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Early treatment for HIV slows damage to immune system and reduces risk of transmission, study suggests

17 January 2013

A 48-week course of antiretroviral therapy (ART) 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 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 ART 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 co-ordinated by the Medical Research Council Clinical Trials Unit and Imperial College London. Immunology studies are conducted by the University of Oxford.

All volunteers in SPARTAC were identified within six months of becoming infected with HIV and randomly allocated to receive ART for 48 weeks, 12 weeks or none (the standard practice in HIV management at this stage of infection). The researchers then measured the time until the trial end point, defined as the time that a person’s CD4 T-cell count fell below 350 cells per cubic millimetre and/or they began a lifelong course of ART.

On average, participants who had received no ART reached that end point 157 weeks (~36 months) after infection. For those in the group receiving ART for 12 weeks the average time was 184 weeks (~42 months) and, for those who received ART for 48 weeks, 222 weeks (~51 months). This 65-week delay between the no ART and 48 weeks of ART groups represents an important delay, but overall was not significantly longer than the time those participants had already spent on treatment.

In addition, over the whole time in the study, participants on the 48 week course had higher CD4 T-cell counts than those in the other two treatment groups, potentially reducing their risk of developing secondary infections such as tuberculosis. They also had lower levels of HIV in the blood for over a year after stopping treatment compared to the other volunteers, which could play a role in reducing the risk of passing on the virus to sexual partners.

Results also suggested that the 48-week treatment was more beneficial the closer it was started to the time of infection.