New Trial Data Suggests Aztreonam-Avibactam Maintains Strong Performance Against Highly Resistant Infections

A recent analysis of 28-day mortality data from a comparative trial highlights the promising performance of aztreonam-avibactam, particularly in patients battling highly resistant infections. The study evaluated outcomes across two major infection types: complicated intra-abdominal infections (cIAI) and hospital-acquired or ventilator-associated pneumonia (HAP/VAP), with enrollment skewed nearly 2:1 toward the aztreonam-avibactam.

In the cIAI cohort, mortality rates were low and comparable between the two treatment groups. Four patients (1.9%) in the aztreonam-avibactam group died, versus three patients (2.9%) receiving meropenem with optional colistin—differences largely explained by the higher number of patients enrolled in the investigational arm. These findings suggest noninferiority in a population with generally similar clinical severity.

More striking results emerged in the HAP/VAP subgroup. Here, eight of 74 patients (12%) treated with aztreonam-avibactam died, compared with seven of 36 patients (19.4%) in the meropenem/colistin group. Although small sample sizes limit definitive statistical conclusions, the percentage difference favors aztreonam-avibactam—especially considering the greater burden of metallo-β-lactamase (MBL) producers. Six patients in the aztreonam-avibactam arm had MBL infections, compared with only one in the comparator group.

Because MBL-producing organisms represent a rapidly growing global threat—and remain resistant to most existing antibiotics—the ability of aztreonam-avibactam to achieve comparable or better survival in sicker, more resistant cases is noteworthy. With data suggesting resilience against both traditional and emerging resistance mechanisms, this combination therapy may play a critical future role as MBL prevalence continues to rise.