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Maintenance of antiretroviral therapy despite low-level viremia in HIV patients appears to be appropriate

A recent study from the University of Pennsylvania Center for Education and Research on Therapeutics (CERT) found that maintaining the same well-tolerated antiretroviral therapy among patients with HIV disease, despite low-level HIV viremia (between 50 and 500 copies of HIV RNA per ml), provided sustained immunological benefit for two-thirds of the patients studied over the 2-year period. One-third of the group returned to an undetectable viral load (less than 50 copies per ml), one-third continued to have low-level viremia without reaching 1,000 copies per ml, and one-third (37 percent) had an increase in viral load (more than 1,000 copies per ml; virologic failure). The study was supported in part by the Agency for Healthcare Research and Quality through the Agency's CERTs program (HS10399).

The researchers retrospectively observed 79 HIV-infected adults with low-level HIV viremia who had been on a stable antiretroviral regimen for at least 3 months, which they continued for at least 3 more months. Changes in CD4 cell count (a lower count indicates weaker immune system function) were modest. Even the group experiencing virologic increase had a smaller loss of CD4 count (median decrease of 1.8 cells/mm3 per month) than would be expected in untreated individuals. The other two groups had modest gains in CD4 cell counts (median increase of 0.5 cell/mm3 per month).

These findings indicate that maintenance of a well-tolerated regimen despite low-level viral replication may be beneficial. Changing antiretroviral drug regimens is not without complications, such as reduced medication adherence, additional toxic effects from new therapies, and depletion of useful therapeutic options. However, the study results should be interpreted with caution, since continued antiretroviral therapy in the presence of low-level HIV viremia has been shown to lead to the accumulation of drug-resistant mutations and loss of subsequent treatment options. Also, this study involved a relatively small sample size, had relatively brief followup time, involved a limited number of study sites, and included a substantial number of patients who were not receiving highly active antiretroviral therapy.

See "Natural history of patients with low-level HIV viremia on antiretroviral therapy," by Vincent Lo Re III, M.D., Leanne Gasink, M.D., Jay R. Kostman, M.D., and others, in the August 2004 AIDS Patient Care and STDs 18(8), pp. 436-442.

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