An antibody indicated in Crohn’s disease has made it possible to fight effectively and durably against HIV. It allows you to do without antiretrovirals.
Would researchers around the world coordinate in their fight against HIV? The road to definitive treatment is in any case well underway. Ten days after a British team, it is the United States which announces encouraging results. The National Institutes of Health (NIH) succeeded in inducing lasting remission in infected monkeys. They detail their success in the scientific journal Science. Their weapon against the virus: an antibody authorized across the Atlantic in Crohn’s disease.
An experimental treatment
18 rhesus macaques were able to achieve these results. All were infected with SIV, the equivalent of HIV in monkeys. 5 weeks later, they all received antiretrovirals for 90 days. These drugs fight the virus effectively by reducing the number of copies of the virus in the blood. But the reservoirs persist. At the slightest stop, the infection therefore resumes. This supposes a lifelong treatment, sometimes heavy in side effects.
Achieving permanent remission: this is the goal of many teams around the world. That of the NIH proposes a new approach to achieve it. The vedolizumab antibody has been adapted to suit infected macaques. 11 of them received this experimental treatment for 23 weeks. It targets a receptor present on immune cells attacked by the virus. After 32 weeks, the monkeys were left without medication. The researchers observed their evolution.
A benefit that lasts
3 macaques developed resistance to the experimental treatment from the start. Among the control animals, 7 saw their viral load skyrocket as happens when stopping antiretrovirals. The 8 monkeys treated with antibodies, on the other hand, exhibited a different reaction. 6 of them experienced a temporary rebound, before regaining control of the infection. The other two never relapsed. “This experimental treatment seems to have given the immune system of monkeys the boost necessary to push the virus into lasting remission,” said Anthony Fauci, co-author of the study. In fact, at 23 months, the benefit was still there.
The other good news is that the SIV virus remains undetectable in both blood and gastrointestinal tissue. This is where the first reservoirs form. This detail is therefore the witness of an in-depth success. “These new results suggest that an alternative form of HIV treatment could eliminate the need to take antiretrovirals for life,” suggests Aftab Ansari, the main author of the work. In terms of quality of life and costs, the repercussions could be major.
Human trials
It is still necessary to succeed in translating these good results in humans. One obstacle remains: the researchers have not been able to determine the mechanism of the antibody. “If we can determine how the antibody works, then an effective vaccine against HIV could be developed on the basis of this mechanism,” says Aftab Ansari.
Can these results be reproduced in humans? Small clinical trials are already underway at the NIH Clinical Trials Center in Bethesda (USA). They will assess the safety and tolerability of a 30 week cycle of vedolizumab. Preliminary results are expected by the end of 2017.
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