Objective: A minority of HIV-1 positive individuals treated with antiretroviral therapy (ART) in primary HIV-1 infection
(PHI) maintain viral suppression on stopping. Whether this is related to ART duration has not been explored.
Design: And Methods: Using SPARTAC trial data from individuals recruited within 6 months of seroconversion, we
present an observational analysis investigating whether duration of ART was associated with post-treatment viraemic
control. Kaplan-Meier estimates, logistic regression and Cox models were used.
Results: 165 participants reached plasma viral loads (VL) <400 copies/ml at the time of stopping therapy (ART stop).
After ART stop, 159 experienced confirmed VL ≥400 copies/ml during median (IQR) follow-up of 167 (108,199)
weeks.
Most participants experienced VL rebound within 12 weeks from ART stop, however, there was a suggestion of a
higher probability of remaining <400 copies/ml for those on ART >12 weeks compared to ≤12 weeks (p=0.061).
Cumulative probabilities of remaining <400 copies/ml at 12, 52 and 104 weeks after ART stop were 21%
(95%CI=13,30), 4% (1,9), and 4% (1,9) for ≤12 weeks ART, and 32% (22,42), 14% (7,22), and 5% (2,11) for >12
weeks.
In multivariable regression, ART for >12 weeks was independently associated with a lower probability of being
≥400 copies/ml within 12 weeks of ART stop (OR=0.11 (95%CI=0.03,0.34), p<0.001)). In Cox models of time to VL
≥400 after 12 weeks, we only found an association with female sex (OR=0.2, p=0.001).
Conclusion: Longer ART duration in PHI was associated with a higher probability of viral control after ART stop.