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FDA Review Finds No Link Between Abacavir Use and Heart Attacks

A meta-analysis by the U.S. Food and Drug Administration (FDA) offers further evidence that the NRTI abacavir (Ziagen, also in the Epzicom and Trizivir coformulations) is not significantly associated with an increased risk of myocardial infarction, according to a report published in the August 28, 2012, online edition of the Journal of Acquired Immune Deficiency Syndromes.

In 2008 researchers with the large observational D:A:D study first reported that they had seen an increased risk of myocardial infarction (MI) among people taking abacavir-containing regimens. A meta-analysis by abacavir manufacturer GlaxoSmithKline (now part of ViiV Healthcare) of more than 50 studies -- a majority of them randomized controlled trials -- did not see a link.

This set off a flurry of new studies and re-analyses of older data to look for a similar correlation, but findings have been conflicting. DHHS antiretroviral treatment guidelines demoted abacavir from a "preferred" to an "alternative" regimen largely due to concern about heart risk, but in recent years most evidence has not shown an association.

To better estimate the effect of abacavir use on MI risk, the FDA conducted a trial-level meta-analysis of randomized controlled trials in which participants were randomly assigned to receive abacavir as part of a combined antiretroviral regimen.

After performing a literature search of 4 four databases, the study authors selected 26 randomized controlled trials conducted between 1996 and 2010 that included adult patients, had a sample size greater than 50 participants, were completed (not terminated prematurely), were not pharmacokinetic trials, and were not conducted in Africa. Additional alternative analyses were based on FDA-requested adverse event reports of MIs provided by study investigators.

Results

• The 26 randomized controlled trials included a total of 9868 participants, 5028 of them assigned to abacavir and 4840 assigned to other drugs or placebo.
• The mean follow-up time was 1.43 person-years in the abacavir group and 1.49 person-years in the non-abacavir group.
• 46 MIs were reported overall, involving 0.47% of participants, with no significant differences between the 2 groups:

o   Abacavir use: 24 MIs, or 0.48%;

o   No abacavir:  22 MIs, or 0.46%.

"To the best of our knowledge, our study represents the largest trial-level meta-analysis to date of clinical trials in which abacavir use was randomized," the researchers concluded. "Our analysis found no association between abacavir use and MI risk."

9/11/12

Reference

X Ding, E Andraca-Carrera, C Cooper, et al. No Association of Abacavir Use with Myocardial Infarction: Findings of an FDA Meta-analysis. Journal of Acquired Immune Deficiency Syndromes. August 28, 2012 (Epub ahead of print).