Boceprevir for previously treated chronic HCV genotype 1 infection

New treatment options of chronic hepatitis C virus infection

Chronic hepatitis C virus (HCV) infection is the major etiology and the reason of chronic liver disease, liver cirrhosis, hepatic decompensation, hepatocellular cancer and liver transplantation. Less than half of patients with HCV-related chronic hepatitis achieve sustained viral clearance with current pegylated interferon and ribavirin (P+R) combination therapy. Due to the insufficient treatment success, an extended search for new, direct acting anti-HCV agents (DAAs) is ongoing, already leading to submissions of applications for marketing authorization of the protease-inhibitors boceprevir and telaprevir. Both are effective only in triple combinations with P+R. Studies demonstrate a 50% success rate advantage for triple therapies above current standards. In addition, treatment duration can be shortened, and half of the patients who failed previous therapy with P+R can be cured with triple therapies. A major concern with new DAAs is rapid development of DAA-resistant viral mutants, a reason as well as a consequence of insufficient triple therapy. Clinical studies with boceprevir and telaprevir are reviewed in this paper. Orv. Hetil., 2011, 152, 887–897.

Impact of HCV protease-inhibitor-based triple therapy for chronic HCV genotype 1 infection

Boceprevir and telaprevir are the first HCV protease inhibitors to be approved for the treatment of chronic hepatitis C genotype 1 infection. These drugs must be used in combination with pegylated interferon plus ribavirin (P/R) to maximize efficacy and prevent the emergence of resistance-associated variants (RAVs). In randomized, placebo-controlled international studies in treatment-naive and previously treated HCV patients, treatment with either boceprevir- or telaprevir-based triple therapy regimens significantly increased sustained virological response rates compared with placebo plus P/R. Protease inhibitors have the potential, not only to significantly increase cure rates among patients with genotype 1 infection, but also to reduce the duration of treatment for patients who have an extended rapid virological response. Boceprevir is associated with an increased incidence of anaemia and dysgeusia and telaprevir is associated with an increased incidence of rash and anaemia. The emergence of RAVs was associated with an increased risk of virological failure in clinical studies. Although these new drugs bring significant promise, it remains unclear if all genotype 1 patients will need triple therapy. Here, we review some of the complexities uncovered and controversies highlighted by the introduction of HCV protease inhibitors.

Managing Viral Hepatitis C: HCV: New Opportunities, High CostTwo new biologics establish a higher standard of care. Managing these agents, however, will be highly complex

Two new biologics for HCV present treatment and cost-management challenges.

Intravenous silibinin as 'rescue treatment' for on-treatment non-responders to pegylated interferon/ribavirin combination therapy

BACKGROUND

Intravenous silibinin (ivSIL) is a potent antiviral agent against HCV. In vitro silibinin (SIL) inhibits viral replication, possibly by inhibiting HCV RNA polymerase. In this proof-of-concept study, ivSIL was tested in on-treatment non-responders to full-dose of pegylated interferon-α2a/ribavirin (standard of care [SOC]).

METHODS

A total of 27 treatment-naive patients with <2 log drop in viral load after 12 weeks or still detectable HCV RNA after 24 weeks of SOC treatment (mean age 54.4 ±6.8 years, male/female 19/8, HCV genotype 1 n=19, 3a n=4 and 4 n=4, liver fibrosis F4 n=14, F3 n=5 and F2 n=3, and interleukin 28B polymorphism C/C n=1, T/C n=22 and T/T n=4) received additionally 20 mg/kg/day SIL (Legalon-SIL(®); Rottapharm-Madaus, Monza, Italy) intravenously for 14 or 21 days. Thereafter, pegylated interferon/ribavirin was continued. HCV RNA was quantified by TaqMan(®) (Roche Diagnostics, Pleasanton, CA, USA).

RESULTS

At the end of ivSIL treatment, 23/27 (85.1%) patients had undetectable HCV RNA. In one of the four remaining patients HCV RNA became undetectable 8 weeks after ivSIL on SOC. Five patients relapsed after ivSIL, three of them responded to repeated administration of ivSIL, but relapsed again. The best predictor of response was a low pre-ivSIL HCV RNA level. A total of 19 patients reached one treatment end point (end of SOC treatment HCV RNA undetectable n=11 and non-response n=8); 8 patients were still on SOC (all HCV-RNA-negative). All 11 patients with end-of-treatment response completed 24 weeks of follow-up; 7 patients remained HCV-RNA-negative and 4 relapsed. Except for a slight increase in bilirubin (mean ±SD 0.98 ±0.35 to 2.12 ±0.99 mg/dl), treatment was well-tolerated.

CONCLUSIONS

ivSIL is an effective 'rescue treatment' for on-treatment non-responders to full-dose of SOC.