Presidio to present PPI-461 data for HCV infection at AASLD meeting

Presidio Pharmaceuticals, Inc. announced today that Nathaniel Brown, M.D., Chief Medical Officer, will present a late-breaker poster, "Safety and Pharmacokinetics of PPI-461, a Potent New Hepatitis C virus (HCV) NS5A Inhibitor with Pan-Genotype Activity" at the 61^st AASLD meeting in Boston, MA, on November 1, 2010. The presentation provides the results of the first clinical trial of PPI-461, and will be available for review from 8:00A to 5:00P (EDT) in Exhibit Hall C at the Hynes Convention Center.

“We are pleased to begin initial assessments of the tolerance and antiviral efficacy of PPI-461 in patients with chronic hepatitis C, following the encouraging results of the recent Phase 1a study”

PPI-461

PPI-461 is a novel and promising NS5A inhibitor that interferes with HCV replication. Discovered at Presidio, PPI-461 exhibits highly potent and selective activity against all seven major HCV genotypes in laboratory assays. Inhibitors of the HCV NS5A protein represent a promising new class of HCV antivirals that are mechanistically distinct from HCV agents that target the viral protease or replicase (polymerase). Laboratory data suggest that NS5A inhibitors can potentially be used in combination with any of these other HCV agents, to achieve better efficacy in hepatitis C patients and combat the emergence of antiviral resistance.

About the Phase 1a Trial Results

The data to be reported at the AASLD meeting are the results of a Phase 1a dose-ranging trial of PPI-461 in healthy volunteers completed this year. This trial assessed the safety and pharmacokinetics of five different oral dosing regimens for PPI-461: four single doses (20, 50, 100, and 200 mg), and a multi-dose regimen (200 mg daily for five days). A total of 40 subjects participated in the study, with eight subjects in each of the five dosing groups.

As indicated in the LB-12 abstract, now viewable on the AASLD meeting website (AASLD.org), all PPI-461 dose regimens were well tolerated. All subjects completed the study, and there were no patterns of clinical adverse events or laboratory abnormalities associated with administration of PPI-461. The pharmacokinetic results indicated that all subjects rapidly achieved substantial blood levels of PPI-461, which far exceeded the concentrations of PPI-461 needed to inhibit HCV (genotypes 1-7) in the laboratory. For PPI-461 doses of 50 mg or more, all subjects achieved blood levels of PPI-461 that would be expected to inhibit HCV replication for 24 hours or longer. This profile suggests that PPI-461 may be effective when administered to hepatitis C patients at relatively low oral doses on a once-daily dosing schedule, which would facilitate its convenient use in future co-formulated combination therapies. Additional details of the Phase 1a results will be given with the November 1 presentation at AASLD.

First Study of PPI-461 in Hepatitis C Patients Underway

Based on the encouraging Phase 1a results, Presidio has initiated a Phase 1b proof-of-concept clinical trial of PPI-461 in hepatitis C patients. This dose-ranging trial will evaluate the safety, pharmacokinetics and antiviral efficacy of PPI-461 in previously-untreated patients with HCV genotype-1 infection.

"We are pleased to begin initial assessments of the tolerance and antiviral efficacy of PPI-461 in patients with chronic hepatitis C, following the encouraging results of the recent Phase 1a study," said Nathaniel Brown, M.D., Chief Medical Officer. "HCV-related mortality and severe debilitation are projected to increase continually in the coming years, so there is an urgent need for improved therapies for hepatitis C."