Safety and Efficacy of Ledipasvir/Sofosbuvir (LDV/SOF) Fixed-Dose Combination (FDC) for 6 Weeks in Adults With Acute Genotype 1 or 4 Hepatitis C Virus (HCV) and Chronic Human Immunodeficiency Virus (HIV)-1 Co-Infection

Open-Label Study to Evaluate the Safety and Efficacy of Ledipasvir/Sofosbuvir (LDV/SOF) Fixed-Dose Combination (FDC) for 6 Weeks in Subjects With Acute Genotype 1 or 4 Hepatitis C Virus (HCV) and Chronic Human Immunodeficiency Virus (HIV)-1 Co-Infection

The primary objectives of this study are to determine the antiviral efficacy, safety, and tolerability of ledipasvir/sofosbuvir (LDV/SOF) fixed-dose combination (FDC) in adults with acute genotype 1 or 4 hepatitis C virus (HCV) and chronic human immunodeficiency virus (HIV)-1 co-infection.

Key Inclusion Criteria:

• Acute, untreated, hepatitis C infection, genotype 1 or 4, with an estimated duration less than 24 weeks
• Confirmed HIV-1 infection
• CD4 T cell count >200/μL for individuals receiving antiretroviral therapy (ART), CD4 T cell count > 500/μL at screening for individuals without ART
• Use of two effective contraception methods if female of childbearing potential or sexually active male with female partner

Key Exclusion Criteria:

• Pregnant or nursing female or male with pregnant female partner
• Chronic liver disease of a non HCV etiology
• Coinfection with hepatitis B virus (HBV)
• Treatment with any investigational drug or device within 60 days of the screening visit.
• History of clinically significant illness or any other medical disorder that may interfere with the individual's treatment, assessment or compliance with the protocol

Note: Other protocol defined Inclusion/Exclusion criteria may apply