First prospective comparison of genotypic vs phenotypic tropism assays in predicting virologic responses to Maraviroc (MVC) in a phase 3 study: MODERN

摘要

IntroductionMODERN (A4001095) was the first prospective phase 3 study comparing genotype vs phenotype (Trofile?) tropism assessments.Materials and MethodsTreatment-na?ve adults with HIV-1 RNA >1000 copies/mL were randomized 1:1 at screening to either genotype or Trofile for tropism assessment. Genotype was determined using the geno2pheno algorithm to assess triplicate HIV-1 gp120 V3 loop sequences (plasma); false-positive rate=10%. R5-virus-infected subjects were then randomized 1:1 to receive Maraviroc (MVC) 150 mg QD or Truvada 200/300 mg QD each with DRV/r 800/100 mg QD. Tropism of screening samples from enrolled subjects was also retrospectively determined using the alternate testing method. Positive predictive values (PPV) were estimated by%R5 subjects with Week 48 HIV-1 RNA < 50 c/mL. PPV for each assay was estimated using the response rate among those randomized to that assay and using model-based response estimates in those with R5 by that assay (at screening or retest).ResultsThe observed response rate was 146/181 (80.7%) for genotype vs 160/215 (74.4%) for Trofile (stratification adjusted difference=6.9%, 95% CI 1.3% to 15%). The model-based estimates of PPV (±SE) were 79.1% (±2.42) and 76.3% (±2.38), respectively (difference = 2.8%, 95% CI ?2.1% to 7.2%). There was no difference in response rate between assays in the Truvada arm (observed difference=? 0.1%, 95% CI ?6.8% to 6.6%). Most enrolled subjects had R5 results at screening using both assays (285/396 (72%)), and of these subjects, 79.3% (226/285) had HIV-1 RNA <50 c/mL at week 48 (Table 1). The few subjects classified as non-R5 by the alternate assay had similar virologic responses to the concordant R5 group.Table 1MVC week 48 response (HIV-1 RNA<50c/mL), n/N (%)