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/muL. 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 greater than or equal to 50 000 copies/mL. Lower CD4 cell counts were observed during TI in patients with lipodystrophy, zenith HIV RNA greater than or equal to50 000 copies/mL, history of AIDS, HIV infection greater than or equal to5 years and presuppression CD4 count less than or equal to350 cells/muL. Patients who reinitiated therapy had shorter TI duration, presuppression CD4 count <350 cells/pL, 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.