The challenge of antimicrobial resistance: new regulatory tools to support product development.

The antibiotic pipeline is thin and lacks diversity, particularly for agents targeting Gram-negative pathogens. The reasons for our anemic global development pipeline are often summarized as (i) discovery of new antibiotics is difficult, (ii) clinical development of new antibiotics is difficult, and (iii) the economics for new antibiotics are unfavorable for the developer. Here, we review recent efforts directed at the second of these challenges.