-USPTO to grant patent covering the anti-HCV drug PSI-6130 and its active metabolites PRINCETON, N.J., June 26
PRINCETON, N.J., June 26 /PRNewswire-FirstCall/ -- Pharmasset, Inc.
(Nasdaq: VRUS) announced that the United States Patent and Trademark Office
has issued a Notice of Allowance for patent application Serial No. 10/828,753
titled, "Modified Fluorinated Nucleoside Analogues," covering the composition
of matter of a family of molecules invented at Pharmasset for the treatment of
hepatitis C virus (HCV), including PSI-6130 and the active metabolite of
PSI-7851. R7128, a prodrug of PSI-6130, a nucleoside analogue polymerase
inhibitor of HCV, is being developed through Pharmasset's collaboration with
Roche. PSI-7851 is a proprietary nucleotide analogue polymerase inhibitor of
HCV that Pharmasset has nominated as a lead development candidate.
"We are pleased that the USPTO has recognized our intellectual property
rights in our growing pipeline of HCV nucleoside polymerase inhibitors,"
stated Schaefer Price, Pharmasset's Chief Executive Officer. "The success
that our in-house research team has had in discovering new HCV product
candidates can now be translated into potentially significant commercial
value."
About R7128
R7128 is being developed for the treatment of chronic HCV infection.
R7128 is a prodrug of PSI-6130, a cytidine nucleoside analog inhibitor of HCV
RNA polymerase. A prodrug is a chemically modified form of a molecule designed
to enhance the absorption, distribution and metabolic properties of that
molecule. Results from an oral single ascending dose study of PSI-6130 in 24
healthy male volunteers showed that PSI-6130 was generally well tolerated with
no serious adverse events in doses up to 3000 mg.
R7128 demonstrated potent, dose-dependent antiviral activity across four
prior treatment-failure patient cohorts (n=40) receiving 750 mg or 1500 mg
administered either once-daily or twice-daily for 14 days as monotherapy. The
greatest mean decrease in HCV RNA from baseline was demonstrated in the
patient cohort that received 1500 mg twice-daily, the highest dose of R7128
administered in the study. These patients demonstrated a mean 2.7 log10 IU/mL
(>99%) decrease in HCV RNA. There was no evidence of the development of viral
resistance in any dose cohort after 14 days of dosing.
In a 4-week Phase 1 combination study that was conducted in 50
treatment-naive patients chronically infected with HCV genotype 1, R7128
demonstrated potent short-term antiviral activity and was generally safe and
well tolerated. Eighty-five percent (85%) of patients receiving R7128 1500mg
twice-daily (BID) with Pegasys plus Copegus for 4 weeks achieved undetectable
HCV RNA levels with safety and tolerability comparable to placebo with Pegasys
plus Copegus.
We have commenced dosing two additional cohorts of this 4-week Phase 1
study. Cohort 3 will continue dose-exploration with administration of R7128
1000mg twice-daily (BID) with Pegasys plus Copegus in treatment-naive patients
with HCV genotype 1. Cohort 4 will evaluate R7128 1500mg BID with Pegasys plus
Copegus in treatment-experienced patients with genotypes 2 or 3 who did not
achieve a sustained virologic response (SVR) with previous interferon-based
therapy.
About Hepatitis C
Hepatitis C is a blood-borne infectious disease of the liver and is a
leading cause of chronic liver disease and liver transplants. The WHO
estimates that nearly 180 million people worldwide, or approximately 3% of the
world's population, are infected with hepatitis C virus (HCV). The CDC has
reported that almost four million people in the United States have been
infected with HCV, of whom 2.7 million are chronically infected.
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 on the development of oral
therapeutics for the treatment of hepatitis B virus (HBV), hepatitis C virus
(HCV) and human immunodeficiency virus (HIV).
Pharmasset is currently developing three product candidates. Clevudine,
for the treatment of chronic HBV infection, is enrolling Phase 3 clinical
trials for registration in North, Central and South America and Europe.
Clevudine is already approved for HBV in South Korea and marketed by Bukwang
Pharmaceuticals in South Korea under the brand name Levovir. R7128, an oral
treatment for chronic HCV infection, is in a 4-week Phase 1 clinical trial in
combination with Pegasys(R) plus Copegus(R) through a strategic collaboration
with Roche. Racivir, which is being developed for the treatment of HIV in
combination with other approved HIV drugs, has completed a Phase 2 clinical
trial.
Pegasys(R) and Copegus(R) are registered trademarks of Roche.
Contact
Kurt Leutzinger
Chief Financial Officer
kurt.leutzinger@pharmasset.com
Office: +1 (609) 613-4110
Forward-Looking Statements
Pharmasset "Safe Harbor" Statement under the Private Securities Litigation
Reform Act of 1995: Statements in this press release regarding our business
that are not historical facts are "forward-looking statements" that involve
risks and uncertainties, including without limitation the risk that the USPTO
will withdraw the Notice of Allowance, adverse events could cause the
cessation or delay of any of the ongoing or planned clinical trials and/or our
development of our product candidates, the risk that we cannot enroll enough
patients for the Phase 3 registration clinical trial for clevudine, the risk
that our collaboration with Roche will not continue or will not be successful
and the risk that any one or more of our product candidates will not be
successfully developed and commercialized. For a discussion of these risks and
uncertainties, any of which could cause our actual results to differ from
those contained in the forward-looking statements, see the section of our
Annual Report on Form 10-K for the fiscal year ended September 30, 2007 filed
with the Securities and Exchange Commission entitled "Risk Factors" and
discussions of potential risks and uncertainties in our subsequent filings
with the Securities and Exchange Commission.
SOURCE Pharmasset, Inc.
