Effectiveness of efavirenz compared with ritonavir-boosted protease-inhibitor-based regimens as initial therapy for patients with plasma HIV-1 RNA above 100,000 copies/ml.
BACKGROUND
There are no clinical trials in which the main objective is to compare the efficacy of efavirenz versus ritonavir-boosted protease inhibitor (PI/r)-based initial antiretroviral therapy (ART) in patients with high plasma HIV-1 RNA levels. This study aims to compare these regimens in this patient population in the setting of routine clinical practice.


METHODS
This was a multicentre, observational cohort study, including 596 consecutive treatment-naive patients with plasma HIV-1 RNA>100,000 copies/ml initiating efavirenz or PI/r-based ART between 2000 and 2010. The primary effectiveness end point was the percentage of patients with HIV-1 RNA<50 copies/ml at week 48 by intent-to-treat analysis.


RESULTS
Among a total of 596 patients, 57% initiated efavirenz and 43% PI/r-regimens (73% lopinavir and fosamprenavir [62% lopinavir, 11% fosamprenavir]). HIV-1 RNA suppression to <50 copies/ml at week 48 was higher in the efavirenz group (84% versus 74% [difference 10%, 95% CI 3.4%, 16.7%; P=0.002]). The percentage of virological failures was similar (efavirenz 4% versus PI/r 4%; P=0.686), but voluntary discontinuations and toxicity-related treatment changes were higher with PI/r (4% versus 1%; P=0.006 and 11% versus 6%; P=0.069, respectively). However, resistance selection at failure was higher in patients receiving efavirenz (89% versus 50%; P=0.203). Efavirenz was significantly more effective than lopinavir/r or fosamprenavir/r, whereas no significant differences were observed between efavirenz and darunavir/r or atazanavir/r. The high viral suppression in the efavirenz group was also evident in patients with very high viral loads (>500,000 copies/ml) and in those with low CD4(+) T-cell counts.


CONCLUSIONS
In routine clinical practice, the effectiveness of initial efavirenz-based regimens was at least similar to or even higher than various PI/r-based regimens in HIV-1-infected patients with plasma HIV-1 RNA>100,000 copies/ml.
HIV Unit, Department of Infectious Diseases, Hospital Universitari de Bellvitge, L'Hospitalet de Llobregat, Spain. aimaz@bellvitgehospital.cat.
Arkaitz
A
Imaz
Josep M
JM
Llibre
Jordi
J
Navarro
Jordi
J
Curto
Bonaventura
B
Clotet
Manuel
M
Crespo
Elena
E
Ferrer
Maria
M
Saumoy
Juan M
JM
Tiraboschi
Oscar
O
Murillo
Daniel
D
Podzamczer
D000328:Adult; D000480:Alkynes; D023241:Antiretroviral Therapy, Highly Active; D048588:Benzoxazines / Q000494:pharmacology / Q000627:therapeutic use*; D018791:CD4 Lymphocyte Count; D060085:Coinfection; D003521:Cyclopropanes; D005260:Female; D015658:HIV Infections / Q000175:diagnosis / Q000188:drug therapy* / Q000821:virology*; D017320:HIV Protease Inhibitors / Q000494:pharmacology / Q000627:therapeutic use*; D015497:HIV-1 / Q000187:drug effects / Q000235:genetics*; D006801:Humans; D008297:Male; D008875:Middle Aged; D012189:Retrospective Studies; D018894:Reverse Transcriptase Inhibitors / Q000494:pharmacology / Q000627:therapeutic use*; D012307:Risk Factors; D019438:Ritonavir / Q000494:pharmacology / Q000627:therapeutic use*; D013997:Time Factors; D017211:Treatment Failure; D016896:Treatment Outcome; D019562:Viral Load
D000480:Alkynes; D048588:Benzoxazines; D003521:Cyclopropanes; D017320:HIV Protease Inhibitors; D018894:Reverse Transcriptase Inhibitors; C098320:efavirenz; D019438:Ritonavir