LONDON -(Dow Jones)- GlaxoSmithKline PLC's (GSK) HIV treatment Ziagen may be linked to increased risk of heart attack, according to an article published Wednesday on the Web site of U.K. medical journal The Lancet.

After analyzing data from a study investigating six HIV medicines, researchers at the Rigshospitalet and University of Copenhagen, Denmark, found that recent use of Ziagen was linked to a twofold increase in the risk of heart attack.

Ziagen's active ingredient, abacavir, is also used in GlaxoSmithKline's combination HIV drugs Trizivir and Epzicom.

Another less commonly used HIV treatment, Bristol-Myers Squibb Co.'s (BMY) Videx, reported a 50% increased risk of heart attack.

No links were found between the rate of heart attack and cumulative or recent use of the other treatments: zidovudine and stavudine, which are available generically, and GlaxoSmithKline's Epivir.

The researchers suggested the increased incidence of heart attack from Ziagen and Videx could be attributed to a cardiovascular inflammatory response to the drugs, but pointed out more research is needed in this area.

In a letter published alongside the article, GlaxoSmithKline said its own analysis of 54 pooled studies didn't suggest an increased risk of heart attack from Ziagen.

In a linked comment to both the article and GlaxoSmithKline's response, James Stein of the University of Wisconsin School of Medicine and Public Health, and Judith S. Currier of the University of California David Geffen School of Medicine disagreed with GlaxoSmithKline's analysis, saying it wasn't designedto detect meaningful differences.

They said that that although findings from observational studies should not lead to changes in clinical practice, the significantly increased risk of heart attack cannot be ignored.

"Alternatives to abacavir and didanosine in high-risk patients should be considered," they added.

Although Ziagen is one of GlaxoSmithKline's smaller products, reporting sales of GBP109 million in 2007, combined sales from all HIV products marketed by the company were GBP1.44 billion last year.

Journal web site: www.thelancet.com

-By Elena Berton, Dow Jones Newswires; 44 20 7842 9267; elena.berton@ dowjones.com

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  04-01-08 1916ET
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