PSI-7977
+ BMS-790052 Trial for Hepatitis C
SUMMARY
Pharmasset announced the start of a Phase 2a study of an all-oral
antiviral regimen of HCV polymerase inhibitor PSI-7977 plus
NS5A replication complex inhibitor BMS-790052. |
The
advent of direct-acting antiviral agents that target different
steps of the hepatitis C virus (HCV) lifecycle is expected to
revolutionize chronic hepatitis C treatment.
The first 2 such drugs approved by the U.S. Food and Drug Administration
-- the HCV protease inhibitors boceprevir
(Victrelis) and telaprevir
(Incivek) -- are indicated for use in combination with current
standard therapy consisting of pegylated interferon plus ribavirin.
But hepatitis C patients and clinicians are eagerly awaiting all-oral
regimens that will avoid injected interferon and its difficult
side effects.
Pharmasset, Inc. announced last week that it will test a variety
of 24-week regimens of PSI-7977 plus Bristol-Myers Squibb's BMS-790052.
As reported at this year's EASL meeting in April, PSI-7977
worked well both with standard therapy and in an all-oral
regimen with PSI-938. A
combination of BMS-790052 plus BMS-650032 produced high response
rates in prior non-responders.
The new Phase 2a trial will enroll treatment-naive patients with
both hard-to-treat HCV genotype 1 and genotypes 2 or 3. Some participants
will have a 1-week PSI-7977 monotherapy lead-in period before
adding BMS-790052. Other arms will start the 2 experimental drugs
plus ribavirin at the same time.
Below is an edited excerpt from a recent
Pharmasset press release describing the trial.
All-Oral
Combination Study with PSI-7977 for
HCV Genotypes 1, 2 and 3 Initiated
Princeton,
N.J. -- May 26, 2011 -- Pharmasset, Inc. (Nasdaq: VRUS) announced
today the initiation of a Phase 2a trial investigating the combination
of Pharmasset's PSI-7977, a nucleotide polymerase inhibitor, and
BMS-790052, Bristol-Myers Squibb Company's (NYSE: BMY) 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.
"We are happy to announce the initiation of this important
combination trial," stated William Symonds, Pharmasset's
Senior Vice President of Clinical Pharmacology and Translational
Medicine. "Recent data from Bristol-Myers Squibb's combination
study demonstrated that individuals with HCV can be cured without
the traditional interferon and ribavirin, but only if two potent
DAAs are used and drug resistance is avoided. We believe Pharmasset's
nucleotide analogs have demonstrated potent antiviral activity
and a high barrier to resistance and therefore have the potential
to be the future backbone of interferon-free treatment."
About the Trial
This Phase 2a trial is planned to enroll approximately 84 patients
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). The trial will be conducted in the U.S. Subjects
will be randomized equally across each of the following arms:
 |
PSI-7977
400mg QD for 7 days, then add BMS-790052 60mg QD for further
23 weeks in genotype 1 subjects; |
|
PSI-7977
400mg QD for 7 days, then add BMS-790052 60mg QD for further
23 weeks in genotype 2 or 3 subjects; |
|
PSI-7977
400mg QD and BMS-790052 60mg QD for 24 weeks in genotype 1
subjects; |
|
PSI-7977
400mg QD and BMS-790052 60mg QD for 24 weeks in genotype 2
or 3 subjects; |
|
PSI-7977
400mg QD, BMS-790052 60mg QD and ribavirin for 24 weeks in
genotype 1 subjects; |
|
PSI-7977
400mg QD, BMS-790052 60mg QD and ribavirin for 24 weeks in
genotype 2 or 3 subjects. |
Additional
details can be found at www.clinicaltrials.gov.
About Pharmasset
Pharmasset
is a clinical-stage pharmaceutical company committed to discovering,
developing, and commercializing novel drugs to treat viral infections.
Pharmasset's primary focus is development of oral therapeutics
for the treatment of hepatitis C virus (HCV) infection. Our research
and development efforts are focused 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 advancing in trials
in various populations. Our pyrimidine, PSI-7977, an unpartnered
uracil nucleotide analog, is currently under study in three Phase
2b trials in patients with HCV genotypes 1 through 6, including
abbreviated duration interferon and interferon-free regimens.
Our purine, PSI-938, an unpartnered guanosine nucleotide analog,
recently reported safety and efficacy data from 14-days of monotherapy
as well as 14 days in combination with the pyrimidine, PSI-7977.
An SVR-endpoint study of the purine-pyrimidine combination is
anticipated to begin third quarter 2011. Mericitabine (RG7128)
continues in two Phase 2b trials and one interferon-free trial
conducted through a strategic collaboration with Roche.
For more information, see www.pharmasset.com.
6/3/11
Source
Pharmasset,
Inc. All-Oral Combination Study with PSI-7977 for HCV Genotypes
1, 2 and 3 Initiated. Press release. May 26, 2011.
