One of the most advanced HIV treatments seeks to inhibit the virus’ ability to replicate its RNA and produce more copies of itself. A similar approach is commonly used to treat herpes infections, and although it doesn’t get fully rid of the virus, it can stop its spread.
The French company Abivax showed last year in a clinical trial that this approach has the potential to become a functional cure for HIV. The key to its potential is that it can target the reservoir of HIV viruses that “hide” inactive within our cells.
“Current therapies suppress the virus in circulation by inhibiting the formation of new viruses, but they don’t touch the reservoir. Once you stop, the virus comes back in 10-14 days,” says Hartmut Ehrlich, CEO of Abivax. “ABX464 is the first drug candidate ever shown to reduce the HIV reservoir.”
The drug, called ABX464, binds to a specific sequence in the RNA of the virus, inhibiting its replication. In a Phase 2a trial, several patients were given the drug in addition to antiretroviral therapy. Eight out of 15 patients treated with ABX464 showed a 25% to 50% reduction of their HIV reservoir after 28 days, compared to no reduction in those taking only antiretroviral therapy.
HIV infects a type of white blood cell in the body’s immune system called a T-helper cell (also called a CD4 cell). These vital cells keep us healthy by fighting off infections and diseases.
HIV cannot grow or reproduce on its own. Instead, the virus attaches itself to a T-helper cell and fuses with it. It then takes control of the cell’s DNA, replicates itself inside the cell, and finally releases more HIV into the blood – continuing the multiplication process. This is the HIV lifecycle.
In this way HIV weakens the body’s natural defences and over time severely damages the immune system. How quickly the virus develops depends on a person’s general health, how soon after getting HIV they’re diagnosed and start antiretroviral treatment, and how consistently they take their treatment.
Antiretroviral treatment combines a range of drugs that target different stages in the HIV lifecycle, making it very effective. If it’s taken correctly, it keeps the immune system healthy, prevents the symptoms and illnesses associated with AIDS from developing, and means that people can enjoy long and healthy lives.
If someone doesn’t take their treatment correctly or consistently, drug resistance can develop. At this point the drugs are no longer stopping the virus from replicating.
The virus attaches itself to a T-helper cell and releases HIV into the cell.
Fusion or entry inhibitor drugs stop this happening.
Once inside the T-helper cell, HIV changes its genetic material so it can enter the nucleus of the cell and take control of it.
NRTIs (nucleoside reverse transcriptase inhibitors), NNRTIs (non-nucleoside reverse transcriptase inhibitors) and integrase inhibitor drugs stop this happening.
The infected T-helper cell then produces more HIV proteins that are used to produce more HIV particles inside the cell.
The new HIV particles are then released from the T-helper cell into the bloodstream which infect other cells; and so the process begins again.
Protease inhibitor drugs stop this happening.
Knowing how HIV infects the body helps people understand prevention and treatment options, and why it’s important to start antiretroviral treatment as soon as possible after testing positive. If you’d like to find out more about the HIV lifecycle, take a look at our Science of HIV and AIDS section.