Nov. 3, 2009 (PR Newswire) --

BOSTON, Nov. 3 /PRNewswire-FirstCall/ -- Pharmasset, Inc (Nasdaq: VRUS) and InterMune, Inc. (Nasdaq: ITMN) today announced results from all patient cohorts of the INFORM-1 trial, an innovative Phase 1 study of two direct-acting antiviral (DAA) compounds administered without interferon or ribavirin for the treatment of patients chronically infected with the hepatitis C virus (HCV).(i) The study, conducted by Roche as part of its collaborations with InterMune and Pharmasset, combined the oral NS3 protease inhibitor RG7227 (also known as ITMN-191) and the oral nucleoside analog polymerase inhibitor RG7128.

The results announced today focused on the recently completed final three cohorts of the INFORM-1 study, consisting of higher-dose, twice-daily regimens, presented during the Presidential Plenary Session at the 60th Annual Meeting of the American Association for the Study of Liver Diseases (AASLD) in Boston by Edward Gane, M.D., Associate Professor, University of Auckland, and Director, Auckland Clinical Studies Limited, and Principal Investigator in the INFORM-1 study. The initial four lower-dose cohorts of patients from INFORM-1 were previously reported at the European Association for the Study of the Liver (EASL) meeting in Copenhagen in April, 2009.

INFORM-1 Results

Viral Kinetic Performance of Twice-Daily Regimens

The full dose combination of RG7128 1000mg and RG7227 900mg administered twice-daily without pegylated interferon or ribavirin, the current standard of care for HCV, for 13 days resulted in 88% of HCV-positive treatment-naive patients achieving HCV RNA below the lower limit of quantification (LLOQ; <43 IU/mL), and 63% of patients having HCV RNA below the lower limit of detection (LLOD; <15 IU/mL). The same regimen in "null responders" resulted in 50% of patients with HCV RNA below LLOQ and 25% of patients with HCV RNA below LLOD. Null responders were defined as patients with an HCV RNA reduction of <1 log10 IU/mL in 4 weeks or <2 log10 IU/mL in 12 weeks of prior treatment with pegylated interferon and ribavirin. At the twice-daily dose of 600mg of RG7227 in combination with 1000mg of RG7128 twice-daily for 13 days in treatment-experienced patients, somewhat lower viral load reduction and categorical responses were observed, an observation that will guide dosing in future studies in these patients.

All patients receiving a twice-daily regimen experienced a continual decline in HCV RNA during the study period. Viral decline displayed a biphasic pattern with a rate of HCV RNA decline in the second phase that was similar to that observed when a single direct acting antiviral is added to pegylated interferon and ribavirin. No treatment-emergent resistance to RG7227 or RG7128 was observed in the study.