The release of two new oral medications, IncivekTM and VictrelisTM, in May 2011 marks another significant advance in the fight against hepatitis C. (See “Sea Change: New Wave of Drugs for Hepatitis C Patients.) There are three major strains of hepatitis C in the United States: genotypes 1, 2 and 3. The standard therapy for hepatitis C has included weekly injections of interferon and the oral medication ribavirin. This older regimen is effective against genotypes 2 and 3, with cure rates of 70% to 80%, but is less effective against genotype 1, with cure rates of about 40%. However, genotype 1 accounts for the majority of infections in the U.S.
Incivek and Victrelis are called protease inhibitors because they interfere with a protease protein specific to the hepatitis C virus and critical to its activity. The drugs were approved for patients with genotype 1 and are not used together. But either agent, when used with interferon and ribavirin, brings the cure rate for patients with genotype 1 into the 67% to 80% range. These three-drug regimens are now the standard of care in patients with genotype 1. They allow treatment to be shortened from the previous standard of 48 weeks to 24 weeks in about 55% to 60% of patients. The medicines have also increased cure rates in traditionally difficult-to-treat patients.
Still, the new agents come with some caveats. They have more interactions with other medications, which are usually manageable but require vigilance on the medical provider’s part. In addition, the protease inhibitors have side effects beyond those seen with interferon and ribavirin, which also must be managed properly.
More work is being done with these new regimens, but there is reason to believe they will be effective in individuals with hemophilia. In addition, they are being studied in patients who are co-infected with HIV and hepatitis C, and in patients who have had liver transplants.
The new HCV medications are exciting to liver specialists because of their high cure rates and because they allow us to gauge treatment response quickly. Equally important, these drugs represent the first of a broad range of medications designed against multiple targets in the hepatitis C virus. The new agents are expected to further increase cure rates and diminish the need for interferon—the main cause of side effects—in the next few years.
Dilip Moonka, MD, is medical director of liver transplantation at Henry Ford Hospital in Detroit.