Real-world outcomes in patients with chronic hepatitis C: primary results of the PROBE study.

BACKGROUND: This large prospective multicentre cohort study aimed to improve knowledge of therapy for chronic hepatitis C (CHC) in real clinical practice. METHODS: A diverse population of adults with CHC including patients with comorbid conditions, laboratory abnormalities and demographic features [comorbidities or special populations (CSP)] who were under-represented or excluded from peginterferon registration studies was treated with peginterferon α-2a (40 kDa) or α-2b (12 kDa) plus ribavirin at the investigator's discretion. RESULTS: During the study, 5399 treatment-naive patients [2527 (46.8%) with CSP] received peginterferon α-2a (n=3513, 65.1%) or peginterferon α-2b (n=1886, 34.9%). The sustained virological response rate was 56.6% (3057/5399) overall, 59.7% (1716/2872) in patients without CSP and 53.1% (1341/2527) in patients with CSP. Significant predictors of sustained virological response included hepatitis C virus genotype 2 or 3 infection, absence of cirrhosis, hepatitis C virus RNA≤500 000 IU/ml, alanine transaminase quotient >3× the upper limit of normal, age ≤65 years, BMI<25 kg/m, at least 80% of the planned exposure to peginterferon and ribavirin and prescription of peginterferon α-2a. CONCLUSION: The results provide detailed information on the outcome of therapy for CHC in a diverse Italian population that included a large number of patients with CSP and provides an insight into the generalizability of the results obtained in the more restricted setting of randomized registration trials.

Role of lymphocyte multidrug resistance protein 1 in HIV infection: expression, function, and consequences of inhibition.

The multidrug resistance protein 1 (MRP1) is a drug transporter that protects cells from oxidative stress, which increases HIV-1 replication. The aim of this study was to characterize the expression, function, and role of lymphocyte MRP1 in HIV-1 infection and its modulation by antiretroviral drugs such as the protease inhibitors (PIs). Peripheral blood mononuclear cells (PBMCs) from HIV-positive individuals do not show significant alterations of MRP1 expression despite highly active antiretroviral therapy and HIV plasma viral load levels; however, they exhibit different intracellular MRP1 expression as compared with healthy subjects. By contrast, MRP efflux function is increased in subjects with primary HIV infection and becomes defective in later stages of the infection. PI- and probenecid (PBCD)-mediated inhibition of MRP lowers the in vitro stress-induced response of lymphoid cells by reducing the level of the specific reactive oxygen species superoxide anion and hydrogen peroxide. Finally, the blockade of MRP by PBCD and PIs down-modulates HIV-1 replication by a mechanism independent of inhibition of the HIV-1 protease. Our results are consistent with a model wherein HIV replication is favored by the MRP1-related oxidative stress and inhibition of MRP1 may contribute to the antiviral activity of PIs.

Anti-HIV effects of chloroquine: inhibition of viral particle glycosylation and synergism with protease inhibitors.

OBJECTIVE: We tested the effects of chloroquine (CQ) on glycosylation of HIV particles and in combination with protease inhibitors (PIs) on HIV replication and on P-glycoprotein (P-gp)/multidrug resistance protein-1 (MRP1). DESIGN: CD4 cell lines were infected with laboratory strains and peripheral blood mononuclear cells were infected with primary isolates for evaluation of the anti-HIV effects. Peripheral blood lymphocytes were evaluated for of P-gp and MRP1 functions. METHODS: HIV replication was assessed by enzyme-linked immunosorbent assay. HIV glycosylation was measured by metabolic labeling of viral particles with [H] glucosamine. Synergism was tested using isobolograms. P-gp and MRP1 functions were assayed using rhodamine 123 (Rh123) and carboxyfluorescein (CF) efflux assays, respectively. RESULTS: CQ alone inhibited HIV replication and glycosylation in a dose-dependent manner. In combination with indinavir (IDV), ritonavir, or saquinavir (SQV), CQ had a synergistic effect at concentrations found in plasma of subjects receiving malaria prophylaxis. CQ decreased the 50% effective concentration of IDV in primary isolates from Africa and restored the response to IDV or SQV in 3 PI-resistant isolates. CQ increased the block of Rh123 and CF efflux activity exerted by PIs. CONCLUSION: The inhibitory effects of CQ on HIV glycosylation are associated with synergistic effects in combination with PIs. The CQ/PI combination exerts combined inhibitory effects on P-gp and MRP1 function.