Adaptive Phase I HCV Study With Nucleoside Analogue, in Combination With Interferon and Ribavirin

This is an adaptive Phase I study to evaluate RO5024048 in the following groups: * Healthy Volunteers (Part 1 - Single Ascending Dose Study) -Enrollment completed * Hepatitis C virus (HCV) genotype 1 infected patients who have failed interferon therapy (Part 2- Multiple Ascending Dose Study)-Enrollment Completed * HCV genotype 1-infected patients who are treatment naive, to be dosed in combination with PEG-IFN and RBV (Part 3 - Combination Dose Study)-Currently Enrolling * HCV genotype 2-3 infected patients who have previously been treated with interferon but who did not respond, to be dosed in combination with PEG-IFN and RBV (Part 3 - Combination Dose Study)- Currently enrolling The study aims to determine if RO5024048 is safe and well-tolerated in healthy people and in people infected with hepatitis C virus. The amount of RO5024048 in the blood will be measured during the study and the amount of hepatitis C virus in the blood after each dose will also be measured. During Part 3 of the study, RO5024048 will be given with PEG-IFN and RBV, two drugs currently used and approved for the treatment of HCV.

Part 3: During Part 3 of the study, HCV gentoype 1-infected patients who are treatment-naive (have not been treated for HCV) will be enrolled. Up to 75 patients (3 groups of 25) will be dosed for 28 days with RO5024048, PEG-IFN, and RBV. The first dose of RO5024048 to be given in Part 3 will be 500 mg BID, the second dose will be 1500 mg BID, and the third group will be 1000 mg BID. Standard doses of PEG-IFN and RBV will be used during Part 3. Doses of PEG-IFN and RBV will be modified if necessary. An 4th group of 25 HCV genotype 2 or 3-infected patients who have been previously treated with interferon but who did not respond will also be enrolle in part 3. The dose given to this 4th group will be 1500 mg BID, in combination with standard doses of PEG-IFN and RBV. Following 28 days of combination dosing with RO5024048, PEG-IFN, and RBV, patients will be dosed an additional 28 days (through Day 56 of the study) with just PEG-IFN, and RBV. After completing 56 days under this study, patients who participate in Part 3 will be optionally enrolled into a standard of care protocol with PEG-IFN and RBV, to be conducted by Roche. Patients who opt to enroll into the standard of care protocol will be given up to 40 weeks of PEG-IFN and RBV. The primary objective for Part 3 is to assess the safety, tolerability and pharmacokinetics of RO5024048 in treatment-naive HCV Genotype 1-infected patients, and in non-responder HCV Genotype 2/3-infected patients, after once or twice daily dosing in combination wtih PEG-IFN and RBV for 28 days on an outpatient basis. The secondary objective of Part 3 (COMBO) is to evaluate the short-term decrease in viral load in treatment-naive HCV Genotype 1-infected patients, and in non-responder HCV Genotype 2/3-infected patients, after once or twice daily dosing of RO5024048 in combination with PEG-IFN and RBV for 28 days. Part 1 (closed for enrollment): Single ascending dose study During Part 1, 5 escalating single oral doses of RO5024048 or placebo were given to 40 healthy volunteers, when fasted (have not eaten any food for at least 10 hours). The doses given were 500 mg, 1500 mg, 4500 mg, 6000 mg, and 9000 mg. Another group of 6 volunteers was given 1500 mg with food. The primary objective of Part 1 was to assess the safety, tolerability, and pharmacokinetics (amount of drug in the blood) of RO5024048 under fasting conditions. The secondary objective of Part 1 was to explore the effect of food on the pharmacokinetics of RO5024048. Part 2: (Closed for enrollment) Multiple ascending dose study During Part 2 of the study, 40 HCV-genotype 1-infected patients were given multiple-ascending oral doses of RO5024048 or placebo for 14 days. The doses given were 750 mg once daily, 1500 mg once daily, 750 mg twice daily, and 1500 mg twice daily. The primary objective of Part 2 was to assess the safety, tolerability and pharmacokinetics of RO5024048 in HCV Genotype 1-infected patients after daily or twice daily dosing for 14 days. The secondary objective was to evaluate the decrease in viral load in HCV Genotype 1-infected patients after daily or twice daily dosing of RO5024048 for 14 days