According to a new Danish study involving 33,347 people, giving patients Abacavir for HIV treatment may significantly raise their risk of having a heart attack (myocardial infarction). Abacavir, which is commonly used in combination with other medications, reduces the amount of HIV in the body (HIV nucleoside reverse transcriptase inhibitor). Despite this new identified risk, the scientists, who looked at a range of anti-HIV drugs, stress that the benefits of this drug may still be greater.
You can read about this study in The Lancet.
The success of HIV antiretroviral therapy has meant that the majority of people with HIV infection will take a combination of drugs (often a protease inhibitor and a nucleoside reverse transcriptase inhibitor [NRTI]) for life. Earlier studies have attempted to investigate the long-term effects of these drug classes, especially with regard to cardiovascular outcomes. Attention has focused mainly on protease inhibitors and their potential effect on increased risk of heart attack.
Of all the drugs that were investigated in this study only Abacavir and Didanosine were found to have an impact on heart attack risk. Abacavir is not only much more popular than Didanosine, the researchers said, but Didanosine’s 50% raised risk is much small than Abacavir’s almost 100%.
The scientists also found that if a patient stopped taking Abacavir his/her heart attack risk soon went back to pre-medication levels – in other words, the risk is not cumulative.
“If the decision is made to consider discontinuation of either drug, then a full assessment of the possible risks and benefits of their continued use should be undertaken. Such an assessment must be individualized for each patient. It should take into account their underlying risk of heart attacks, the availability of other treatment options after taking into account their history of past treatment and HIV resistance testing, and the safety profile of alternative HIV medication,” head researcher Jens Lundgren said.
According to the makers of Abacavir, GSK (GlaxoSmithKline), its own 54 studies never revealed such an increased risk of heart attack. Even so, the company says it is taking this latest finding seriously and is committed to understanding these data more fully. The company added that it will communicate openly with treating physicians and regulatory agencies globally.
The researchers believe that underlying biological mechanisms leading to a cardiovascular inflammatory response could be responsible for the increased incidence of heart attack from abacavir and didanosine, although more research is needed in this area.
“Use of nucleoside reverse transcriptase inhibitors and risk of myocardial infarction in HIV-infected patients enrolled in the D:A:D study: a multi-cohort collaboration”
Jens D Lundgren et al
The Lancet DOI: 10.1016/S0140-6736(08)60423-7
Written by – Christian Nordqvist