The impact of inosine triphosphatase variants on hemoglobin level and sustained virologic response of chronic hepatitis C in Korean

Impact of ITPA gene polymorphism for predicting anemia and treatment outcome in HCV infected patients taking Sofosbuvir Ribavirin therapy

BACKGROUND

Globally, 80 million people are suffering from chronic Hepatitis C virus (HCV) infection. Sofosbuvir ribavirin-based anti-HCV therapy is associated with anemia and other adverse effects. Polymorphisms of Inosine triphosphatase (ITPA) gene may cause functional impairment in the Inosine triphosphate pyrophosphatase enzyme, resulting in enhanced sustained viral response (SVR) and protection from ribavirin-associated anemia in patients on therapy. The study objective was to investigate the effect of Inosine triphosphatase gene polymorphism on SVR achievement, hemoglobin decline and ribavirin dose reduction in patients on therapy.

METHODS

This prospective cohort study was of 170 hepatitis C infected patients received 6-month sofosbuvir ribavirin therapy. Patient viral load, reduction in ribavirin amount, liver function test, and complete blood count were noted monthly. Inosine triphosphatase variants rs1127354 and rs7270101 were assessed through the restriction fragment length polymorphism and confirmed using Sanger sequencing. The impact of polymorphism on cumulative reduction of ribavirin, and anti-HCV therapy outcome were studied.

RESULTS

A total of 74.3% of patients had ITPA rs1127354 CC genotype, 25.7% were CA and AA 0%. The frequency of ITPA genotype rs7270101-AA was 95%, AC 5%, and CC was 0%. ITPA rs1127354-CA had a notably positive impact on SVR achievement with a zero-relapse rate. ITPA rs1127354-CA genotype was significantly (P ˂0.05) protective against ≥ 2 g/dl Hb reduction from baseline to 1st, 2nd and 6th months of therapy. During treatment, Hb reduction ≥ 10 g/dl was frequently observed in rs1127354-CC genotype and rs7270101-AA genotype patients. Ribavirin dose reduction was significantly (P ˂0.05) high in rs1127354-CC genotype as compared to genotype CA whereas no significant difference was observed in ribavirin dose reduction in rs7270101 AA and non-AA genotype. Patient baseline characteristics such as age, body mass index, rs1127354-CC genotype, and baseline Hb were significantly associated with significant Hb reduction.

CONCLUSION

Pretreatment evaluation of ITPA polymorphism can be a diagnostic tool to find out patients at risk of anemia and improve treatment adherence. ITPA genotype rs1127354-CA contributes to improved compliance with ribavirin dose and protects against hemoglobin decline in HCV patients while taking ribavirin-based therapy. However, ITPA rs1127354, rs7270101 polymorphism have no significant impact on SVR achievement.

Associations of ITPA gene polymorphisms with outcomes among chronic hepatitis C patients treated with Peg-interferon/ribavirin: A 5-year follow-up study

To investigate associations between inosine triphosphatase (ITPA) gene polymorphisms and long-term outcomes among chronic hepatitis C (CHC) patients in Northeast China treated with Peg-interferon (IFN)/ribavirin (RBV). CHC patients who received Peg-IFN-2a/RBV treatment during between 2011 and 2013 at 5 hepatitis centers in Northeast China were enrolled. ITPA single nucleotide polymorphisms rs1127354 and rs7270101 from all patients were detected and their associations with 5-year outcomes were analyzed. A total of 635 patients, including 421 infected with hepatitis C virus (HCV) genotype 1 and 214 infected with non-genotype 1 were included. No significant differences were observed in the distribution frequencies of ITPA rs1127354 variants and ITPase activity between patients with HCV genotype 1 and non-genotype 1. In patients who received more than 80% of the planned RBV dose, the 5-year virological response rate and the improvement in liver fibrosis were higher in those with ITPA rs1127354 non-CC with ITPase activity <25% compared with these outcomes in patients with ITPA rs1127354 CC with 100% ITPase activity. Multiple regression analysis revealed that HCV genotype non-1, low baseline HCV ribose nucleic acid (RNA) levels (≤4 × 105 IU/mL), interleukin-28B rs12979860 CC genotype, low baseline liver fibrosis (Fibroscan 0-2), and ITPA rs1127354 non-CC genotype were independent predictors for a high long-term virological response rate, whereas interleukin-28B rs12979860 CC genotype, ITPA rs1127354 non-CC genotype, and low baseline liver fibrosis were independent predictors for improvement of liver fibrosis. ITPA rs1127354 polymorphisms is predictors of long-term outcomes in CHC patients treated with Peg-IFN/RBV.

