Jesper Waldenström

Variants of the inosine triphosphate pyrophosphatase gene are associated with reduced relapse risk following treatment for HCV genotype 2/3

The present study evaluated the impact of variations in the inosine triphosphate pyrophosphatase (ITPase) gene (ITPA) on treatment outcome in patients with hepatitis C virus (HCV) genotype 2/3 infection receiving peginterferon‐α2a and lower, conventional 800 mg daily dose of ribavirin. Previous studies using higher, weight‐based ribavirin dosing report that patients carrying polymorphisms encoding reduced predicted ITPase activity show decreased risk of ribavirin‐induced anemia but increased risk of thrombocytopenia, with no impact on elimination of virus. In all, 354 treatment‐naïve HCV genotype 2/3‐infected patients, enrolled in a phase III trial (NORDynamIC), were genotyped for ITPA (rs1127354 and rs7270101). Homo‐ or heterozygosity at Ars1127354 or Crs7270101, entailing reduced ITPase activity, was observed in 37% of patients and was associated with increased likelihood of achieving sustained virological response (SVR) (P = 0.0003 in univariate and P = 0.0002 in multivariate analyses) accompanied by a reduced risk of relapse among treatment‐adherent patients. The association between ITPA variants and SVR remained significant when patients were subdivided by the 12‐ and 24‐week treatment duration arms, HCV genotype, fibrosis stage, and IL28B genotype, and was not secondary to improved adherence to therapy or less pronounced anemia. Gene variants predicting reduced predicted ITPase activity were also associated with decreased risk of anemia (P < 0.0001), increased risk of thrombocytopenia (P = 0.007), and lower ribavirin concentrations (P = 0.02). Conclusion: These findings demonstrate a novel ribavirin‐like association between polymorphisms at ITPA and treatment efficacy in chronic hepatitis C mediated by reduced relapse risk. We hypothesize that patients (63%) being homozygous for both major alleles, leading to normal ITPase activity, may benefit more from the addition of ribavirin to present and future treatment regimens for HCV in spite of concomitant increased risk of anemia. (Hepatology 2014;59:2131–2139)

High incidence of the hepatitis C virus recombinant 2k/1b in Georgia: Recommendations for testing and treatment

The first hepatitis C virus (HCV) recombinant, RF2k/1b, was initially described from Russia and has since then been identified from patients in Ireland, Estonia, Uzbekistan and Cyprus. Many of these patients originated from Georgia; however, there is no information on its prevalence in Georgia or its susceptibility to antiviral treatment.

Impact of Soluble CD26 on Treatment Outcome and Hepatitis C Virus-Specific T Cells in Chronic Hepatitis C Virus Genotype 1 Infection

Background Interferon and ribavirin therapy for chronic hepatitis C virus (HCV) infection yields sustained virological response (SVR) rates of 50–80%. Several factors such as non-1 genotype, beneficial IL28B genetic variants, low baseline IP-10, and the functionality of HCV-specific T cells predict SVR. With the pending introduction of new therapies for HCV entailing very rapid clearance of plasma HCV RNA, the importance of baseline biomarkers likely will increase in order to tailor therapy. CD26 (DPPIV) truncates the chemokine IP-10 into a shorter antagonistic form, and this truncation of IP-10 has been suggested to influence treatment outcome in patients with chronic HCV infection patients. In addition, previous reports have shown CD26 to be a co-stimulator for T cells. The aim of the present study was to assess the utility of CD26 as a biomarker for treatment outcome in chronic hepatitis C and to define its association with HCV-specific T cells. Methods Baseline plasma from 153 genotype 1 and 58 genotype 2/3 infected patients enrolled in an international multicenter phase III trial (DITTO-HCV) and 36 genotype 1 infected patients participating in a Swedish trial (TTG1) were evaluated regarding baseline soluble CD26 (sCD26) and the functionality of HCV-specific CD8+ T cells. Results Genotype 1 infected patients achieving SVR in the DITTO (P = 0.002) and the TTG1 (P = 0.02) studies had lower pretreatment sCD26 concentrations compared with non-SVR patients. Sixty-five percent of patients with sCD26 concentrations below 600 ng/mL achieved SVR compared with 39% of the patients with sCD26 exceeding 600 ng/mL (P = 0.01). Patients with sCD26 concentrations below 600 ng/mL had significantly higher frequencies of HCV-specific CD8+ T cells (P = 0.02). Conclusions Low baseline systemic concentrations of sCD26 predict favorable treatment outcome in chronic HCV infection and may be associated with higher blood counts of HCV-specific CD8+ T cells.

