Modifications of residual viraemia in human immunodeficiency virus-1-infected subjects undergoing repeated highly active antiretroviral therapy interruptions.

Residual viraemia is detectable in the majority of human immunodeficiency virus (HIV)-infected subjects with plasma HIV-1 RNA <50 copies ml(-1). In the present study, the impact of repeated treatment interruptions on residual HIV-1 viraemia was investigated in 58 subjects enrolled in the ISS-PART, a multicentre, randomized clinical trial comparing 24 months of continuous (arm A) and intermittent (arm B) highly active antiretroviral therapy (HAART). Residual viraemia was measured by a modified Roche Amplicor HIV-1 RNA assay (limit of detection 2.5 copies ml(-1)). At baseline, the median value of residual viraemia was 2.5 copies ml(-1) in both arms; after 24 months, the median value was 2.5 in arm A and 8.3 in arm B. The median change from baseline to month 24 was significantly different between patients under continuous or intermittent HAART: 0 copies ml(-1) (range -125.2 to +82.7) of HIV-1 RNA in arm A versus 2.1 copies ml(-1) (range -80 to +46.8) in arm B (P=0.024). These results suggest that intermittent HAART tends to modify HIV-1 viraemia set point even if a virological response is achieved after HAART reinstitution.