New 12 Week, Interferon-Free Treatment Arms Added to All-Oral Combination Study of PSI-7977 and Daclatasvir (BMS-790052) for HCV Genotype 1

PRINCETON, N.J., Nov. 4, 2011 /PRNewswire via COMTEX/ -- Pharmasset, Inc. VRUS -6.77% and Bristol-Myers Squibb Company BMY -1.64% announced today the addition of four treatment arms to the ongoing Phase IIa trial evaluating the combination of Pharmasset's PSI-7977, a nucleotide polymerase inhibitor, and Bristol-Myers Squibb Company's daclatasvir (BMS-790052), an investigational NS5A replication complex inhibitor, for the treatment of chronic hepatitis C (HCV). This trial is the result of a clinical collaboration agreement between Pharmasset and Bristol-Myers Squibb announced in January 2011.

"Recent data from Pharmasset's ELECTRON trial as well as other all-oral DAA combination studies have demonstrated the potential of 12 week treatment regimens," stated William Symonds, Pharmasset's Senior Vice President of Clinical Pharmacology and Translational Medicine. "This study will evaluate whether the potent antiviral activity and high barrier to resistance seen in Phase II studies of PSI-7977 may enable shorter treatment durations with an interferon-free regimen than the current standard of care."

"Hepatitis C is a rapidly evolving field of research. As the science evolves, we are evolving our clinical development programs to continue to drive advances in HCV research," said Brian Daniels, senior vice president, Development, Bristol-Myers Squibb. "Shorter duration, all-oral therapy and effective treatment options for patients who have failed approved triple therapy regimens are clear unmet medical needs in HCV. With this study, we aim to understand the potential for daclatasvir to help address these needs, as part of a novel combination treatment regimen."


About the Trial

This Phase IIa trial completed enrollment in September 2011 with approximately 84 subjects with chronic HCV genotypes 1, 2 or 3 who have not been treated previously. The primary endpoint of the trial is sustained virologic response (SVR). Subjects were randomized equally across each of the following arms:

• PSI-7977 400mg QD for 7 days, then add daclatasvir 60mg QD for a further 23 weeks in genotype 1 subjects;
• PSI-7977 400mg QD for 7 days, then add daclatasvir 60mg QD for a further 23 weeks in genotype 2 or 3 subjects;
• PSI-7977 400mg QD and daclatasvir 60mg QD for 24 weeks in genotype 1 subjects;
• PSI-7977 400mg QD and daclatasvir 60mg QD for 24 weeks in genotype 2 or 3 subjects;
• PSI-7977 400mg QD, daclatasvir 60mg QD and ribavirin for 24 weeks in genotype 1 subjects;
• PSI-7977 400mg QD, daclatasvir 60mg QD and ribavirin for 24 weeks in genotype 2 or 3 subjects.

Four new treatment arms are now being added to the study; two in genotype 1 treatment-naïve subjects and two in subjects who have failed therapy with pegylated interferon and ribavirin in combination with telaprevir or boceprevir. One hundred and twenty patients will be enrolled in the following four arms (2:2):

• PSI-7977 400mg QD and daclatasvir 60mg QD for 12 weeks in HCV genotype 1 treatment-naïve patients;
• PSI-7977 400mg QD, daclatasvir 60mg QD and ribavirin for 12 weeks in HCV genotype 1 treatment-naive patients;
• PSI-7977 400mg QD and daclatasvir 60mg QD for 12 weeks in genotype 1 HCV patients who have previously failed telaprevir or boceprevir treatment;
• PSI-7977 400mg QD, daclatasvir 60mg QD and ribavirin for 12 weeks in HCV genotype 1 patients who have previously failed telaprevir or boceprevir treatment.

Additional details can be found at www.clinicaltrials.gov .

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