title: Virologic therapy response significantly correlates with the number of active drugs as evaluated using a LiPA HIV-1 resistance scoring system.
abstract: BACKGROUND
  Resistance testing is increasingly accepted as a tool in guiding the selection of human immunodeficiency virus type 1 (HIV-1) antiretroviral therapy in HIV-1 infected individuals who fail their current regimen.
  
  
  OBJECTIVE
  To descriptively compare the correlation between virologic treatment response and results using three genotypic HIV-1 drug resistance interpretation systems: the VERSANT HIV-1 Resistance Assay (LiPA) system and two sequence-based interpretation systems.
  
  
  METHODS
  Specimens from 213 HIV-1-infected subjects, either starting (n=104) or switching to (n=109) a regimen of three or four antiretroviral drugs, were collected retrospectively at baseline and after 3 months of uninterrupted therapy. The correlation between viral load change and the number of predicted active drugs in the treatment regimen was assessed. An interpretation algorithm was recently developed to process VERSANT HIV-1 Resistance Assay (LiPA) data. The number of active drugs predicted using this algorithm was rank correlated with the viral load change over a 3-month treatment period. For comparison, a similar calculation was made using two sequence-based algorithms (REGA version 5.5 and VGI GuideLines Rules 4.0), both applied on the same sequences.
  
  
  RESULTS
  Statistically significant (p<0.05) correlation coefficients for each of the three HIV-1 drug resistance interpretation systems were observed in the treatment-experienced subjects on a 3-drug regimen (-0.39, -0.38, and -0.42, respectively) as well as on a 4-drug regimen (-0.33, -0.31, and -0.37, respectively). However, no significant correlation was observed in treatment-naive subjects, probably due to the very low frequency of drug resistance in these subjects.
  
  
  CONCLUSIONS
  All three genotypic drug resistance interpretation systems (LiPA version 1, REGA version 5.5, and VGI GuideLines Rules 4.0) were statistically significantly correlated with virologic therapy response as measured by viral load testing.
authors.affiliation: Bayer HealthCare LLC, Diagnostics Division, 800 Dwight Way, Berkeley, CA 94710, USA.
authors.forename: Rainer
authors.initials: R
authors.lastname: Ziermann
authors.forename: Linda
authors.initials: L
authors.lastname: Celis
authors.forename: Inge
authors.initials: I
authors.lastname: Derdelinckx
authors.forename: Christine
authors.initials: C
authors.lastname: Lambert
authors.forename: Jürgen
authors.initials: J
authors.lastname: Veeck
authors.forename: Maria Gabriella
authors.initials: MG
authors.lastname: Rizzo
authors.forename: Bart
authors.initials: B
authors.lastname: Vanderborght
authors.forename: Georges
authors.initials: G
authors.lastname: Zissis
authors.forename: Nathan
authors.initials: N
authors.lastname: Clumeck
authors.forename: Katrien
authors.initials: K
authors.lastname: Fransen
authors.forename: Dolores
authors.initials: D
authors.lastname: Vaira
authors.forename: David
authors.initials: D
authors.lastname: Hendricks
authors.forename: Kristel
authors.initials: K
authors.lastname: Van Laethem
authors.forename: Anne-Mieke
authors.initials: AM
authors.lastname: Vandamme
authors.forename: Jean-Claude
authors.initials: JC
authors.lastname: Schmit
authors.forename: Heribert
authors.initials: H
authors.lastname: Knechten
authors.forename: Andrea
authors.initials: A
authors.lastname: De Luca
authors.forename: Joost
authors.initials: J
authors.lastname: Louwagie
authors.forename: Pascale
authors.initials: P
authors.lastname: Segers
authors.forename: Kristel
authors.initials: K
authors.lastname: De Boeck
authors.forename: Hans
authors.initials: H
authors.lastname: Pottel
authors.forename: Annelies
authors.initials: A
authors.lastname: De Brauwer
authors.forename: Frank
authors.initials: F
authors.lastname: Hulstaert
mesh_terms: D000328:Adult; D000465:Algorithms; D019380:Anti-HIV Agents / Q000494:pharmacology* / Q000627:therapeutic use; D024882:Drug Resistance, Viral / Q000235:genetics; D005260:Female; D015658:HIV Infections / Q000188:drug therapy* / Q000821:virology; D015497:HIV-1 / Q000187:drug effects* / Q000235:genetics; D006801:Humans; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D015337:Multicenter Studies as Topic; D011933:Reagent Kits, Diagnostic; D012189:Retrospective Studies; D016896:Treatment Outcome
chemical_list: D019380:Anti-HIV Agents; D011933:Reagent Kits, Diagnostic