PEDIATRICS Vol. 107 No. 1 January 2001, p. e4
Received May 24, 2000; accepted Aug 30, 2000.
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From * Hospital del Niño, Servicio de Infectologia, Panama
City, Republic of Panama;
Department of Hematology and Oncology,
Indiana University, Indianapolis, Indiana; § Pediatric Infectious
Disease, University of South Florida College of Medicine, Tampa,
Florida;
Department of Pediatrics, Jacobi Medical Center, Bronx, New
York; ¶ Division of Pediatric Infectious Diseases, University of Miami
School of Medicine, Miami, Florida; # Division of Clinical Allergy and
Immunology, Childrens Hospital of Los Angeles, Los Angeles,
California; ** Division of Infectious Disease and Immunology, University
of Florida at Gainesville, Gainesville, Florida; 
Department of
Pediatrics, Tulane University School of Medicine, New Orleans,
Louisiana; and §§ Glaxo Wellcome Inc, Research Triangle Park, North
Carolina.
Objectives. Abacavir (ABC) is a potent inhibitor of human immunodeficiency virus type 1 (HIV-1) reverse transcriptase. We compared the efficacy, safety, and tolerability of combination therapy with ABC, lamivudine (3TC), and zidovudine (ZDV) versus 3TC and ZDV in antiretroviral experienced HIV-1-infected children over 48 weeks.
Methods. Two hundred five HIV-1-infected children who had
received previous antiretroviral therapy and had CD4+ cell
counts
100 cells/mm3 were stratified by age and by
previous treatment. Participants were randomly assigned to receive ABC
(8 mg/kg twice daily [BID]) plus 3TC (4 mg/kg BID) and ZDV (180 mg/m2 BID; ABC/3TC/ZDV group) or ABC placebo plus 3TC (4 mg/kg BID) and ZDV (180 mg/m2; 3TC/ZDV group). Participants
who met a protocol-defined switch criteria (plasma HIV-1 RNA >0.5
log10 copies/mL above baseline at week 8 or >10 000
copies/mL after week 16) had the option to switch to open-label ABC
plus any antiretroviral combination or continue randomized therapy or
withdraw from the study.
Results. The Kaplan-Meier estimates (95% confidence
interval) of the proportion of participants who maintained HIV-1 RNA
levels
10 000 copies/mL for 48 weeks or more was significantly
better in the ABC/3TC/ZDV group compared with the 3TC/ZDV group: 33%
(23%-42%) versus 21% (13%-29%). At week 48, the
proportions of participants with HIV-1 RNA
10 000 copies/mL were
36% versus 26% for the ABC/3TC/ZDV and 3TC/ZDV groups, respectively,
by intent-to-treat analysis. For the subgroup of participants with
baseline HIV-1 RNA >10 000 copies/mL, a significantly higher
proportion of participants in the ABC/3TC/ZDV group had HIV-1 RNA
10 000 copies/mL compared with the 3TC/ZDV group (29% vs 12%) but
no difference was observed in the subgroup of participants with
baseline HIV-1 RNA
10 000 copies/mL (78% vs 72%). The median
changes from baseline in CD4+ cell counts were greater in
the ABC/3TC/ZDV group than in the 3TC/ZDV group. Few participants (3%)
experienced abacavir-related hypersensitivity reaction.
Conclusions. ABC, in combination with 3TC and ZDV, provides additional antiretroviral activity over 48 weeks, compared with combination therapy with 3TC and ZDV in antiretroviral experienced HIV-1-infected children. ABC was safe and generally well-tolerated and should be considered an active component of combination antiretroviral therapy in this pediatric population. Key words: human immunodeficiency virus type 1, abacavir, lamivudine, zidovudine, viral ribonucleic acid, CD4, antiretroviral therapy, pediatric.