START study shows the long-term benefit of starting HIV treatment early

24 Oct 2022

Long-term results from the START study show that, for people living with HIV, delays in starting HIV treatment lead to long-term risk to health even after starting treatment. These results were presented at the ID Week Conference in Washington D.C. on 22 October.

Antiretroviral therapy is very effective at treating HIV, but it does have side effects. START was the first large-scale randomised controlled trial to establish that starting antiretroviral treatment straight away benefits HIV-infected individuals regardless of the state of their immune system. Following the release of these results in 2015, HIV treatment guidelines around the world have been updated to recommend people living with HIV start antiretroviral therapy as soon as possible.

In START, people taking part were randomised to either

start HIV treatment immediately (early treatment),
or wait until their CD4 cell count fell to 350 cells/mm³ to start treatment (deferred treatment)

CD4 cells are a type of blood cell that helps to protect the body from infections. Most healthy people who are not infected with HIV have CD4 cell counts of over 500 cells/ mm³. HIV attacks the immune system, and over time reduces the CD4 count, leaving people vulnerable to other infections.

Since the results came out in 2015, participants who had not yet started HIV treatment were offered treatment. Participants have been followed-up to see if there are long-term benefits from early treatment.

The long-term follow-up confirms that starting antiretroviral therapy substantially reduces the risk of people developing AIDS or serious non-AIDS health problems. However, those who started antiretroviral therapy later were still at increased risk of developing AIDS or serious non-AIDS health problems compared to people who started antiretroviral therapy early.

These results reinforce the importance of early diagnosis and treatment of HIV.

The START trial was carried out by the International Network for Strategic Initiatives in Global HIV Trials (INSIGHT) at 215 sites in 35 countries across six continents. 4,685 HIV-positive men and women took part in the study. To take part in the study, people had to have never taken HIV treatment, and also to have a CD4 count of over 500 per cubic millimetre (mm³) of blood.

The University of Minnesota is the regulatory sponsor and statistical and data management centre of the trial. The Medical Research Council Clinical Trials Unit at University College London; the Copenhagen HIV Program at the Rigshospitalet, University of Copenhagen in Denmark; the Kirby Institute at the University of New South Wales in Sydney, Australia; and the Veterans Affairs Medical Center affiliated with George Washington University in Washington, D.C. coordinated the work of the 215 START sites.

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