A recent study published in Nature reported that an experimental therapy with broadly neutralising antibodies, given intravenously, drastically reduced the amount of HIV virus in the blood of the treated patients. If the results can be replicated this might lead to an exciting new strategy for fighting HIV or even potentially preventing HIV.
There are several reasons why it is so difficult to treat and so far impossible to cure HIV. One of the biggest obstacles is the virus’s ability to change its shape, which means that our immune systems stop recognising it, leaving us defenceless. Although we constantly make new antibodies the virus always seems to be one step ahead. In this study conducted by Micel Nussenzweig at his Laboratory of Immunology, they found a potent antibody, 3BNC117, that seems to have the ability to catch HIV off guard and reduce viral loads.
3BCN117 is a new generation of so called broadly neutralising antibodies, which can fight over 80% of HIV strains.
Around 10-30% of people develop these broadly neutralising antibodies naturally during the first few years of infection, but then the virus mutates and the antibodies become ineffective. However what they have done here is isolate these antibodies from patients who make them, clone them and then given to patients who’s virus has not yet had time to evolve and become resistant.
The patients were given a single dose of the antibody intravenously and then monitored for 56 days. In patients who received the highest dose there was a 300 fold reduction in the amount of virus in their blood. The drop was dependant on the patients viral load before starting and their sensitivity to this specific antibody. This is the first time that this new generation of antibodies have been tested in humans. It appears to be completely safe and in half of the patients viral load was still below the starting point even at the end of the 8 weeks. The patients also didn’t develop resistance to the antibody.
The hope is that eventually this could lead to treatments that can suppress viral loads sufficiently so that patients wont have to take daily medications. It also raises the hope that an HIV vaccine might be possible . The team will now start looking at several other antibodies and combination treatments. Lets hope they can build on these exiting results.