficient to detect less common adverse effects of drugs. Ongoing safety monitoring of drug side effects in larger real-world populations is vital."
Avandia and Actos carry the Food and Drug Administration's "black box" warning about heart failure.
British drug giant Glaxo and Takeda each took issue with the JAMA study in statements Tuesday.
The findings "are not consistent with other epidemiological studies and long-term clinical trials, which do not show a difference in cardiovascular risk between Avandia and other anti-diabetic medicines," Glaxo said. "The inconsistency could be due to the fact that the Avandia patients were older, sicker and had more chronic diseases."
Takeda's medical director, Dr. Bob Spanheimer, said there "is no increase in heart attacks or deaths with Actos."
In the wake of scrutiny of Avandia this summer by a high-profile FDA advisory panel, Glaxo's market share has plummeted to less than 5 percent of new prescriptions written by primary-care doctors for non-insulin prescriptions, according to New Jersey-based ImpactRx Inc.
In July, the panel advised putting a black-box warning about heart attack risk on Avandia, which last year generated more than $3 billion in worldwide sales.
The panel acknowledged that Actos has not been as aggressively studied as Avandia. Since that panel announced its findings, Actos' market share has fluctuated between 15 percent and 20 percent, ImpactRx figures show.
"After some share gains in the immediate aftermath to the Avandia issue, Actos is now essentially back to where it was one year ago," said Patrick Angelastro, senior vice president of strategic development at ImpactRx.
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