Efficacy and Safety of Sofosbuvir Plus Ribavirin in Chronic Genotype 1, 2 and 3 Hepatitis C Virus (HCV) and Human Immunodeficiency Virus (HIV) Co-infected Adults

Inclusion Criteria: * Willing and able to provide written informed consent * Male or female, age ≥ 18 years with chronic HCV and HIV-1 infection * HCV RNA \> 1 x 10\^4 IU/mL at screening * Infection with HCV genotype 1, 2 or 3 as determined at screening * HIV-1 infection confirmed with positive ELISA or Western blot at screening * Medical records must be sufficient to be categorized on interferon (IFN) eligibility or prior treatment history with PEG/RBV. * Confirmation of chronic HCV infection * Ability to determine presence/absence of cirrhosis. * HIV antiretroviral therapy (ARV) criteria of one of the following: * ARV untreated with a CD4 T-cell count \> 500 cells/mm\^3 * On a stable, protocol-approved, ARV for \> 8 weeks prior to screening with a CD4 T-cell count \> 200 cells/mm\^3 and a documented undetectable plasma HIV-1 RNA level for ≥ 8 weeks preceding the screening visit * Approved HIV antiretroviral medications based on drug interaction studies * Not been treated with any investigational drug or device within 30 days of the screening visit * Females if confirmed that she is not pregnant or nursing of non-childbearing potential or of childbearing potential but has a negative serum pregnancy test at screening and agrees to use protocol approved method of birth control from screening through 6 months after the last dose of RBV * Males who agree to consistently and correctly use a condom while their female partner agrees to use protocol approved method of birth control from screening through 7 months after the last dose of RBV * Must be of generally good health as determined by the investigator. * Liver imaging within 6 months of baseline/Day 1 is required in cirrhotic patients only, to exclude hepatocellular carcinoma (HCC) Exclusion Criteria: * Non-genotype 1/2/3 or mixed genotype at screening * Genotype 1 with prior treatment for HCV * Poor control with ARV regimen * Prior exposure to a direct-acting antiviral targeting the HCV nonstructural protein (NS)5B polymerase * Chronic liver disease of a non-HCV etiology (eg, hemochromatosis, Wilson's disease, α1 antitrypsin deficiency, cholangitis) * A new AIDS-defining condition diagnosed within 30 days prior to screening * Active, serious infection (other than HIV or HCV) requiring parenteral antibiotics, antivirals or antifungals within 30 days prior to baseline * Infection with hepatitis B virus (HBV) * Contraindication to RBV therapy * Chronic use of systemically administered immunosuppressive agents (eg, prednisone equivalent \> 10 mg/day) * History of solid organ transplantation or malignancy diagnosed or treated within 5 years * Current or prior history of clinical hepatic decompensation or other significant gastrointestinal disorder