Experts say the first human trial of an antibody that can supress HIV – at least temporarily – shows promise as a new treatment.
A study published in the journal Nature reports on HIV-1 immunotherapy in which patients are infused with virus-fighting antibodies.
Broadly neutralising antibodies
The technique initially proved ineffective in early trials. However, a new generation of more potent ‘broadly neutralising antibodies’ have since been shown to prevent infection and supress the virus in animal studies.
In a first-in-man trial, scientists tested 3BNC117, described as a potent human CD4 binding site antibody, in 17 individuals infected with HIV-1 and 12 uninfected people.
They report that the antibody “significantly reduced” the amount of HIV-1 in the blood of infected individuals for 28 days.
They also say that the antibody was generally safe and well tolerated in the volunteers. The authors caution, though, that treatment with the antibody alone is insufficient to control infection because the HIV virus can mutate and become resistant to single agents. For this reason they recommend that antibody–drug or antibody–antibody combinations will be required for complete control of the virus.
The authors conclude that immunotherapy should be further explored for prevention, therapy and cure of HIV-1.
‘Well conducted study‘
Commenting on the study in a statement, Dr Andrew Freedman, reader and honorary consultant in infectious diseases at Cardiff University, says: “Although combination antiretroviral drug therapy is highly effective at controlling HIV replication in infected individuals, treatment needs to be taken indefinitely and on a daily basis.
“This new study demonstrates that specific antibodies targeted against the outer coat (envelope) of the HIV virus can also suppress viral replication, when administered by intravenous infusion to HIV-infected subjects. A single infusion was able to reduce the level of virus replication for over four weeks in some individuals, while resistance to the treatment developed in others. No significant side effects were seen.
“This was a small, but well conducted, proof of concept study in just 17 patients with HIV. No significant response was seen in the six patients who received low doses of the antibody, but 10 of the 11 who were given higher doses had variable but significant reductions in virus replication. This suggests a real effect of the antibody treatment, but clearly much larger trials would be required before such treatment could be introduced into clinical practice.”
Results ‘look promising’
Professor Robin Weiss, emeritus professor of virology at University College London, says in a statement: “There are a number of potent monoclonal antibodies that prevent infection of a majority of HIV strains. This one is the first to be tested for safety in people and the results look promising and it results in a moderate reduction in the amount of virus in the bloodstream.
“However, we know that HIV is clever at evolving resistance to antibodies just as it does to anti-retroviral drugs. Therefore a combination of antibodies will probably become the best approach to immune control.”
Published: 9th April 2015. By Peter Russell
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