This is a Phase I/II, multi-site, open-label, single arm study to describe the pharmacokinetics (PK) and safety of glecaprevir/pibrentasvir (GLE/PIB) initiated during pregnancy in women with hepatitis C virus (HCV) infection (acute or chronic) with or without HIV and to evaluate safety for their infants through 10 weeks postpartum.

Inclusion Criteria:

• Of legal age or circumstance to provide independent informed consent as determined by site standard operating procedures (SOPs) and consistent with institutional review board/ethics committee (IRB/EC) policies and procedures

• Willing and able to provide written informed consent for their own and their infant's study participation

• At entry, 16-45 years of age (inclusive)

• At entry, gestational age of 14-32 weeks, defined as greater than 13 weeks plus six days and less than or equal to 32 completed weeks gestation, as determined by the site investigator based on best obstetric estimate

• At screening and at study entry, no evidence of multiple gestation, fetal anomalies, or intrauterine fetal growth restriction, as determined by the site investigator based on ultrasound

• At screening, detectable HCV RNA test result based on testing of a specimen collected within 30 days prior to entry

• At screening, negative test results for hepatitis B surface antigen based on testing of a specimen collected within 30 days prior to entry

• At screening (i.e., from specimens collected within 30 days prior to entry), has normal, grade 1, grade 2, or grade 3 results for the following

  • Aspartate aminotransferase (AST) (<10.0 x ULN)
  • Alanine aminotransferase (ALT) (<10.0 x ULN)

• At screening (i.e., from specimens collected within 30 days prior to entry), has normal, grade 1, or grade 2 results for the following

  • Hemoglobin (≥8.5 g/dL)
  • Creatinine (≤1.8 x ULN)

• At screening (i.e., from specimens collected within 30 days prior to entry), has normal or grade 1 results for the following

  • International normalized ratio (INR) (<1.5 x ULN)
  • Platelet count (≥100,000 cells/mm3)
  • Total bilirubin (<1.6 x ULN)

• HIV status determined based on testing meeting the requirements specified in protocol

• For pregnant participants living with HIV: has a suppressed HIV viral load (HIV-1 RNA below the limit of quantification of the assay) on an ARV regimen for at least 30 consecutive days prior to entry that does not include efavirenz, etravirine, cobicistat, or any protease inhibitor (e.g., atazanavir, darunavir, lopinavir, ritonavir), as determined by the site investigator based on available medical records

• At entry, expects to remain in the geographic area of the study site during pregnancy and for 10 weeks postpartum (or for 20 weeks post-entry, depending on gestational age at entry), as determined by the site investigator based on pregnant participant report

Exclusion Criteria:

• Any previous treatment for hepatitis C, including HCV DAAs or interferon-based treatment

• High risk of preterm delivery, defined as either of the following:

  • History of spontaneous preterm delivery at less than 34 weeks, as determined by the site investigator based on pregnant participant report and available medical records, or
  • Shortened cervix less than 20 mm if noted on ultrasound during the current pregnancy, as determined by the site investigator based on available medical records

• Receipt of any prohibited medication, within 14 days prior to entry, as determined by the site investigator based on pregnant participant report and available medical records

• Any of the following liver-related conditions:

  • Clinical diagnosis of acute hepatitis not otherwise attributable to hepatitis C with AST or ALT ≥2.5 x ULN
  • Evidence of decompensated cirrhosis including history of or present variceal hemorrhage, ascites, spontaneous bacterial peritonitis, hepatic encephalopathy, hepatocellular carcinoma, hepatorenal syndrome, or hepatopulmonary syndrome

• Has any other documented or suspected clinically significant medical condition or any other condition that, in the opinion of the site investigator, would make participation in the study unsafe, complicate interpretation of study outcome data, or otherwise interfere with achieving study objectives

Beginning 3 months following publication and available throughout period of funding of the International Maternal Pediatric Adolescent AIDS Clinical Trial (IMPAACT) Network by NIH.

• Researchers who provide a methodologically sound proposal for use of the data that is approved by the IMPAACT Network.
• For what types of analyses?
• To achieve aims in the proposal approved by the IMPAACT Network.
• By what mechanism will data be made available?
• Researchers may submit a request for access to data using the IMPAACT "Data Request" form at: https:// www.impaactnetwork.org/ resources/study-proposals.htm. Researchers of approved proposals will need to sign an IMPAACT Data Use Agreement before receiving the data.