Nitazoxanide plus pegylated interferon and ribavirin in the treatment of genotype 4 chronic hepatitis C, a randomized controlled trial

Therapeutic Potential of Nitazoxanide: An Appropriate Choice for Repurposing versus SARS-CoV-2?

The rapidly growing COVID-19 pandemic is the most serious global health crisis since the "Spanish flu" of 1918. There is currently no proven effective drug treatment or prophylaxis for this coronavirus infection. While developing safe and effective vaccines is one of the key focuses, a number of existing antiviral drugs are being evaluated for their potency and efficiency against SARS-CoV-2 in vitro and in the clinic. Here, we review the significant potential of nitazoxanide (NTZ) as an antiviral agent that can be repurposed as a treatment for COVID-19. Originally, NTZ was developed as an antiparasitic agent especially against Cryptosporidium spp.; it was later shown to possess potent activity against a broad range of both RNA and DNA viruses, including influenza A, hepatitis B and C, and coronaviruses. Recent in vitro assessment of NTZ has confirmed its promising activity against SARS-CoV-2 with an EC50 of 2.12 μM. Here we examine its drug properties, antiviral activity against different viruses, clinical trials outcomes, and mechanisms of antiviral action from the literature in order to highlight the therapeutic potential for the treatment of COVID-19. Furthermore, in preliminary PK/PD analyses using clinical data reported in the literature, comparison of simulated TIZ (active metabolite of NTZ) exposures at two doses with the in vitro potency of NTZ against SARS-CoV-2 gives further support for drug repurposing with potential in combination chemotherapy approaches. The review concludes with details of second generation thiazolides under development that could lead to improved antiviral therapies for future indications.

Evolution of efficacious pangenotypic hepatitis C virus therapies

Hepatitis C compromises the quality of life of more than 350 million individuals worldwide. Over the last decade, therapeutic regimens for treating hepatitis C virus (HCV) infections have undergone rapid advancements. Initially, structure-based drug design was used to develop molecules that inhibit viral enzymes. Subsequently, establishment of cell-based replicon systems enabled investigations into various stages of HCV life cycle including its entry, replication, translation, and assembly, as well as role of host proteins. Collectively, these approaches have facilitated identification of important molecules that are deemed essential for HCV life cycle. The expanded set of putative virus and host-encoded targets has brought us one step closer to developing robust strategies for efficacious, pangenotypic, and well-tolerated medicines against HCV. Herein, we provide an overview of the development of various classes of virus and host-directed therapies that are currently in use along with others that are undergoing clinical evaluation.

Hydroxychloroquine augments early virological response to pegylated interferon plus ribavirin in genotype-4 chronic hepatitis C patients

The therapeutic effect of pegylated interferon (peg-IFN) alfa-2a combined with ribavirin (RBV) on chronic hepatitis C Egyptian patients is low and further efforts are required to optimize this therapy for achievement of higher rates of virological response. This study aimed to evaluate the safety and efficacy of hydroxychloroquine (HCQ) in combination with pegylated interferon plus ribavirin on early virological response (EVR) in chronic hepatitis C Egyptian patients. Naïve 120 Egyptian patients with chronic hepatitis C virus infection were divided into two groups. Group 1 have administered the standard of care therapy (pegylated interferon alfa-2a plus ribavirin) for 12 weeks, (n = 60). Group 2 have administered hydroxychloroquine plus standard of care therapy for 12 weeks, (n = 60). Therapeutics included hydroxychloroquine (200 mg) oral twice daily, peginterferon alfa-2a (160 μg) subcutaneous once weekly and oral weight-based ribavirin (1000-1200 mg/day). Baseline characteristics were similar in the two groups. The percentage of early virological response was significantly more in patients given the triple therapy than in patients given the standard of care [54/60 (90%) vs. 43/60 (71.7%); P = 0.011; respectively]. Biochemical response at week 12 was also significantly higher in patients given the triple therapy compared with the standard of care [58/60 (96.7%) vs. 42/60 (70%); P < 0.001; respectively]. Along the study, the observed adverse events were mild and similar across treatment groups. Addition of hydroxychloroquine to pegylated interferon plus ribavirin improves the rate of early virological and biochemical responses in chronic hepatitis C Egyptian patients without an increase in adverse events. J. Med. Virol. 88:2170-2178, 2016. © 2016 Wiley Periodicals, Inc.

Impact of nitazoxanide on sustained virologic response in Egyptian patients with chronic hepatitis C genotype 4: a double-blind placebo-controlled trial

BACKGROUND

Nitazoxanide, approved for the treatment of Cryptosporidium parvum and Giardia lamblia, was found to inhibit hepatitis C virus replication.

AIM

The aim of this study was to assess the impact of nitazoxanide as an add-on therapy to pegylated interferon α-2a and ribavirin on sustained virologic response (SVR) in patients with chronic hepatitis C.

