title: Virological failure and drug resistance in patients on antiretroviral therapy after treatment interruption in Lilongwe, Malawi.
abstract: BACKGROUND
  Since 2004, Malawi has rapidly scaled up access to antiretroviral therapy (ART) in the national program following a public health approach with limited laboratory monitoring. We examined virological outcomes in patients with treatment interruption at 2 clinics of the Lighthouse Trust, Lilongwe, Malawi.
  
  
  METHODS
  We evaluated patients who resumed first-line ART after having at least 1 treatment interruption documented in the electronic data system in 2008-2009. Viral load (VL) was analyzed at least 2 months after resumption of ART. For VL ≥1000 copies/mL, drug-resistance genotype was characterized using the Stanford database.
  
  
  RESULTS
  Between June and November 2009, we enrolled 133 patients (58.7% female) with a mean age of 38.4 years. Mean duration of ART prior to treatment interruption was 14.3 months. After a minimum of 2 months following ART resumption, VL was undetectable in 81 (60.9%) patients, was 400-1000 copies/mL in 12 (9.0%) patients, and was ≥1000 copies/mL in 40 (30.1%) patients. Genotyping and drug-resistance testing were successfully performed for 36 of 40 patients, all carrying human immunodeficiency virus type 1 subtype C. Relevant mutations affecting nonnucleoside reverse transcriptase inhibitors were found in 32 of 133 (24.1%) patients and combined with relevant nucleoside reverse transcriptase mutations in 27 of 133 (20.3%) patients.
  
  
  CONCLUSIONS
  Virological failure combined with drug resistance after resumption of first-line ART occurred in 24.1% of the patients with treatment interruption, requiring a switch to protease inhibitor-based second-line therapy. Patients with treatment interruption should receive VL assessment after resumption of ART to detect treatment failure and to reduce development and spread of drug resistance.
authors.affiliation: Institute of Public Health, University of Heidelberg, Germany.
authors.forename: Julia
authors.initials: J
authors.lastname: Luebbert
authors.forename: Hannock
authors.initials: H
authors.lastname: Tweya
authors.forename: Sam
authors.initials: S
authors.lastname: Phiri
authors.forename: Thom
authors.initials: T
authors.lastname: Chaweza
authors.forename: Johnbosco
authors.initials: J
authors.lastname: Mwafilaso
authors.forename: Mina C
authors.initials: MC
authors.lastname: Hosseinipour
authors.forename: Heribert
authors.initials: H
authors.lastname: Ramroth
authors.forename: Paul
authors.initials: P
authors.lastname: Schnitzler
authors.forename: Florian
authors.initials: F
authors.lastname: Neuhann
mesh_terms: D000328:Adult; D044966:Anti-Retroviral Agents / Q000008:administration & dosage*; D023241:Antiretroviral Therapy, Highly Active / Q000379:methods*; D024882:Drug Resistance, Viral; D005260:Female; D015658:HIV Infections / Q000188:drug therapy* / Q000453:epidemiology / Q000821:virology*; D015497:HIV-1 / Q000187:drug effects* / Q000302:isolation & purification; D006801:Humans; D008295:Malawi / Q000453:epidemiology; D008297:Male; D015995:Prevalence; D017211:Treatment Failure
chemical_list: D044966:Anti-Retroviral Agents