In Part 1, participants who previously participated in one of nine boceprevir studies (P03523 [NCT00423670], P03659 [NCT00160251], P04487 [No NCT], P05101 [NCT00708500], P05216 [NCT00705432], P05411 [NCT00959699], P05514 [NCT00910624], P05685 [NCT00845065], and P06086 [NCT01023035]) were followed for response. In Part 2, participants who previously participated in one narlaprevir study (P05104 [NCT00797745]) were followed for response.