In Pediatric AIDS Clinical Trials Group 377, antiretroviral therapy-experienced children were randomized to 4 treatment arms that included different combinations of stavudine, lamivudine (3TC), nevirapine (Nvp), nelfinavir (Nfv), and ritonavir (Rtv). Previous treatment with zidovudine (Zdv), didanosine (ddI), or zalcitabine (ddC) was acceptable. Drug resistance (R) mutations were assessed before study treatment (baseline) and at virologic failure. ZdvR, ddIR, and ddCRmutations were detected frequently at baseline but were not associated with virologic failure. Children with drug resistance mutations at baseline had greater reductions in virus load over time than did children who did not. NvpRand 3TCRmutations were detected frequently at virologic failure, and NvpRmutations were more common among children receiving 3-drug versus 4-drug Nvp-containing regimens. Children who were maintained on their study regimen after virologic failure accumulated additional NvpRand 3TCRmutations plus RtvRand NfvRmutations. However, RtvRand NfvRmutations were detected at unexpectedly low rates.
Bibliographical noteFunding Information:
Financial support: National Institutes of Health (NIH; Pediatric and Adult AIDS Clinical Trials Groups [NIH/Division of Allergy and Infectious Diseases]; AI-35173 and R29 34348 to S.H.E.; AI-25883 and contract 97PVCL08 to P.P); Pediatric AIDS Foundation (Elizabeth Glaser scientist award to P.K.; support to S.H.E.). Applied Biosystems supplied reagents for this study.