The AASLD/IDSA Guideline for Treatment of Hepatitis C Virus: An In-Depth Guide

This article was originally published on the Specialty Pharmacy Times website.

With the availability of new agents in the rapidly changing field of hepatitis C virus (HCV), clinicians are expected to understand the treatment options for HCV infection and discuss the importance of testing with at-risk patients. Currently in the United States, approximately half of the people estimated to have chronic HCV infection are aware that they even have the infection, while only 13% to 18% of all patients receive treatment.

HCV infection affects approximately 3 to 4 million Americans, about three-fourths of whom are members of the generation born between 1945 and 1965—baby boomers. Because approximately 3% of people in this age group are thought to have HCV infection, several medical societies —including the Centers for Disease Control, American Association for the Study of Liver Disease, Infectious Diseases Society of America, and United States Preventive Services Task Force—recommend universal one-time testing for all patients born between 1945 and 1965.

Other populations for whom testing is recommended include:

• Anyone who has ever been incarcerated (approximately 29% of people who have ever been incarcerated are estimated to have anti-HCV antibodies)
• Patients who have ever used an illicit drug (including intranasal and intravenous drugs)
• Anyone who received a blood transfusion before July 1992
• Recipients of clotting factor concentrates manufactured prior to 1987
• Anyone who has received a tattoo in an unregulated setting
• Anyone who has undergone long-term hemodialysis (even if the person has had a kidney transplant and is no longer on hemodialysis)
• Health care workers after an accidental needle stick or other exposure to potentially infective fluids
• Anyone with HIV infection
• Anyone with unexplained elevations of liver enzyme levels
• Children of mothers with chronic HCV infection
• Other populations, as indicated by guidelines

Testing Specifics

Initial testing for HCV involves a test for the presence or absence of anti-HCV antibodies, followed by a test for the presence of HCV RNA copies. It is important to understand the meaning of the results for each of these tests:

• A patient with a positive test result for anti-HCV antibodies may have had an acute infection of HCV that resolved spontaneously (spontaneous resolution occurs in many cases of acute HCV infection, but even after resolution of an acute infection, anti-HCV antibodies remain in circulation)
• If a patient had a positive test result for anti-HCV antibodies, the next step is confirmatory testing for the presence or absence of copies of HCV RNA through polymerase chain reaction (PCR)
• Patients with suspected exposure to HCV in the 6 months prior to receiving a positive test result for anti-HCV antibodies should be tested using a special assay called a nucleic acid test. This test detects the presence or absence of active virus in the body

In patients with a positive test result for presence of HCV RNA through PCR testing, testing involves characterization of:

• The concentration of virus (in IU per mL)
• The virus genotype (HCV genotypes 1, 2, 3, 4, 5, and 6 exist, with additional subtypes denoted by letters, such as genotype 1a or 1b)

Treatment Efficacy

With hepatitis C, the efficacy of treatments is measured in terms of rates of sustained viral response. HCV RNA levels are assessed 12 to 24 weeks after the end of treatment. Patients who have undetectable levels of HCV RNA 12 to 24 weeks after the end of treatment are functionally cured, meaning that they have a 98% to 99% chance of remaining free of HCV infection indefinitely.

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