Uptake of direct-acting antiviral treatment for chronic hepatitis C in Australia

A government-funded interferon-free direct-acting antiviral (DAA) treatment programme for chronic hepatitis C virus (HCV) infection has been available in Australia since March 2016. This study assessed the levels and patterns of DAA treatment uptake during March-December 2016 in Australia and described the key features in the development of the programme. All prescriptions in Australia are submitted to the Pharmaceutical Benefits Scheme by dispensing pharmacies. Data on dispensed DAA prescriptions for a longitudinal cohort of individuals, representing a 10% random sample of the Pharmaceutical Benefits Scheme database, were used for estimating DAA treatment uptake and subgroup analyses. The estimated number of 32 400 individuals initiated DAA treatment in 2016, equating to 14% of people with chronic HCV infection in Australia. Most commonly prescribed DAA regimens included sofosbuvir/ledipasvir (56%, n = 18 020), sofosbuvir + daclatasvir (39%, n = 12 600) and sofosbuvir + other agents (4%, n = 1220). Among individuals initiated DAA treatment, 66% (n = 21 430) were men, 43% (n = 13 870) were ≤50 years old and 36% (n = 11 670) had cirrhosis. DAA prescriptions were 62% (n = 20 080) by specialists, 19% (n = 6000) by general practitioners (GP) and 20% (n = 6320) by other physicians. Proportion of individuals prescribed DAA by GPs increased from 8% to 31% and proportion of individuals ≤50 years old increased from 28% to 61% between March and December. In conclusion, rapid treatment scale-up was observed in the first 10 months of unrestricted DAA programme in Australia. The proportion of prescriptions by GPs increased over time, important for broadened access. A trend towards younger age treatment suggested the broadening of DAA-treated population, potentially including individuals at higher risk of HCV transmission.

IFN-free therapy is associated with restoration of type I IFN response in HIV-1 patients with acute HCV infection who achieve SVR

Interferon (IFN)-free direct-acting antiviral agents (DAAs) have revolutionized chronic hepatitis C virus (HCV) treatment; early studies suggest excellent efficacy in acute HCV. However, changes in innate immune responses during DAA therapy for acute HCV are unknown. We studied interferon-stimulated gene (ISG) expression and related cytokines/chemokines in HIV-infected patients with acute HCV receiving sofosbuvir plus ribavirin (SOF+RBV) as part of the A5327 clinical trial. ISG expression was determined from PBMCs, and circulating cytokines/chemokines were quantified from serum from study participants. The overall sustained virologic response (SVR) was 57%; all treatment failures were due to virologic relapse. Apart from NOS2a, baseline ISG/chemokine/cytokine levels were similar irrespective of treatment outcome. Downregulation of ISGs was observed at treatment week four and end of treatment (EOT), implicating HCV in establishing elevated ISGs early during HCV infection. Levels of many of these ISGs increased at post-treatment week 12 (PTW12) in relapsers only, coinciding with recurrent HCV RNA. Eleven ISGs were differentially expressed in responders vs relapsers. On-treatment viral suppression was also associated with a reduction in IP-10, CXCL11 and MIP-1β levels. In contrast, circulating IFN-α levels were significantly higher at EOT and PTW12 in responders vs relapsers. Upregulation of peripheral ISG expression is established early in the course of HCV infection during acute HCV infection, but did not predict subsequent treatment outcome with SOF+RBV. ISGs were downregulated during therapy and increased post-therapy in relapsers. IFN-α levels were higher in responders at EOT/PTW12, suggesting that impaired type I IFN production/secretion may contribute to relapse.

Frequency of, and factors associated with, hepatitis B virus reactivation in hepatitis C patients treated with all-oral direct-acting antivirals: Analysis of a Japanese prospective cohort

AIM

Several case reports have shown that hepatitis B virus (HBV) reactivation developed in hepatitis C patients with a current or previous HBV infection during direct-acting antiviral (DAA) treatment, which led to severe hepatitis or death in some cases. However, its precise frequency and risk factors are not entirely clear. We analyzed a prospective cohort.

