Treatment News

Compiled by Gus Cairns

Bad news for abacavir…

The dual-drug pill Kivexa® (abacavir plus 3TC) has been downgraded to a second-choice component of initial HIV drug regimens in the 2008 draft treatment guidelines issued by the British HIV Association (BHIVA). The guidelines now state that Truvada (tenofovir/FTC) plus efavirenz is the preferred first-choice regimen.

The downgrade comes after one study reported a near-doubling of the risk of heart attacks when patients took abacavir and another found that patients who started treatment with a high viral load appeared to do less well on Kivexa than Truvada® (tenofovir plus FTC).

The D:A:D study, as reported in the last issue of PN, found a 90% increase in heart attacks in patients taking abacavir, which went back to normal after the drug was stopped – a finding scientists still
can’t explain.

The ACTG5202 study, which compared Kivexa and Truvada paired with either efavirenz or atazanavir, found that although patients in general did just as well on Kivexa, those starting with a viral load over 100,000 were significantly less likely to achieve a viral load under 200.

As a result the influential BHIVA guidelines’ first choice therapy is Truvada/efavirenz, advising that Kivexa should be used with “caution” in patients with a known risk of heart disease.

Abacavir’s manufacturers GlaxoSmithKline questioned the D:A:D and ACTG 5202 findings. They said that in a previous study called HEAT, “treatment with Epzicom® (Kivexa’s US brand name) reduced viral load to the target at 24 weeks in 94 percent of patients, compared to 95 percent in the Truvada arm—a comparable level of effectiveness.”

However GSK’s attempts to downplay the D:A:D findings ran into trouble when researchers pointed out that GSK’s own studies were not large enough to discount an increased risk of heart attacks in the long term, and the Independent found that the firm had been warned in 2005 by a group of Swedish doctors about an unexpected cluster of 34 heart attacks in people taking abacavir.

Alistair Benbow, GSK’s European Medial Director, said that the firm had not published the 2005 letter because regulatory agencies had found “no convincing evidence” of an abacavir/heart attack link.

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