HIV-1 infection: Abacavir and Didanosine linked to increased risk of myocardial infarction

The FDA ( Food and Drug Administration ) has been made aware of recent findings from analyses of data collected from " The Data Collection on Adverse Events of Anti-HIV Drugs ( D:A:D ) Study ".
The D:A:D Study is a large observational study of 33,347 HIV-1 infected patients living in North America, Europe and Australia.
Patients in this study are being followed to evaluate the short- and long-term adverse effects of treatment with anti-HIV drugs.

Analyses of data collected through February 1, 2007 examined the risk of myocardial infarction in patients taking selected HIV drugs from the class of drugs known as nucleoside reverse transcriptase inhibitors ( NRTIs ): Zidovudine ( Retrovir ), Stavudine ( Zerit ), Abacavir ( Ziagen ), Didanosine ( Videx ), and Lamivudine ( Epivir ).
The analyses, specifically, describe the relative risk of myocardial infarction among cumulative use, recent use ( currently using or use within the past 6 months ), and past use ( last use greater than 6 months ago ) of these drugs.

These analyses showed that recent use of Abacavir or Didanosine was associated with an increased risk of myocardial infarction. Patients taking either of these drugs had a greater chance of developing a myocardial infarction than patients taking other medications. The risk did not appear to increase over time, but remained stable and appeared to be reversible after Abacavir or Didanosine were stopped.

In late 2007, GlaxoSmithKline ( GSK ), the manufacturer of Abacavir, received the preliminary findings from the D:A:D Study analyses and conducted a search of their own clinical study databases. The results of the GSK analysis are inconclusive, but did not show an increased risk.
Bristol Myers Squibb ( BMS ), the manufacturer of Didanosine, conducted an analysis of their clinical databases, and similarly, found no increased risk for myocardial infarction with Didanosine use. The results of the BMS analysis are also inconclusive.

Key findings from the D:A:D Study are as follows:

a) The excess risk of heart attack in patients taking at least some NRTIs appears to be greater in patients with other risk factors for heart disease. Risk factors include a history of heart disease, high cholesterol, high blood pressure, diabetes, smoking, and age.

b) Certain analyses found the risk of myocardial infarction increased by 49% in patients taking Didanosine and increased by 90% in patients taking Abacavir.

c) The increased risk for myocardial infarction remained stable over the course of treatment and the effect was not seen 6 months after stopping the drugs.

FDA currently believes analyses conducted with D:A:D Study data are incomplete; no analyses were conducted evaluating the risk of heart attack when patients take Tenofovir ( Viread ) or Emtricitabine ( Emtriva ), two other drugs in the class of NRTIs.

Source: FDA, 2008


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