- Limited or no treatment options due to resistance or intolerance to multiple antiretroviral regimens, documented resistance to at least one drug in each of the 3 classes of oral ARTs (NRTI, NNRTI, PI) by genotype or phenotype testing, intolerance defined as having had a clinically significant adverse event which in the opinion of the clinician provides a contraindication to the use of any drug in that class iii. Patient did not achieve virologic suppression on ART regimen prior to receipt of raltegravir iv. Patient was clinically stable at time of initiation of raltegravir, eg. clinical status and all chronic medications (except ARTs) unchanged for >= 2 weeks prior to raltegravir receipt.