Since its discovery in 1989, the road to a cure for hepatitis C virus (HCV) has been slow, but most patients can now expect to achieve a sustained virological response (SVR). With direct-acting antiviral (DAA) combination therapies such as glecaprevir/pibrentasvir and velpatasvir/sofosbuvir, 98% of patients successfully eradicate the virus, even if previous treatments failed or if resistance-associated substitutions (RASs) are present. Adverse events are rare or mild, and patients with compensated cirrhosis and other co-morbidities are often eligible for treatment. However, a small number of patients fail to eradicate the virus even after retreatment. The cause of failure is mainly due to emergence of NS5A P32 deletion mutants after initial DAA therapy in genotype 1b patients, although the reason is unknown for some patients. Alternative therapies that do not rely on NS5A inhibitors, such as sofosbuvir plus ribavirin, can be attempted in these patients. While scaled-up treatment efforts present a challenge, another problem is that many carriers are unaware of their infection. Long-term damage to the liver becomes irreversible, and patients who are not diagnosed in time can develop liver cancer or liver failure even after eliminating the virus. The long-term costs of treatment of advanced liver disease in undiagnosed patients relative to the immediate costs of DAA therapy should be considered. As no vaccine is yet available, eventual elimination of the virus requires identifying and treating undiagnosed cases and screening of high-risk populations such as injection drug users and men who have sex with men and female sex workers.
Keywords: P32 deletion; direct-acting antivirals; glecaprevir/pibrentasvir; sustained virological response; velpatasvir/sofosbuvir.
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