This is an independent optional sub-study parallel to TARGET-HCC (NCT02954094). The purpose of Direct-Acting Antiviral-Post Authorization Safety Study (DAA-PASS) is to investigate the impact of exposure to direct-acting antivirals (DAAs) on early recurrence of hepatocellular carcinoma (HCC) in hepatitis C virus (HCV)-infected patients following successful HCC treatment interventions.

Screening Inclusion Criteria:

• Current participant in TARGET-HCC
• Adults, age ≥18 years
• First diagnosis of HCC (mixed HCC/cholangiocarcinoma may be included). Diagnosis may be histological/cytological and/or radiological.
• BCLC Stage A
• Underwent, undergoing, or planned to undergo therapy for HCC, with exception that transplant as prior or planned treatment for HCC is excluded.
• HCV RNA positive

Screening Exclusion Criteria:

• Inability to provide informed consent
• HCC-free imaging (as defined in Section 9.1.1) after treatment of initial HCC prior to Screening (see Section 9.2.9 for imaging details)
• Prior liver transplantation
• Hepatitis B Virus (HBV) surface antigen positive (HBsAg)
• Previously treated with direct-acting antiviral agents (not DAA-naïve); Note that prior (peg)IFN and/or ribavirin therapy is allowed

Enrollment Inclusion Criteria:

• Continued participation in TARGET-HCC
• No recurrence or progression of initial HCC beyond BCLC Stage A prior to Enrollment/Baseline
• HCC-free imaging (as defined in Section 9.1.1) at Enrollment/Baseline (see Section 9.2.9 for imaging details; participants may remain in Screening until an HCC-free image is obtained)
• Remains DAA-naïve (prior therapy with (peg)IFN and/or ribavirin is allowed)

Enrollment Exclusion Criteria:

- Liver transplantation since Screening

The prospective DAA-PASS cohort will include a subset of HCV RNA positive participants in the TARGET-HCC study who meet entry criteria including hepatitis C (with no prior history of DAA therapy) and newly diagnosed Barcelona Clinic Liver Cancer (BCLC) Stage A HCC. Participants will be enrolled in the countries participating in TARGET-HCC which will include: United States (US), France, Germany, Italy, and Spain.