Ombitasvir
Ombitasvir is a direct acting antiviral medication used as part of combination therapy to treat chronic Hepatitis C, an infectious liver disease caused by infection with Hepatitis C Virus (HCV). HCV is a single-stranded RNA virus that is categorized into nine distinct genotypes, with genotype 1 being the most common in the United States, and affecting 72% of all chronic HCV patients. Treatment options for chronic Hepatitis C have advanced significantly since 2011, with the development of Direct Acting Antivirals (DAAs) such as Ombitasvir. Ombitasvir is an inhibitor of NS5A, a protein essential for viral replication and virion assembly. The barrier for develoment of resistance to NS5A inhibitors is lower than that of NS5B inhibitors, another class of DAAs.   In a joint recommendation published in 2016, the American Association for the Study of Liver Diseases (AASLD) and the Infectious Diseases Society of America (IDSA) recommend Ombitasvir as a first line therapy option when used in combination with other antivirals for genotypes 1a, 1b, and 4. Depending on the genotype, Ombitasvir is often used in combination with other antivirals such as [DB09183], [DB09297], [DB00503], and [DB00811] with the intent to cure, or achieve a sustained virologic response (SVR), after 12 weeks of daily therapy. SVR and eradication of HCV infection is associated with significant long-term health benefits including reduced liver-related damage, improved quality of life, reduced incidence of Hepatocellular Carcinoma, and reduced all-cause mortality. Treatment with direct acting antivirals such as Ombitasvir is associated with very minimal side effects, with the most common being headache and fatigue. Lack of significant side effects and short duration of therapy is a considerable advantage over older interferon-based regimens, which were limited by infusion site reactions, reduced blood count, and neuropsychiatric effects.  Ombutasvir first came on the market as a fixed-dose combination product with [DB09183], [DB09297], and [DB00503] as the FDA-approved product Viekira Pak. First approved in December 2014, Viekira Pak is indicated for the treatment of HCV genotype 1b without cirrhosis or with compensated cirrhosis, and when combined with Ribavirin for the treatment of HCV genotype 1a without cirrhosis or with compensated cirrhosis.  Ombutasvir is also available as a fixed-dose combination product with [DB09297] and [DB00503] as the FDA- and Health Canada-approved product Technivie. First approved in July 2015, Technivie is indicated in combination with Ribavirin for the treatment of patients with genotype 4 chronic hepatitis C virus (HCV) infection without cirrhosis or with compensated cirrhosis.  In Canada, Ombutasvir is also available as a fixed-dose combination product with [DB09183], [DB09297], and [DB00503] as the Health Canada-approved, commercially available product Holkira Pak. First approved in January 2015, Holkira Pak is indicated for the treatment of HCV genotype 1b with or without cirrhosis, and when combined with [DB00811] for the treatment of HCV genotype 1a with or without cirrhosis.