Rate of CD4+ cell count increase over periods of viral load suppression: relationship with the number of previous virological failures.

Background: Although the kinetics of CD4(+) cell counts have been extensively studied in antiretroviral-naive HIV-infected patients, data on individuals who have failed combination antiretroviral therapy (cART) are lacking.
Methods: This analysis was based on the ICONA Foundation Study. Subjects with > or = 1 episode of viral suppression after starting first-line cART were included (n = 3537). Following a viral rebound, patients who achieved another episode of viral suppression could reenter the analysis. The percentage of patients with an increase in CD4(+) cell count >300 cells/mm(3) was estimated using Kaplan-Meier techniques; the rate of CD4(+) cell count increase per year was estimated using a multivariable, multilevel linear model with fixed effects of intercept and slope. Multivariable models were also fitted to include several covariates.
Results: The median time to reach a CD4(+) cell count increase >300 cells/mm(3) from baseline was significantly associated with the number of failed regimens: 34 months, 41 months, 51 months, and 45 months in subjects without evidence of previous virological failure, or 1, 2, or > or = 3 previous virologically failed regimens, respectively (P < .001, by log-rank test). The annual estimated increases in CD4(+) cell count were 36 cells/mm(3) (95% confidence interval [CI], 34-38 cells/mm(3)), 28 cells/mm(3) (95% CI, 11-21 cells/mm(3)), 31 cells/mm(3) (95% CI, 26-36 cells/mm(3)), and 26 cells/mm(3) (95% CI, 18-33 cells/mm(3)), respectively. Differences in the annual CD4(+) cell count increase were observed between specific antiretrovirals.
Conclusions: Subjects with > or = 1 virological failure took a longer time to reach a CD4(+) cell count >300 cell/mm(3) and had a slower annual increase than those without virological failure. Efforts should be made to optimize first-line cART, because this represents the best chance of achieving an effective CD4(+) response.