Plasma HIV-1 RNA dynamics in antiretroviral-naive subjects receiving either triple-nucleoside or efavirenz-containing regimens: ACTG A5166s.
OBJECTIVE
We sought to compare clearance rates of plasma human immunodeficiency virus type 1 (HIV-1) RNA in men and women starting triple-nucleoside-based versus efavirenz (EFV)-based regimens.


METHODS
First- and second-phase decay rates of plasma HIV-1 were compared in men and women initiating a triple nucleoside reverse-transcriptase inhibitor (NRTI) regimen versus regimens that included EFV plus an NRTI. Subjects (n=64) were randomized to receive zidovudine/lamivudine/abacavir (triple-nucleoside regimen), zidovudine/lamivudine plus EFV (3-drug EFV regimen) or zidovudine/lamivudine/abacavir plus EFV (4-drug EFV regimen). Plasma HIV-1 RNA levels were fitted to a biexponential viral-dynamics model using a nonlinear mixed-effects model. Nonparametric Wilcoxon tests compared empirical Bayes estimates of first- and second-phase viral decay rates between treatment arms and sex.


RESULTS
Median first-phase viral decay rates were significantly faster in subjects receiving the 3-drug EFV regimen (0.67/day), compared with those receiving the triple-nucleoside regimen (0.56/day; P=.02). The second-phase viral decay rate was also faster in the 3-drug EFV group than in the triple-nucleoside group (P=.09). Decay rates in the 4-drug EFV group were intermediate. Viral decay rates were not significantly different in men and women. CONCLUSIONS Faster initial viral decay in subjects randomized to a 3-drug EFV-based regimen corresponded to the overall superior efficacy of that regimen. Viral decay rates did not differ by sex.
Kuritzkes
Daniel R
DR
Section of Retroviral Therapeutics, Brigham and Women's Hospital, Cambridge, MA 02139, USA. dkuritzkes@partners.org
Ribaudo
Heather J
HJ
Squires
Kathleen E
KE
Koletar
Susan L
SL
Santana
Jorge
J
Riddler
Sharon A
SA
Reichman
Richard
R
Shikuma
Cecilia
C
Meyer
William A
WA
Klingman
Karin L
KL
Gulick
Roy M
RM
D000480:Alkynes; D019380:Anti-HIV Agents / Q000008:administration & dosage / Q000494:pharmacology*; D048588:Benzoxazines / Q000008:administration & dosage / Q000494:pharmacology; D003521:Cyclopropanes; D015224:Dideoxynucleosides / Q000008:administration & dosage / Q000494:pharmacology; D004359:Drug Therapy, Combination; D005260:Female; D015658:HIV Infections / Q000097:blood / Q000188:drug therapy* / Q000821:virology; D015497:HIV-1 / Q000187:drug effects* / Q000235:genetics; D006801:Humans; D019259:Lamivudine / Q000008:administration & dosage / Q000494:pharmacology; D008297:Male; D011446:Prospective Studies; D012367:RNA, Viral / Q000097:blood*; D012044:Regression Analysis; D013997:Time Factors; D015215:Zidovudine / Q000008:administration & dosage / Q000494:pharmacology; D000099227:Abacavir
D000480:Alkynes; D019380:Anti-HIV Agents; D048588:Benzoxazines; D003521:Cyclopropanes; D015224:Dideoxynucleosides; D019259:Lamivudine; D012367:RNA, Viral; D015215:Zidovudine; D000099227:Abacavir; C098320:efavirenz