PATIENTS AND METHODS

A total of 200 patients with chronic hepatitis C were enrolled in the study, assigned randomly in a 1 : 1 ratio to two groups: group A (placebo group) and group B (nitazoxanide group). Five patients withdrew from the study after they signed the consent form.A total of 195 patients were evaluated: 97 patients in group A versus 98 patients in group B at a dose of 500 mg twice daily. Placebo and nitazoxanide were administered as an add-on therapy to pegylated interferon α-2a plus ribavirin following a 12-week lead-in phase. SVR was evaluated. Statistical analysis was carried out using the SPSS software.

RESULTS

The mean age of the patients in group A was 46.5 versus 45.7 years in group B. In group A, 85 out of 97 (87.6%) patients were men and in group B, 84 out of 98 (85.7%) patients were men.In group A, 59 out of 97 (60.82%) patients achieved an SVR versus 57 out of 98 (58.16%) patients in group B (P=0.70); this difference was not significant.

CONCLUSION

Our data did not show any significant impact of nitazoxanide on SVR.

Host-Targeting Agents to Prevent and Cure Hepatitis C Virus Infection

Chronic hepatitis C virus (HCV) infection is a major cause of liver cirrhosis and hepatocellular carcinoma (HCC) which are leading indications of liver transplantation (LT). To date, there is no vaccine to prevent HCV infection and LT is invariably followed by infection of the liver graft. Within the past years, direct-acting antivirals (DAAs) have had a major impact on the management of chronic hepatitis C, which has become a curable disease in the majority of DAA-treated patients. In contrast to DAAs that target viral proteins, host-targeting agents (HTAs) interfere with cellular factors involved in the viral life cycle. By acting through a complementary mechanism of action and by exhibiting a generally higher barrier to resistance, HTAs offer a prospective option to prevent and treat viral resistance. Indeed, given their complementary mechanism of action, HTAs and DAAs can act in a synergistic manner to reduce viral loads. This review summarizes the different classes of HTAs against HCV infection that are in preclinical or clinical development and highlights their potential to prevent HCV infection, e.g., following LT, and to tailor combination treatments to cure chronic HCV infection.

Update on the treatment of hepatitis C genotypes 2-6

PURPOSE OF REVIEW

The hepatitis C virus remains a global health issue, and the established standard of care has consisted of pegylated interferon alpha in conjunction with ribavirin. However, this regimen is associated with significant side-effects and poor sustained virological responses. The aim of this review is to assess the effects of the direct-acting antivirals upon hepatitis C genotypes 2-6 from publications from the past 18 months.

RECENT FINDINGS

The impact of direct-acting antivirals has already substantially improved treatments for genotypes 2-6, with the size of improvement much less marked for genotype 3. Although still responsive to these agents, genotype 3 has inherent resistance to treatments possibly owing to its effects on host metabolic pathways. These treatments have moved sustained virological responses to the threshold of 90%, with reduced side-effects and shortened courses of treatment and some options for interferon-free therapy. These newer medications are transforming clinical guidelines at a rapid rate, but this will have to be balanced with the impact it places on global health budgets.

SUMMARY

Although direct-acting antivirals are transforming the treatment of all hepatitis C genotypes, ongoing studies will optimize treatment duration and provide interferon-free alternatives.

The efficacy of a Hansenula-derived 20 kDa pegylated interferon alpha-2a in the treatment of genotype 4 chronic hepatitis C

Pending the emergence and approval of an effective interferon-free regimen, pegylated interferon will remain an integral part of the treatment of genotype 4 hepatitis C virus (HCV). A new 20 kDa pegylated interferon has been developed in a cost-saving fungal-based system and is commercialized in Egypt at a quarter to a third of the price of conventional pegylated interferon. We hereby test the efficacy and safety of this novel cost-saving interferon. One hundred ninety-three consecutive treatment-naive patients with genotype 4 HCV were treated using the following regimen: subcutaneous 20 kDa pegylated interferon 160 μg once weekly plus oral ribavirin 1,000 or 1,200 mg daily (based on body weight <75 kg or ≥75 kg, respectively) for 48 weeks. A sustained virological response (SVR) of 51% was achieved. Interim responses included rapid virological response (RVR): 54%, early virological response (EVR): 78% (complete EVR: 71%, partial EVR: 7%), and end of treatment response: 63%. The most common adverse events were flu-like symptoms, dyspepsia, anorexia, and pruritus. Treatment-related serious adverse events were encountered in only 2 patients (1%). Discontinuation of treatment due to adverse events occurred in only 13 patients (7%). Multiple logistic regression analyses revealed the following factors as predictors of SVR: RVR (P<0.001), alpha-fetoprotein<upper limit of normal (ULN) (P=0.007), and early biochemical response (alanine aminotransferase <ULN at week 12, P=0.018). Hansenula-derived 20 kDa pegylated interferon alpha-2a is an effective and safe treatment for genotype 4 chronic HCV. These results highlight the presence of a less costly treatment for chronic HCV, pending the emergence of an effective inexpensive interferon-free regimen. A direct comparison with 40 kDa interferon remains essential to adequately compare the efficacy and safety.