April 8, 2015

expert reaction to study reporting results of first-in-man trial of an antibody therapy for HIV

Researchers publishing in the journal Nature have reported the findings of a first-in-man trial of an antibody treatment for use against HIV, stating that it is safe and effective in reducing HIV-1 pathology and suggesting that be explored for treatment of the disease.

Prof. Robin Weiss, Emeritus Professor of Virology, UCL, said:

“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.”

Dr Andrew Freedman, Reader and Honorary Consultant in Infectious Diseases, Cardiff University, said:

“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.

“Although such antibody treatment would not be sufficient on its own, it might prove useful in combination with drug therapy, as a means of achieving better long term control or even cure of HIV infection. It may also be effective as a way of preventing HIV infection, in the absence of a vaccine. However, further studies will be required to determine its utility in practice.”

Prof. Vincent Piguet, Director of the Institute of Infection and Immunity, Cardiff University, said:

“This exciting novel study shows for the first time that antibodies may have a place in the line of therapies directed against HIV.

“The difficulties of obtaining an anti HIV-1 vaccine or eradicating infection in infected individuals have led researchers to identify novel approaches. Among them, passive infusion of broadly neutralising antibodies is an attractive approach.

“Antibodies are used already very successfully to improve diseases such as cancer, inflammatory diseases or skin diseases. Although the study evaluated the efficacy of the antibody 3BNC117 for only a short time (56 days) in HIV patients, it could decrease the levels of the virus in the blood.

“This is an important development in the fight against HIV, however, the emergence of resistance was observed in some but not all patients. The cost of antibodies is generally greater than drugs and it will be interesting to see if more potent and less costly antibodies can be developed to prevent or treat established HIV-1 infection.

“This is good news for the fight against HIV but a fully developed antibody to treat HIV-1 might still take a few years to develop.”

‘Viraemia suppressed in HIV-1-infected humans by broadly neutralizing antibody 3BNC117’ by Marina Caskey et al. published in Nature on Wednesday 8 April 2015. 

Declared interests

Prof. Vincent Piguet: “I have no conflicts of interest. My main research is on HIV and dendritic cells and early events of HIV transmission.”