PRINCETON, N.J., June 26 /PRNewswire-FirstCall/ -- Pharmasset, Inc. 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.
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.
CONTACT: Kurt Leutzinger, Chief Financial Officer, Pharmasset, Inc.,
+1-609-613-4110, kurt.leutzinger@pharmasset.com
Web site: http://www.pharmasset.com//
