Mpex Pharmaceuticals, Inc. Presents New Data on MP-376 in Cystic Fibrosis

Details to be presented at NACFC and ICAAC/IDSA meetings this week

SAN DIEGO, Oct. 23 /PRNewswire/ -- Mpex Pharmaceuticals, Inc. today announced additional clinical and preclinical results with MP-376, the company's novel formulation of levofloxacin inhaled solution delivered by an Investigational eFlow Nebulizer System for use in cystic fibrosis (CF) and chronic obstructive pulmonary disease (COPD). Clinical results show that aerosol dosing of MP-376 was well tolerated at all dose levels tested after 14 days of dosing. Encouraging signs of drug activity were also observed in this trial. New preclinical results demonstrate that MP-376 has potent activity against Pseudomonas aeruginosa (P. aeruginosa) infection under a wide array of conditions, avoids resistance development when used at high concentrations achievable with aerosol dosing and has anti-inflammatory properties in pulmonary tissues in addition and unrelated to its antibacterial effects. Detailed results are being presented at the North American Cystic Fibrosis Conference (NACFC) and ICAAC/IDSA meetings taking place this week in Orlando, Florida and Washington, D.C., respectively.

Clinical Results

The clinical results being presented at NACFC are from a Phase 1b safety, tolerability and pharmacokinetic (PK) study performed in 40 CF patients with stable disease at 11 U.S. clinical sites (Mpex 203). The study was a placebo-controlled, dose escalation trial to analyze the effects of 14 days of dosing at three different dose levels of MP-376 when administered by inhalation using an Investigational eFlow Nebulizer System.

All patients were required to be culture positive for P. aeruginosa at baseline. P. aeruginosa is a bacterial pathogen that is a leading cause of morbidity in CF patients. The great majority of CF patients over the age of 18 are chronically infected with this pathogen and chronic infection has been shown to lead to acute exacerbations and subsequent loss of lung function.

Results from this clinical trial indicated that MP-376 was well tolerated, with no serious drug related adverse events reported. Dose escalation proceeded successfully through the highest planned dose with no dose limiting toxicities. PK results also met expectations, with sputum drug levels increasing with increasing doses of inhaled MP-376.

Although this trial was not designed as an efficacy study, evidence of drug activity was observed in this trial. Patients receiving MP-376 experienced a reduction in P. aeruginosa counts well in excess of one log on average after 14 days of treatment, whereas counts in placebo treated patients increased slightly over the treatment period. In addition, FEV1, a standard measure of lung function, showed dose-related improvements in MP-376 treated patients, with the highest dose group experiencing increases in FEV1 of greater than 15%.

"The results from this study are very encouraging," stated Dr. Jeff Loutit, Chief Medical Officer of Mpex Pharmaceuticals. "The safety and PK results were consistent with our expectations and support advancing the compound into larger clinical trials. Furthermore, the effects seen on bacterial counts and pulmonary function give us confidence as we move MP-376 through development. This is particularly true given that the results were obtained in a patient population that had significant prior inhaled antibiotic experience and many patients were infected with multi-drug resistant P. aeruginosa."

Based on these results Mpex initiated a 28-day Phase 2 study in 140 CF patients earlier this year at sites in the U.S., Germany and the Netherlands. This study is expected to complete enrollment in the second quarter of 2009. Results from this study, if successful, are expected to allow Mpex to choose the optimal dosing regimen for Phase 3 clinical trials anticipated to begin later in 2009.

Preclinical Results

MP-376 was designed to address many of the shortcomings of available inhaled antibiotic formulations for CF patients. These shortcomings include the following:

Preclinical results presented at the meetings this week show MP-376 offers potentially substantial improvements in each of these areas:

In addition to these preclinical studies, Mpex is also presenting data at the NACFC meeting indicating that MP-376 has anti-inflammatory activity that is independent of its antibacterial effect. This was demonstrated in both in vitro and in vivo models and includes effects on both IL-6 and IL-8, cytokines which have both been implicated in destructive inflammatory processes in CF lungs. These beneficial anti-inflammatory effects were not observed with tobramycin or aztreonam.

"We believe that taken together these studies show a very attractive profile for MP-376 in the treatment of chronic bacterial infections in CF patients," stated Dr. Michael Dudley, Senior VP of R&D and Chief Scientific Officer of Mpex Pharmaceuticals. "MP-376 has the potential to address many of the current shortcomings with inhaled antibiotic treatments in CF. The combination of the inherent potency of levofloxacin and the novel formulation we have developed for aerosol administration may allow us to achieve the desired pharmacokinetic and pharmacodynamic parameters that are necessary for long-term success in this indication. We look forward to working with CF patients and caregivers to move this potentially important new treatment option through development."

About MP-376

MP-376 is a proprietary formulation of levofloxacin that has been optimized for aerosol delivery using a customized Investigational eFlow(R) Nebulizer System (PARI Pharma, Munich, Germany). Levofloxacin is a fluoroquinolone antibiotic that has been widely used in a variety of indications for over a decade and has established safety and efficacy when administered orally or intravenously against many bacterial pathogens, including P. aeruginosa. Administration of MP-376 with a high efficiency nebulizer to the lungs allows for the delivery of high concentrations of active drug directly to the site of infection, while minimizing systemic exposure. Mpex believes this approach has the potential to improve bacterial killing and reduce resistance development versus traditional oral or IV routes of administration.

About Mpex Pharmaceuticals

Mpex Pharmaceuticals is a clinical stage biopharmaceutical company whose mission is to develop important new therapies to combat the growing issue of antibiotic resistance. The company's internal development pipeline focuses on combining proprietary formulations, PK/PD strategies and novel potentiating agents with proven antibiotics to overcome or directly inhibit the molecular mechanisms in bacteria responsible for antibiotic resistance. Mpex's most advanced product candidate, MP-376, is a proprietary aerosol formulation of levofloxacin that is being developed clinically as a maintenance therapy for the prevention of bacterial exacerbations in patients with cystic fibrosis and COPD. The company has also built a discovery and development platform and intellectual property estate around inhibitors of multi-drug resistant (MDR) efflux pumps (EPIs) found in many gram-negative bacterial pathogens. Bacterial efflux of antibiotics is a leading source of multi-drug resistance, particularly in gram-negative organisms. Mpex compounds have been shown in both in vitro and in vivo studies to overcome efflux-based resistance to multiple classes of antibiotics. Mpex recently entered into a collaboration with GlaxoSmithKline focused on developing multiple drug candidates utilizing Mpex's EPI technology. Company website: www.mpexpharma.com.

CONTACT: Daniel Burgess, President & CEO of Mpex Pharmaceuticals,
+1-858-875-6675; or Jennifer Larson, +1-415-725-2017, jlarson@labfive.com,
for Mpex Pharmaceuticals

Web site: http://www.mpexpharma.com/

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