Implementation of Raltegravir in Routine Clinical Practice: Selection Criteria for Choosing This Drug, Virologic Response Rates, and Characteristics of Failures

Background: Raltegravir (RAL) achieved remarkable virologic suppression rates in randomized-clinical trials, but today efficacy data and factors for treatment failures in a routine clinical care setting are limited. Methods: First, factors associated with a switch to RAL were identified with a logistic regression including patients from the Swiss HIV Cohort Study with a history of 3 class failure (n = 423). Second, predictors for virologic outcome were identified in an intent-to-treat analysis including all patients who received RAL. Last observation carried forward imputation was used to determine week 24 response rate (HIV-1 RNA >= 50 copies/mL). Results: The predominant factor associated with a switch to RAL in patients with suppressed baseline RNA was a regimen containing enfuvirtide [odds ratio 41.9 (95% confidence interval: 11.6-151.6)]. Efficacy analysis showed an overall response rate of 80.9% (152/188), whereas 71.8% (84/117) and 95.8% (68/71) showed viral suppression when stratified for detectable and undetectable RNA at baseline, respectively. Overall CD4 cell counts increased significantly by 42 cells/mu L (P < 0.001). Characteristics of failures were a genotypic sensitivity score of the background regimen <= 1, very low RAL plasma concentrations, poor adherence, and high viral load at baseline. Conclusions: Virologic suppression rates in our routine clinical care setting were promising and comparable with data from previously published randomized-controlled trials.