Stanislas Pol

New treatments for chronic hepatitis C virus infection

The treatment of hepatitis C virus infection (HCV) by a combination of pegylated interferon and ribavirin, according to early viral kinetics, leads to a sustained virological response (SVR) in more than 50% of patients with chronic infection. This SVR is a complete recovery of the infection but more than 50% of genotype 1-infected patients do not achieve SVR. A better understanding of the viral cycle, and the characterization of viral enzymes which are potential targets, resulted in the development of new molecules, direct acting antivirals (DAA) targeted against HCV, either specific of genotype 1 (protease inhibitors NS3/NS4A and polymerase inhibitors NS5B) or with a wider spectrum (NS5A or entry inhibitors), and non-specific antivirals (new interferons, cyclophilin inhibitors). We describe the results of phase II and III trials which clearly demonstrated a 20 to 30% increase in the SVR rate of genotype 1-infected patients, either naïve or treatment experienced. These new drugs should be approved by the end of 2011, after a temporary approval for compassionate use in cirrhotic patients with previous relapse or partial response to the combination therapy. In the future, the main limitations of triple therapy will be safety (cutaneous rash or anemia which may be controlled), cost, compliance, viral resistance, and drug interactions that must be avoided by educating patients and physicians.

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.

Nouveaux traitements de l’hépatite C chronique

The current treatment of chronic hepatitis C since several years, the association of pegylated interferon and ribavirine, allows to obtain a virological eradication in 55% of patients, all genotypes and 45% of those infected with the genotype 1, the most prevalent. The cure, defined by an undetectable viremia 24 weeks after the discontinuation of treatment is associated to a improvement of the prognosis of the patients with a decrease of mortality and morbidity. The development of news antiviral C molecules, efficient against the genotype 1, two protease inhibitors, boceprevir or telaprevir (which approval has been recently obtained), in association with pegylated interferon and ribavirine, allows to obtain a viral eradication in 70 to 75% of cases, with a reduction of treatment duration to 24 weeks in half of patients. This evolution will modify the therapeutic indications, the therapeutic schemas, the virologic follow-up, the risk factors of sustained virological reponse, the tolerance with the appearance of new adverse effects.