INVITED ABSTRACT
Treatment with aerosol PUR003, a novel cationic airway lining modulator, reduces influenza replication in vitro and significantly diminishes the severity of Influenza infection in swine and ferrets

WESLEY H. DEHAAN (1), David L. Hava (1), Lester C Griel (2), Jean Sung (1), Ashley Prasse (1), Mike Lipp (1), Rob Lambkin-Williams (3), Shobana Balasingam (3), and Robert Clarke (1)

(1) Pulmatrix Inc, Lexington, MA, USA, (2) Penn State University, State College, PA, (3) Retroscreen Virology Ltd, London, England

     Abstract Number: 939
     Last modified: April 27, 2009

Abstract
Pulmatrix Inc is developing novel aerosol therapeutics referred to as inhaled cationic airway lining modulators (iCALM) that harness the inherent biophysical and biochemical properties of the airway lining to treat influenza and other respiratory infectious diseases.

Influenza replication in air-liquid interface Calu-3 cell cultures following topical administration of PUR003, a lead iCALM formulation, has been examined. Cells were exposed to increasing aerosol doses of PUR003 and infected 1hr later with Influenza A/WSN/33/1 (10$^(4.5) TCID$_(50)). Twenty four hours post-infection (PI), the apical surface was washed with PBS and the concentration of virus was titered by endpoint dilution (TCID$_(50)) assay on confluent MDCK cells. As the concentration of PUR003 aerosol increased, there was a corresponding decrease in the concentration of virus released apically (up to > 3 log reduction). Studies conducted in which the cells are exposed to virus for one hour prior to aerosol treatment with formulations similar to PUR003 also showed significant reduction in viral titer (>1.5 log).

To study this treatment hypothesis in vivo, swine infected intranasally (IN) with influenza (10$^6 EID$_(50) swine adapted H1N1) were untreated (air control) or treated QD via face mask with aerosol PUR003, on day 2 and day 3 following infection (~0.57 mg/kg PUR003). Following PUR003 treatment, animals had a significantly reduced body temperature compared to the untreated group (80% lower AUC post-treatment; p < 0.03). Gross lung pathology was assessed at euthanasia (day 9 PI) and showed dramatic differences between treated and untreated animals (p < 0.001). In untreated animals, lung consolidation scores of 25% or higher were common (n=5/8) and all animals had some degree of consolidation (n=8/8; Mean consolidation=47%). In contrast, in the treated animals, consolidation scores ranged between zero and 10%, with half of the animals free of lung consolidation (n=4/8; Mean consolidation=4%).

To understand the potential prophylactic benefit of PUR003, ferrets were infected with influenza (10$^6 TCID$_(50) H3N2 A/Panama/99). PUR003 was delivered by nose-only inhalation with the first dose administered 1 hr pre-infection followed by BID dosing for 7 days PI (0.64 mg/kg/dose PUR003). Comparing PUR003-treated animals to water-treated controls, peak body temperatures, weight loss, and inflammatory cell counts in nasal lavages were all significantly reduced. The results of these studies suggest that iCALM is a novel therapeutic approach for influenza. Additional in vitro work is ongoing to understand the dual mechanistic action of the therapy.