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Hepatitis C virus ( HCV) vaccines may be able to increase viral clearance in combination with antiviral therapy. We analysed viral dynamics and HCV-specific immune response during retreatment for experienced patients in a phase Ib study with E1E2 MF59 vaccine. Seventy-eight genotype 1a/1b patients [relapsers (30), partial responders (16) and nonresponders (32) to interferon-( IFN)/ribavirin-( RBV)] were randomly assigned to vaccine ( V:23), Peg- IFNα2a-180-ug/qw and ribavirin 1000-1200-mg/qd for 48 weeks ( P/R:25), or their combination ( P/R + V:30). Vaccine (100 μg/0.5 mL) was administered intramuscularly at week 0-4-8-12-24-28-32-36. Neutralizing of binding ( NOB) antibodies and lymphocyte proliferation assay ( LPA) for E1E2-specific- CD4 + T cells were performed at week 0-12-16-48. Viral kinetics were analysed up to week 16. The vaccine was safe, and a sustained virological response ( SVR) was achieved in 4 P/R + V and 2 P/R patients. Higher SVR rates were observed in prior relapsers (P/R + V = 27.3%; P/R = 12.5%). Higher NOB titres and LPA indexes were found at week 12 and 16 in P/R + V as compared to P/R patients ( P = 0.023 and 0.025, P = 0.019 and <0.001, respectively). Among the 22 patients with the strongest direct antiviral effects of IFN (ε ≥ 0.800), those treated with P/R + V (10) reached lower HCV- RNA levels ( P = 0.026) at week 16. HCV E1E2 MF59 vaccine in combination with Peg- IFNα2a + RBV was safe and elicited E1E2 neutralizing antibodies and specific CD4 + T cell proliferation. Upon early response to IFN, vaccinations were associated with an enhanced second phase viral load decline. These results prompt phase II trials in combination with new antiviral therapies. [ABSTRACT FROM AUTHOR]

A novel biomathematical model that analyzes the combined alanine transaminase (ALT) and viral-load kinetics during the first month of pegylated interferon (Peg-IFN) plus ribavirin (RBV) therapy was successfully applied in 90 of 97 (93%) chronic hepatitis C patients in order to compute the number of infected cells at the end of therapy (Ieot). The Ieot indices were lower in sustained virological responders than in relapsers (RELs) and nonresponders (NRs) (median values: 31 vs. 2,190 vs. 1,090,000; P < 0.001), and were independently associated with treatment outcomes (P = 0.003). A threshold of 250 Ieot was shown to identify sustained virological response (SVR) with high positive predictive value (93%) and good diagnostic accuracy (81%). The time taken to attain 250 Ieot ranged from 3 to 11 months in patients with hepatitis C virus (HCV) genotypes 2 or 3 and from 3 to 18 months in those with HCV genotypes 1 or 4. Overall, the duration of therapy would have been 49 months less than that suggested by the most recent algorithms based on a rapid virological response (RVR) at week 4.Clinical Pharmacology & Therapeutics (2008); 84, 2, 212–215 doi:10.1038/clpt.2008.21 [ABSTRACT FROM AUTHOR]