title: Quantification of Core Antigen Monitors Efficacy of Direct-acting Antiviral Agents in Patients With Chronic Hepatitis C Virus Infection.
abstract: Widespread use of direct-acting antiviral (DAA) agents to treat patients with hepatitis C virus (HCV) infection has reduced the need for monitoring of HCV RNA levels, because viral kinetics do not predict sustained virologic response (SVR) to these drugs. However, the performance of cheaper tests such as the assay to quantify HCV core antigen (HCV Ag) has not been determined. We investigated the accuracy of the HCV Ag test in predicting which patients receiving DAAs will achieve SVRs at week 12 (SVR12).
  
  
  
  We performed a prospective study of 58 patients infected with HCV genotypes 1-5 (45% with HCV genotype 1, 72% with cirrhosis) receiving DAA therapy from the Liver Center at the Università degli Studi of Milan in Italy from January to March 2015. We collected blood samples and measured levels of HCV Ag and HCV RNA at baseline, after 2 and 4 weeks of treatment, the end of treatment, and 12 weeks after treatment ended. We compared the ability of these assays to predict which patients would have SVR12.
  
  
  
  The median baseline level of HCV RNA was 5.79 log10 IU/mL (range, 3.51-7.31 log10 IU/mL) and of HCV Ag was 3226.87 fmol/L (range, 17.30-54,927.00 fmol/L). HCV Ag became undetectable in 71% of patients at week 2, 84% at week 4, and 93% at the end of treatment. HCV RNA became undetectable in 10% of patients at week 2, 43% at week 4, and 100% at the end of treatment (P < .0001). Concordance between the tests in identifying patients who would achieve SVR12 was 40% at week 2, 55% at week 4, and 95% at the end of treatment. Fifty-three of 58 patients (91%) achieved an SVR12; the test for HCV Ag identified 97% of these patients. The tests for HCV Ag and HCV RNA predicted which patients would have SVR12 with positive predictive values of 90% vs 83%, respectively, at week 2 and 89% vs 92%, respectively, at week 4.
  
  
  
  Tests that measure HCV Ag monitor efficacy of DAA therapy for HCV infection as well as assays that measure HCV RNA and can be recommended for clinical practice. However, measurement of HCV RNA after treatment can rule out relapse in HCV Ag-positive patients.
authors.affiliation: A.M. and A. Migliavacca Center for Liver Disease, Division of Gastroenterology and Hepatology, Fondazione IRCCS CA' Granda Ospedale Maggiore Policlinico, Università degli Studi di Milano, Milan, Italy. Electronic address: alessio.aghemo@policlinico.mi.it.
authors.forename: Alessio
authors.initials: A
authors.lastname: Aghemo
authors.affiliation: A.M. and A. Migliavacca Center for Liver Disease, Division of Gastroenterology and Hepatology, Fondazione IRCCS CA' Granda Ospedale Maggiore Policlinico, Università degli Studi di Milano, Milan, Italy.
authors.forename: Elisabetta
authors.initials: E
authors.lastname: Degasperi
authors.affiliation: A.M. and A. Migliavacca Center for Liver Disease, Division of Gastroenterology and Hepatology, Fondazione IRCCS CA' Granda Ospedale Maggiore Policlinico, Università degli Studi di Milano, Milan, Italy.
authors.forename: Stella
authors.initials: S
authors.lastname: De Nicola
authors.affiliation: Virology Unit, Fondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico, Milan, Italy.
authors.forename: Patrizia
authors.initials: P
authors.lastname: Bono
authors.affiliation: Virology Unit, Fondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico, Milan, Italy.
authors.forename: Anna
authors.initials: A
authors.lastname: Orlandi
authors.affiliation: A.M. and A. Migliavacca Center for Liver Disease, Division of Gastroenterology and Hepatology, Fondazione IRCCS CA' Granda Ospedale Maggiore Policlinico, Università degli Studi di Milano, Milan, Italy.
authors.forename: Roberta
authors.initials: R
authors.lastname: D'Ambrosio
authors.affiliation: A.M. and A. Migliavacca Center for Liver Disease, Division of Gastroenterology and Hepatology, Fondazione IRCCS CA' Granda Ospedale Maggiore Policlinico, Università degli Studi di Milano, Milan, Italy.
authors.forename: Roberta
authors.initials: R
authors.lastname: Soffredini
authors.affiliation: A.M. and A. Migliavacca Center for Liver Disease, Division of Gastroenterology and Hepatology, Fondazione IRCCS CA' Granda Ospedale Maggiore Policlinico, Università degli Studi di Milano, Milan, Italy.
authors.forename: Riccardo
authors.initials: R
authors.lastname: Perbellini
authors.affiliation: Virology Unit, Fondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico, Milan, Italy.
authors.forename: Giovanna
authors.initials: G
authors.lastname: Lunghi
authors.affiliation: A.M. and A. Migliavacca Center for Liver Disease, Division of Gastroenterology and Hepatology, Fondazione IRCCS CA' Granda Ospedale Maggiore Policlinico, Università degli Studi di Milano, Milan, Italy.
authors.forename: Massimo
authors.initials: M
authors.lastname: Colombo
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000818:Animals; D000998:Antiviral Agents / Q000627:therapeutic use*; D016903:Drug Monitoring / Q000379:methods*; D005260:Female; D019698:Hepatitis C, Chronic / Q000188:drug therapy*; D006801:Humans; D007558:Italy; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D012367:RNA, Viral / Q000097:blood; D014758:Viral Core Proteins / Q000097:blood*; D019562:Viral Load
chemical_list: D000998:Antiviral Agents; D012367:RNA, Viral; D014758:Viral Core Proteins; C069130:nucleocapsid protein, Hepatitis C virus
keywords: Core Antigen; HCV; HCV-RNA; IFN Free; SVR; Sofosbuvir