In a randomized trial comparing nevirapine ( NVP ) - based versus lopinavir/ritonavir ( LPV/r ) - based antiretroviral therapy ( ART ) in HIV-infected children -LSB- primary endpoint discontinuation of study treatment for any reason or virologic failure by week @ -RSB- aged @ months to @ years , we assessed whether clinical , virologic , immunologic and safety outcomes varied by prior single-dose NVP exposure ( PrNVP ) for prevention of mother-to-child HIV transmission and other covariates .