Aztreonam–Avibactam (Emblaveo®) for Carbapenem-Resistant and Metallo-β-Lactamase-Producing Gram-Negative Infections: A Comprehensive Review

Metallo-β-lactamase (MBL)-producing Enterobacterales represent a major antimicrobial-resistance threat because MBLs hydrolyse most clinically used β-lactams and are not inhibited by currently approved serine β-lactamase inhibitors. Aztreonam–avibactam (ATM-AVI; Emblaveo®) addresses this therapeutic gap by combining aztreonam, a monobactam that is stable to MBL-mediated hydrolysis, with avibactam, which inhibits many co-produced class A, class C, and selected class D serine β-lactamases. This narrative review synthesizes evidence on ATM-AVI pharmacology, microbiological activity, pharmacokinetics/pharmacodynamics, clinical efficacy, safety, resistance, and regulatory positioning. Large surveillance datasets show high in vitro activity against most MBL-producing Enterobacterales, including many co-producing β-lactamases from multiple Ambler classes. Population pharmacokinetic modelling supports a renal-function-adjusted fixed 3:1 dosing ratio and more reliable joint target attainment than separately administered ceftazidime–avibactam plus aztreonam. In the phase 3 REVISIT trial, clinical cure with ATM-AVI was comparable to meropenem in the overall population; however, few participants had confirmed MBL-positive infections. Direct clinical evidence therefore remains limited, supported by convergent microbiological, pharmacokinetic, and observational data. Regulatory indications differ substantially between the European Union and the United States. ATM-AVI is an important advance for selected MBL-producing and multi-class-co-producing Gram-negative infections, but its long-term value will depend on targeted use, reliable susceptibility testing, continued surveillance, and further trials in the intended target population.