Presidio Pharmaceuticals to advance PPI-1301 inhibitor from HCV NS5A program into clinical development

Presidio Pharmaceuticals, Inc. announced today that they have selected a second clinical candidate, PPI-1301, from their hepatitis C virus (HCV) NS5A program for advancement into clinical development. Presidio's first NS5A inhibitor, PPI-461, is currently undergoing evaluation in a Phase 1a clinical study.

“The advancement of PPI-1301 further demonstrates the breadth and depth of our NS5A program pipeline.”

Inhibitors of the HCV NS5A protein represent an exciting, highly potent class that is distinct from other classes of HCV antivirals that target the viral protease or replicase. With poor response and tolerance issues associated with the current standard of care treatment—pegylated-IFN and ribavirin—there is clear need for more potent and better tolerated inhibitors that can be administered orally in future combination therapies.

PPI-1301 was derived from a chemical series that is distinct from PPI-461, but similar to PPI-461, exhibits potent and selective activity against all HCV genotypes in HCV replicon assays. PPI-1301 also shows good oral bioavailability and tolerance in animal studies, with elevated liver concentrations relative to serum levels, as well as the potential for once daily dosing in humans. IND-enabling studies for PPI-1301 are currently underway.

"The selection of PPI-1301 underscores Presidio's continued commitment to generating best-in class compounds for treating HCV," commented Richard Colonno, PhD, Chief Scientific Officer, who added, "The advancement of PPI-1301 further demonstrates the breadth and depth of our NS5A program pipeline."

Current therapy with pegylated IFN-α and ribavirin results in sustained virologic response (SVR) in 40-80% of patients, depending on the HCV genotype. However, such therapy is prolonged, associated with significant side effects and not suitable for many patients. Also, clinical studies have shown that infection with genotypes 1a and 1b, the major genotypes found throughout the developed world, is associated with a poor response to IFN-α therapy. Thus, there is an urgent need to develop more effective and well-tolerated therapeutics for HCV infection.