Effects of EP395, a novel macrolide, on acute neutrophilic airway inflammation.

Macrolide antibiotics have been shown to reduce exacerbations of respiratory diseases, including chronic obstructive pulmonary disease (COPD) and asthma. This effect is believed to be due to the immunomodulatory properties of macrolides rather than their antimicrobial activity. However, prolonged use of macrolide antibiotics can result in the development of antimicrobial resistance, which prompted us to develop EP395, a compound with similar pharmacological actions to macrolides, but without antimicrobial activity. We investigated EP395 in several established models of neutrophilic airway inflammation in male BALB/c mice. Oral pretreatment with EP395 for 2 weeks had significant anti-inflammatory effects, reducing cytokines and neutrophil infiltration into bronchoalveolar lavage fluid (BAL) induced by either lipopolysaccharide (LPS), tobacco smoke or respiratory syncytial virus (RSV). EP395 had comparable inhibitory effects to azithromycin in all three models. The PDE4 inhibitor, roflumilast, was also included as a positive control in the LPS model, with comparable effects on neutrophil numbers. In vitro assays on neutrophil function revealed both stimulatory and inhibitory effects of treatment with EP395. These data demonstrate the beneficial pharmacological activity of EP395, a macrolide with negligible antimicrobial activity, in models of acute neutrophilic inflammation and on neutrophil activity and supported its progression into clinical development as a potential treatment for COPD.