Federal drug safety reviewers have determined that there does not appear to be any link between side effects of abacavir, an HIV drug sold under the brand names Ziagen, Epzicom and Trizivir, and an increased risk of heart attacks.
On Tuesday, the FDA issued an update on an ongoing safety review of abacavir, announcing that the agency had conducted a meta-analysis of 26 randomized clinical trials and found no association with increased risk of myocardial infarction, or heart attack.
Abacavir, which is the generic name for the medication Ziagen, is a potent nucleoside reverse transcriptase inhibitor used as an oral medication to treat AIDS and HIV. Other medications containing abacavir include Epzicom (abacavir and lamivudine) and Trizivir (abacavir, lamivudine and zidovudine).
In the human body, abacavir converts into its active form, carbovir triphosphate, which is similar in form to deoxyguanosine triphosphate (dGTP), which is needed by HIV to synthesize DNA for self-replication. The enzyme reverse transcriptase mistakenly uses carbovir triphosphate instead of deoxyguanosine triphosphate to make DNA. This interferes with the enzyme’s activity and reduces the chances of successful replication of the virus. However, abacavir does not kill existing HIV nor is it a cure for HIV. It can be used alone or with other anti-HIV drugs.
The FDA began conducting its review of abacavir after a study of HIV drugs using data collected through 2007 suggested the drugs Videx (didanosine) and abacavir increased heart attack risk. Both are members of a class of drugs known as nucleoside reverse transcriptase inhibitors (NRTIs).
The randomized trials looked at a total of 9,868 subjects either on abacavir or a similar drug that did not contain abacavir. The FDA found a total of 46 reported heart attacks; 24 suffered by the group taking abacavir and 22 suffered by the group taking another drug. The FDA said the difference was statistically insignificant.
In July 2008, the FDA issued an abacavir health alert, warning that some users may suffer abacavir hypersensitivity. The use of medications containing abacavir is not being recommended for patients who test positive for the HLA-B*5701 allele, and the FDA indicates they should only be considered under exceptional circumstances when the potential benefit outweighs the risk.