Aztreonam-Avibactam Demonstrates Noninferior Cure Rates and Strong Safety Profile Compared With Meropenem/Colistin

New clinical trial findings show that Aztreonam-avibactam delivers noninferior cure rates compared with meropenem plus colistin, an encouraging outcome given the significant presence of carbapenemase-producing pathogens in the study population. Clinicians note that “clinical cure” is often difficult to measure—especially in critically ill ICU patients with HAP/VAP—because many variables influence patient status beyond the infection itself. Instead of relying solely on fever curves or sputum cultures, real-world indicators such as ventilator liberation, improved oxygenation, and stabilization of vital signs offer a more meaningful assessment. Against that backdrop, achieving noninferiority is both expected and clinically reassuring, particularly in a study designed to detect equivalence rather than superiority.

Safety outcomes tell a similarly positive story. In the intra-abdominal infection arm, aztreonam-avibactam (administered with metronidazole) showed modest increases in liver function tests—ALT (7%) and AST (8%)—and higher rates of diarrhea. These findings were not observed in the HAP/VAP population and were largely attributed to intra-abdominal disease itself and the known effects of metronidazole, a confounding agent. Other adverse events, including mild hypokalemia, were also consistent with gastrointestinal losses. Importantly, the safety profile was comparable to that of aztreonam monotherapy, and no unexpected toxicities emerged.

Crucially, mortality outcomes favored aztreonam-avibactam percentage-wise, reinforcing confidence in its overall safety. With rising global resistance and increasing reliance on agents active against difficult enzymes like carbapenemases, aztreonam-avibactam’s balance of efficacy and tolerability positions it as a valuable therapeutic option for severe infections.