title: Tenofovir and abacavir combination therapy: lessons learned from an urban clinic population.
abstract: Regimens containing abacavir (ABC), tenofovir (TDF), and lamivudine (3TC) have recently been demonstrated to have high failure rates. This poses a clinical dilemma of how to manage patients currently being treated with other regimens containing tenofovir/abacavir. We evaluated the outcomes of tenofovir/abacavir regimens in our clinical practice through a retrospective review of 2655 charts. Two hundred patients (7%) were on a tenofovir/abacavir-containing regimen. Fifty-nine patients met the criteria for analysis and were grouped into three groups: (1) antiretroviral naïve, (2) virally suppressed patients switched to TDF/ABC, and (3) patients with failure of their first antiretroviral regimen. Rates of viral suppression in the naïve, switch, and first-failure groups were 95%, 86%, and 46%, respectively. In the first-failure group, viral suppression was 66% without and 18% with a preexisting M184V. A composite analysis of the groups revealed a success rate of 86% when the regimen contained zidovudine (ZDV) and 62% when it did not. No K65R mutations were noted. These findings support continued caution in the use of TDF/ABC in combination. However, these data suggest that this combination may be successfully used in selected situations such as in combination with ZDV. In patients already virally suppressed on a TDF/ABC-containing regimen, considerations include continuing the regimen or adding zidovudine, in the attempt to protect against the development of a K65R mutation and/or virologic failure, versus changing a stable regimen.
authors.affiliation: Institute of Human Virology, University of Maryland School of Medicine, Baltimore, Maryland 21201, USA. gilliam@umbi.umd.edu
authors.forename: Bruce L
authors.initials: BL
authors.lastname: Gilliam
authors.forename: Mohammad M
authors.initials: MM
authors.lastname: Sajadi
authors.forename: Anthony
authors.initials: A
authors.lastname: Amoroso
authors.forename: Charles E
authors.initials: CE
authors.lastname: Davis
authors.forename: Farley R
authors.initials: FR
authors.lastname: Cleghorn
authors.forename: Robert R
authors.initials: RR
authors.lastname: Redfield
mesh_terms: D000163:Acquired Immunodeficiency Syndrome / Q000188:drug therapy*; D000225:Adenine / Q000008:administration & dosage / Q000031:analogs & derivatives* / Q000627:therapeutic use; D000328:Adult; D000368:Aged; D019380:Anti-HIV Agents / Q000008:administration & dosage / Q000627:therapeutic use*; D015142:Baltimore; D015224:Dideoxynucleosides / Q000008:administration & dosage / Q000627:therapeutic use*; D004359:Drug Therapy, Combination; D005260:Female; D006801:Humans; D008297:Male; D008499:Medical Records; D008875:Middle Aged; D015337:Multicenter Studies as Topic; D063065:Organophosphonates / Q000008:administration & dosage / Q000627:therapeutic use*; D012189:Retrospective Studies; D000068698:Tenofovir; D017211:Treatment Failure; D014505:Urban Population; D019562:Viral Load; D000099227:Abacavir
chemical_list: D000225:Adenine; D019380:Anti-HIV Agents; D015224:Dideoxynucleosides; D063065:Organophosphonates; D000068698:Tenofovir; D000099227:Abacavir