title: Risk factors for raltegravir resistance development in clinical practice.
abstract: OBJECTIVE
  To investigate the best conditions of raltegravir use to avoid the selection of resistance mutations in the three main genetic pathways: 148, 155 and 143.
  
  
  METHODS
  A total of 161 patients failing on raltegravir with two consecutive HIV-1 viral loads >20 copies/mL were studied. Ten parameters [HIV-1 RNA and CD4 at baseline and failure, genotypic sensitivity score (GSS) of treatment associated with raltegravir, protease inhibitors used, time spent on raltegravir, subtype, sex and age] were tested in univariate and multivariate logistic regression analyses and compared with the emergence of resistance mutations to raltegravir at failure. Phenotypic susceptibility to raltegravir was studied in 16 patients without the main resistance mutations to raltegravir at failure.
  
  
  RESULTS
  At raltegravir failure, 46/161 patients (28.6%) had integrase resistance mutations, whereas 115/161 (71.4%) had no resistance mutations. High HIV-1 viral load level at failure (OR = 2.81, 95% CI 1.8-4.6, P < 0.001) and low GSS of treatment associated with raltegravir (OR = 11.6, 95% CI 4.5-36.4, P < 0.001) were independently associated with the selection of raltegravir mutations. The percentages of patients with integrase resistance mutations were 7.7% (6/78) versus 48.1% (40/83) when viral load is ≤200 or >200 copies/mL and 47.5% (39/82) versus 8.9% (7/79) when GSS is <2 or ≥2. Among patients without main resistance mutations, two patients showed raltegravir phenotypic resistance, one naturally with F121Y at baseline and the other acquiring G118R at failure.
  
  
  CONCLUSIONS
  Our results show that to avoid the selection of raltegravir resistance mutations, patients have to be treated with at least two active drugs in combination with raltegravir and to maintain a viral load ≤200 copies/mL.
authors: Laboratoire de Virologie, AP-HP, Groupe Hospitalier Pitié-Salpêtrière, UPMC Université Pierre et Marie Curie, INSERM U943, Paris, France. isabelle.malet@psl.aphp.fr
authors: Isabelle
authors: I
authors: Malet
authors: Slim
authors: S
authors: Fourati
authors: Laurence
authors: L
authors: Morand-Joubert
authors: Philippe
authors: P
authors: Flandre
authors: Marc
authors: M
authors: Wirden
authors: Stéphanie
authors: S
authors: Haim-Boukobza
authors: Sophie
authors: S
authors: Sayon
authors: Theresa
authors: T
authors: Pattery
authors: Anne
authors: A
authors: Simon
authors: Christine
authors: C
authors: Katlama
authors: Pierre-Marie
authors: PM
authors: Girard
authors: Vincent
authors: V
authors: Calvez
authors: Anne-Geneviève
authors: AG
authors: Marcelin
mesh_terms: D000328:Adult; D000368:Aged; D019380:Anti-HIV Agents / Q000008:administration & dosage* / Q000494:pharmacology; D023241:Antiretroviral Therapy, Highly Active / Q000379:methods*; D018791:CD4 Lymphocyte Count; D024882:Drug Resistance, Viral; D005260:Female; D015497:HIV-1 / Q000187:drug effects* / Q000302:isolation & purification; D006801:Humans; D008297:Male; D008826:Microbial Sensitivity Tests; D008875:Middle Aged; D011760:Pyrrolidinones / Q000008:administration & dosage* / Q000494:pharmacology; D000068898:Raltegravir Potassium; D012307:Risk Factors; D019562:Viral Load; D055815:Young Adult
chemical_list: D019380:Anti-HIV Agents; D011760:Pyrrolidinones; D000068898:Raltegravir Potassium