Pharmasset, Inc. and Roche have announced that the first patient has been dosed in a Phase IIb study of R7128, the nucleoside polymerase inhibitor most advanced in development for the treatment of chronic hepatitis C (HCV).
The trial will evaluate the dose and duration of treatment of R7128 in combination with Roche's PEGASYS(R) (peginterferon alfa-2a) and COPEGUS(R) (ribavirin) - in HCV patients who have not been treated previously. The goal of adding R7128 to the existing standard therapy is to improve rates of sustained virological response (SVR) and to shorten the length of treatment for patients.
R7128 is being developed by Roche and Pharmasset under a partnership agreement entered into in 2004. The first patient dosed in this study triggered a $10 million payment to Pharmasset from Roche.
A Phase I/IIa trial demonstrated the ability of R7128 to generate high rapid virologic response rates (RVR) in combination with PEGASYS and COPEGUS. Unlike protease inhibitors in development, R7128 is active against multiple HCV genotypes and presents a high barrier to the development of resistance.
"We look for the Phase IIb study to further support the efficacy and safety of R7128, and nucleoside polymerase inhibitors as a class," said Michelle Berrey, MD, MPH, Pharmasset's Chief Medical Officer. "We believe nucleoside inhibitors have a number of advantages over other classes of HCV drugs, including a higher barrier to resistance and activity across multiple genotypes, as well as a high level of potency."
"The collaboration with Pharmasset underscores Roche's commitment to develop new therapies that will meet the needs of a growing population of patients with hepatitis C," said Rob Mitchell, Global Head of Roche's Virology business. "We are hopeful that a combination of R7128 and the current gold standard of PEGASYS and COPEGUS can provide a more potent - and potentially shorter - treatment regimen."
These collaborations position Roche as a leader, and they underscore Roche's role as a pioneer, in the next evolution of hepatology treatments.
The Phase IIb trial is anticipated to enroll about 400 HCV-infected patients with genotypes 1 or 4 who have not been treated previously. The primary efficacy endpoint of the trial will be the proportion of patients who achieve an SVR, defined as undetectable levels of HCV (measured by Roche TaqMan assay) 24 weeks after completion of treatment. The trial will be conducted in North America, Europe and Australia. Patients will be enrolled into one of 5 arms: