Antiviral response and resistance analysis of treatment-naïve HCV infected patients receiving multiple doses of the NS3 protease inhibitor GS-9256

Protease inhibitor therapy for hepatitis C virus-infection

INTRODUCTION

The hepatitis C virus (HCV) has affected an estimated of 80 million individuals worldwide and is a strain on public health. Around 25-30% of patients in Europe and the US who are infected with HIV are coinfected with HCV. Prior to 2013, treatment modalities containing an NS3/4A protease inhibitor in combination with pegylated interferon and ribavirin improved sustained virological response (SVR) rates. However, rates of severe side effects were high. Nowadays, oral direct-acting antiviral (DAA) combination therapy offers excellent treatment efficacy, safety and tolerability.

AREAS COVERED

This review focuses on the current literature and clinical evidence and their impact regarding NS3/4A protease inhibitors. The pitfalls encountered in treating HIV- and HBV-coinfected patients are also discussed.

EXPERT OPINION

In the era of DAA treatment, third-generation pan-genotypic NS3/4A protease inhibitors (mainly glecaprevir and voxilaprevir) show high antiviral activity and a genetic resistance barrier with cure rates of over 95% when combined with an NS5A inhibitor, irrespective of baseline resistance associated variants (RASs) being present. These new key components of DAA combination therapy are impressive options to eradicate HCV in the so-called difficult-to-treat population (e.g. compensated cirrhosis, end-stage renal disease and patients who failed previous DAA treatment).

Protease inhibitors for the treatment of hepatitis C virus infection

The hepatitis C virus (HCV) has affected an estimate of 80 million individuals worldwide and is a strain of public health. Around 25-30% of patients in Europe and the US infected with HIV are coinfected with HCV. Despite treatment modalities containing a NS3/4A protease inhibitor in combination with pegylated interferon and ribavirin prior to 2013 improved SVR rates, the amount of severe side effects was high. Nowadays, oral direct-acting antivirals (DAAs) combination therapy offers excellent treatment efficacy, safety and tolerability. This review focuses on current literature and clinical evidence and their impact regarding NS3/4A protease inhibitors. In addition, pitfalls in treatment from HIV- and HBV-coinfected patients will also be discussed. In the era of DAA treatment, the third-generation pan-genotypic NS3/4A protease inhibitors (mainly grazoprevir, glecaprevir and voxilaprevir) show a high antiviral activity and genetic resistance barrier with cure rates of over 95% when combined with an NS5A inhibitor, irrespectively of baseline resistance associated variants (RASs) being present. These new key components of DAA combination therapy are impressive options to eradicate HCV in the so called difficult-to-treat population (e.g. compensated cirrhosis, end-stage renal disease and patients who failed previous DAA treatment).

Evaluation of sofosbuvir, velpatasvir plus voxilaprevir as fixed-dose co-formulation for treating hepatitis C

INTRODUCTION

The fixed-dose combination of three direct-acting antivirals (DAA), namely sofosbuvir, velpatasvir and voxilaprevir is the first pangenotypic, single tablet regimen developed for the treatment of HCV infection. Areas covered: The pharmacokinetics, pharmacodynamics, efficacy and safety of the co-formulation are reviewed. Information on drug absorption, distribution, metabolism and excretion of each of the three antivirals is evaluated. Finally, antiviral activity, safety and potential for drug interactions in phase II/III clinical trials in distinct patient populations are discussed. Expert opinion: The triple co-formulation of sofosbuvir-velpatasvir-voxilaprevir represents a major step towards HCV eradication. It depicts high efficacy even in patients infected with viruses harboring resistance-associated substitutions (RAS), including those selected after DAA failures. Likewise, very high success rates and good tolerance are seen in special patient populations, including decompensated cirrhotics, HIV coinfection, organ transplantation or renal insufficiency. A pill once daily for 8 weeks gives SVR rates above 95%. In prior DAA failures, extending treatment to 12 weeks maximizes SVR rates.