Predicting likelihood of post treatment control in HIV cure-related studies that interrupt ART

Simon Collins, HIV i-Base

HIV cure research often includes asking study participants to take an analytic treatment interruption (ATI) to look at the range of viral load responses without ART.

These generally small studies, also need to allow for people whose immune response might control viral load  independently of the intervention being studied (called post treatment controllers).

A research letter in the journal AIDS reports on the frequency of post treatment controllers and how they are defined in ATI studies. [1]

The study modelled likelihood of being able to identify post treatment controllers using an interactive viral rebound calculator. This was developed from a pooled analysis of plasma viral load results from over 700 participants in 12 ATI trials. [2]

The paper concludes that four weeks in sufficient time to identify post treatment control with 100% sensitivity and 90% specificity.


  1. Fajnzylber J et al. Frequency of post treatment control varies by ART restart and viral load criteria. AIDS, doi: 10.1097/QAD.0000000000002978. (14 June 2021).
  2. Sharaf R et al. An interactive tool to estimate viral rebound in HIV-1 treatment interruption trials based on ACTG & CHAMP studies

This report was first published on 15 June 2021.

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