This 7 cohort study will evaluate the efficacy and safety of combination treatment with an HCV nucleoside polymerase inhibitor(RO5024048)and an HCV protease inhibitor(RO5190591/ITMN-191/danoprevir) in patients with chronic hepatitis C, genotype 1.Cohorts A,B,C,D and G will be treatment-naive patients, cohort E will be treatment-experienced excluding null responders, and cohort F will be null responders. Cohorts A and B will evaluate doses of 500mg po bid RO5024048 and 100mg po q8h RO5190591, alone or in combination, for up to 7 or 14 days. Cohort C will evaluate combination treatment with either 1000mg po bid RO5024048 and 100mg q8h RO5190591 or 500mg po bid RO5024048 and 200mg q8h RO5190591 for 14 days. Cohort D will evaluate 1000mg po bid RO5024048 and 200mg q8h RO5190591 for 14 days.Cohort E will evaluate 1000mg RO5024048/600mg RO5190591 po twice daily for 14 days, and Cohorts F and G will evaluate 1000mg RO5024048/900mg RO5190591 po twice daily for 14 days. Cohorts will be tested sequentially or in parallel, if supported by appropriate safety and pharmacokinetic data.Following the last dose of study medication patients have the option of continuing treatment with Standard of care therapies. The anticipated time on study treatment is <3 months, and the target sample size is <100 individuals.

Inclusion Criteria:

• adult patients, 18-65 years of age;
• chronic hepatitis C, genotype 1.

Exclusion Criteria:

• decompensated liver disease, or impaired liver function;
• presence or history of non-hepatitis C chronic liver disease;
• HBsAg or HIV infection;
• history of cancer within 5 years, other than localized or in situ cancer of the skin.