Correlation between polymorphism in the inosine triphosphatase and the reductions in hemoglobin concentration and ribavirin dose during sofosbuvir and ribavirin therapy

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.

Analysis of genetic dominance in the UK Biobank

Classical statistical genetics theory defines dominance as any deviation from a purely additive, or dosage, effect of a genotype on a trait, which is known as the dominance deviation. Dominance is well documented in plant and animal breeding. Outside of rare monogenic traits, however, evidence in humans is limited. We systematically examined common genetic variation across 1060 traits in a large population cohort (UK Biobank, N = 361,194 samples analyzed) for evidence of dominance effects. We then developed a computationally efficient method to rapidly assess the aggregate contribution of dominance deviations to heritability. Lastly, observing that dominance associations are inherently less correlated between sites at a genomic locus than their additive counterparts, we explored whether they may be leveraged to identify causal variants more confidently.

Novel variant in glycophorin c gene protects against ribavirin-induced anemia during chronic hepatitis C treatment

BACKGROUND

The current use of ribavirin in difficult-to-cure chronic hepatitis C patients (HCV) and patients with severe respiratory infections is constrained by the issue of ribavirin-induced hemolytic anemia that affects 30% of treated patients, requiring dosage modification or discontinuation. Though some genetic variants have been identified predicting this adverse effect, known clinical and genetic factors do not entirely explain the risk of ribavirin-induced anemia.

METHODS

We assessed the associations of previously identified variants in inosine triphosphatase (ITPA), solute carrier 28A2 (SLC28A2) and vitamin D receptor (VDR) genes with ribavirin-induced anemia defined as hemoglobin decline of ≥30 g/L on treatment, followed by a staged discovery (n = 114), replication (n = 74), and combined (n = 188) genome-wide association study to uncover potential new predictive variants.

RESULTS

We identified a novel association in the gene coding glycophorin C (rs6741425; OR:0.12, 95%CI:0.04-0.34, P = 2.94 × 10^-6) that predicts protection against ribavirin-induced anemia. We also replicated the associations of ITPA and VDR genetic variants with the development of ribavirin-induced anemia (rs1127354; OR:0.13, 95%CI:0.04-0.41, P = 8.66 ×10^-5; and rs1544410; OR:1.65, 95%CI:1.01-2.70, P = 0.0437).

CONCLUSIONS

GYPC variation affecting erythrocyte membrane strength is important in predicting risk for developing ribavirin-induced anemia. ITPA and VDR genetic variants are also important predictors of this adverse reaction.

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.

Sofosbuvir-based therapies in genotype 2 hepatitis C virus cirrhosis: A real-life experience with focus on ribavirin dose

This study aimed to investigate the efficacy and safety of sofosbuvir-based therapies for the treatment of cirrhosis from hepatitis C virus (HCV) genotype 2 infection. Data of all consecutive HCV genotype 2 cirrhotic patients who started sofosbuvir-based treatments between January 2015 and March 2017 in eight Italian tertiary hospitals were collected retrospectively. Overall, 273 patients (Child A: 94.5%) were enrolled. In the 194 subjects treated with sofosbuvir/ribavirin, median initial ribavirin dosage was 13.9 mg/kg/day, and therapy duration was 16 weeks. Sustained virological response (SVR) rates were 93.8% in intention-to-treat (ITT) and 95.3% in per-protocol (PP) analyses for the 129 treatment-naïve patients, and 96.9% (ITT) and 98.4% (PP) for the 65 treatment-experienced subjects. Adverse events were reported in 142 patients (73.2%), but only 1.5% discontinued treatment. Eighty-eight subjects with treatment-induced anemia (mild: 34.5%, moderate: 7.7%, severe: 3.1%) had to reduce ribavirin dosage, but SVR rates were comparable to the weight-based dose group, both in ITT (95.4% and 94.3%) and PP (97.7% and 95.2%) analyses, respectively. Moreover, ITT and PP SVR rates were similar between shorter (<20 weeks) (94.1% and 96.0%, respectively) and prolonged (≥20 weeks) regimens (95.7% and 96.7%, respectively). SVR rates in the 79 subjects treated with sofosbuvir/daclatasvir (without ribavirin) were similar (ITT: 96.2%; PP: 97.4%, respectively), without de novo/worsening anemia. In conclusion, in a real-life study centered on genotype 2 patients with well-compensated cirrhosis, sofosbuvir-based regimens were associated with good SVR and tolerability rates, regardless of previous antiviral treatments, without a significant impact of on treatment ribavirin dose reductions.

Association between inosine triphosphatase rs1127354 polymorphisms and ribavirin-induced anaemia and outcome in hepatitis C virus-infected patients: A meta-analysis

WHAT IS KNOWN AND OBJECTIVES

The association between inosine triphosphatase (ITPA) rs1127354 polymorphisms in HCV-infected patients receiving ribavirin (RBV)-based therapy, and the risk of adverse drug reaction and outcomes is still unclear. A meta-analysis was conducted to summarize and clarify this association systematically.

METHODS

A comprehensive search was performed in PubMed, Embase and Web of Sciences, and twenty-two studies were selected from the literature search. Pooled odds ratio (OR) and 95% confidence interval (95% CI) were estimated by either fixed- or random-effects models.

