FDA Approves Combination Antibiotic for Complicated Infections

The FDA has approved AbbVie’s Emblaveo (aztreonam and avibactam), a fixed-dose, intravenous antibiotic to treat patients with complicated intra-abdominal infections (cIAI), which are a common cause of sepsis and frequently occur in intensive care unit (ICU) patients. These infections are the second most common cause of sepsis in critically ill patients, and affect approximately 5% of ICU patients, with mortality ranging from 5% to 50%.

Emblaveo is a combination of a monobactam/β-lactamase inhibitor for patients 18 years and older who have limited or no alternative options. It is approved to treat complicated infections, including those caused by Gram-negative microorganisms: Escherichia coli, Klebsiella pneumoniae, Klebsiella oxytoca, Enterobacter cloacae complex, Citrobacter freundii complex, and Serratia marcescens. Emblaveo will be available in the third quarter of 2025.

Gram-negative bacterial infections are among the most challenging types of infections. Because of the risk of antimicrobial resistance, medicines intended to treat these infections may become ineffective, increasing the risk of morbidity and mortality. Patients most at risk are those in healthcare settings. An estimated 1.14 million deaths globally were attributed to bacterial antimicrobial resistance in 2021 alone, according to an analysis published last year in The Lancet.

“The continued evolution of antimicrobial resistance among Gram-negative bacteria has left some patients with little to no treatment options, resulting in extended hospital stays, additional morbidity and death,” James A. McKinnell, M.D., infectious disease specialist, Milefchik-Rand Medical Group, Torrance Memorial Medical Center in Torrance, California, said in a news release.

The approval is based limited clinical safety and efficacy data for Emblaveo. It combines aztreonam, a monobactam β-lactam, with avibactam, a broad-spectrum β-lactamase inhibitor. The approval was supported by prior findings regarding the efficacy and safety of aztreonam for the treatment of complicated intra-abdominal infections.

The approval was also supported by clinical trial results from the phase 3 REVISIT study, which evaluated the efficacy, safety, and tolerability of Emblaveo to treat serious infections due to Gram-negative bacteria. In this study, 422 patients were evaluated and were randomized to receive Emblaveo ± metronidazole or the combination of meropenem ± colistin in patients with complicated intra-abdominal infections or hospital-acquired bacterial pneumonia/ventilator-associated bacterial pneumonia.

The primary endpoint was clinical cure at the test-of-cure visit in the intent-to-treat population. Secondary endpoints included 28-day mortality in the intent-to-treat population, and safety in patients in the intent-to-treat population who received the study drug.

Investigators found that 193 of the 282 patients in the Emblaveo group and 92 of 140 in the meropenem group had clinical cure at the test-of-cure visit. For patients with complicated intra-abdominal infection, the adjudicated clinical cure rate was 76.4% for the Emblaveo group and 74·0% for the meropenem group.

Emblaveo was well tolerated, and there were no treatment-related serious adverse events in the Emblaveo group.

Results from this study were published in February 2025 in The Lancet Infectious Diseases.

In April 2024, the European Commission granted marketing authorization for Emblaveo for the treatment of adult patients with complicated intra-abdominal infections, hospital-acquired pneumonia (HAP), including ventilator-associated pneumonia (VAP), and complicated urinary tract infections (cUTI). It is also indicated for the treatment of infections due to aerobic Gram-negative organisms in adult patients with limited treatment options. The marketing authorization was approved in Great Britain in June 2024, and other global submissions are ongoing.

Emblaveo was jointly developed with Pfizer. AbbVie holds the rights to commercialize the therapy in the United States and Canada, with Pfizer responsible for commercialization in all other areas.