We have recently demonstrated that the lead, pegylated PIC1 compound, PA-dPEG24 (amino acid sequence IALILEPICCQERAA containing a 24 units PEG moiety attached to the C terminus, total molecular weight 2,771 Da), can inhibit MPO activity in cystic fibrosis sputum, as well as from neutrophils and purified MPO [9]. The gene discussed is MPO; the disease is cystic fibrosis.