title: The influence of abacavir and other antiretroviral agents on virological response to HCV therapy among antiretroviral-treated HIV-infected patients.
abstract: BACKGROUND
  It remains unclear if certain antiretroviral medications, particularly abacavir, compromise response to HCV therapy. Such data could inform the selection of appropriate antiretrovirals in HIV/HCV-coinfected patients. The aim of this study was to determine if use of abacavir, as well as other antiretrovirals, was associated with reduced response to pegylated interferon (PEG-IFN) plus ribavirin.
  
  
  METHODS
  A cohort study was performed among antiretroviral-treated HIV/HCV-coinfected patients initiating PEG-IFN plus ribavirin between January 2001 and June 2007 at six sites in the United States. Abacavir and other antiretrovirals represented exposures of interest. Study outcomes included an early virological response (> or =2 log IU/ml decrease in HCV viral load at 12 weeks) and sustained virological response (undetectable HCV viral load 24 weeks after treatment discontinuation).
  
  
  RESULTS
  Among 212 patients, 74 (35%) received abacavir. For patients infected with HCV genotype 1 or 4, no differences were observed between abacavir users and non-users in early virological response (26 [40%] versus 53 [44%]; adjusted odds ratio [OR] 1.00; 95% confidence interval [CI] 0.50-2.00) or sustained virological response (8 [13%] versus 13 [12%]; adjusted OR 1.34; 95% CI 0.50-3.62). Among genotype 2 and 3 patients, rates of early virological response (7 [78%] versus 16 [89%]; OR 0.44; 95% CI 0.05-3.76) and sustained virological response (3 [33%] versus 8 [44%]; OR 0.63; 95% CI 0.12-3.32) were also similar between abacavir users and non-users. No association was found between other antiretrovirals and a lack of early or sustained response.
  
  
  CONCLUSIONS
  Use of abacavir or other antiretroviral medications was not associated with reduced early or sustained virological response rates.
authors.affiliation: Division of Infectious Diseases, Department of Medicine, University of Pennsylvania School of Medicine, Philadelphia, PA, USA.
authors.forename: Valerianna K
authors.initials: VK
authors.lastname: Amorosa
authors.forename: Jihad
authors.initials: J
authors.lastname: Slim
authors.forename: Karam
authors.initials: K
authors.lastname: Mounzer
authors.forename: Christopher
authors.initials: C
authors.lastname: Bruno
authors.forename: Margaret
authors.initials: M
authors.lastname: Hoffman-Terry
authors.forename: Zachariah
authors.initials: Z
authors.lastname: Dorey-Stein
authors.forename: Thomas
authors.initials: T
authors.lastname: Ferrara
authors.forename: Jay R
authors.initials: JR
authors.lastname: Kostman
authors.forename: Vincent
authors.initials: V
authors.lastname: Lo Re
mesh_terms: D000328:Adult; D000998:Antiviral Agents / Q000627:therapeutic use*; D015331:Cohort Studies; D015224:Dideoxynucleosides / Q000627:therapeutic use*; D004347:Drug Interactions; D004359:Drug Therapy, Combination; D005260:Female; D015658:HIV Infections / Q000150:complications / Q000188:drug therapy* / Q000821:virology; D015497:HIV-1 / Q000187:drug effects; D016174:Hepacivirus / Q000187:drug effects*; D019698:Hepatitis C, Chronic / Q000188:drug therapy* / Q000209:etiology; D006801:Humans; D000077190:Interferon alpha-2; D016898:Interferon-alpha / Q000627:therapeutic use; D008297:Male; D008875:Middle Aged; D011092:Polyethylene Glycols / Q000627:therapeutic use; D011994:Recombinant Proteins; D012189:Retrospective Studies; D012254:Ribavirin / Q000627:therapeutic use; D016896:Treatment Outcome; D019562:Viral Load / Q000187:drug effects; D000099227:Abacavir
chemical_list: D000998:Antiviral Agents; D015224:Dideoxynucleosides; D000077190:Interferon alpha-2; D016898:Interferon-alpha; D011092:Polyethylene Glycols; D011994:Recombinant Proteins; D012254:Ribavirin; D000099227:Abacavir; C417083:peginterferon alfa-2b; C100416:peginterferon alfa-2a