Assessment of Data Supporting the Efficacy of New Antibiotics for Treating Infections Caused by Multidrug-resistant Bacteria

Dafna Yahav, Noam Tau, Daniel Shepshelovich

Research output: Contribution to journalArticlepeer-review


Background: Infections caused by multidrug-resistant (MDR) bacteria are a major public health threat. We aimed to assess the data supporting US Food and Drug Administration (FDA) approval of new agents aimed to treat MDR bacterial infections and the data provided by postmarketing studies. Methods: We identified all drugs with in vitro activity against MDR bacteria initially approved by the FDA between January 2010 and December 2018. Characteristics of trials supporting approval and regulatory pathways were collected from Drugs@FDA. Characteristics of postmarketing studies were extracted from drug labels and entries effective 1 June 2019. Results: Initial approval of 11 newly approved antibiotics with anti-MDR activity was supported by 20 trials, all with noninferiority design. All initially approved indications were for common infections, mostly acute bacterial skin and skin-structure infections, regardless of causative microorganism. The proportion of MDR bacteria in most trials was low (<10% for gram-negative infections, <1% for gram-positive pneumonia). Most trials (90%) excluded immunocompromised and critically ill patients. Of 16 additional postmarketing randomized controlled trials identified through, only 2 exclusively included infections caused by MDR bacteria, comprising 116 patients. No drug was granted accelerated approval, which would mandate postmarketing efficacy studies. Conclusions: The approval of new drugs with potential clinical activity against MDR bacteria is supported by trials evaluating infections caused by non-MDR organisms, using noninferiority design and excluding the patients most likely to require these agents. Subsequent postmarketing efficacy data against these organisms are scarce. Healthcare professionals and regulators should demand more robust data to support clinical decision making.

Original languageEnglish
Pages (from-to)1968-1974
Number of pages7
JournalClinical Infectious Diseases
Issue number11
StatePublished - 1 Jun 2021


  • FDA approval
  • clinical trials
  • multidrug resistant bacteria
  • novel antibiotics


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