PolyMedix completes Phase 1B clinical study with PMX-30063 defensin-mimetic antibiotic

Mar 31 2010

PolyMedix, Inc. (OTC BB: PYMX), an emerging bio-technology company focused on developing new therapeutic drugs to treat acute cardiovascular disorders and infectious diseases, has successfully completed a Phase 1B clinical study with its novel defensin-mimetic antibiotic, PMX-30063. The data from the study demonstrate that administration of multiple doses of PMX-30063 are safe and well-tolerated at dose levels which showed bactericidal activity in blood samples drawn from subjects in the study. PMX-30063, a small-molecule mimetic of host defense proteins, has a novel mechanism of action distinct from other antibiotics, which is believed to make bacterial resistance unlikely to develop. PolyMedix is planning to initiate a Phase 2 clinical trial with PMX-30063 in patients with Staph infections in the second quarter of 2010.

“Drug-resistant bacterial infections are one of the most serious problems facing the world”

PolyMedix will host a webcast on Tuesday, April 6, 2010 at 10:00 A.M. ET.

Top-line results from this study demonstrated:

• The dose-limiting total daily dose of PMX-30063 in healthy subjects was the same regardless of whether PMX-30063 was administered every 12 or 24 hours.
• Doses of PMX-30063 below the dose-limiting total daily dose killed Staph bacteria, including MRSA, in human serum in blood samples drawn from subjects in the study.
• Dose-limiting effects were generally seen at levels higher than anticipated therapeutic levels.
• Doses administered in the study exceeded theoretical efficacious levels predicted by animal models as well as dose levels which demonstrated bactericidal activity in blood drawn from healthy subjects.

"These data are promising and support the encouraging safety and tolerability profile of our novel antibiotic compound," commented Dr. Eric McAllister, Vice President, Clinical Development and Chief Medical Officer of PolyMedix. "Based upon preclinical and clinical findings to date, we believe we should be able to achieve effective therapeutic levels of PMX-30063 that will be well-tolerated with multiple dose administrations. The results from this Phase 1B clinical study will be used to determine the doses in our upcoming Phase 2 clinical study."

The Phase 1B clinical study was designed as a blinded, randomized, placebo-controlled, ascending, multiple-dose study. A total of 77 healthy subjects were enrolled with 55 receiving PMX-30063 and 22 receiving placebo. The study contained three parts, each of which utilized different dosing durations including every 12, 24 or 48 hours, over five or ten days, for a planned total of five to ten doses. Doses in each part ranged from 0.08 to 0.60 mg/kg per day. The primary endpoints of the study were to further delineate the pharmacokinetics and to find the dose-limiting dose for PMX-30063 when administered as multiple doses over five days.

The results from the entire study showed no difference in tolerability or dose-limiting effects when PMX-30063 was administered every 12 or 24 hours. In addition, the dose-limiting total dose for healthy subjects was 3.0 mg/kg (0.6 mg/kg every 24 hours or 0.3 mg/kg every 12 hours). The dose-limiting effect was paresthesias (abnormal sensations of numbness and tingling), generally localized to the oral area and extremities, which were mild and non-disabling. There were no other clinically significant adverse effects reported.

To test the antimicrobial activity of PMX-30063, blood samples were drawn from healthy subjects in the study after they had been dosed with 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 multiple administrations of PMX-30063 below the identified limiting-dose may have a bactericidal effect on MSSA and MRSA in human subjects.

"Drug-resistant bacterial infections are one of the most serious problems facing the world," commented Nicholas Landekic, President & C.E.O. of PolyMedix. "PMX-30063 is the first and only small molecule defensin-mimetic in clinical development for the treatment of systemic infections, and the first and only such compound whose mechanism of action is intended to make bacterial drug resistance unlikely to develop. We believe these unique characteristics may allow PMX-30063 to address a major unmet medical need and large market opportunity."

PolyMedix plans to initiate a Phase 2 clinical efficacy study in the United States with PMX-30063 by the end of the second quarter of 2010. The trial will be conducted in patients with any type of Staph infection, including both MSSA and MRSA strains. Patients are expected to receive multiple doses of PMX-30063 or an active comparator. The clinical target is expected to be Acute Bacterial Skin and Skin Structure Infections (ABSSSI). It is anticipated that results from this trial could be available by the end of the first quarter of 2011.