An experimental immunotherapy for treating HIV-1 has been shown to dramatically reduce the viral load in infected individuals for up to 28 days, reports new research published in Nature.

Although previous trials of HIV-1 immunotherapy with antibodies have shown promise in reducing the viral load in humanized mice and nonhuman primates, they have yielded disappointing results in humans. However, the new antibody 3BNC117 targets the CD4 binding site of the HIV envelope and shows activity against 195 out of 237 HIV strains. In this study, 17 HIV-1 infected individuals and 12 non-infected individuals received a single intravenous dose of 1, 3, 10, or 30mg/kg of 3BNC117. At the highest dosage level, all eight HIV-1 infected individuals showed up to a 300-fold decrease in viral load, with most reaching their lowest viral load one week following treatment. The decrease in viral load appears to vary based on the individual’s viral load at baseline and the sensitivity of their particular strains of HIV to the antibody. In half of those individuals receiving the highest dosage, viral loads remained below starting levels for a period of 28 days; no resistance to 3BNC117 was observed.

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This is the first study to assess the safety and efficacy of the new generation of HIV antibodies in humans and all doses were well tolerated and effective in temporarily reducing viral loads. The researchers believe that this immunotherapy will be most effective in combination with other antibodies or antiretroviral treatments. It also may be part of future vaccine research, as production of antibodies like 3BNC117 by an uninfected individual’s immune system may block HIV infection before it can be established.

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