Short interferon and ribavirin treatment for HCV genotype 2 or 3 infection: NORDynamIC trial and real-life experience

Abstract Objective: Interferon-free therapy for hepatitis C virus (HCV) infection is costly, and therefore patients with advanced fibrosis are prioritized. Although coupled with considerable side effects, a large proportion of genotype 2/3 infected patients achieve a sustained virological response (SVR) following interferon-based therapy. The present study evaluates experimental clinical trial and verifying real-life data with the aim of identifying patients with a high likelihood of favorable outcome following short interferon-based treatment. Material and methods: The impact of established response predictors, e.g. age, ITPA and IL28B genetic variants, IP-10, liver histopathology and early viral kinetics on outcome was evaluated among HCV genotype 2/3 infected patients enrolled in the NORDynamIC trial. Similarly outcome was evaluated among Finnish and Swedish real-life genotype 2/3 infected patients treated for 12–16 weeks in accordance with national guidelines. Results: In the NORDynamIC trial, age <40 years or achieving HCV RNA <1000 IU/mL day 7 were highly predictive of favorable outcome following 12 weeks therapy. Among 255 Finnish real-life patients below the age of 40 years treated for 12 weeks with interferon and ribavirin, 87% of HCV genotype 2 and 79% of genotype 3 infected patients achieved SVR, and among 117 Swedish real-life patients treated for 12–16 weeks, 97% of HCV genotype 2 and 94% of genotype 3 infected achieved SVR. Conclusions: Short interferon-based therapy offers a high likelihood of achieving SVR for selected HCV genotype 2/3 infected patients, and is an acceptable option given that a thorough discussion of the side effects is provided prior to initiation.

Prevalence and comorbidities of chronic hepatitis C: a nationwide population-based register study in Sweden

Abstract Purpose: The aim of this study was to estimate the prevalence of physician-diagnosed and registered chronic hepatitis C (CHC), and to estimate the reported frequencies of Charlson comorbidities compared with matched comparators from the general population. Materials and methods: Patients were identified according to ICD codes for CHC in the Swedish National Patient Register (1997–2013). Prevalence was estimated according to different patient identification algorithms and for different subgroups. Charlson comorbidities were ascertained from the same register and compared with age/sex/county of residence matched general population comparators. Results: A total of 34,633 individuals with physician-diagnosed CHC were alive in Sweden in 2013 (mean age, 49 years; 64% men), corresponding to a physician-diagnosed prevalence of 0.36%. The prevalence varied by case definition (0.22%-0.36%). The estimate dropped to 0.14% for monitored CHC disease (defined as ≥1 CHC-related visit in 2013). Overall, 41.3% of the CHC patients had ≥1 physician-registered Charlson comorbidity; the most common was liver diseases (22.1%). Compared with matched comparators from the general population (n = 171,338), patients with CHC had more physician-diagnosed and registered diseases such as chronic pulmonary disease (10.2% vs. 4.0%), diabetes (10.6% vs. 5.5%) and liver-related cancer (1.3% vs. 0.2%; all p < .01). No information on behavioural factors, such as smoking, alcohol consumption or on-going illicit drug use, was available. Conclusion: The physician-diagnosed prevalence of CHC was slightly lower than previously reported estimates, and varied by case definition. The additional comorbidities observed in the CHC group should be taken into consideration, as these comorbidities add to the disease burden.

Randomized Trial Evaluating the Impact of Ribavirin Mono-Therapy and Double Dosing on Viral Kinetics, Ribavirin Pharmacokinetics and Anemia in Hepatitis C Virus Genotype 1 Infection

In this pilot study (RibaC), 58 hepatitis C virus (HCV) genotype 1 infected treatment-naïve patients were randomized to (i) 2 weeks ribavirin double dosing concomitant with pegylated interferon-α (pegIFN-α), (ii) 4 weeks ribavirin mono-therapy prior to adding pegIFN-α, or (iii) standard-of-care (SOC) ribavirin dosing concurrent with pegIFN-α. Four weeks of ribavirin mono-therapy resulted in a mean 0.46 log10 IU/mL HCV RNA reduction differentially regulated across IL28B genotypes (0.89 vs. 0.21 log10 IU/mL for CC and CT/TT respectively; P = 0.006), increased likelihood of undetectable HCV RNA week 4 after initiating pegIFN-α and thus shortened treatment duration (P<0.05), and decreased median IP-10 concentration from 550 to 345 pg/mL (P<0.001). Both experimental strategies impacted on ribavirin concentrations, and high levels were achieved after one week of double dosing. However, by day 14, double dosing entailed a greater hemoglobin decline as compared to SOC (2.2 vs. 1.4 g/dL; P = 0.03). Conclusion: Ribavirin down-regulates IP-10, and may have an anti-viral effect differently regulated across IL28B genotypes. Trial Registration ClinicalTrials.gov NCT01226771

Neonatal transfusion-transmitted hepatitis C virus infection following a pre-seroconversion window-phase donation in Sweden

Abstract A 9-day-old child developed a transfusion-transmitted hepatitis C virus (HCV) infection following a pre-seroconversion window-phase donation. Retrospective analysis of donor plasma revealed detectable HCV core antigen (154 fmol/l), as well as HCV RNA (87,000 IU/ml). Of 5.24 million Swedish plasma samples from December 1998 to September 2012, 5 additional window-phase donations were identified.

