1074 
Efficacy of Pegylated Interferon + Ribavirin Treatment in HIV/HCV-co-infected Patients Receiving Abacavir + Lamivudine or Tenofovir + either Lamivudine or Emtricitabine as Nucleoside Analogue Backbone
Jose Mira*1, L Lopez-Cortes2, P Barreiro3, C Tural4, M Torres-Tortosa5, I de los Santos Gil6, P Martin-Rico7, M Rios-Villegas8, J Macias1, and J Pineda1
1Hosp Univ de Valme, Seville, Spain; 2Hosp Univ Virgen del Rocio, Seville, Spain; 3Hosp Carlos III, Madrid, Spain; 4Hosp Univ Germans Trias i Pujol, Badalona, Spain; 5Hosp Punta Europa, Algeciras, Spain; 6Hosp Univ de la Princesa, Madrid, Spain; 7Hosp Univ Carlos Haya, Malaga, Spain; and 8Hosp Univ Virgen Macarena, Seville, Spain
Background: Recent studies
have provided data suggesting that the administration of abacavir (ABC) along
with pegylated interferon (peg-IFN) and ribavirin (RBV) is associated with
higher rates of non-response to hepatitis C virus (HCV) therapy. However, in
most of these studies, ABC was combined with zidovudine (AZT) in a substantial
proportion of patients, which could act as a confounder. The
aim of this study was to compare the efficacy of peg-IFN + RBV combination
among HIV/HCV-co-infected patients taking a NRTI backbone consisting of
ABC + lamivudine (3TC) with that observed in subjects who receive tenofovir
(TDF) + 3TC or emtricitabine (FTC).
Methods: We included in this retrospective multicenter study 256
patients starting first-line peg-IFN + RBV while under a 3-drug antiretroviral
regimen including 1 protease inhibitor (PI) or 1 NNRTI and ABC + 3TC or TDF + 3TC
or FTC as NRTI backbone. Sustained virologic response rates in both groups were
compared. Other
potential predictors of sustained virologic response were evaluated.
Results: In
an intention-to-treat analysis, 20 of 70 (29%) individuals receiving ABC and 83
of 186 (45%) who were treated with TDF showed sustained virologic response (p
= 0.02). NRTI backbone containing TDF was an independent predictor of sustained
virologic response in the multivariate analysis (adjusted odds ratio, 95%CI:
2.6; 1.05 to 6.9); p = 0.03). HCV genotype 2 or 3, baseline LDL
cholesterol levels ≥100 mg/dL, lower baseline plasma HCV RNA load and
undetectable baseline HIV viral load also predicted sustained virologic
response. The association between ABC use and lower sustained virologic
response rate was mainly seen in patients with plasma HCV RNA load higher than
600,000 IU/mL, HCV genotype 1 or 4 and in who received lower dose of RBV. In
more detail, among individuals treated with daily dose of RBV <13.2 mg/kg, 3
(20%) of those under ABC vs 22 (52%) under TDF reached sustained virologic
response (p = 0.03), whereas the rates were 31% and 38% (p = 0.4),
respectively, in those receiving RBV dose ≥13.2 mg/kg.
Conclusions: HIV/HCV-co-infected
patients who receive ABC + 3TC respond worse to peg-IFN + RBV than those who
are given TDF + 3TC or FTC as NRTI backbone. Differences between these NRTI
combinations are chiefly observed in subjects receiving lower RBV doses and in
who need higher dosage of this drug. These finding suggest a negative
interaction between RBV and ABC.
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