Mechanism of Action of SPR206, a Next-Generation Polymyxin Active against Gram-Negative Pathogens Posted on June 24, 2019 at 3:19 pm.Written by Spero Therapeutics View Presentation Post navigation Optimisation of Next-Generation Polymyxins Leading to SPR206 as a Development CandidateSafety, Tolerability, Pharmacokinetics, and Drug Interaction Potential of SPR741, An Intravenous Potentiator, After Single and Multiple Ascending Doses and When Combined with Beta-Lactam Antibiotics in Healthy Subjects