An evaluation of the US public-private Combating Antibiotic-Resistant Bacteria Accelerator (CARB-X) initiative.

Introduction: Developing novel antibiotics to replace ineffective existing ones is a priority policy objective. The Combating Antibiotic-Resistant Bacteria Accelerator (CARB-X) is the largest global public-private initiative to advance this goal. The US-based CARB-X has committed over $1 billion US dollars through 2028 to innovators, and provides financial and technical support for the development of novel antibiotics through a competitive request for proposal application process. Methods: We evaluated the outcomes of all applications to CARB-X between the program's inception in 2016 through 2019. Outcomes were evaluated through February 2024 and we used a quasi-experimental design controlling for application quality using multivariate logit regression. Results: We found that 77 applications were funded and 59 applications were not funded. CARB-X-funded projects, controlling for funding score, were more likely to advance in the clinical development phase, but other outcomes were positively but not statistically significantly associated with CARB-X support, compared with unfunded projects. No applications had advanced to regulatory approval or commercial launch. Conclusion: Our results suggest that CARB-X is positively associated with some intermediate project outcomes. Future work should examine later-stage outcomes associated with CARB-X. Evidence-based initiatives are needed to address the threat of antibiotic resistance.