Virological suppression at 6 months is related to choice of initial regimen in antiretroviral-naive patients: a cohort study.
BACKGROUND
Guidelines recommend both protease inhibitor (PI)- and non-nucleoside reverse transcriptase inhibitor (NNRTI)-containing regimens for initial therapy in HIV-positive individuals whilst clinical trial data comparing treatment options remain limited.


OBJECTIVE
To assess whether drug selection (PI versus NNRTI) in antiretroviral-naive patients is related to virological response at 6 months within a clinical cohort.


METHODS
Databases from two large clinics were used to identify all treatment-naive patients initiating highly active antiretroviral therapy (PI/ two PI or NNRTI). Statistical models determined the likelihood of suppressing HIV viral load < 500 copies/ml, the risk of treatment failure by 6 months, and factors associated with treatment success.


RESULTS
Of 1109 potentially eligible patients 888 met study criteria and were included; 484 were prescribed a PI (40% indinavir, 41% nelfinavir) and 404 were prescribed NNRTI (40% efavirenz, 60% nevirapine). Three treatment arms were compared: efavirenz versus nevirapine versus PI. After stratification by year and centre and adjustment for baseline variables, only treatment group and baseline viral load remained significantly associated with virological suppression at 6 months. Patients on efavirenz were significantly more likely to achieve an undetectable viral load than those on PI or nevirapine. The relative hazard for nevirapine was 0.77 (95% confidence interval, 0.61-0.96, P = 0.02) and that for PI was 0.74 (95% confidence interval, 0.58-0.94, P = 0.01). Efavirenz also performed better in the analysis of treatment failure at 6 months.


CONCLUSIONS
Although observational cohort data may be susceptible to significant bias, this study suggests a better initial virological response for efavirenz compared to either nevirapine or the PI. Clinical trial data is required to confirm these findings.
Matthews
Gail V
GV
Department of HIV Medicine, Chelsea Hospital, London, UK.
Sabin
Caroline A
CA
Mandalia
Sundhiya
S
Lampe
Fiona
F
Phillips
Andrew N
AN
Nelson
Mark R
MR
Bower
Mark
M
Johnson
Margaret A
MA
Gazzard
Brian G
BG
D000328:Adult; D000368:Aged; D000480:Alkynes; D019380:Anti-HIV Agents / Q000627:therapeutic use*; D048588:Benzoxazines; D015331:Cohort Studies; D003521:Cyclopropanes; D004334:Drug Administration Schedule; D005260:Female; D015658:HIV Infections / Q000188:drug therapy* / Q000821:virology*; D015497:HIV-1 / Q000187:drug effects* / Q000502:physiology; D006801:Humans; D019469:Indinavir / Q000627:therapeutic use; D008297:Male; D008875:Middle Aged; D019888:Nelfinavir / Q000627:therapeutic use; D019829:Nevirapine / Q000627:therapeutic use; D010078:Oxazines / Q000627:therapeutic use; D011480:Protease Inhibitors / Q000627:therapeutic use; D012367:RNA, Viral / Q000097:blood; D018894:Reverse Transcriptase Inhibitors / Q000627:therapeutic use*; D016896:Treatment Outcome; D019562:Viral Load
D000480:Alkynes; D019380:Anti-HIV Agents; D048588:Benzoxazines; D003521:Cyclopropanes; D010078:Oxazines; D011480:Protease Inhibitors; D012367:RNA, Viral; D018894:Reverse Transcriptase Inhibitors; D019469:Indinavir; D019829:Nevirapine; D019888:Nelfinavir; C098320:efavirenz