ViroPharma Incorporated Announces Presentation Of Pharmacokinetic Data From HCV-796 Phase 1a Study

EXTON, Pa., May 1 /PRNewswire-FirstCall/ -- ViroPharma Incorporated today announced that pharmacokinetic (PK) data from a Phase 1a trial of HCV-796, an orally dosed non-nucleoside viral polymerase inhibitor with the potential to interfere with the replication of hepatitis C virus, that is being co-developed with Wyeth Pharmaceuticals, a division of Wyeth , were presented at the 2006 European Association for the Study of the Liver (EASL) meeting in Vienna, Austria, which concluded yesterday. These data concluded that the safety and PK profile of the compound supported additional clinical evaluation. HCV-796 is currently in Phase 1b testing in combination with PEG-interferon.

“These initial Phase 1a data were the first set of data from our human clinical analyses of HCV-796, and important in that they set the stage for our ongoing multiple dose studies,” commented Steve Villano, ViroPharma’s vice president of clinical research and development. “Overall, the findings demonstrate that the absorption and elimination profile, distribution, half life, and tolerability of HCV-796 are acceptable, and supportive of our ongoing clinical development.”

Trial Description

This Phase 1a study was an ascending single dose, placebo-controlled trial designed to assess the safety and tolerability of HCV-796 in healthy adult volunteers. Fasting healthy subjects were randomly assigned to receive 25, 50, 100, 250, 500, 1000, or 2000 mg oral doses of HCV-796 or placebo (six active, two placebo per dose group). Subjects in the 100-mg dose cohort received HCV-796 in a fasting and fed state.

Results

The safety profile from this study indicates that single oral doses of HCV-796 are generally well tolerated with no serious treatment-emergent adverse events. Mild to moderate headache was the most frequently reported adverse event. There were no apparent dose-related increases in frequency for any adverse event. There were no significant differences in the rate of adverse events between patients on drug compared to placebo. The PK data showed that the maximum concentration (Cmax) and drug exposure as measured by the area under the curve (AUC) increased less than proportionally with increasing dose, and appeared to reach a plateau at the 1000 mg cohort. HCV- 796 displayed a long half life. When dosed with food at the 100 mg dose level, drug exposure as measured by AUC increased approximately 1.4 fold, providing the first evidence that systemic exposure to the drug may be increased by dosing with food and leading to an additional study designed to specifically assess the potential enhancement of drug exposure when dosed with food.

HCV-796 is an investigational non-nucleoside polymerase inhibitor compound for the treatment of hepatitis C that is being evaluated in ongoing clinical trials in combination with PEG-Interferon by ViroPharma and Wyeth. In previously disclosed results from the Phase 1b study of HCV-796 as a monotherapy, the patient cohort with the highest exposure to drug achieved a peak mean HCV viral load reduction of 1.4 log10, or 96 percent, on day four of a 14-day dosing period. HCV-796 was found to be generally well tolerated, with favorable pharmacokinetics and no dose-limiting toxicities. Mild to moderate headache was the most frequent adverse event reported overall. There were no treatment-emergent serious adverse events.

About Hepatitis C

Hepatitis C is a blood-borne virus recognized as a major cause of chronic hepatitis worldwide. The World Health Organization estimates that 170 million persons worldwide are chronically infected with HCV, and three to four million persons are newly infected globally each year. According to the U.S. Centers for Disease Control and Prevention (CDC), about four million people in the U.S., or 1.8 percent of the population, are infected with HCV.

Currently, there is no specific antiviral agent directed against HCV that is commercially available, and no vaccine for prevention of HCV infection. Several interferon (IFN) products are available worldwide, but there are substantial limitations to the use of these products when given as monotherapy or in conjunction with ribavirin in the treatment of chronic HCV infection. In addition to the relatively poor treatment response in patients infected with genotype 1 HCV, the most common strain in the U.S., Western Europe and Japan, the considerable side effects frequently associated with the use of IFN can lead to discontinuation of therapy in approximately 20% of patients.

About ViroPharma Incorporated

ViroPharma Incorporated is a biopharmaceutical company dedicated to the development and commercialization of products that address serious diseases treated by physician specialists and in hospital settings. ViroPharma commercializes Vancocin(R), approved for oral administration for treatment of antibiotic-associated pseudomembranous colitis caused by Clostridium difficile and enterocolitis caused by Staphylococcus aureus, including methicillin- resistant strains (for prescribing information, please download the package insert at http://www.viropharma.com/docs/pulvules_pi.pdf). ViroPharma currently focuses its drug development activities in viral diseases including cytomegalovirus (CMV) and hepatitis C (HCV). For more information on ViroPharma, visit the company’s website at http://www.viropharma.com.

Certain statements in this press release may contain forward-looking statements that involve a number of risks and uncertainties, including those relating to our anticipated continued development of HCV-796 and our ability to find an effective small molecule antiviral treatment for HCV disease. Our actual results could differ materially from those results expressed in, or implied by, these forward-looking statements. The development and commercialization of pharmaceutical products is subject to risks and uncertainties. There can be no assurance that Wyeth and ViroPharma’s additional HCV studies will yield positive results, or that ViroPharma will be successful in gaining regulatory approval of any of its HCV product candidates. These factors, and other factors, including, but not limited to those described in ViroPharma’s annual report on Form 10-K for the year ended December 31, 2005 filed with the Securities and Exchange Commission could cause future results to differ materially from the expectations expressed in this press release. The forward-looking statements contained in this press release may become outdated over time. ViroPharma does not assume any responsibility for updating any forward-looking statements.

ViroPharma Incorporated

CONTACT: William C. Roberts, Director, Corporate Communications,ViroPharma Incorporated, +1-610-321-6288

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