title: Immunological and Virological Outcomes of Patients Switched from LPV/r to ATV/r-Containing Second- Line Regimens.
abstract: BACKGROUND
  Atazanavir/ritonavir (ATV/r) recently became the preferred protease inhibitor (PI) for use in Nigeria since it is dosed once daily, which may improve treatment adherence and has fewer side effects than lopinavir/ritonavir (LPV/r)--the most widely available PI in resource-limited settings. We, therefore, aimed to evaluate the immunologic and virologic effects of switching patients to an ATV/r-containing regimen.
  
  
  METHODS
  In a large antiretroviral treatment programme at the Lagos University Teaching Hospital in Nigeria, 400 patients were switched to ATV/r-based second-line ART. We conducted a retrospective evaluation of immunologic and virologic outcomes following 24 months on the ATV/r regimens.
  
  
  RESULTS
  Of the 400 patients switched to an ATV/r containing regimen, 255 were virologically suppressed on LPV/r prior to switch, 107 were switched due to failure on a first-line regimen, 28 were on saquinavir/ritonavir (SQV/r)-based regimen, while 10 were unintentionally switched while non-suppressed on a LPV/r-based regimen. Demonstrable and sustained immunological responses were documented as the median (IQR) CD4+ cell count increased steadily from 466 (323) cells/mm3 at the time of switch to 490 (346) cells/mm3 at 6 months, and 504 (360) cells/mm3 at 24 months. Of 99 patients evaluated 12 months after ATV/r switch, 2 (2%) had detectable viral load (VL). None of the 26 (0%) in this group evaluated at 24 months had detectable viral load. In a comparison group of 576 patients who were maintained on LPV/r-based second line regimens, 359 (62.3%) had undetectable viral loads. Of 318 patients with VL data 24 months later, 25 (7.9%) had detectable VL. There was no significant difference between the proportion of patients maintained on LPV/r (7.9%) and those switched to ATV/r (0%) in the development of virologic failure after 24 months of follow-up.
  
  
  CONCLUSIONS
  Among patients that were switched to ATV/r-containing regimens, we found improvements in immunological responses and no increase in risk of virologic failure.
authors.affiliation: University of Lagos College of Medicine, University of Lagos, Lagos, Nigeria. asulaimona@gmail.com.
authors.forename: A S
authors.initials: AS
authors.lastname: Akanmu
authors.forename: T
authors.initials: T
authors.lastname: Adeyemo
authors.forename: F
authors.initials: F
authors.lastname: Lesi
authors.forename: F O
authors.initials: FO
authors.lastname: Bello
authors.forename: K
authors.initials: K
authors.lastname: Okwuegbuna
authors.forename: K
authors.initials: K
authors.lastname: Oloko
authors.forename: A
authors.initials: A
authors.lastname: Awolola
authors.forename: F T
authors.initials: FT
authors.lastname: Ogunsola
authors.forename: P
authors.initials: P
authors.lastname: Okonkwo
authors.forename: P J
authors.initials: PJ
authors.lastname: Kanki
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D019380:Anti-HIV Agents / Q000627:therapeutic use*; D023241:Antiretroviral Therapy, Highly Active / Q000379:methods*; D000069446:Atazanavir Sulfate / Q000627:therapeutic use*; D018791:CD4 Lymphocyte Count; D005260:Female; D015658:HIV Infections / Q000188:drug therapy* / Q000276:immunology / Q000821:virology; D006784:Hospitals, Teaching; D006801:Humans; D061466:Lopinavir / Q000627:therapeutic use*; D008297:Male; D008875:Middle Aged; D009549:Nigeria; D012189:Retrospective Studies; D019438:Ritonavir / Q000627:therapeutic use*; D016896:Treatment Outcome; D019562:Viral Load; D055815:Young Adult
chemical_list: D019380:Anti-HIV Agents; D061466:Lopinavir; D000069446:Atazanavir Sulfate; D019438:Ritonavir