Ribavirin priming improves the virological response to antiviral treatment in transplanted patients with recurrent hepatitis C: a pilot study

Hepatitis C viral dynamics during ribavirin priming differ according to prior treatment response and HCV type

The mode of action of ribavirin is not completely understood. Ribavirin monotherapy has a measurable antiviral effect, which shows great variability. It might lead to an earlier steady state of plasma concentration and therefore enhance the effect of following combination treatment. The aim of this study was to evaluate the antiviral effect of ribavirin priming and its influence on sustained virologic response after combination treatment in a group of patients with different hepatitis C virus (HCV) types with or without prior treatment experience. Retrospective analysis of 75 patients (37 treatment naïve, 20 prior relapse, 16 prior nonresponse, genotype 1 present in 60 patients) from five centres who received ribavirin priming as part of an individual strategy in order to improve treatment outcome. All patients received ribavirin monotherapy with a mean dose of 14.5 mg kg^-1 body weight for a mean of 28 days. After ribavirin priming, dual combination treatment with pegylated interferon alfa and ribavirin was started. The mean HCV RNA decline after ribavirin priming was 0.6 log₁₀  IU mL^-1 (P<.001). The initial viral decline depended on HCV type and previous treatment status being highest among prior relapsers (0.8 log₁₀  IU mL^-1 ; P=.002) and HCV type 2/3 (1.2 log₁₀  IU mL^-1 ; P=.05) and lowest among those with prior nonresponse (0.3 log₁₀  IU mL^-1 , P=.01). IFNL4 (formerly IL28B) genotype for rs12979860 and IFNL3 genotype rs8099917 did not influence the initial viral decline. The study demonstrates a significant variability in the viral dynamics and antiviral efficacy of ribavirin monotherapy, which is mainly influenced by prior treatment status. The fact that the lowest response pattern was observed in prior nonresponder patients to pegylated interferon alfa plus ribavirin combination therapy can be taken as a hint that not only the individual interferon, but also the ribavirin sensitivity contributes significantly to the nonresponsive state.

Ribavirin at the Era of Novel Direct Antiviral Agents for the Treatment of Hepatitis C Virus Infection: Relevance of Pharmacological Monitoring

Ribavirin is often used for the treatment of hepatitis C virus (HCV) infection. Although its mechanisms of action remain to be clearly elucidated, ribavirin plays a beneficial role for achieving virological response and decreasing the rate of virological relapse after treatment cessation. However, ribavirin may induce side effects leading to early treatment discontinuation. Among them, hemolytic anemia is the most frequent and results from intraerythrocyte accumulation. Pharmacological studies have shown that early ribavirin exposure assessed by the area under the curve (AUC) at day 0 and ribavirin trough concentration during the first three months of therapy were correlated with sustained virological response (SVR). These studies highlighted the relevance of ribavirin pharmacologic monitoring and early dose adaptation during therapy. Although the role of ribavirin within new direct acting antiviral (DAA) combinations will probably decrease in the future, its potential benefit in difficult-to-treat patients such as patients with severe hepatopathy or patients who failed triple therapy including patients with multiresistance will need to be further investigated.

Effects of ribavirin monotherapy on the viral population in patients with chronic hepatitis C genotype 1: direct sequencing and pyrosequencing of the HCV regions

Ribavirin remains essential to chronic hepatitis C treatment. This paper investigates the influence of ribavirin priming to steady state before combined pegylated-interferon/ribavirin treatment on viral kinetics, ribavirin trough concentrations, genetic variability within HCV-core, -NS5B and -NS5A, and response to antiviral therapy. A prospective cohort study was made of 27 chronic hepatitis C genotype 1 naïve patients who received four weeks of ribavirin followed by pegIFN-α-2a/ribavirin for 48 weeks (Group A). The results obtained were compared with those for a control/historical group (Group B). In addition, direct sequencing and pyrosequencing were applied to determine ribavirin monotherapy-induced sequence changes. The rapid, early, and sustained virological response values obtained were 48%, 89%, and 52%, respectively, in Group A, and 52%, 90%, and 52% in Group B (P > 0.05). In the four-week combined treatment, the Group A patients showed a greater decrease in HCV-RNA (2.3 log10  IU/ml vs. 1.2 log10  IU/ml; P = 0.04), lower alanine aminotransferase levels (23.5 ± 1.33 U/L vs. 60.11 ± 18 U/L; P < 0.001) and higher mean ribavirin trough concentrations (3.28 ± 1.26 mg/L vs. 1.74 ± 0.7 mg/L; P = 0.001). No general increase in rates of nucleotide substitutions in the ribavirin monotherapy-treated patients was observed in NS5B, ISDR, or PKRbd, but there was a decrease in silent mutations in the HCV core (P = 0.04). This result was confirmed by pyrosequencing in the NS5A region. It is concluded that the ribavirin priming combined treatment with pegIFN-α-2a does not improve sustained virological response rates in HCV genotype 1 naïve infected patients. However, the greater reductions in viral load and alanine aminotransferase levels, together with the higher ribavirin trough concentration values obtained, could reflect the greater effectiveness of the treatment. Ribavirin does not have a mutagenic effect on the virus in patients with chronic hepatitis C.

