Four drugs no better than three for initial HIV Tx.
"The high rates of virologic suppression achieved in this study support current guidelines that recommend two nucleosides plus efavirenz among preferred regimens for the initial treatment of HIV-1 infection. Adding abacavir as a fourth drug to the standard initial three-drug regimen did not change toxicity or adherence but provided no additional benefit," said Dr. Roy M. Gulick of Weill Cornell Medical College, New York.
The standard three-drug regimen is effective for most individuals with HIV, but some researchers have hypothesized that if three is good, four must be better, Dr. Gulick said at a press briefing.
To test this theory, the AIDS Clinical Trials Group (ACTG) A5095 study looked at 765 treatment-naive subjects in a double-blind, placebo-controlled study conducted between March 2001 and March 2005. The patients were randomized to a three-drug regimen consisting of zidovudine/lamivudine plus efavirenz (382 patients) or to a four-drug regimen consisting of zidovudine/lamivudine/abacavir plus efavirenz (383).
The primary objectives of the study were to determine the safety and tolerability of the two regimens, to show a noninferior rate of virologic failure with the four-drug regimen, and to compare the time to virologic failure between the two treatments. Virologic failure was defined as two consecutive HIV RNA measurements that were at least 200 copies/mL at week 16 or later.
Overall, the results of the two regimens were virtually identical, Dr. Gulick said. With a median of 3 years of follow-up, virologic failure occurred in 99 (26%) of subjects on the three-drug regimen and 94 (25%) of subjects on the four-drug regimen. Similarly, time to first virologic failure did not differ significantly between the two groups. Virologic load was also similar with the two regimens at 3 years, as were the CD4 cell counts and incidence of adverse events.
The study participants did well, with more than 80% reducing their HIV RNA levels to less than 50 copies/mL at 3 years, he noted.
"Our study affirms that the three-drug regimen we use to treat HIV infection today is very effective for most people, and adding a fourth drug is of no benefit in terms of decreasing viral load levels or increasing T cells," Dr. Gulick added in an interview.
BY FRAN LOWRY
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|Title Annotation:||Infectious Diseases|
|Publication:||Internal Medicine News|
|Date:||Sep 15, 2006|
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