Chronic hepatitis E infection with an emerging virus strain in a heart transplant recipient successfully treated with ribavirin: a case report.

IntroductionDuring the last decade hepatitis E infections have been recognized as a health problem in high-income countries, where hepatitis E virus genotype 3 is endemic. The infection is often self-limiting, but may develop into chronic infection in immunocompromised patients, especially in solid organ recipients. If these patients or patients with underlying liver disease get hepatitis E infection, they may develop liver failure and cirrhosis. Hepatitis E virus is occasionally found in blood products and transfusion transmission has been reported. We present the first case of chronic hepatitis E infection in a heart transplant recipient in Sweden.Case presentationA 63-year-old Swedish white man presented with highly elevated liver enzymes 6 months after heart transplantation. Polymerase chain reaction revealed chronic hepatitis E infection, caused by a virus strain found infecting symptomatic cases in Sweden and other European countries. During transplantation, he received blood products from 17 donors, and transfusion transmission is highly likely. The only detectable marker for hepatitis E infection was hepatitis E virus ribonucleic acid for more than 2 months before anti-hepatitis E virus developed. He was treated successfully with ribavirin and decreased immunosuppression.ConclusionsOur patient was probably infected through contaminated blood products and subsequently developed chronic infection, which was cured upon treatment. This highlights the need for evaluating the problem with chronic hepatitis E infection in immunocompromised patients, and for discussion concerning screening of blood products. Polymerase chain reaction-based methods are recommended for diagnosing hepatitis E infection in patients with compromised immunity. In addition, knowledge needs to be gained on the infecting virus strain, which may be more virulent than other strains.

Reply: To PMID 24519039.

(78%-93%) of RBV than in a lower dose (62%-65%) of RBV per body weight. Because the RVR was reported as the most important predictor of SVR in HCV G2-infected patients, even when interleukin28B variants were taken into consideration, and ITPA variants were reported not to increase SVR in G2/3-infected patients with higher dose of RBV, it is interesting to know whether the RVR is associated with ITPA variations and SVR in the present study of the NORDynamIC trial. Particularly, because RVR is currently the most important factor for individualized therapy for G2/3-infected patients, the effect of the ITPA variants on determining the duration of Peg-IFN/RBV therapy for patients with or without RVR deserves to be explored.

Inosine Triphosphate Pyrophosphatase Dephosphorylates Ribavirin Triphosphate and Reduced Enzymatic Activity Potentiates Mutagenesis in Hepatitis C Virus

This study highlights the multiple modes of action of ribavirin, including depletion of intracellular GTP and increased hepatitis C virus mutagenesis. In cell culture, reduced ITP pyrophosphatase (ITPase) enzyme activity affected the intracellular concentrations of ribavirin triphosphate (RTP) and augmented the impact of ribavirin on the mutation rate and virus production. Additionally, our results imply that RTP, similar to ITP, a naturally occurring substrate of ITPase, is dephosphorylated in vitro by ITPase. ABSTRACT A third of humans carry genetic variants of the ITP pyrophosphatase (ITPase) gene (ITPA) that lead to reduced enzyme activity. Reduced ITPase activity was earlier reported to protect against ribavirin-induced hemolytic anemia and to diminish relapse following ribavirin and interferon therapy for hepatitis C virus (HCV) genotype 2 or 3 infections. While several hypotheses have been put forward to explain the antiviral actions of ribavirin, details regarding the mechanisms of interaction between reduced ITPase activity and ribavirin remain unclear. The in vitro effect of reduced ITPase activity was assessed by means of transfection of hepatocytes (Huh7.5 cells) with a small interfering RNA (siRNA) directed against ITPA or a negative-control siRNA in the presence or absence of ribavirin in an HCV culture system. Low ribavirin concentrations strikingly depleted intracellular GTP levels in HCV-infected hepatocytes whereas higher ribavirin concentrations induced G-to-A and C-to-U single nucleotide substitutions in the HCV genome, with an ensuing reduction of HCV RNA expression and HCV core antigen production. Ribavirin triphosphate (RTP) was dephosphorylated in vitro by recombinant ITPase to a similar extent as ITP, a naturally occurring substrate of ITPase, and reducing ITPA expression in Huh 7.5 cells by siRNA increased intracellular levels of RTP in addition to increasing HCV mutagenesis and reducing progeny virus production. Our results extend the understanding of the biological impact of reduced ITPase activity, demonstrate that RTP is a substrate of ITPase, and may point to personalized ribavirin dosage according to ITPA genotype in addition to novel antiviral strategies. IMPORTANCE This study highlights the multiple modes of action of ribavirin, including depletion of intracellular GTP and increased hepatitis C virus mutagenesis. In cell culture, reduced ITP pyrophosphatase (ITPase) enzyme activity affected the intracellular concentrations of ribavirin triphosphate (RTP) and augmented the impact of ribavirin on the mutation rate and virus production. Additionally, our results imply that RTP, similar to ITP, a naturally occurring substrate of ITPase, is dephosphorylated in vitro by ITPase.