Two new studies in small numbers of people show that infusions of anti-HIV antibodies may completely suppress the virus for long periods.
According to the UN, nearly 37m worldwide are living with HIV. The advent of anti-HIV drugs has prevented millions of untimely deaths from AIDS, but those who take the pills must do so every day on a lifelong basis.
Examining other HIV treatment options
New early-stage clinical trials from Rockefeller University, New York, show that a mix of two monoclonal antibodies against HIV lowered the virus levels in patients not taking antiretroviral medication. According to the research, most patients could keep the virus at bay for two to three months before it came back.
Immunologist at the university and study lead, Dr Michel Nussenzweig, told Science: “Ultimately, this may not be good for everybody, and it’s expensive. But, if you think about cancer, we’ve really made a big difference with immune therapies. For HIV, there’s no such thing.”
The researchers said the combination of two proteins was able to suppress the virus in patients for up to 30 weeks at a time. The average duration was around 15 weeks. Volunteers stopped taking their antiretroviral medicine and received infusions of two antibodies. These are normally found in people who can control HIV without the need for medication.
The Nature study tested three antibody infusions on 11 people who had been controlling infections with antiretroviral drugs. They then stopped taking their medication for the trial.
The Nature Medicine study involved seven volunteers who were not on treatment. These patients exhibited relatively high levels of the virus at the beginning. The first study showed nine of the 11 people suppressed HIV to below standard levels of detection in tests for an average of 15 weeks. Four of the seven in the second study suppressed the virus for approximately three months.
Researchers administered the two proteins in tandem to prevent the HIV virus from developing immunity. This was a problem that had seen other similar studies stumble. The antibodies target proteins on the outside of the virus, using the patient’s own immune system to battle infection. The patients received infusions again after three weeks and then after six.
Anthony Fauci, director of the National Institute of Allergy and Infectious Diseases in the US state of Maryland, said: “A safe, reliable, antibody-based treatment regimen would open new possibilities for people living with HIV. This represents an important, early step towards that goal.”
Nussenzweig explained: “This has been tried in the past with antibodies that were far less potent and it did not work. Our idea is to modify them to make them even longer-lasting so that people can receive therapy a couple of times a year instead of pills every day.”
More work to do
Two similar studies from Prof Katharine Bar had used a single antibody, but resistant viruses emerged. She told Science that these new studies represented a “really exciting advance”.
Nussenzweig said that there is much more to be explored before the treatment of HIV with antibodies gains enough traction. His group is modifying the antibodies so they last longer in the body and is also working on figuring out how to find who would be most likely to respond to treatment. He said the team may soon have antibodies that work effectively for nearly a year.