title: Resistance costs and future drug options of antiretroviral therapies: analysis of the role of NRTIs, NNRTIs, and PIs in a large clinical cohort.
abstract: OBJECTIVE
  To investigate future drug options (FDOs), resistance cost (RCVF), and virologic response to genotypic-driven rescue highly active antiretroviral therapy (HAART), according to type of therapy.
  
  
  METHODS
  This was a retrospective analysis in naïve or antiretroviral-experienced patients. Virologic response was defined as HIV RNA <50 copies.
  
  
  RESULTS
  There were 108 patients failing first-line HAART; there were 328 experienced patients. FDOs were reduced in subjects failing a thymidine-analogue (TA) regimen (median 3.65, IQR 1.29 ) compared to patients without TA (median 3.82, IQR 1.12) (p = .011). FDOs after first failure were higher for patients with non-nucleoside reverse transcriptase inhibitor (NNRTI; median 3.82; IQR 1.24) than with protease inhibitor (PI; median 3.64, IQR 1.15) (p = .027). In experienced patients, FDOs were much higher for TA (p = .005). Patients responding to genotypic-modified regimens had higher FDOs (median 3.9 4, IQR 2.53) than patients not responding (median 2.18, IQR 3.65) (p > .0001). Switching from an NNRTI-based HAART to a boosted PI had a higher chance (48.1%) of achieving a full virologic suppression, compared to switching from PI to NNRTI (21.4%, p < .0001).
  
  
  CONCLUSIONS
  FDOs and RCVF are parameters that can quantify the therapeutic choices at virologic failure. Different drugs induce different FDOs and RCVF. In successive-line regimens, the higher antiviral effect and genetic barrier of boosted PIs may overcome the limits of using nucleoside reverse transcriptase backbones, with only partial effectiveness.
authors: Divisione di Malattie Infettive, Ospedali Riuniti, Bergamo, Italy. franco31556@hotmail.com
authors: Franco
authors: F
authors: Maggiolo
authors: Diego
authors: D
authors: Ripamonti
authors: Monica
authors: M
authors: Airoldi
authors: Annapaola
authors: A
authors: Callegaro
authors: Claudio
authors: C
authors: Arici
authors: Veronica
authors: V
authors: Ravasio
authors: Enrico
authors: E
authors: Bombana
authors: Antonio
authors: A
authors: Goglio
authors: Fredy
authors: F
authors: Suter
mesh_terms: D000328:Adult; D019380:Anti-HIV Agents / Q000494:pharmacology / Q000627:therapeutic use*; D023241:Antiretroviral Therapy, Highly Active; D015331:Cohort Studies; D024921:Drug Resistance, Multiple, Viral; D005260:Female; D015658:HIV Infections / Q000188:drug therapy* / Q000821:virology; D015497:HIV-1 / Q000187:drug effects; D006801:Humans; D007558:Italy; D008297:Male; D011480:Protease Inhibitors / Q000627:therapeutic use*; D012189:Retrospective Studies; D018894:Reverse Transcriptase Inhibitors / Q000627:therapeutic use*; D018119:Stavudine / Q000627:therapeutic use; D016896:Treatment Outcome; D019562:Viral Load; D015215:Zidovudine / Q000627:therapeutic use
chemical_list: D019380:Anti-HIV Agents; D011480:Protease Inhibitors; D018894:Reverse Transcriptase Inhibitors; D015215:Zidovudine; D018119:Stavudine