The effects of antiretroviral dose modification on the re-emergence of HIV-1 wild-type strains.

Four human immunodeficiency virus type 1 (HIV-1) treatment-naïve Thai patients began antiretrovival therapy with a triple drug regimen -zidovudine plus lamivudine plus indinavir; this regimen was modified at week 20 of therapy because of drug toxicity. The virus in all patients was suppressed to lower than 400 copies/ml while they were taking the triple antiretroviral drug regimen. However, suppression was lost after changing the antiretroviral regimen. A comparison of HIV-1 DNA sequences taken from the baseline (day 0) and week 24 showed no significant overgrowth in HIV-1 drug-resistant strains. There was no difference in the protease and reverse transcriptase (RT) mutation profiles. Resistant variants did not emerge, even after sub-therapeutic levels of antiretroviral drugs had been introduced to these patients for 4 weeks. These findings may have clinical implications for long-term treatment strategies.