RESULTS

Four outcomes were evaluated: (a) haemoglobin decline: significant associations with haemoglobin decline were found for rs1127354 CC VS CA + AA (OR = 10.59, 95% CI = 6.39-17.54); (b) severe anaemia: significant association with severe anaemia was observed for rs1127354 CC VS CA + AA (OR = 16.24, 95% CI = 6.21-42.43); (c) sustained virological response (SVR): CC genotype carriers had a decrease SVR during treatment (OR = 0.65, 95% CI = 0.52-0.81); (d) RBV dose reduction or stopping treatment: although statistical evidence of an association was found between the polymorphism and RBV dose reduction during treatment (OR = 1.80, 95% CI = 1.03-3.13), the sensitivity analysis suggested this result was not robust.

WHAT IS NEW AND CONCLUSION

Patients with ITPA rs1127354 CC polymorphism are more likely to develop haemolytic anaemia, severe anaemia and decreased SVR. Testing for this genetic polymorphism may benefit patients.

Predictors of adverse drug reactions associated with ribavirin in direct-acting antiviral therapies for chronic hepatitis C

PURPOSE

To identify factors associated with the development of adverse drug reactions (ADR) in ribavirin therapeutic regimens.

METHODS

A multicenter, prospective study was conducted in three public health hospitals in Rio de Janeiro between November 2015 and March 2018. Inclusion criteria were defined by patient follow-up at pharmaceutical consultation at the time of drug dispensing as those who used sofosbuvir in combination with simeprevir, daclatasvir, and/or ribavirin. All patients were invited to participate in the study during the first interview. Adverse drug reactions were reported according to the treatment regimen and frequency of occurrence. Statistical analysis was used to compare adverse reactions between treatments and their associated factors.

RESULTS

A total of 405 patients were included in the study (mean age 59.6 ± 9.6 years); 61.0% were female, 88.1% were infected with genotype 1, and 65.4% were cirrhotic. The most prescribed treatment was the combination of sofosbuvir, daclatasvir, and ribavirin (55.3%). The majority of patients reported at least one ADR during treatment (83.2%), of which fatigue, anemia, and headache were the most common. Being female (OR = 1.86, [1.08-3.20]) and use of ribavirin (OR: 2.39; 95% CI [1.38-4.13]) were predictors for the development of ADR, which was also associated with development of anemia (OR: 10.28; 95% CI: [5.78-18.30]). Treatment efficacy was 98.1%.

CONCLUSIONS

Direct-acting antiviral has been shown to be safe and effective. Therefore, use of ribavirin is questionable due to associated adverse reactions and similar efficacy to other treatments.

Real-world effectiveness of sofosbuvir plus ribavirin for chronic hepatitis C genotype 2 in Asia: a systematic review and meta-analysis

Background

Sofosbuvir plus ribavirin (SOF+RBV) for 12 weeks is the standard treatment for chronic hepatitis C (CHC) genotype 2 (GT2) in most of Asia despite availability of new CHC medications. SOF-RBV real-world effectiveness has only been reported in small and/or single-centre studies. Our goal was to determine the real-world effectiveness of 12-week SOF+RBV therapy for CHC GT2 in Asia.

Methods

A systematic search on PubMed and Embase was conducted through 30 June 2017. We identified full articles and conference proceedings of at least 10 adult patients with CHC GT2 treated with SOF+RBV for 12 weeks under real-world setting in Asia.

Results

A total of 2208 patients from 13 studies were included. The pooled sustained virological response 12 weeks after the end of treatment (SVR12) was 95.8% (95% CI 94.6% to 96.9%) with non-significant heterogeneity (I²=34.4%). Anaemia (27.9%) was the most common adverse event (AE), with serious AEs in 2.0% and only 0.7% discontinued therapy prematurely. In subgroup analyses, patients with cirrhosis had 8.7% lower SVR12 than non-cirrhotic patients (P<0.0001), and treatment-experienced patients had 7.2% lower SVR12 than treatment-naïve patients (P=0.0002). Cirrhotic treatment-experienced patients had the lowest SVR12 at 84.5%. There were no significant differences in pooled SVR12 among patient subgroups: RBV dose reduction versus no dose reduction (P=0.30); hepatocellular carcinoma (HCC) versus no HCC (P=0.10); GT 2a versus 2b (P=0.86); and <65 vs ≥65 years of age (P=0.20).

Conclusions

SOF+RBV for 12 weeks was safe and effective for patients with CHC GT2 in Asia, although those with cirrhosis and prior treatment failure had a lower pooled SVR12 rate.

Trial registration number

CRD42017067928.

Treatment of Real-World HCV Genotype 2-Infected Japanese Patients with Sofosbuvir plus Ribavirin

The aim of this study was to characterize the treatment response and tolerability of sofosbuvir plus ribavirin therapies in Japanese patients infected with hepatitis C virus (HCV) genotype (GT)-2. This retrospective study analyzed 114 Japanese HCV GT-2 patients treated for 12 weeks with 400 mg of sofosbuvir plus weight-based ribavirin daily. This treatment led to higher sustained virologic response at 12-weeks post-treatment (SVR12) rates in both treatment-naïve and treatment-experienced patients. The efficacy of this treatment in compensated cirrhotics was the same as that in patients with chronic hepatitis. HCV GT-2a infection and lower estimated glomerular filtration rates (eGFR) tended to be associated with SVR12. Of 114 patients, 113 completed the combination of sofosbuvir plus ribavirin for 12 weeks. Seven patients without SVR12 did not have HCV NS5B-S282 mutations. The overall SVR12 rate was 90.4% (103 of 114). More effective therapeutic options with less adverse events are desired to achieve higher SVR rates in HCV GT-2 Japanese patients.