Paediatric antiretroviral therapy audit in South London K Doerholt, 1 M Sharland, 1 C Ball 2 and G DuMont 3 1 Paediatric Infectious Diseases Unit, St George's Hospital, 2 Department of Paediatrics, King's College Hospital and 3 Department of Paediatrics, Guy's and St Thomas's Hospital, London, UK Objectives To audit clinical and surrogate marker outcome data following the introduction of combination antiretroviral therapy to HIV-infected children in South London. Methods We performed a retrospective cohort study of 110 HIV-infected children under the care of the Paediatric HIV in South London Network (PHILS-NET) from January 1996 to September 1999. The following were identi®ed: type of antiretroviral therapy used; duration of therapy; toxicity; impact on viral load and CD4 count; reasons for changing therapy; and clinical progression. Results Ninety-one (83%) of the 110 children (55 females; median age 6.3 years) received 166 antiretroviral therapy regimens. Sixty per cent of the regimens were triple therapy: either two nucleoside reverse transcriptase inhibitors (NRTIs) and one protease inhibitor (58; 34.9%) or two NRTIs and one non- nucleoside reverse transcriptase inhibitor (39; 23.5%). The mean duration of completed therapy was 46 weeks for ®rst line therapy with a standard deviation (SD) of 38 weeks and 40 weeks in third line therapywithanSDof22weeks.Changesinantiretroviralregimenswereowingtovirologicalfailurein 60% and toxicity in 10%. Overall, 46% of children on ®rst line and 37% on second line antiretroviral therapy achieved an undetectable viral load of , 400 HIV-1 RNA copies/mL. Clinical progression for the whole cohort fell from 3.7% per year for children on dual therapy to 0.7% per year for children on highly active antiretroviral therapy. Conclusions This audit shows the clinical bene®t of antiretroviral therapy use in a cohort of children with moderately advanced HIV disease. The surrogate outcome data seen for the viral load and CD4 count are similar to those of reports from clinical trials. Antiretroviral therapy regimens were sequenced rapidly, mainly owing to virological failure. Keywords: antiretroviral therapy, audit, children, HIV/AIDS Received: 21 June 2001, accepted 12 October 2001 Introduction The use of highly active antiretroviral therapy (HAART) has been associated with a dramatic clinical improvement and reduction in mortality in children with symptomatic HIV infection [1]. The results of the AIDS Clinical Trials Group (ACTG) protocol 152 study, an early comparative trial of single and dual therapy, showed that the relative risk of disease progression in children was reduced by 54% for each log 10 reduction in viral load. The Paediatric AIDS Clinical Trials Group (PACTG) protocol 300 demonstrated that combining the nucleoside reverse transcriptase in- hibitors (NRTIs) zidovudine (ZDV) and lamivudine (3TC) decreased the chance of disease progression, including death, by 70% compared to didanosine (ddI) mono- therapy [2]. In the PACTG protocol 338 study, 58% of children treated with the combination of ZDV  3TC  ritonavir (RTV) reached a viral load , 400 HIV-1 RNA copies/mL by 48 weeks [3]. Other studies observed an un- detectable viral load in 30±50% of children on HAART [4±6] and a less signi®cant viral load reduction in non-naive children [7]. Following these studies, dual NRTI therapy was introduced to UK children in 1996. Triple therapy using a protease inhibitor (PI) or nonnucleoside reverse 44 Correspondence: Dr Mike Sharland, Paediatric Infectious Diseases Unit, St George's Hospital, Blackshaw Road, London SW17 0QT, UK. Tel/fax:  44 20 8725 3262; e-mail: msharlan@sghms.ac.uk ß 2002 British HIV Association HIV Medicine (2002), 3, 44±48 ORIGINAL RESEARCH