title: Nevirapine resistance mutations of human immunodeficiency virus type 1 selected during therapy.
abstract: Drug susceptibility and mutations in the reverse transcriptase (RT) gene were analyzed with 167 virus isolates from 38 patients treated with nevirapine, a potent nonnucleoside inhibitor of human immunodeficiency virus type 1 (HIV-1) RT. Resistant isolates emerged quickly and uniformly in all patients administered nevirapine either as monotherapy or in combination with zidovudine (AZT). Resistance developed as early as 1 week, indicating rapid turnover of the virus population. The development of resistance was associated with the loss of antiviral drug activity as measured by CD4 lymphocyte counts and levels of HIV p24 antigen and RNA in serum. In addition to mutations at amino acid residues 103, 106, and 181 that had been identified by selection in cell culture, mutations at residues 108, 188, and 190 were also found in the patient isolates. Sequences from patient clones documented cocirculating mixtures of populations of different mutants. The most common mutation with monotherapy, tyrosine to cysteine at residue 181, was prevented from emerging by coadministration of AZT, which resulted in the selection of alternative mutations. The observations documented that, under selective drug pressure, the circulating virus population can change rapidly, and many alternative mutants can emerge, often in complex mixtures. The addition of a second RT inhibitor, AZT, significantly altered the pattern of mutations in the circulating population of HIV.
authors.affiliation: Department of Pathology, University of California, San Diego 92093-0679.
authors.forename: D D
authors.initials: DD
authors.lastname: Richman
authors.forename: D
authors.initials: D
authors.lastname: Havlir
authors.forename: J
authors.initials: J
authors.lastname: Corbeil
authors.forename: D
authors.initials: D
authors.lastname: Looney
authors.forename: C
authors.initials: C
authors.lastname: Ignacio
authors.forename: S A
authors.initials: SA
authors.lastname: Spector
authors.forename: J
authors.initials: J
authors.lastname: Sullivan
authors.forename: S
authors.initials: S
authors.lastname: Cheeseman
authors.forename: K
authors.initials: K
authors.lastname: Barringer
authors.forename: D
authors.initials: D
authors.lastname: Pauletti
mesh_terms: D000998:Antiviral Agents / Q000494:pharmacology* / Q000627:therapeutic use; D001483:Base Sequence; D015496:CD4-Positive T-Lymphocytes / Q000166:cytology; D004352:Drug Resistance, Microbial / Q000235:genetics; D004359:Drug Therapy, Combination; D005838:Genotype; D016655:HIV Core Protein p24 / Q000097:blood; D015658:HIV Infections / Q000188:drug therapy*; D054303:HIV Reverse Transcriptase; D015497:HIV-1 / Q000235:genetics*; D006801:Humans; D007958:Leukocyte Count; D008969:Molecular Sequence Data; D016296:Mutagenesis; D019829:Nevirapine; D010641:Phenotype; D011725:Pyridines / Q000494:pharmacology* / Q000627:therapeutic use; D012367:RNA, Viral / Q000097:blood; D012194:RNA-Directed DNA Polymerase / Q000235:genetics*; D018894:Reverse Transcriptase Inhibitors; D012641:Selection, Genetic; D013997:Time Factors; D015215:Zidovudine / Q000494:pharmacology / Q000627:therapeutic use
chemical_list: D000998:Antiviral Agents; D016655:HIV Core Protein p24; D011725:Pyridines; D012367:RNA, Viral; D018894:Reverse Transcriptase Inhibitors; D015215:Zidovudine; D019829:Nevirapine; D054303:HIV Reverse Transcriptase; D012194:RNA-Directed DNA Polymerase