A Study to Assess Resistance and Durability of Response to ABT-493 and/or ABT-530

Maintaining a sustained virologic response (SVR) is defined as having Hepatitis C virus ribonucleic acid (HCV RNA) value consistently below the lower limit of quantification (< LLOQ) from the end of treatment in the previous study throughout Study M13-576 (this study).

Relapse was defined as confirmed Hepatitis C virus ribonucleic acid (HCV RNA) greater than or equal to the lower limit of quantification (≥ LLOQ) between end of treatment and up to and including the last HCV RNA measurement collected in this study for a participant with HCV RNA < LLOQ at Final Treatment Visit who completed treatment, excluding reinfection. HCV reinfection was defined as confirmed HCV RNA ≥ LLOQ after the end of treatment in a participant who had HCV RNA < LLOQ at Final Treatment Visit, along with the post-treatment detection of a different HCV genotype, subtype, or clade compared with baseline, as determined by phylogenetic analysis of the NS3 or NS5A, and/or NS5B gene sequences.

Plasma samples for HCV resistance testing were collected at study visits. The variants in nonstructural viral protein 3 (NS3) and nonstructural viral protein 5A (NS5A) at amino acid positions of interest were analyzed by next generation sequencing relative to baseline and prototypic reference sequences.

Any events (i.e., diagnoses) related to liver disease progression and/or HCV infection considered to be clinically significant by the investigator that began or worsened after Day 1 were documented until the end of the study or initiation of re-treatment for HCV (if applicable). Significant events related to liver disease progression include the development of cirrhosis, events indicative of hepatic decompensation, (including: variceal bleeding, new ascites, spontaneous bacterial peritonitis, hepatic encephalopathy, hepato-renal syndrome, hepatic hydrothorax or other evidence of hepatic decompensation considered to be significant by the investigator), change in the Child-Pugh category (e.g., change from Child-Pugh Class A to Child-Pugh Class B), the occurrence of hepatocellular carcinoma, liver transplantation and/or death.

A plasma sample for IP-10 testing was collected at study visits for all participants, until the end of the study or initiation of re-treatment for HCV (if applicable). IP-10 is used to assess liver fibrosis in participants with chronic liver disease.

A serum sample for FibroTest evaluation was collected at study visits for all participants, until the end of the study or initiation of re-treatment for HCV (if applicable). FibroTest uses six biomarkers to generate a score that correlates to the degree of liver damage in participants. Scores range from 0 to 1, with higher scores indicating more severe liver fibrosis.

A serum sample for aspartate transaminase evaluation and platelets were collected at study visits for all participants, until the end of the study or initiation of re-treatment for HCV (if applicable). The aspartate transaminase to platelet ratio index (APRI) is used to assess liver fibrosis in participants with chronic liver disease. Scores range from 0 to ≥ 2.0, with scores < 0.5 predictive of no liver fibrosis; scores >1.5 significant fibrosis; and scores > 2.0 indicative of cirrhosis.

The FibroScan test is used to assess liver fibrosis in participants with chronic liver disease. This was not performed as a study procedure, but any available results from source documents were summarized. For participants with Hepatitis C infection, a Fibroscan score of 2-7 kPa indicates no liver scarring or mild scarring; a score of 8 or 9 is associated with moderate liver scarring; 9-14 indicates severe liver scarring; and 14 or higher is indicative of advanced liver scarring, cirrhosis.