“We are encouraged by the early efficacy and safety data being generated with our nucleotide analogs, PSI-7977 and PSI-938,” stated Michelle Berrey, MD, MPH, Pharmasset’s Chief Medical Officer.
“The ATOMIC trial is designed to explore 12 and 24 week durations of PSI-7977. The potency, high barrier to resistance, and consistent antiviral activity across genotypes provided the data to support an interferon free dosing period in this trial, as well as enabling us to enroll multiple genotypes in this trial.”
About the Phase 2b ATOMIC Trial
This Phase 2b trial is planned to enroll approximately 300 patients with chronic HCV genotype 1 who have not been treated previously. The primary endpoint of the trial will be the safety and tolerability of PSI-7977 in combination with peginterferon and ribavirin over 12 or 24 weeks. The trial will be conducted in the U.S. Patients will be randomized (1:2:3) into the following arms:
- PSI-7977 400mg QD with peginterferon and ribavirin for 12 weeks;
- PSI-7977 400mg QD with peginterferon and ribavirin for 24 weeks;
- PSI-7977 400mg QD with peginterferon and ribavirin for 12 weeks, followed by either PSI-7977 400mg QD monotherapy for 12 weeks or PSI-7977 400mg QD plus ribavirin for 12 weeks.
HCV GT1 patients will be stratified by IL28B status and baseline HCV RNA to ensure balance across cohorts. An additional 25 treatment-naïve patients with HCV genotype 4, 5, 6 or indeterminate genotype, will receive PSI-7977 400mg QD with peginterferon and ribavirin for 24 weeks.
Additional details on this and all Pharmasset trials can be found at www.clinicaltrials.gov
Pharmasset is a clinical-stage pharmaceutical company committed to discovering, developing, and commercializing novel drugs to treat viral infections. Pharmasset’s primary focus is on the development of oral therapeutics for the treatment of hepatitis C virus (HCV). Our research and development efforts focus on nucleoside/tide analogs, a class of compounds which act as alternative substrates for the viral polymerase, thus inhibiting viral replication. We currently have three clinical-stage product candidates. Mericitabine (RG7128, MCB), a cytosine nucleoside analog for chronic HCV infection, is in two Phase 2b clinical studies in combination with Pegasys® plus Copegus® and is also in the INFORM studies, the first series of studies designed to assess the potential of combinations of small molecules without Pegasys® and Copegus®, all conducted through a strategic collaboration with Roche. PSI-7977 is our unpartnered uracil nucleotide analog currently dosing in three Phase 2 studies in patients with HCV genotypes 1 through 6, including studies with abbreviated duration or no interferon. PSI-938 is our unpartnered guanosine nucleotide analog which recently completed a 14-day monotherapy and combination study with PSI-7977. We also have in our pipeline an additional purine nucleotide analog, PSI-661, in advanced preclinical development.
Pegasys® and Copegus® are registered trademarks of Roche.
SOURCE Pharmasset, Inc.