Extended antiretroviral treatment interruption in HIV-infected patients with long-term suppression of plasma HIV RNA

Objectives: Evaluation of extended treatment interruption (TI) in chronic HIV infection among patients successfully treated with antiretroviral therapy. Methods: An observational analysis of 25 patients in a prospectively followed cohort with chronic HIV infection, viral loads < 500 HIV-1 RNA copies/mL for at least 6 months, and an interruption in therapy of ≥ 28 days duration was carried out. Follow up was divided into 3-month time periods for analysis. The effects of time period, stratification group and stratification group by time period interactions on CD4 counts were tested using a mixed model. Univariate comparisons among patient characteristics and responses were performed using Fisher's exact test or the Wilcoxon rank sum test. Results: At initiation of TI, the median CD4 count was 799 cells/μL. TI duration was a median of 7.1 months. HIV RNA rebounded to a median maximum level of 75 000 copies/mL. Maximum viral rebound was significantly greater in patients who were male, had lipodystrophy and had zenith HIV RNA prior to TI of ≥ 50 000 copies/mL. Lower CD4 cell counts were observed during TI in patients with lipodystrophy, zenith HIV RNA ≥ 50 000 copies/mL, history of AIDS, HIV infection ≥ 5 years and presuppression CD4 count ≤ 350 cells/μL. Patients who reinitiated therapy had shorter TI duration, presuppression CD4 count ≤ 350 cells/μL, previous AIDS diagnosis and lipodystrophy. No patients developed adverse or AIDS-defining events during TI. Conclusions: Long-term TI resulted in greater immune deterioration in patients with high viral set points or low CD4 cell counts prior to initiation of suppressive antiretroviral therapy.