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By Andrea Gerlin and Michelle Fay Cortez
Sept. 12 (Bloomberg) -- GlaxoSmithKline Plc's Avandia diabetes pill increased the chances of having a heart attack, while Takeda Pharmaceutical Co.'s competing drug lowered the risk, researchers reported.
The Glaxo pill increased heart attacks by 42 percent and doubled rates of heart failure, according to a report in the Sept. 13 Journal of the American Medical Association. Takeda's Actos reduced heart attacks, strokes and deaths by 18 percent, though it also increased heart failure, a separate study funded by the company found.
The findings may help Actos gain further market share from Avandia. The Glaxo medicine, also known as rosiglitazone, was the world's best-selling diabetes pill until May, when Cleveland Clinic researchers reported in the New England Journal of Medicine that it increased heart attack risks by 43 percent.
``Whatever statistical study you use, you find that rosiglitazone still increases the risks of heart attack and heart failure,'' said Yoon Loke, a clinical pharmacologist at the University of East Anglia in Norwich, England, and a co-author of the Avandia study in JAMA. ``If you get the same results with different methods, this implies the finding is quite robust.''
Both JAMA articles analyzed data from previous studies, a method known as meta analysis. The Avandia study, by doctors at Wake Forest University in Winston-Salem, North Carolina, looked at four trials that enrolled 14,291 people for at least 12 months. They found no increased rate of death from cardiovascular causes. The Actos study analyzed data from 16,390 people treated in 19 trials that ranged from 16 weeks to 3.5 years.
Stronger Warnings
Glaxo shares fell 13 pence, or 1 percent, to 1,315 pence at 9:09 a.m. in London trading. The shares have fallen 10 percent since the New England Journal report was published in May. Takeda rose 90 yen, or 1.2 percent, to 7,830 yen in Tokyo.
Avandia and Actos' dosage instructions were strengthened last month with the U.S. Food and Drug Administration's strictest warning about the risk of heart failure, a condition in which the heart can't pump enough blood. The FDA is considering a July 30 advisory panel recommendation that the agency add a caution about heart attacks to Avandia's prescribing information.
Officials at London-based Glaxo, Europe's largest drugmaker, said the JAMA findings conflict with accumulated data on Avandia from 116 clinical trials in more than 52,000 patients, which they said don't show the drug reduces blood flow to the heart compared with other medicines, including Actos. Reduced blood flow to the heart can cause heart attacks.
`Important Option'
``I don't think it adds any new information on the safety of Avandia at all,'' Glaxo Vice President Alastair Benbow said. ``We believe Avandia remains an important option for doctors and their patients.''
Avandia brought in $3.3 billion for Glaxo in 2006. After the heart-attack risk was first reported in May, sales of the medicine fell 22 percent in the second quarter as Actos overtook it in the U.S.
U.S. prescriptions of Avandia fell by more than half to 146,000 a week since the New England Journal study was published on May 21, according to IMS Health Inc. and Citigroup Inc. Avandia now accounts for 5.6 percent of new U.S. prescriptions for diabetes pills, compared with almost 14 percent for Actos.
Steven Nissen, a co-author of the JAMA article about Actos and the May 21 New England Journal study of Avandia, said regulators should act on the two JAMA articles.
Pressure on Regulators
``It's quite a contrast to look at the two analyses side by side,'' Nissen said. ``It puts pressure on regulatory agencies around the world to take some sort of action on rosiglitazone.''
Loke said doctors at Norfolk and Norwich University Hospitals, where he works, are being advised to switch their patients from Avandia to Actos if they require a drug to lower blood sugar.
``We believe it is inappropriate for the author to advise doctors to disregard the FDA's advice, which is to keep patients who are effectively controlling their diabetes on Avandia,'' Glaxo said in a statement.
Takeda won't seek to add the new data to prescribing information for Actos, said Robert Spanheimer, the Osaka, Japan- based company's senior director of diabetes.
The two pills are members of a class of drugs known as thiazolidinediones, or TZDs, which lower blood sugar by making diabetics more sensitive to the hormone insulin. The findings should reassure doctors and patients who link Actos, also called pioglitazone, to studies of Avandia, Spanheimer said.
Confidence in Actos
``This analysis is not only reassuring in that there was no adverse effect, there was a convincing protective effect of pioglitazone against cardiovascular complications,'' said Michael Lincoff, vice chairman for research in cardiovascular medicine at the Cleveland Clinic and the lead author of the Actos study.
Takeda supplied $25,000 to pay for the time it took the Cleveland Clinic statistician to analyze the data, which it provided for every patient who participated in a randomized trial involving Actos. Takeda was not involved in the analysis and was not allowed to see the paper before it was published.
Glaxo wasn't involved in either Avandia study. The company conducted its own analysis -- which suggested the drug increased the risk of cardiovascular complications by 31 percent -- and submitted it to regulators in 2006. The data don't provide a clear picture of the drug's risks and benefits, Glaxo has said.
Loke worked with two researchers at Wake Forest, including FDA advisory committee member Curt D. Furberg. Furberg has said the FDA should consider withdrawing Avandia. He wasn't allowed to vote at the July 30 meeting because the FDA said he has a conflict of interest as a member of another government drug- safety review panel whose research is partly funded by several drugmakers, including Glaxo.
To contact the reporter on this story: Andrea Gerlin in London at agerlin@bloomberg.net ; Michelle Fay Cortez in Minneapolis at mcortez@bloomberg.net
Last Updated: September 12, 2007 04:13 EDT
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发表于 2007-9-12 17:42:37