Prevalence and Predictive Value of Intermittent Viremia With Combination HIV Therapy [Havlir DV, et al. JAMA 2001; 286: 171] The authors analyze long-term results of ACTG 343, which was an induction-maintenance treatment protocol involving two NRTIs plus indinavir. The purpose was to determine the long-term effect of intermittent viremia, defined as plasma HIV RNA levels >50 c/mL. Virologic failure was defined as two consecutive viral load levels >200 c/mL. Among the 241 patients who had viral load levels <50 c/mL after six months, there were 96 (40%) with "blips" and 145 without. The frequency of virologic failure was 10/96 (10.4%) versus 20/145 (14%) in these two groups, respectively. The authors conclude that low-level viremia was not associated with an increased risk of virologic failure with up to 4.5 years of follow-up.
Comment: This is an important paper in terms of HIV management. The standard teaching has been that low-level viremia will inevitably lead to mutations that confer resistance and eventually lead to virologic failure. A major strength of this report is the 4.5-year follow-up among patients with "blips." It appears that the theory is not necessarily discounted by this report, but it does suggest that the threshold at which mutations become clinically significant must be substantially higher than the threshold of the ultrasensitive test, which is in common use in clinical practice.
posted 7/17/2001

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