PolyMedix, Inc. (OTC BB: PYMX), an emerging biotechnology company focused on developing new therapeutic drugs to treat acute cardiovascular disorders and infectious diseases, today presented five posters at the 50th Interscience Conference on Antimicrobial Agents and Chemotherapy (ICAAC). The data presented included results from studies focused on identifying compounds from PolyMedix's library of novel defensin mimetic antibiotics to address foodborne infections and biowarfare pathogens. In addition, results were presented showing antimicrobial activity in human serum collected from subjects in PolyMedix's Phase 1B clinical trial with its lead defensin mimetic, PMX-30063.
“Antimicrobial Activities of Structurally Diverse Host Defense Protein Mimics”
The following posters were presented by PolyMedix and are available on the Company's website at http://www.polymedix.com/presentations.php:
"Antimicrobial Activity in Human Serum After IV Administration of PMX-30063 in a Phase 1B Study" B. Korczak, E. McAllister, R. Scott
In this study, blood samples were drawn from healthy subjects in PolyMedix's Phase 1B study after they had been dosed with PMX-30063 to test the antimicrobial activity of PMX-30063. Four different strains of Staphylococcus aureus bacteria, including two MRSA strains, were added to the blood samples. The results showed that PMX-30063 was bactericidal against both MSSA (methicillin-sensitive Staphylococcus aureus) and MRSA (methicillin-resistant Staphylococcus aureus, or drug-resistant Staph) starting at doses as low as 0.1 to 0.3 mg/kg. These data suggest that administration of PMX-30063 below the identified limiting-dose may have a bactericidal effect on MSSA and MRSA in human subjects.
"Antimicrobial Activities of Structurally Diverse Host Defense Protein Mimics" R. Scott, CE Budu, A. Khanna, D. Clements
In this study, compounds from three structurally diverse series of host defense protein mimics were identified that were highly active against recent clinical isolates of Gram-positive Staphylococcus aureus, Staphylococcus epidermidis, and Enterococcus faecalis, and Gram-negative Escherichia coli and Klebsiella pneumoniae. Importantly, the same antimicrobial activities were observed between drug-susceptible and multi-drug resistant isolates of each organism. This indicates that mechanisms used by bacteria to build resistance to current antibiotics are not effective against the PolyMedix defensin-mimics. The PolyMedix defensin-mimetic compounds rapidly kill the bacteria in 30 minutes to 4 hours, with no signs of resistance emerging in laboratory serial passage assays. Results demonstrate that these novel defensin-mimetic compounds exert their antimicrobial activity by a novel mechanism of action, and rapidly kill both Gram-positive and Gram-negative bacterial pathogens while showing a very low risk for development of resistance.
"Antimicrobial Activities of a Novel Host Defense Protein Mimics Against Foodborne Pathogens" R. Scott, S. Mithal, D. Clements
In this study, PolyMedix screened over 125 synthetic defensin-mimetic compounds from its antimicrobial library for activity against many of the bacterial pathogens associated with foodborne infections, including, E. coli, Shigella, Listeria, and Salmonella. Eleven compounds were potently active against all of the pathogens tested, and were also highly selective for bacteria over mammalian cells, indicating a wide safety margin between concentrations needed to kill bacteria and concentrations where damage to host cell types is first observed. The compounds also demonstrated rapid killing properties where >99.9% of bacteria treated with the active compounds were killed in 30 minutes to 4 hours. Results demonstrate that PolyMedix's defensin-mimetic compounds have potent and rapid antimicrobial activity against foodborne pathogens and low cytotoxicity.
"In Vitro Antimicrobial Activities of Nonpeptidic Mimics of Host Defense Proteins Against Biowarfare Pathogens" R. Scott, H. Heine, D. Clements
In this study, PolyMedix screened over 30 synthetic defensin-mimetic compounds from its antimicrobial library for activity against Category A and B bacterial pathogens that have been identified as potential biowarfare threats, including, B. anthracis, Y. pestis, B. mallei and F. tularensis. Up to 25 compounds were robustly active against B. anthracis and F. tularensis and up to 3 compounds were active against B. mallei and Y. pestis. Many of the active compounds also showed substantial safety indices in mammalian cell cytotoxicity assays. Results demonstrate that PolyMedix's defensin-mimetic compounds have promising antimicrobial activity and low cytotoxicity against biowarfare pathogens.
"Population Pharmacokinetics of PMX-30063 After Single and Repeated Intravenous Doses" Institute for Clinical Research (M. Melhem et al) and PolyMedix (B. Korczak)
In drug development, population pharmacokinetics is used to better understand the quantitative relationships among drug input patterns, patient characteristics, and drug disposition. In this study a population PK model for PMX-30063 was built using the single and multiple dose data obtained from PolyMedix's Phase 1A and 1B studies. This model is expected to provide robust and reliable estimates of PMX-30063 pharmacokinetic exposure and will be useful in pharmacokinetic-pharmacodynamic target attainment analyses to support dose selection decisions for future clinical studies.
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