Pathogen-focused Clinical Development to Address Unmet Medical Need: Cefiderocol Targeting Carbapenem Resistance.

Historically, the regulatory requirements of the US Food and Drug Administration (FDA) and the European Medicines Agency (EMA) for developing new antibiotics have not addressed pathogen-focused indications for drug approval. The design of the necessary randomized controlled trials traditionally involves the enrollment of patients with site-specific infections caused by susceptible as well as resistant pathogens. Cefiderocol has undergone a streamlined clinical development program to address serious carbapenem-resistant infections. The regulatory approach, and the pivotal clinical trials, differed between the FDA and EMA. In the United States, the APEKS-cUTI (Acinetobacter, Pseudomonas, Escherichia coli, Klebsiella, Stenotrophomonas-complicated urinary tract infection) study was conducted to provide the basis for FDA approval of a site-specific cUTI indication. The EMA, however, preferred the CREDIBLE-CR (A MultiCenter, RandomizED, Open-label ClInical Study of S-649266 or Best AvailabLE Therapy for the Treatment of Severe Infections Caused by Carbapenem-Resistant Gram-negative Pathogens) study, in which patients with nosocomial pneumonia, bloodstream infections, or cUTIs were enrolled if they had a carbapenem-resistant pathogen. The resulting European label will be pathogen focused rather than infection site specific (ie, treatment of gram-negative infection in patients with limited treatment options). The implications and limitations of these different regulatory processes are discussed.