METHODS

We analyzed HBV reactivation in 461 consecutive hepatitis C patients who received 12 weeks of ledipasvir/sofosbuvir for genotype 1 or sofosbuvir plus ribavirin for genotype 2 at multiple centers.

RESULTS

By the examination of the preserved sera at baseline, 159 patients (34%) were identified as seropositive for HBV core antibody (anti-HBc) and were included in the subsequent analysis; 4 patients were positive for HBV surface antigen (HBsAg), and the others were negative. Serum HBV DNA was undetectable or was detectable but <20 IU/mL at baseline for all patients. Serial measurement of HBV DNA at 4 weeks and 12 weeks in the preserved serum samples was available in 147 patients and identified HBV reactivation (defined as the appearance of serum HBV DNA ≥20 IU/mL) in 2 HBsAg-positive and 3 HBsAg-negative patients. No patient developed HBV-associated hepatitis. Patients who developed HBV reactivation had significantly lower anti-HBs titers and higher serum alanine transferase levels before treatment.

CONCLUSION

Hepatitis B virus reactivation during direct-acting antiviral therapies occurs in 3.4% (5/147) of patients who are positive for anti-HBc. A low titer of anti-HBs and a high serum alanine transferase level prior to treatment are associated with reactivation in this patient group.

Research priorities to achieve universal access to hepatitis C prevention, management and direct-acting antiviral treatment among people who inject drugs

Globally, it is estimated that 71.1 million people have chronic hepatitis C virus (HCV) infection, including an estimated 7.5 million people who have recently injected drugs (PWID). There is an additional large, but unquantified, burden among those PWID who have ceased injecting. The incidence of HCV infection among current PWID also remains high in many settings. Morbidity and mortality due to liver disease among PWID with HCV infection continues to increase, despite the advent of well-tolerated, simple interferon-free direct-acting antiviral (DAA) HCV regimens with cure rates >95%. As a result of this important clinical breakthrough, there is potential to reverse the rising burden of advanced liver disease with increased treatment and strive for HCV elimination among PWID. Unfortunately, there are many gaps in knowledge that represent barriers to effective prevention and management of HCV among PWID. The Kirby Institute, UNSW Sydney and the International Network on Hepatitis in Substance Users (INHSU) established an expert round table panel to assess current research gaps and establish future research priorities for the prevention and management of HCV among PWID. This round table consisted of a one-day workshop held on 6 September, 2016, in Oslo, Norway, prior to the International Symposium on Hepatitis in Substance Users (INHSU 2016). International experts in drug and alcohol, infectious diseases, and hepatology were brought together to discuss the available scientific evidence, gaps in research, and develop research priorities. Topics for discussion included the epidemiology of injecting drug use, HCV, and HIV among PWID, HCV prevention, HCV testing, linkage to HCV care and treatment, DAA treatment for HCV infection, and reinfection following successful treatment. This paper highlights the outcomes of the roundtable discussion focused on future research priorities for enhancing HCV prevention, testing, linkage to care and DAA treatment for PWID as we strive for global elimination of HCV infection.

Randomized Phase 3 Trial of Ombitasvir/Paritaprevir/Ritonavir and Ribavirin for Hepatitis C Virus Genotype 2-Infected Japanese Patients

INTRODUCTION

In Japan, hepatitis C virus (HCV) genotype (GT) 2 accounts for approximately 32% of HCV infections. Limited treatment options exist in Japan for HCV GT2-infected patients. GIFT-II was a phase 3, randomized, open-label study evaluating the efficacy and safety of 16- and 12-week regimens of co-formulated ombitasvir (OBV)/paritaprevir (PTV)/ritonavir (r) plus ribavirin (RBV) in Japanese adults with HCV GT2 infection.

METHODS

Patients were randomized in a 1:1 ratio to once-daily, co-formulated OBV/PTV/r (25/150/100 mg) with weight-based RBV for 16 or 12 weeks. The primary efficacy endpoint was the sustained virologic response at 12 weeks post-treatment (SVR12) rate in the primary efficacy population of non-cirrhotic treatment-naive patients.