Impact of ribavirin priming on viral kinetics and treatment response in chronic hepatitis C genotype 1 infection

Ribavirin amplifies the interferon-alpha (IFN) signalling cascade. As ribavirin needs 4 weeks to reach steady state, ribavirin priming may optimize hepatic IFN sensitivity before starting a pegylated (PEG)-IFN/ribavirin combination therapy. This study investigated potential benefits of ribavirin priming prior to PEG-IFN2a/ribavirin combination therapy on viral kinetics, on-treatment and sustained virological response (SVR) in chronic hepatitis C virus (HCV) genotype 1 infection. Sixty-eight treatment naive patients were randomized 2:2:1 to ribavirin (ribavirin arm) or placebo (placebo arm) or PEG-IFN2a (PEG-IFN2a arm) for 6 weeks prior to 12 weeks of PEG-IFN2a/ribavirin combination therapy within a double-blind, placebo-controlled trial. Then, standard PEG-IFN2a/ribavirin combination therapy according to the German guidelines was continued under the responsibility of the investigators. Ribavirin was given according to body weight and PEG-IFN2a at a dose of 180 μg subcutaneously once/week. During ribavirin priming, HCV RNA showed a decline of -0.58 log10  IU/mL (P < 0.001) that was unrelated to the IL28B rs12979860 genotype (CC vs CT/TT, P = 0.244). Ribavirin priming did neither increase the PEG-IFN2a-induced first- or second-phase viral decline (P values >0.100) nor on-treatment response or SVR (HCV RNA undetectable at week 12 of combination therapy: ribavirin arm 56%, placebo arm 38%, PEG-IFN2a arm 50%; SVR: ribavirin arm 41%, placebo arm 54%, PEG-IFN2a arm 50%; P values >0.300). In conclusion, ribavirin monotherapy showed a significant antiviral activity that was not influenced by the IL28B genotype. Ribavirin priming prior to PEG-IFN2a/ribavirin combination therapy did neither increase the first- or second-phase viral decline nor on-treatment response or SVR.

Treatment of genotype-1 hepatitis C recurrence after liver transplant improves survival in both sustained responders and relapsers

The aim of this study was to evaluate the factors affecting the response to treatment and how it could affect survival in a large series of genotype-1 HCV-transplanted patients. Three-hundred and twenty six genotype-1 HCV patients were enrolled. One hundred and ninety-six patients (60.1%) were nonresponders and 130 (39.9%) showed negative HCV-RNA at the end of treatment. Eighty-four of them (25.8%) achieved sustained virological response, while 46 (14.1%) showed viral relapse. Five-year cumulative survival was significantly worse in nonresponders (76.4%) compared with sustained viral response (93.2) or relapsers (94.9%). Sustained responders and relapsers were therefore considered as a single 'response group' in further analysis. Pretreatment variables significantly associated with virological response at multivariate regression analysis were the absence of ineffective pretransplant antiviral therapy, the recurrence of HCV-hepatitis more than 1 year after transplant, an histological grading ≥4 at pretreatment liver biopsy, a pretreatment HCV-RNA level <1.2 × 10(6 ) IU/ml, and the absence of diabetes. As expected, also on-treatment variables (rapid and early virological response) were significantly associated to the response to antiviral treatment. In conclusion, this study shows that postliver transplant antiviral treatment results in beneficial effect on survival not only in sustained responders but also in relapsers.

Randomised clinical trial: pre-dosing with taribavirin before starting pegylated interferon vs. standard combination regimen in treatment-naïve patients with chronic hepatitis C genotype 1

BACKGROUND

Combination therapy with the ribavirin (RBV) prodrug taribavirin (TBV) and pegylated interferon (PIFN) has produced lower rates of anaemia than with RBV and PIFN. Studies have demonstrated that the sharpest decline in viral load during TBV therapy occurs at Weeks 4 through 6, when TBV reaches steady-state blood levels.

AIM

The current proof-of-concept study was conducted to examine whether first-order viral kinetics could be influenced by pre-dosing TBV to steady state before introducing PIFN.

METHODS

Therapy-naïve patients with chronic hepatitis C virus (HCV) genotype 1 (G1) were randomised to receive (i) TBV 600 mg BID monotherapy for 4 weeks followed by combination therapy with PIFN [pre-dosing arm (n = 23)] or (ii) TBV administered concurrently with PIFN [standard dosing arm (n = 19)].

RESULTS

More patients achieved undetectable virus or a ≥2-log(10) reduction of HCV RNA at Week 4 in the pre-dosing vs. the standard dosing arm [33% vs. 22% (P = 0.497)]. There was also a trend towards greater reduction in mean log(10) change in HCV RNA in the pre-dosing vs. the standard dosing arm, which was statistically significant at Day 1 [-0.34 ± 0.46 vs. 0.09 ± 0.32 (P < 0.003)] but not at other time points up to Week 24. No significant difference was observed in the rates of anaemia (haemoglobin <10 g/dL) between study arms (4.5% vs. 5.3%).

CONCLUSIONS

Pre-dosing TBV prior to starting PIFN produces a trend towards improved efficacy although statistical significance was not reached in this small patient population. These results warrant larger clinical trials of TBV pre-dosing.