Impact of human immunodeficiency virus type 1 subtypes on virologic response and emergence of drug resistance among children in the Paediatric European Network for Treatment of AIDS (PENTA) 5 trial

The association between virologic response and human immunodeficiency virus type 1 (HIV-1) subtype was investigated in 113 HIV-1-infected children randomly assigned to receive zidovudine plus lamivudine, zidovudine plus abacavir, or lamivudine plus abacavir in the Paediatric European Network for Treatment of AIDS (PENTA) 5 trial. Symptomatic children (n = 68) also received nelfinavir; asymptomatic children (n = 45) were randomly assigned to receive nelfinavir or placebo. HIV-1 subtypes A, B, C, D, F, G, H, A/E, and A/G were found in 15%, 41%, 16%, 9%, 5%, 2%, 1%, 5%, and 7% of the children, respectively. Resistance assay failure rates were higher for non-B subtypes than for B subtypes (genotype, P = .01; phenotype, P = .02). HIV-1 subtype was not associated with virologic response at 24 and 48 weeks after initiation of treatment. No differences were observed in the frequency of development of resistance mutations L90M (P = 1.00) and D30N (P = .61) in B and non-B viruses. In conclusion, no evidence that subtype determined virologic response to therapy was found.