Slower CD4 Cell Decline Following Cessation of a 3 Month Course of HAART in Primary HIV Infection: Findings from an Observational Cohort

Objective: To investigate the effect of a short course of HAART during primary HIV infection (PHI) on rate of CD4 cell and viral load change.

Methods: Data following HAART cessation from 89 individuals (seroconverting 1999-2003) who chose to take a 3 month course of HAART at PHI were compared with 179 untreated controls in CASCADE, using linear and nonlinear random effects models. Participants were non-randomized but frequency matched for age, sex, risk factor, year of seroconversion and presentation within the first 6 months of seroconversion. Time to CD4 cell count < 350 cells/microl and initiation of clinically indicated antiretroviral therapy (ART) were also compared as competing risks.

Results: The rate of CD4 cell decline following therapy cessation appeared significantly slower among treated participants than untreated controls: losses of 51 cells/microl [95% confidence interval (CI), 32-69] and 77 cells/microl (95% CI, 65-89), respectively, 3 years after seroconversion (P = 0.011). Based on extrapolated data, viral loads also differed significantly at this point (4.09 and 4.53 copies/ml, respectively). At 2 years, there was no significant difference in mean viral load levels: 4.31 copies/ml (95% CI, 4.14-4.48) and 4.47 copies/ml (95% CI, 4.28-4.66), respectively. CASCADE seroconverters were more likely to reach CD4 cell count < 350 cells/microl or initiate clinically indicated ART (hazard ratio, 1.45; 95% CI, 1.02-2.05; P = 0.039).

Conclusion: A short course of ART at PHI may delay CD4 cell decline. Confirmation of this requires a randomized clinical trial powered to address definitively the role of ART intervention in PHI (currently underway through SPARTAC).