Real-Life Effectiveness and Safety of Sofosbuvir-Based Therapy in Genotype 2 Chronic Hepatitis C Patients in South Korea, with Emphasis on the Ribavirin Dose

Background/Aims

Sofosbuvir (SOF)-based therapy has been used in Korean patients with chronic hepatitis C virus (HCV) infection since January 2016. This study aimed to investigate the real-life effectiveness and safety of SOF-based therapy in genotype 2 HCV infection.

Methods

From January to December 2016, 458 genotype 2 HCV-infected patients who received ≥1 dose of SOF-based therapy were consecutively enrolled in seven tertiary hospitals. Sustained virologic response (SVR) rates and safety were determined by intention- to-treat (ITT) and per-protocol (PP) analyses.

Results

The mean age of the patients was 61.0 years; 183 (40%) were male, and 13.1% showed a high viral load (>6,000,000 IU/ mL). Among the 378 treatment-naïve patients, the SVR rates were 94.2% (ITT) and 96.7% (PP). Among the 80 treatmentexperienced patients, the SVR rates were 96.3% (ITT) and 98.7% (PP). Patients with a relatively high fibrosis-4 index score (>3.25) had similar SVR rates to those with a relatively low score (p=0.756). A total of 314 patients (68.6%) were treated with a reduced ribavirin dose at the prescriber's discretion, but they showed similar SVR rates to those treated with the weight-based dose (ITT: 95.5% and 92.3%, PP: 97.4% and 96.3%, respectively). Adverse events were observed in 191 patients (41.7%), including 86 (18.8%) with anemia, but only one (0.2%) discontinued antiviral therapy due to nausea.

Conclusions

SOF-based therapy showed high real-life efficacy and tolerability in Korean patients with genotype 2 chronic HCV infection, regardless of previous antiviral treatment experience and fibrosis score. A reduced ribavirin dose can be considered in this patient cohort.

The relationship between ITPA rs1127354 polymorphisms and efficacy of antiviral treatment in Northeast Chinese CHC patients

This prospective study investigated the relationship between 2 inosine triphosphatase (ITPA) polymorphisms (rs7270101 and rs1127354) and the efficacy of ribavirin-based antiviral therapy in hepatitis C virus (HCV)-infected Chinese patients.A total of 906 patients diagnosed with chronic hepatitis C receiving pegylated interferon (PEG-IFN) plus ribavirin combination therapy between January 2011 and January 2014 from 5 hepatitis centers in Northeast China were enrolled. The patients were divided into genotype 1 and non-genotype 1 groups according to the genotype of infected HCV. ITPA single nucleotide polymorphism (SNP) genotyping was performed for all patients. Ribavirin-induced hemolytic anemia and virological response (VR) were monitored during treatment and follow-up. Multivariate regression analysis was used to analyze the predictors for sustained virological response (SVR).IPTA rs7270101 variants were not detected. IPTA rs1127354 variants were detected and showed no difference between the genotype 1 and non-genotype 1 groups. IPTA rs1127354 genotype CC was related to a higher incidence of ribavirin-induced hemolytic anemia. For patients who received >80% of the planned ribavirin dose, rs1127354 variants and related ITPase were related to better SVR. Multivariate analysis showed that IPTA rs1127354 non-genotype CC, HCV genotype, a baseline HCV RNA level <4 × 10 IU/mL, IL-28B rs12979860 genotype CC, and low liver fibrosis were independent predictors for SVR during the combination therapy.IPTA rs1127354 variants and related ITPase were not only related with ribavirin-induced hemolytic anemia but also directly affected the SVR to PEG-IFN plus ribavirin combination therapy in Chinese HCV-infected patients.

