β-Lactam/β-Lactamase Inhibitor Combination Antibiotics Under Development

Antimicrobial resistance remains a public health problem of global concern with a great health and financial burden. Its recognition as a threat by political leadership has boosted the research and development of new antibiotics and particularly novel combinations of β-lactams/β-lactamase inhibitors against multidrug-resistant (MDR) Gram-negative pathogens, which remain the major concern in clinical practice. The incorporation of ceftolozane/tazobactam, ceftazidime/avibactam, meropenem/vaborbactam, and imipenem/cilastatin/relebactam has provided new therapeutic options in the treatment of patients with infections due to MDR pathogens. Cefiderocol along with cefepime/enmetazobactam, avibactam/aztreonam, and sulbactam/durlobactam have been recently added to these agents as therapeutic choices, particularly for metallo-β-lactamase producing Gram-negative bacteria. Currently, many combinations are being studied for their in vitro activity against both serine- and metallo-β-lactamases. However, only a few have advanced through phase 1, 2, and 3 clinical trials. Among them, in this article, we focus on the most promising combinations of cefepime/zidebactam, cefepime/taniborbactam, and imipenem/cilastatin/funobactam, which are currently under investigation in phase 3 trials.