Potential mechanism for sustained antiretroviral efficacy of AZT-3TC combination therapy

Science. 1995 Aug 4;269(5224):696-9. doi: 10.1126/science.7542804.

Abstract

Combinations of antiretroviral drugs that prevent or delay the appearance of drug-resistant human immunodeficiency virus-type 1 (HIV-1) mutants are urgently required. Mutants resistant to 3'-azidothymidine (AZT, zidovudine) became phenotypically sensitive in vitro by mutation of residue 184 of viral reverse transcriptase to valine, which also induced resistance to (-)2'-deoxy-3'-thiacytidine (3TC). Furthermore, AZT-3TC coresistance was not observed during extensive in vitro selection with both drugs. In vivo AZT-3TC combination therapy resulted in a markedly greater decreased in serum HIV-1 RNA concentrations than treatment with AZT alone, even though valine-184 mutants rapidly emerged. Most samples assessed from the combination group remained AZT sensitive at 24 weeks of therapy, consistent with in vitro mutation studies.

Publication types

  • Clinical Trial
  • Clinical Trial, Phase II
  • Clinical Trial, Phase III
  • Randomized Controlled Trial

MeSH terms

  • Antiviral Agents / pharmacology*
  • Antiviral Agents / therapeutic use
  • Base Sequence
  • CD4 Lymphocyte Count
  • Cell Line
  • Codon
  • Drug Resistance, Microbial
  • Drug Therapy, Combination
  • HIV Infections / drug therapy*
  • HIV Infections / virology
  • HIV Reverse Transcriptase
  • HIV-1 / drug effects*
  • HIV-1 / enzymology
  • HIV-1 / genetics
  • HIV-1 / growth & development
  • HeLa Cells
  • Humans
  • Lamivudine
  • Molecular Sequence Data
  • Mutagenesis, Site-Directed
  • Point Mutation
  • RNA, Viral / blood
  • RNA-Directed DNA Polymerase / genetics
  • Reverse Transcriptase Inhibitors*
  • Serial Passage
  • Zalcitabine / analogs & derivatives*
  • Zalcitabine / pharmacology
  • Zalcitabine / therapeutic use
  • Zidovudine / pharmacology*
  • Zidovudine / therapeutic use

Substances

  • Antiviral Agents
  • Codon
  • RNA, Viral
  • Reverse Transcriptase Inhibitors
  • Lamivudine
  • Zidovudine
  • Zalcitabine
  • HIV Reverse Transcriptase
  • RNA-Directed DNA Polymerase