HIV This Week

Orrell C, Harling G, Lawn SD, Kaplan R, McNally M, Bekker LG, Wood R. Conservation of first-line antiretroviral treatment regimen where therapeutic options are limited. Antivir. Ther. (Lond.). 2007;12(1):83-8

Orrelle et al aimed to determine rates and causes of switching from first- to second-line antiretroviral treatment (ART) regimens in a large treatment-naive cohort (a South African community-based ART service) where a targeted adherence intervention was used to manage initial virological breakthrough. They studied ART-naive adults (n=929) prospectively who were commencing first-line non-nucleoside-based ART [according to WHO (2002) guidelines] between September 2002 and August 2005. Viral load (VL) and CD4+ T-cell counts were monitored every 4 months. All drug switches were recorded. Counsellor-driven adherence interventions were targeted to patients with a VL > 1000 copies/ml at any visit (virological breakthrough) and the VL measurement was repeated within 8 weeks. Two consecutive VL measurements > 1000 copies/ml was considered virological failure, triggering change to a second-line regimen. During 760 person-years of observation [median (IQR) 189 (85-441) days], 823 (89%) patients were retained on ART, 2% transferred elsewhere, 7% died and 3% were lost to follow-up. A total of 893 (96%) patients remained on first-line therapy and 16 (1.7%) switched to second-line due to hypersensitivity reactions (n=9) or lactic acidosis (n=7). A Kaplan-Meier estimate for switching to second-line due to toxicity was 3.0% at 32 months. Virological breakthrough occurred in 67 (7.2%) patients, but, following use of a targeted adherence intervention, virological failure was confirmed in just 20 (2.2%). Kaplan-Meier estimates at 32 months were 20% for virological breakthrough but only 5.6% for confirmed virological failure. Overall the authors found that regimen switches were due to virological failure or toxicity. Although follow-up time was limited, over 95% of individuals remained on first-line ART using a combination of viral monitoring and a targeted adherence intervention.

Editors’ note: This study highlights the importance of close monitoring of CD4 counts and viral load to conserve the effectiveness of first line regimens by heading off virological failure through targeted adherence support.