Background.  Combined antiretroviral therapy (cART) initiation during primary human immunodeficiency virus (HIV) infection (PHI) yields a larger decrease in cell-associated HIV-DNA (CA-HIV-DNA) than initiation during the chronic phase. Our objective was to model the short and long-term decay of CA-HIV-DNA blood reservoir in patients initiating cART during PHI and to assess the impact of the timing of cART initiation on CA-HIV-DNA decay.

Methods.  We included patients enrolled during PHI in the Agence Nationale de Recherche sur le Sida PRIMO cohort, treated within the month following enrollment and achieving sustained virologic response. The decay of CA-HIV-DNA over time while on successful cART was modeled with a 3-slope linear mixed-effects model according to the delay between estimated date of infection and cART initiation.

Results.  Three hundred twenty-seven patients were included, accounting for 1305 CA-HIV-DNA quantifications. Median time between infection and cART initiation was 41 days (interquartile range, 33–54 days). Median follow-up under cART was 2.3 years (range, 0.4–16.6 years). The timing of cART initiation had significant impact on the first slope of decrease: The earlier cART was initiated after HIV infection, the faster CA-HIV-DNA level decreased during the first 8 months of cART: −0.171, −0.131, and −0.068 log₁₀ copies/10⁶ peripheral blood mononuclear cells (PBMCs) per month when cART was initiated 15 days, 1 month, and 3 months after infection, respectively (P < .0001). The predicted mean CA-HIV-DNA level achieved after 5 years of successful cART was 1.62 and 2.24 log₁₀ copies/10⁶ PBMCs when cART was initiated 15 days and 3 months after infection, respectively (P = .0006).

Conclusions.  This study provides strong arguments in favor of cART initiation at the earliest possible time point after HIV infection.