High antiviral activity of NS5A inhibitor ABT-530 with paritaprevir/ritonavir and ribavirin against hepatitis C virus genotype 3 infection

Efficacy and Safety of Ombitasvir plus Paritaprevir, Ritonavir and Ribavirin in Non-cirrhotic Treatment-naïve and Treatment-experienced Egyptians with Chronic HCV Genotype-4 Infection

Hepatitis C virus genotype 4 (HCV-GT4) is a risk factor for cirrhosis, hepatocellular carcinoma and liver failure. A combination of three new direct-acting antivirals ombitasvir, paritaprevir, and ritonavir has been recommended for treatment of HCV-GT4 infection. The current study was aimed to assess the efficacy and safety of this combination plus ribavirin in non-cirrhotic, treatment-naïve and -experienced Egyptians with HCV-GT4 infection in a real-world setting. A total of 255 Egyptians with HCV-GT4 infection were enrolled, including 82 treatment-experienced and 173 treatment-naïve patients. All of them completed 12-week treatment protocol of ombitasvir, paritaprevir and ritonavir as an oral dose combination with ribavirin. Virological response (VR) was measured, as well as the biochemical parameters related to treatment efficacy and adverse events at baseline and after treatment, at 4 (VR4) and 12 (VR12) weeks post-treatment. The results showed that the VR4 rates were 98.8% in both groups, and VR12 rates were 97.7% and 96.3% in treatment-naïve and -experienced patients, respectively, with no significant differences found between the groups concerning VR4 (P=0.9) and VR12 (P=0.3). The most common adverse events were headache and fatigue, which were significantly more common (P=0.001 and 0.003, respectively) in treatment-experienced than in treatment-naïve group. The quadruple regimen was well-tolerated, and the reported adverse events were generally mild to moderate. This real-world setting study confirms that the combination of ombitasvir, paritaprevir, ritonavir, and ribavirin is highly effective in the treatment of HCV- GT4 infection with a good safety and tolerability profile.

Use of Hepatitis C Nucleic Acid Test-Positive Liver Allografts in Hepatitis C Virus Seronegative Recipients

Because of underutilization of liver allografts, our center previously showed that hepatitis C virus (HCV) antibody-positive/nucleic acid test (NAT)-negative livers when transplanted into HCV nonviremic recipients were safe with a 10% risk of HCV transmission. Herein, we present our single-center prospective experience of using HCV NAT+ liver allografts transplanted into HCV NAT- recipients. An institutional review board-approved matched cohort study was conducted examining post- liver transplantation (LT) outcomes of HCV- patients who received HCV NAT+ organs (treatment group) compared with matched recipients with HCV NAT- organs (matched comparator group) between June 2018 to October 2019. The primary endpoint was success of HCV treatment and elimination of HCV infection. The secondary outcomes included the 30-day and 1-year graft and patient survival as well as perioperative complications. There were 32 recipients enrolled into each group. Because of 1 death in the index admission, 30/31 patients (97%) were given HCV treatment at a median starting time of 47 days (18-140 days) after LT. A total of 19 (63%) patients achieved sustained virological response at week 12 (SVR12). Another 6 patients achieved end-of-treatment response, while 5 remained on therapy and 1 is yet to start treatment. No HCV treatment failure has been noted. There were no differences in 30-day and 1-year graft and patient survival, length of hospital stay, biliary or vascular complications, or cytomegalovirus viremia between the 2 groups. In this interim analysis of a matched cohort study, which is the first and largest study to date, the patients who received the HCV NAT+ organs had similar outcomes regarding graft function, patient survival, and post-LT complications.

In vitro resistance profile of hepatitis C virus NS5A inhibitor velpatasvir in genotypes 1 to 6

Velpatasvir is a pan-genotypic hepatitis C virus (HCV) NS5A inhibitor, which is used with sofosbuvir for treatment of infection with HCV genotypes 1-6. In vitro resistance studies were performed to characterize NS5A changes that might confer reduced velpatasvir susceptibility in vivo. Resistance selection studies using HCV replicon cells for subtypes 1a, 1b, 2a, 2b, 3a, 4a, 5a and 6a identified NS5A resistance-associated substitutions (RASs) at nine positions, most often 28M/S/T, 31F/I/M/P/V and 93D/H/N/S. In subtype 1a, RASs were selected at positions 31 and/or 93, while in subtype 1b, replicons with two or more RASs at positions 31, 54 or 93 were selected. Y93H was selected in subtypes 1a, 1b, 2a, 3a and 4a. In subtype 5a or 6a, L31P or P32L/Q was selected, respectively. Velpatasvir susceptibility of 358 replicons from genotypes 1 to 6 containing one or more NS5A RASs was also evaluated. The majority (63%) of subtypes 1a and 1b single RAS-containing replicons retained susceptibility to velpatasvir (<2.5-fold change in EC₅₀ ). High levels of resistance to velpatasvir were observed for six single mutants in subtype 1a, including M28G, A92K, Y93H/N/R/W and for one mutant, A92K, in subtype 1b. Most single mutants in subtypes 2a, 2b, 3a, 4a and 5a displayed low levels of reduced velpatasvir susceptibility. High-level resistance was observed for C92T and Y93H/N in subtype 2b, Y93H/S in 3a, and L31V and P32A/L/Q/R in 6a, and several double mutants in these subtypes. Overall, velpatasvir maintained activity against most common RASs that are known to confer resistance to first-generation NS5A inhibitors.

