In May 2011, an interim analysis of the HIV Prevention Trials Network (HPTN) 052 trial showed that early initiation of antiretroviral therapy (ART) prevented 96% of genetically-linked HIV infections in serodiscordant couples. ART was then offered to all index participants and the trial continued until May 2015. This report describes virologic outcomes in index participants who initiated ART in HPTN 052.
Virologic outcomes were evaluated in three study groups: (1) early ART arm (ART initiation at enrollment, CD4 350-550 cells/mm3), (2) delayed ART arm with ART initiation before May 2011 (ART initiation at CD4 <250 cells/mm3 or with an AIDS-defining illness), and (3) delayed ART arm with ART initiation after May 2011 (with ART initiation at any CD4 cell count). Viral suppression was defined as two consecutive viral loads ≤400 copies/mL. Virologic failure was defined as two consecutive viral loads >1,000 copies/mL >24 weeks after ART initiation.
There was no significant difference in virologic outcomes in the three study groups (early ART arm [N=832]; delayed ART arm before May 2011 [N=204]; delayed ART arm after May 2011 [N=530]). Longer time to viral suppression was associated with higher baseline (pre-ART) viral load (p<0.0001), age (<25 years; compared to 25-39 years, p=0.0006, compared to ≥40 years, p=0.0002), and region (Africa; compared to Asia, p=0.005). Virologic failure was associated with higher baseline CD4 cell count (p=0.02), lack of viral suppression by 6 months (p<0.0001), age (<25 years; compared to ≥40 years, p=0.0005), region (Americas; compared to Africa, p=0.001), and education (none; compared to primary or secondary-schooling, p=0.004 and compared to post-secondary schooling, p=0.002).
Higher baseline CD4 cell count and higher baseline viral load were associated with worse virologic outcomes. Demographic factors such as age, region, and education were also associated with time to viral suppression and ART failure. In this study, awareness of the interim findings of the trial (personal health benefits and lower risk of HIV transmission with early ART initiation) did not improve virologic outcomes in those who initiated ART at higher CD4 cell counts. Additional resources may be needed to optimize treatment outcomes, especially among younger individuals and those who start ART at higher CD4 cell counts.