Use of first-generation HCV protease inhibitors in patients coinfected by HIV and HCV genotype 1

Grazoprevir/elbasvir combination therapy for HCV infection

Interferon-free regimens combine different second-wave direct-acting antiviral agents (DAAs), which target the main viral proteins involved in the replication cycle of hepatitis C virus (HCV): NS3/4A protease inhibitors (simeprevir or paritaprevir boosted by ritonavir), NS5B nucleos(t)idic (sofosbuvir) and nonnucleos(t)idic (dasabuvir) polymerase inhibitors, NS5A replication complex inhibitors (daclatasvir, ledipasvir, elbasvir, velpatasvir). Combinations of two or three DAAs, given for 8-24 weeks reach sustained virology response (SVR) rates greater than 90% with good tolerance. SVR rates and safety are similar in clinical trials and in real life, usually higher than 95% in the per-protocol analysis. Next-generation DAAs are now expected. To be competitive, these new combinations need to prove their added value regarding the pill burden, the reduced duration of treatment, the drug-drug interaction profile and safety. Zepatier is a fixed-dose combination product coformulating MK-5172 [grazoprevir (GZR), 100 mg QD] and MK-8742 [elbasvir or (EBR) 50 mg QD]: it combines highly potent inhibitors of the HCV NS3/4A protease and NS5A replication complex, respectively. This review provides a summary of the main evidence available for the use of GZR/EBR and highlights the strength of this combination.

Treatment of hepatitis C: perspectives

The treatment of hepatitis C virus (HCV) infection has significantly improved in the last 2 decades. The association of pegylated interferon alfa and ribavirin (PR) has allowed a sustained virologic response (SVR) for nearly 15 years i.e. a viral cure of the infection for 45% of genotype 1-, 65% of genotype 4-, 70% of genotype 3- and around 85% of genotype 2-infected patients. A better understanding of the HCV life cycle has led to the development of direct-acting antiviral drugs (DAAs) targeted against viral proteins (NS3/4A protease, NS5B polymerase with nucleotide and non-nucleotide inhibitors, NS5A viral replication complex). The combination of first-generation protease inhibitors with PR demonstrated a high antiviral effectiveness (75% of SVR but restricted to genotypes 1) with substantial adverse effects for the first-generation protease inhibitors, which obtained market approval in 2011 (telaprevir and boceprevir), recommendations for use in HCV monoinfected patients in 2012, and in HCV/HIV coinfected in 2013. Then, the combination of second-generation protease inhibitors with PR increased SVR rates from 75 to 90%, while reducing treatment duration, adverse effects, and the number of pills. The next step will be using an interferon and ribavirin-free combination of DAAs; it should become the standard of care in 2015. These excellent results in "easy-to-treat" patients and in small populations in the first studies were confirmed in phase III studies and in "difficult-to-treat" patients (treatment-- especially protease inhibitors--previously treated patients, cirrhotic patients, liver and renal transplant patients, HIV coinfected patients, and multi-drug treated patients, at increased risk of drug interaction). The high antiviral potency of these new combinations has changed the definition of "difficult-to-treat patients". These unique achievements in drug history make any previous publication on hepatitis C treatment obsolete.