Hepatitis C virus drug resistance associated substitutions and their clinical relevance: Update 2018

Nowadays, due to the development of potent Direct-Acting Antiviral Agents (DAAs) that specifically target NS3, NS5A and NS5B viral proteins, several new and highly efficacious options to treat chronic Hepatitis C virus (HCV) infection are available. The natural presence of resistance associated substitutions (RASs), as well as their rapid emergence during incomplete drug-pressure, are intrinsic characteristics of HCV that greatly affect treatment outcome and the chances to achieve a virolgical cure. To date, a high number of RASs in NS3, NS5A, and NS5B have been associated in vivo and/or in vitro with reduced susceptibility to DAAs, but no comprehensive RASs list is available. This review thus provides an updated, systematic overview of the role of RASs to currently approved DAAs or in phase II/III of clinical development against HCV-infection, discriminating their impact in different HCV-genotypes and DAAs, providing assistance for a fruitful use of HCV resistance testing in clinical practice.

Interferon-free therapies for patients with chronic hepatitis C genotype 3 infection: A systematic review

Treatment of hepatitis C virus (HCV) infection with genotype 3 remains a challenge. The HCV elimination rate with direct-acting antivirals (DAAs) is lower than the values reported for other HCV genotypes. In addition, genotype 3-infected patients have a higher risk of disease progression and hepatocellular carcinoma. The aim of this study was to review the relevant literature concerning the treatment of HCV genotype 3 patients with interferon-free regimens. A literature search was conducted in the PubMed/Medline, Embase and Web of Science electronic databases. Trials enrolling patients with chronic hepatitis C infection treated with DAAs with or without ribavirin were included. Two investigators independently evaluated the trials for inclusion criteria, risk of bias and data extraction. The primary outcome was sustained virological response (SVR). In total, 323 references were identified, and 29 met the inclusion criteria: 18 general clinical trials, three general observational studies, three studies in patients with decompensated liver cirrhosis and four studies in HIV-HCV-coinfected patients. Overall, 4068 genotype 3 patients were included. As compared with sofosbuvir and ribavirin for 24 weeks, sofosbuvir/velpatasvir for 12 weeks or sofosbuvir plus daclatasvir plus ribavirin for 12 weeks provided higher SVR rates, particularly in patients with cirrhosis. Treatment of patients with decompensated cirrhosis remains a great challenge. Sofosbuvir/ledipasvir+ribavirin for 12 weeks were associated with an SVR of 85% in these patients. In summary, treatment of HCV genotype 3 patients is improving rapidly, and this population may no longer be considered a difficult-to-treat subgroup in the near future.

Pharmacokinetics, Safety, and Tolerability Following Single and Multiple Doses of Pibrentasvir in a First-in-Human Study

This first-in-human dose-ascending study investigated pharmacokinetics, safety, and tolerability of pibrentasvir following single and multiple doses in healthy volunteers. Additionally, the effects of food and ritonavir on pibrentasvir were assessed in a crossover study design. The starting dose of pibrentasvir was selected based on the no-observed-adverse-effect-level exposure from preclinical studies. Dose escalations of subsequent cohorts were dependent on reviews of the safety, tolerability, and pharmacokinetic data from previous dose cohorts. Pibrentasvir exposures increased in a greater than dose-proportional manner across the 1.5- to 120-mg dose range and became linear across the 120- to 600-mg dose range. Following multiple dosing, pibrentasvir steady state was attained by day 5 with an accumulation ratio of 25% to 35%. Pibrentasvir harmonic mean terminal half-life ranged from 20 to 22 hours. Food had minimal effect (<14%) on pibrentasvir bioavailability, but ritonavir increased pibrentasvir peak concentration and area under the concentration-time curve by 60% and 89%, respectively. All adverse events were assessed by the investigator as mild, and no clinically significant vital signs, electrocardiogram, or clinical laboratory values were observed. The pharmacokinetic results from this study support once-daily dosing and administration of pibrentasvir without regard to food. A maximum tolerated dose was not attained in the single- and multiple-ascending-dose assessments for pibrentasvir.