RESULTS

A total of 171 patients were randomized to OBV/PTV/r + RBV. In the primary efficacy population, SVR12 rates were 91.5% (43/47; 95% confidence interval 83.5-99.5%) and 75.0% (36/48; 95% confidence interval 62.8-87.2%) in the 16-week arm and 12-week arm, respectively. No patient in the 16-week arm relapsed by post-treatment week 12. Among non-cirrhotic treatment-experienced patients, the overall SVR rate in the 16-week arm was 75.8% (25/33) and was highest [93.8% (15/16)] among those who had relapsed after previous interferon-based therapy. SVR12 rates were consistently higher in patients with HCV GT2a infection versus HCV GT2b infection [16-week treatment arm: 93.9% (31/33) versus 85.7% (12/14) and 93.8% (15/16) versus 56.3% (9/16) among non-cirrhotic treatment-naive and treatment-experienced patients, respectively]. No patient discontinued treatment because of an adverse event. The most common adverse events were anemia, increased blood bilirubin, and nasopharyngitis.

CONCLUSIONS

OBV/PTV/r + RBV for 16 weeks resulted in high SVR12 rates in non-cirrhotic Japanese patients infected with HCV GT2 who were treatment-naive or who had relapsed after an interferon-based therapy. Higher SVR12 rates were observed among patients with HCV GT2a infection versus those with GT2b infection. This regimen demonstrated a favorable safety profile.

TRIAL REGISTRATION

ClinicalTrials.gov identifier, NCT02023112.

FUNDING

AbbVie.

Ombitasvir/Paritaprevir/Ritonavir and Dasabuvir Combination Treatment in Patients with HIV/HCV Co-Infection: Results of an Italian Compassionate Use Program

Patients co-infected with hepatitis C virus (HCV) and human immunodeficiency virus (HIV) are at high risk of liver disease progression. We report a favorable safety profile and SVR12 rates of 96.7% among HIV/HCV co-infected patients participating in an Italian compassionate-use program of ombitasvir/paritaprevir/ritonavir + dasabuvir (OBV/PTV/r + DSV) ± ribavirin (RBV).

Hepatitis C Virus RNA Persists in Liver Explants of Most Patients Awaiting Liver Transplantation Treated With an Interferon-Free Regimen

We assessed the presence of hepatitis C virus (HCV) RNA in liver explants from 39 patients awaiting liver transplantation who were treated with an interferon-free regimen and had undetectable serum HCV RNA at the time of liver transplantation. Interestingly, HCV RNA was detected in most liver explants (67%). Patients with HCV RNA-positive explants had received shorter courses of treatment, and HCV RNA was undetectable in serum for shorter periods before transplantation compared to patients with HCV RNA-negative explants (P = .014 and P = .013, respectively). Levels of HCV RNA in explants were significantly higher in patients with a relapse of HCV infection than patients who responded to treatment (P = .016), but most patients (85%) with residual HCV-RNA in the explant achieved a sustained virologic response after receiving their liver transplant.

Sofosbuvir plus ledipasvir in combination for the treatment of hepatitis C infection

Sofsobuvir is the first-in-class NS5B nucleotide inhibitor to be launched as a treatment for the hepatitis C virus (HCV). Its viral potency, pan genotypic activity and high barrier to resistance make it the ideal candidate to become a backbone for several IFN-free regimens. Ledipasvir is a NS5A inhibitor with multi genotypic activity but modest barrier to resistance. The once-daily fixed-dose combination of sofosbuvir plus ledipasvir is the first-in-market single-tablet regimen for the treatment of hepatitis C infection. Recent data demonstrated that this FDC alone, or in combination with ribavirin, is able to achieve HCV cure of at least 90% or more among genotype 1,4, 5 and 6 patients. This combination appears to be suboptimal in genotype 3 patients and other direct acting antiviral combinations with sofosbuvir will help to fulfill this gap in the near future. The safety profile of the fixed dose combination is good. Resistance is not an issue with sofosbuvir but may be a significant issue with regards to ledipasvir for those rare individuals who harbor baseline HCV NS5A resistance-associated variants that conferred a high resistance level. The rational for using FDCs and the available clinical data are reviewed.

