Trial of Maraviroc (UK-427,857) in Combination With Zidovudine/Lamivudine Versus Efavirenz in Combination With Zidovudine/Lamivudine

Percentage of participants with viral load of less than 400 copies/mL and less than 50 copies/mL of HIV-1 RNA were not analyzed for participants originally randomized to maraviroc once daily arm since after termination, focus was shifted from efficacy and safety to only safety as reflected in the abbreviated set of efficacy measures noted in the amended planned analysis.

Change from baseline in log 10-transformed plasma viral load (HIV-1 RNA) levels (log10 copies/mL). Baseline value calculated as average of pre-dose measurements collected at screening, randomization, and immediately pre-dose.

TAD from baseline was calculated as area under the curve (AUC) of HIV-1 RNA load (log10 copies/mL) divided by time period minus baseline HIV-1 RNA load (log10 copies/mL). Baseline value calculated as average of pre-dose measurements collected at screening, randomization, and immediately pre-dose. Data not analyzed for participants originally randomized to maraviroc once daily arm since after termination, focus was shifted from efficacy and safety to only safety as reflected in the abbreviated set of efficacy measures noted in the amended planned analysis.

Baseline value calculated as the average of pre-dose measurements collected at screening and immediately pre-dose.

Baseline value calculated as the average of pre-dose measurements collected at screening and immediately pre-dose. Change from baseline in lymphocyte CD8 count at Week 48 and 96 was not analyzed for participants originally randomized to maraviroc once daily arm since after termination, focus was shifted from efficacy and safety to only safety as reflected in the abbreviated set of efficacy measures noted in the amended planned analysis.

Time to virologic failure based on observed HIV-1 RNA levels and failure events (death;permanent discontinuation of drug;lost to follow-up [LTFU];new anti-retroviral drug added [except background drug change to drug of same class];or on open label for early non-response or rebound). Failure:at Time 0 if level not <400 copies/mL(2 consecutive visits) before events or last available visit;at time of earliest event if level <400 copies/mL(2 consecutive visits);failure if level >=400 copies/mL(2 consecutive visits) or 1 visit >=400 copies/mL followed by permanent discontinuation of drug or LTFU.

Number of participants per tropism status (C-X-C chemokine receptor 5 {CCR5} [R5], C-X-C chemokine receptor type 4 {CXCR4} [X4], Dual/mixed [DM], or Non-reportable/Non-phenotypable [NR/NP]) at baseline and time of treatment failure analyzed through week 48 visit. Treatment failure: discontinuation due to insufficient clinical response. Tropism result was censored for participants with viral load <500 copies/mL at time of treatment failure categorized as below lower limit of quantification (BLQ). The assessment for time of treatment failure was defined as last on treatment assessment.

Number of participants per tropism status (R5, X4, DM, or NR/NP) at baseline and time of treatment failure analyzed through week 96 visit. Treatment failure defined as insufficient clinical response. Tropism result was censored for participants with viral load <500 copies/mL at time of treatment failure categorized as BLQ. The assessment for time of treatment failure was defined as last on treatment assessment.

Phenotypic resistance to nucleoside reverse transcriptase inhibitors (NRTIs) and non-nucleoside reverse transcriptase inhibitors (NNRTIs) assessed at screening by Monogram Bioscience PhenoSense genotype (MBPSGT) assay, repeated if viral load >500 copies/mL at treatment failure through week 48, 96. Phenotypic resistance to maraviroc was assumed in maraviroc treatment failures with X4-using virus and in R5 maraviroc treatment failures using Monogram Bioscience PhenoSense Entry Assay. Phenotypic resistance to zidovudine, lamivudine, efavirenz and maraviroc at time of failure was summarized.

Genotypic resistance to NRTIs was assessed by identification of relevant mutations at screening using MBPSGT assay and repeated for all participants with HIV-1 viral load more than 500 copies/mL at treatment failure through week 48 and week 96. Following mutations associated with NRTIs were summarized at time of failure: Any zidovudine/lamivudine (Zid/Lam), Any thymidine analogue-associated mutation (TAM), methionine (M) to valine/isoleucine (V/I) substitution at residue (r) 184 (M184V/I), lysine (K) to arginine (R) substitution at residue 65 (K65R) and any other NRTI mutations.

Genotypic resistance: mutations at screening by MBPSGT assay, repeated if viral load >500 copies/mL at treatment failure through week 48, 96. Efavirenz mutation:lysine to aspargine at r103(K103N);tyrosine to cysteine/isoleucine at r181(Y181C/I);tyrosine to cysteine/leucine/histidine at r188(Y188C/L/H);glycine to alanine/serine at r190(G190A/S);valine to alanine to r106(V106A);leucine to isoleucine at r100(L100I);alanine to glycine at r98(A98G);lysine to glutamic acid at r101(K101E);valine to isoleucine at r108(V108I);proline to histidine at r225(P225H);methionine to leucine at r230(M230L).

Association between baseline resistance and virological response was assessed as percentage of participants with HIV-1RNA levels less than 50 copies/mL by OSS at screening. OSS categorized as 0, 1, 2, >3 (maximum value of 6) and calculated as the sum of the net assessment of in-vitro phenotypic and genotypic susceptibility using a binary scoring system (0= resistant, 1= sensitive or susceptible) for each antiretroviral agent in OBT. Higher scores indicate greater susceptibility.