Regimen simplification to atazanavir-ritonavir alone as maintenance antiretroviral therapy: final 48-week clinical and virologic outcomes.
BACKGROUND
Simplified maintenance therapy with ritonavir-boosted atazanavir (ATV/RTV) alone is attractive because of nucleoside reverse-transcriptase inhibitor (NRTI)-sparing benefits, low pill burden, once-daily dosage, and safety.


METHODS
Subjects with virologic suppression after > or = 48 weeks of initial antiretroviral therapy with 2 NRTIs and a protease inhibitor (PI) were enrolled. Subjects switched to ATV/RTV at entry and discontinued NRTIs after 6 weeks. The primary end point was time to virologic failure (confirmed HIV-1 RNA level > or = 200 copies/mL). Drug resistance at virologic failure was evaluated by standard genotyping and single-genome sequencing (SGS). Residual viremia (1.1-49 copies/mL) was measured by single-copy assay.


RESULTS
Thirty-four subjects simplified to ATV/RTV alone, of whom 30 (88%) did not experience virologic failure by 48 weeks after simplification. Residual viremia did not change significantly after NRTI discontinuation among those without virologic failure but did increase 4-12 weeks before confirmed virologic failure. No major PI-resistance mutations were identified at virologic failure by standard genotyping or SGS.


CONCLUSIONS
In this pilot study, simplified maintenance therapy with ATV/RTV alone maintained viral suppression in most subjects through 48 weeks. PI resistance was not detected among subjects experiencing virologic failure. Larger, randomized trials are warranted to further define the efficacy and safety of this strategy.
Wilkin
Timothy J
TJ
Division of International Medicine and Infectious Diseases, Weill-Cornell Medical College, New York, New York, USA. tiw2001@med.cornell.edu
McKinnon
John E
JE
DiRienzo
A Gregory
AG
Mollan
Katie
K
Fletcher
Courtney V
CV
Margolis
David M
DM
Bastow
Barbara
B
Thal
Gary
G
Woodward
William
W
Godfrey
Catherine
C
Wiegand
Ann
A
Maldarelli
Frank
F
Palmer
Sarah
S
Coffin
John M
JM
Mellors
John W
JW
Swindells
Susan
S
D000328:Adult; D019380:Anti-HIV Agents / Q000627:therapeutic use*; D000069446:Atazanavir Sulfate; D018791:CD4 Lymphocyte Count; D004359:Drug Therapy, Combination; D005260:Female; D015658:HIV Infections / Q000188:drug therapy*; D017320:HIV Protease Inhibitors / Q000627:therapeutic use; D006801:Humans; D008297:Male; D008875:Middle Aged; D009842:Oligopeptides / Q000627:therapeutic use*; D010865:Pilot Projects; D011725:Pyridines / Q000627:therapeutic use*; D019438:Ritonavir / Q000627:therapeutic use*; D016896:Treatment Outcome; D014766:Viremia / Q000188:drug therapy; D055815:Young Adult
D019380:Anti-HIV Agents; D017320:HIV Protease Inhibitors; D009842:Oligopeptides; D011725:Pyridines; D000069446:Atazanavir Sulfate; D019438:Ritonavir