title: Minority quasispecies of drug-resistant HIV-1 that lead to early therapy failure in treatment-naive and -adherent patients.
abstract: BACKGROUND
  Early virological failure of antiretroviral therapy associated with the selection of drug-resistant human immunodeficiency virus type 1 in treatment-naive patients is very critical, because virological failure significantly increases the risk of subsequent failures. Therefore, we evaluated the possible role of minority quasispecies of drug-resistant human immunodeficiency virus type 1, which are undetectable at baseline by population sequencing, with regard to early virological failure.
  
  
  METHODS
  We studied 4 patients who experienced early virological failure of a first-line regimen of lamivudine, tenofovir, and either efavirenz or nevirapine and 18 control patients undergoing similar treatment without virological failure. The key mutations K65R, K103N, Y181C, M184V, and M184I in the reverse transcriptase were quantified by allele-specific real-time polymerase chain reaction performed on plasma samples before and during early virological treatment failure.
  
  
  RESULTS
  Before treatment, none of the viruses showed any evidence of drug resistance in the standard genotype analysis. Minority quasispecies with either the M184V mutation or the M184I mutation were detected in 3 of 18 control patients. In contrast, all 4 patients whose treatment was failing had harbored drug-resistant viruses at low frequencies before treatment, with a frequency range of 0.07%-2.0%. A range of 1-4 mutations was detected in viruses from each patient. Most of the minority quasispecies were rapidly selected and represented the major virus population within weeks after the patients started antiretroviral therapy. All 4 patients showed good adherence to treatment. Nonnucleoside reverse-transcriptase inhibitor plasma concentrations were in normal ranges for all 4 patients at 2 separate assessment times.
  
  
  CONCLUSIONS
  Minority quasispecies of drug-resistant viruses, detected at baseline, can rapidly outgrow and become the major virus population and subsequently lead to early therapy failure in treatment-naive patients who receive antiretroviral therapy regimens with a low genetic resistance barrier.
authors.affiliation: Institute of Clinical and Molecular Virology, University of Erlangen-Nuremberg, Erlangen, Germany. Karin.Metzner@usz.ch
authors.forename: Karin J
authors.initials: KJ
authors.lastname: Metzner
authors.forename: Stefano G
authors.initials: SG
authors.lastname: Giulieri
authors.forename: Stefanie A
authors.initials: SA
authors.lastname: Knoepfel
authors.forename: Pia
authors.initials: P
authors.lastname: Rauch
authors.forename: Philippe
authors.initials: P
authors.lastname: Burgisser
authors.forename: Sabine
authors.initials: S
authors.lastname: Yerly
authors.forename: Huldrych F
authors.initials: HF
authors.lastname: Günthard
authors.forename: Matthias
authors.initials: M
authors.lastname: Cavassini
mesh_terms: D000225:Adenine / Q000031:analogs & derivatives / Q000627:therapeutic use; D000480:Alkynes; D000483:Alleles; D019380:Anti-HIV Agents / Q000627:therapeutic use; D023241:Antiretroviral Therapy, Highly Active; D048588:Benzoxazines / Q000627:therapeutic use; D003521:Cyclopropanes; D024882:Drug Resistance, Viral; D005260:Female; D005838:Genotype; D015658:HIV Infections / Q000188:drug therapy* / Q000821:virology*; D054303:HIV Reverse Transcriptase / Q000235:genetics; D015497:HIV-1 / Q000145:classification* / Q000187:drug effects* / Q000235:genetics; D006801:Humans; D019259:Lamivudine / Q000627:therapeutic use; D008297:Male; D055118:Medication Adherence; D020125:Mutation, Missense; D019829:Nevirapine / Q000627:therapeutic use; D063065:Organophosphonates / Q000627:therapeutic use; D010949:Plasma / Q000821:virology; D016133:Polymerase Chain Reaction / Q000379:methods; D012641:Selection, Genetic; D000068698:Tenofovir; D017211:Treatment Failure
chemical_list: D000480:Alkynes; D019380:Anti-HIV Agents; D048588:Benzoxazines; D003521:Cyclopropanes; D063065:Organophosphonates; D019259:Lamivudine; D019829:Nevirapine; D000068698:Tenofovir; C514824:reverse transcriptase, Human immunodeficiency virus 1; D054303:HIV Reverse Transcriptase; D000225:Adenine; C098320:efavirenz