Current therapy for chronic hepatitis C: The role of direct-acting antivirals

One of the most exciting developments in antiviral research has been the discovery of the direct-acting antivirals (DAAs) that effectively cure chronic hepatitis C virus (HCV) infections. Based on more than 100 clinical trials and real-world studies, we provide a comprehensive overview of FDA-approved therapies and newly discovered anti-HCV agents with a special focus on drug efficacy, mechanisms of action, and safety. We show that HCV drug development has advanced in multiple aspects: (i) interferon-based regimens were replaced by interferon-free regimens; (ii) genotype-specific drugs evolved to drugs for all HCV genotypes; (iii) therapies based upon multiple pills per day were simplified to a single pill per day; (iv) drug potency increased from moderate (∼60%) to high (>90%) levels of sustained virologic responses; (v) treatment durations were shortened from 48 to 12 or 8 weeks; and (vi) therapies could be administered orally regardless of prior treatment history and cirrhotic status. However, despite these remarkable achievements made in HCV drug discovery, challenges remain in the management of difficult-to-treat patients.

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HCV genotype-specific drugs evolve to pan-genotypic drugs.

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Drug potency increases from moderate (∼60%) to high (>90%) levels of sustained virologic response.

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Treatment durations are shortened from a 48-week to 12-week or 8-week period.

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HCV therapies based upon multiple pills per day are simplified to a single pill per day.

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HCV therapies are administered orally regardless of prior treatment history and cirrhotic status.

Efficacy and safety of daclatasvir plus pegylated-interferon alfa 2a and ribavirin in previously untreated HCV subjects coinfected with HIV and HCV genotype-1: a Phase III, open-label study

BACKGROUND

Daclatasvir (DCV) is a potent, pangenotypic, hepatitis C virus (HCV) non-structural protein 5A inhibitor with low potential for drug interactions with antiretroviral therapy (ART). We evaluated the safety and efficacy of DCV plus peginterferon alfa-2a/ribavirin (PegIFN/RBV) in HIV-1/HCV genotype-1-coinfected patients.

METHODS

AI444043 (NCT01471574), an open-label, Phase III, single-arm, response-guided treatment (RGT) study included 301 patients. They received DCV doses of 30, 60 or 90 mg once daily (depending on concomitant ART), plus weight-based RBV (<75 kg, 1000 mg/day; or ≥75 kg, 1200 mg/day), and once-weekly PegIFN 180 μg, for 24 weeks. If required by RGT, PegIFN/RBV without DCV was extended for an additional 24 weeks of therapy. The primary endpoint was the proportion of patients with sustained virologic response at post-treatment Week 12 (SVR12).

RESULTS

Overall, 224 (74%) patients achieved SVR12 and the lower bound of the 95% confidence interval was higher than the historic SVR rate with PegIFN/RBV alone (70 vs. 29%). Most common adverse events (AEs) were fatigue, neutropenia, anemia, asthenia and headache. On-treatment serious AEs occurred in 24/301 (8%) patients; 18/301 (6%) discontinued treatment due to AE.

CONCLUSIONS

DCV + PegIFN/RBV led to sustained HCV virologic response in the majority of HIV-1-HCV-coinfected patients, regardless of concomitant ART. HIV control was not compromised and no new safety signals were identified. This study supports DCV use in HIV-1-HCV-coinfected patients, while allowing the vast majority of patients to remain on their existing ART regimen.

Effectiveness and Safety of Sofosbuvir-Based Regimens for Chronic HCV Genotype 3 Infection: Results of the HCV-TARGET Study

BACKGROUND

Sofosbuvir (SOF) is active against all hepatitis C virus (HCV) genotypes, and SOF-based therapies lead to high rates of sustained virologic response (SVR). However, genotype 3 (GT3) HCV remains a challenge with lower SVR rates reported, particularly in patients with cirrhosis. This study reports the effectiveness and safety of SOF-based therapy in patients with GT3 HCV treated in clinical practice.

METHODS

Hepatitis C Virus Therapeutic Registry and Research Network is an international, prospective observational study evaluating patients treated in usual clinical practice. Patients with GT3 HCV were analyzed to assess predictors of treatment response and adverse events using descriptive statistics and multivariable logistic regression.

RESULTS

Treatment outcomes were available for 197 patients treated with SOF and ribavirin (RBV), with or without peginterferon, including 54% with cirrhosis and 49% who failed prior therapy. Of 178 patients treated with SOF/RBV, 60% achieved SVR at 12 weeks (SVR12), compared with 84% of 19 patients treated with SOF/peginterferon/RBV. For patients treated with SOF/RBV, the SVR12 rate was 58% in treatment-naive patients with cirrhosis, and 42% in those with cirrhosis who failed prior therapy. In noncirrhotic patients, SVR12 rates were 89% in treatment-naive and 88% in treatment-experienced patients. After controlling for age and sex, absence of cirrhosis (odds ratio [OR], 6.4; 95% confidence interval [CI], 2.78-14.74), albumin levels ≥3.2 g/dL (OR, 12.48; 95% CI, 3.86-40.33), and platelet count >10(5) cells/µL (OR, 7.44; 95% CI, 3.51-15.78) were associated with greater odds of SVR12 CONCLUSIONS:  SVR rates were acceptable in patients with GT3 HCV without cirrhosis; however, in those with cirrhosis, treatment with SOF/RBV was suboptimal, highlighting the need for new therapies for this population.