Why I do not treat patients for mild disease

The short-term prognosis of patients with chronic hepatitis C and mild disease is excellent. Monitoring of the progression of fibrosis is easy to perform with non-invasive tests. Current all-oral interferon (IFN)- and ribavirin (RBV)-free regimens offer sustained viral response (SVR) rates of more than 90% as well as 12-weeks of treatment for most patients with mild disease. Several DAA combinations can be selected to optimize efficacy and safety outcomes. A short treatment duration of 8 weeks could be indicated in most patients with mild disease. However, additional data from clinical trials and real-life experience are needed to confirm this option. Moreover, current regimens are not cost-effective for patients with mild disease. In practice, deferral of HCV treatment for a few years and monitoring the progression of fibrosis is a safe option until cheaper, shorter, more effective and more convenient HCV regimens become available.

Ideal oral combinations to eradicate HCV: The role of ribavirin

Current all-oral interferon-free regimens offer sustained virological response (SVR) rates above 90% as well as 12-week treatment durations for the majority of patients with chronic hepatitis C virus (HCV), including treatment-naïve and -experienced patients with or without cirrhosis. There are multiple direct-acting antiviral (DAA) combinations that can be selected to optimize efficacy and safety outcomes. Each of them can be tailored according to different parameters including the use of ribarivin (RBV). For sofosbuvir (SOF)-based combinations, RBV is useful in the following situations: HCV genotype 1, treatment-experienced, cirrhotic patients, or patients with decompensated cirrhosis, and HCV genotype 3, cirrhotic patients. In these situations the addition of RBV allows to shorten the treatment to 12weeks in the majority of cases and therefore decreases the cost of the treatment. The need of RBV remains to be determined in cirrhotic patients with a SOF plus simeprevir regimen. RBV-containing regimens are recommended in all HCV genotype 1a patients who receive the 3-DAA combination: paritaprevir/r, ombitasvir, dasabuvir. Globally, the addition of RBV to the different combinations of DAA increases slightly the risk of anaemia. However severe anaemia was rare and easily manageable with RBV dose reduction without any impact on SVR. In practice, because RBV is cheap and well tolerated when combined with interferon-free regimen, it remains a useful tool to fine tune anti-HCV treatment regimens and optimize their results.

Sofosbuvir as backbone of interferon free treatments

Sofosbuvir is the first-in-class NS5B nucleotide analogues to be launched for hepatitis C virus (HCV) treatment. Its viral potency, pangenotypic activity and high barrier to resistance make it the ideal candidate to become a backbone for several IFN-free regimens. Recent data demonstrated that sofosbuvir either with ribavirin alone or in combination with other direct-acting antivirals (DAAs) as daclatasvir, ledipasvir or simeprevir are able to cure HCV in at least 90% or over of patients. Treatment experienced genotype 3 population may remain the most difficult to treat population, but ongoing DAA combination studies will help to fill this gap. Safety profile of sofosbuvir or combination with other DAAs is good. Resistance to sofosbuvir did not appear as a significant issue. The rationale for using this class of drug and the available clinical data are reviewed.

Investigational nucleoside and nucleotide polymerase inhibitors and their use in treating hepatitis C virus

INTRODUCTION

About 150 million people worldwide are estimated to be chronically infected with the hepatitis C virus (HCV). Successful antiviral treatment can stop the progression of the disease toward liver cirrhosis, hepatocellular carcinoma and death. IFN has been the drug of choice and the backbone of all combinations in the past two decades. However, an IFN-free combination (sofosbuvir and ribavirin) has been recently approved for genotypes 2 and 3 patients with many other drugs in preclinical and clinical development.

AREAS COVERED

This review focuses on investigational nucleoside or nucleotide inhibitors of viral polymerase that are potential treatments of HCV. The article reviews drugs that are currently under investigational status.

EXPERT OPINION

Currently, mericitabine has the most robust data but its efficacy appears to be less than optimal. Other drugs such as ALS-2200 (and its diastereomer VX-135) and BMS-986094 are promising but the data in humans are too scanty to draw conclusions about their future role at this current point in time. Other promising molecules are LG-7501, ACH-3422 and EP-NI266, although no clinical studies have been performed thus far, so this must be rectified. Another drug of promise GS-6620 has displayed a high degree of pharmacokinetic and pharmacodynamic variability, which makes further development unlikely.