Scientists in the US have hailed a radical new gene therapy that uses genetically modified cells to replace the body’s immune ones a success. The treatment helps sufferers’ defences to fight against the deadly virus by replacing the some of their own disease ridden ones, with GM cells that are resistant to the virus.
This was a small-scale trial that had previously never been tested on humans before, but researchers found that the GM cells multiplied in the patient’s bodies. The trials were devised to assess how safe the tests were, but the early results were positive. The trials recorded that in half the patients who were taken off their usual HIV treatment and given the GM cells, after three months they showed reduced levels of the virus.
Bruce Levine, who was helped to run the trial with colleague Carl June at the University of Pennsylvania, said: “We are absolutely encouraged by these results. This is potentially a new therapy for HIV.”
Levine was keen to point out that this treatment wasn’t a cure as such, but could be used alongside existing drugs, and could help those who face a lifetime on antiretroviral drugs. He said: “People diagnosed in their 20s are on antiretroviral therapy for the rest of their lives. There are side effects. People miss days. And there is drug-resistance. This is a continuing problem,” he added: “Cure is a four letter word. We don’t like to use it, particularly with HIV. We are looking at improving the health and immune function of people with HIV.”
The way the treatment works is by mimicking a rare gene mutation that 1% of the population naturally have that make them resistant to the most common strains of HIV. The way the HIV attacks cells in the other 99% of people is that it latches on to the proteins that stick out of the cell surfaces. People who have this gene mutation do not this type of protein, which is called CCR5, so the HIV virus cannot latch on to their immune cells.
This is not the first time scientists have thought about using gene therapy to combat certain diseases. Back in 2008, Timothy Brown, also known as the Berlin patient, was effectively cured of HIV after he had a bone marrow transplant to treat his leukaemia. At the time, doctors saw an opportunity to treat his HIV (as immune cells are formed in the bone marrow) so they found a bone marrow donor who also carried the rare gene mutation that made their immune cells resistant to HIV. The operation was a success and since then, Brown has not had to take any form of anti-HIV drugs as he no longer has any detectable signs of the virus.
The Pennsylvania trial included ten men and two women, who were all diagnosed as HIV positive and aged between 31 to 54. They had their white blood cells collected, which were then modified using gene editing to include the rare mutation. These cells were multiplied in their billions in the lab and infused back into each patient. Half of the twelve were taken off their antiretroviral therapy and given the gene therapy, and half were left on their standard drugs. At first, the amount of HIV in the gene treatment patients began to rise, but once the infused immune cells started to circulate and multiply, the HIV levels dropped. In two of the half on the gene therapy their HIV levels rose quickly again, but the remaining four showed steady improvements, and in fact one patient’s levels dropped so significantly that they could not be detected at all. It was later discovered that this patient had already inherited the rare resistance mutation from one parent, but not the other. Levine said: “That effectively gave his immune system a head start.”
Scientists around the world have welcomed this new treatment; especially as the World Health Organisation estimates were pretty grim. In 2012 more than 1.5 million died from Aids-related causes, whilst around 2.3 million became infected that same year. They estimate that some 35.3 million people globally are infected with HIV, with approximately 100,000 of these in the UK, however, an estimated fifth go undiagnosed and do not know about their condition.
The gene therapy treatment was included in the New England Journal of Medicine where it listed around 130 side effects, ranging from fever, chills, headaches, joint and muscle pain. Despite these, one scientist Angus Dalgleish, an HIV expert at St George’s hospital in London, was keen to point out the benefits of such alternative treatments. He said: “Anything that will prevent patients being on drugs the whole time, that allows you to manage the infection without those drugs, is a serious contender.”
Larger trials are now commencing to try out the efficacy of using GM cells and to test the safety in using larger doses.