Early treatment for HIV slows damage to immune system

A 48-week course of anti-retroviral medication taken in the early stages of HIV infection slows the damage to the immune system and delays the need for long-term treatment, according to research published today in the New England Journal of Medicine. However, the delay was only marginally longer than the time already spent on treatment.

The study, the largest clinical trial ever undertaken looking at treating people with recent HIV infection, also suggests that the treatment lowers the amount of virus in the blood for up to sixty weeks after it is stopped, which potentially reduces the risk of onward transmission.

SPARTAC (Short Pulse Anti-Retroviral Therapy at HIV Seroconversion), a randomised controlled trial, took place over five years and involved 366 adults – mainly heterosexual women and gay men – from Australia, Brazil, Ireland, Italy, South Africa, Spain, Uganda and the UK. It was funded by the Wellcome Trust and coordinated by researchers from Imperial College London and the Medical Research Council's Clinical Trials Unit, with immunology research conducted by the University of Oxford.

Unless regularly tested, most people will be unaware that they are HIV-positive during the first few years after they have become infected. Initial symptoms can be similar to flu or other viral infections, and for most people, there follows a period of many years when they carry the virus but are not sick. However, the immune system never successfully clears HIV; instead, the virus hides away, slowly weakening the body's defences and destroying CD4 T-cells, which play a key part in the immune response.

Without treatment, the immune system steadily becomes more compromised, leaving the individual at increased risk of developing other life-threatening infections. To stop this from happening, when the number of remaining CD4 T-cells reaches a certain level – 350 cells per cubic millimetre – international treatment guidelines recommend that an individual begins life-long treatment with antiretroviral drugs. These drugs not only prevent further damage to the immune system, but also allow it to recover.

Several observational studies have suggested that treatment at the time HIV infection occurs could delay the amount and speed of immune damage and so delay the need to start lifelong antiretroviral medication. SPARTAC is the first large randomised study to test this hypothesis.