ITPA gene polymorphism (94C>A) effects on ribavirin-induced anemia during therapy in Egyptian patients with chronic hepatitis C

Inosine triphosphatase (ITPA) gene variants can protect against ribavirin (RBV)-induced anemia in patients treated for chronic hepatitis C. The aim of this study was to determine the relationship between genetic variants of ITPA polymorphism, anemia, RBV dose reduction, and treatment response in hepatitis C virus (HCV)-infected patients. This study was conducted on 97 Egyptian chronic HCV patients who were scheduled for pegylated-interferon (PEG-INF) /RBV therapy. ITPA genotypes rs1127354 were determined by Real Time PCR melting curve analysis. Effects of ITPA polymorphism on hemoglobin (Hb) levels, RBV dose reduction and treatment response were analyzed. The homozygous wild genotype (CC) was associated with Hb reduction at week 4 (P = 0.004). The minor allele protected against Hb reduction. No association with sustained virological response was observed (P = 0.492). Female gender; lower baseline Hb and higher baseline WBC were associated with week 4 anemia (P = 0.04; P = 0.023; 0.033, respectively). The ITPA gene polymorphism rs1127354 heterozygous genotype (CA) may influence Hb levels and protect against hemolytic anemia during RBV-containing regimens for HCV. However, such findings were not significantly related to treatment outcomes. Patients with wild ITPA genotype (CC) experienced a more Hb drop and RBV dose reductions more frequently.

Pharmacogenetics of ribavirin-induced anemia in HCV patients

Dual therapy (pegylated interferon plus ribavirin) was considered the standard of care for hepatitis C virus (HCV) treatment until 2011, when the first-wave direct-acting antivirals were added to this regimen for HCV genotype-1 patients to increase the sustained virological response rate. The second-wave direct-acting antivirals entered the clinical use also in some ribavirin (RBV)- and/or interferon-free combinations. Nevertheless, since some of the new therapeutic regimens also include RBV and its use results still associated with hemolytic anemia, this requires countermeasures to be prevented. These include the identification of several host predictive factors involved in RBV absorption, distribution, metabolism, elimination and many others that might influence this toxic effect. For this reason, we provided an overview of the potential role of pharmacogenomics in predisposing RBV-treated HCV patients to anemia.

Inosine triphosphatase allele frequency and association with ribavirin-induced anaemia in Brazilian patients receiving antiviral therapy for chronic hepatitis C

Inosine triphosphatase (ITPA) single nucleotide polymorphisms (SNPs) are strongly associated with protection against ribavirin (RBV)-induced anaemia in European, American and Asian patients; however, there is a paucity of data for Brazilian patients. The aim of this study was to evaluate the ITPA SNP (rs7270101/rs1127354) frequency in healthy and hepatitis C virus (HCV)-infected patients from Brazil and the association with the development of severe anaemia during antiviral therapy. ITPA SNPs were determined in 200 HCV infected patients and 100 healthy individuals by sequencing. Biochemical parameters and haemoglobin (Hb) levels were analysed in 97 patients who underwent antiviral therapy. A combination of AArs7270101+CCrs1127354 (100% ITPase activity) was observed in 236/300 individuals. Anaemia was observed in 87.5% and 86.2% of treated patients with AA (rs7270101) and CC genotypes (rs1127354), respectively. Men with AA (rs7270101) showed a considerable reduction in Hb at week 12 compared to those with AC/CC (p = 0.1475). In women, there was no influence of genotype (p = 0.5295). For rs1127354, men with the CC genotype also showed a sudden reduction in Hb compared to those with AC. Allelic distribution of rs7270101 and rs1127354 shows high rates of the genotypes AA and CC, respectively, suggesting that the study population had a great propensity for developing RBV-induced anaemia. A progressive Hb reduction during treatment was observed; however, this reduction was greater in men at week 12 than in women.

Distribution of genetic polymorphisms associated with hepatitis C virus (HCV) antiviral response in a multiethnic and admixed population

The prevalence of genetic polymorphisms identified as predictors of therapeutic-induced hepatitis C virus (HCV) clearance differs among ethnic groups. However, there is a paucity of information about their prevalence in South American populations, whose genetic background is highly admixed. Hence, single-nucleotide polymorphisms rs12979860, rs1127354 and rs7270101 were characterized in 1350 healthy individuals, and ethnicity was assessed in 259 randomly selected samples. The frequency of rs12979860CC, associated to HCV treatment response, and rs1127354nonCC, related to protection against hemolytic anemia, were significantly higher among individuals with maternal and paternal Non-native American haplogroups (64.5% and 24.2%), intermediate among admixed samples (44.1% and 20.4%) and the lowest for individuals with Native American ancestry (30.4% and 6.5%). This is the first systematic study focused on analyzing HCV predictors of antiviral response and ethnicity in South American populations. The characterization of these variants is critical to evaluate the risk-benefit of antiviral treatment according to the patient ancestry in admixed populations.