One of the daunting scientific challenges facing HIV/AIDS researchers is determining if HIV can be eliminated in individuals who are infected with the virus but who have achieved low levels through effective treatment. At NIAID, Anthony S. Fauci, M.D., NIAID director, and his research group are testing one approach to this problem using powerful new drugs to try to destroy dormant virus in individuals who have responded well to years of antiretroviral treatment.
The basis for this approach comes from seven patients in whom treatment was begun soon after they became infected with HIV. Dr. Fauci’s group monitored the patients over nearly five years of treatment and documented consistently decreasing levels of virus. This meant the patients were less likely to develop AIDS, but they could not be assured of being cured and thus could not stop treatment. Because scientists know that small reservoirs of virus can hide in cells and later multiply into widespread infection, Dr. Fauci and his colleagues measured precisely how small these dormant reservoirs were and how susceptible they might be to elimination.
The NIAID group calculated that treatment eliminated about half of the virus in the seven patients every 4.6 months. That left the remaining HIV to replicate—but at a steadily declining rate due to the effective ongoing treatment. Assuming that infected people have about 1 million dormant cells infected with HIV, the research group determined that HIV in the persistent reservoir theoretically could be eliminated with 7.7 years of effective treatment.
Their finding raises the question of whether the time it would take to eliminate the virus could be reduced by introducing aggressive antiretroviral treatment with newer drugs once the initial therapy leaves patients with very low levels of HIV. They have just begun a clinical trial to test this idea.
Chun TW et al. Decay of the HIV reservoir in patients receiving antiretroviral therapy for extended periods: implications for eradication of virus. Journal of Infectious Diseases 195(12):1762-4 (2007).
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Last Updated August 30, 2007