This study implement a values-based motivational interviewing (VBMI) intervention to promote treatment completion with fixed dose combination (FDC) MK-5172/MK-8742 x 12 weeks among 30 Veterans with substance use disorder (SUD) and treatment naïve genotype 1 chronic hepatitis C virus (HCV) infection.

The investigators will conduct a prospective study of 30 Veterans with treatment-naive genotype 1 chronic hepatitis C infection admitted to the Substance Abuse Residential Rehabilitation Treatment Program (SARRTP) at the G.V. (Sonny) Montgomery VA Medical Center. Enrolled veterans will be treated MK-5172/MI-8742 while receiving a 12 week values based motivational intervention to promote completion of HCV treatment. MK-5172/MK-8742 will be prescribed in accordance with the package insert.

Inclusion Criteria:

1. Identified as having treatment-naïve genotype 1 chronic HCV infection; Veterans who are genotype 1a must have baseline NS5a resistance testing
2. Current resident of the SARRTP program
3. Willing to initiate treatment with FDC MK-5172/MK-8742 during SARRTP and up to 30 days post-discharge.
4. Willing to attend coordinated HCV treatment clinic visits and substance abuse aftercare visits every 2 weeks upon SARRTP discharge

Exclusion Criteria:

1. Contraindications for therapy with FDC MK-5172/MK-8742
2. Unable to provide written informed consent
3. Hepatocellular carcinoma or other medical condition precluding HCV treatment
4. Acute HCV infection
5. Prior treatment for chronic HCV
6. History of decompensated cirrhosis
7. Platelet count < 75 K/cmm and/or albumin < 3 grams/dL
8. Females and male sex partners of females who are pregnant, nursing and/or unwilling to use contraception
9. Patients infected with genotype 1a who have not undergone baseline NS5a resistance testing

open label