FDA Panel in Favor of Sulbactam-Durlobactam for Acinetobacter Infections

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A PDUFA target date of May 29, 2023 has been set for the application.

The Food and Drug Administration’s (FDA) Antimicrobial Drugs Advisory Committee unanimously voted 12-0 in favor of the approval of sulbactam-durlobactam for the treatment of adults with hospital-acquired bacterial pneumonia and ventilator-associated bacterial pneumonia caused by susceptible strains of Acinetobacter baumannii-calcoaceticus complex (ABC).

The investigational intravenous product is a combination of sulbactam, a β-lactam antibiotic, and durlobactam, a broad-spectrum β-lactamase inhibitor. The advisory committee reviewed data from the phase 3 ATTACK trial (ClinicalTrials.gov Identifier: NCT03894046), which compared sulbactam-durlobactam to colistin in patients with documented Acinetobacter baumannii hospital-acquired bacterial pneumonia, ventilator-associated bacterial pneumonia, ventilated pneumonia, or bacteremia (Part A of the study).

Sulbactam-durlobactam was found to be statistically noninferior to colistin for the primary endpoint of 28-day all-cause mortality in patients with carbapenem-resistant Acinetobacter infections. The mortality rate was 19.0% (12/63) in the sulbactam-durlobactam arm and 32.3% (20/62) in the colistin arm (treatment difference, 13.2%; 95% CI, -30.0, 3.5). Additionally, a statistically significant difference in clinical cure rates was observed (61.9% with sulbactam-durlobactam vs 40.3% with colistin).

In the open-label portion of the study (Part B), 28-day all-cause mortality among patients with ABC infections who did not tolerate colistin/polymyxin B or whose pathogens were resistant to colistin/polymyxin B was reported to be 17.9% (5/28).

As for safety, a statistically significant reduction in nephrotoxicity (the primary safety objective) was observed in patients treated with sulbactam-durlobactam vs those who received colistin (13.2% vs 37.6%, respectively; P =.0002).

“The Committee’s unanimous recommendation in favor of sulbactam-durlobactam, the first pathogen-targeted therapy for Acinetobacter, moves us closer to potentially addressing the urgent need for new treatment options for patients with serious and life-threatening infections caused by this pathogen,” said David Altarac, MD, Chief Medical Officer, Entasis Therapeutics, a wholly owned subsidary of Innoviva. “We appreciate the committee’s thoughtful deliberation and strong vote of confidence, and look forward to working with the FDA as it completes its review.”

Although not bound by the committee’s recommendations, the FDA does take them into consideration when making decisions on approval. A Prescription Drug User Fee Act target date of May 29, 2023 has been set for the application.


  1. Sulbactam-Durlobactam unanimously recommended for approval by FDA Advisory Committee. News release. Innoviva, Inc. Accessed April 17, 2023. https://www.businesswire.com/news/home/20230417005846/en/Sulbactam-Durlobactam-Unanimously-Recommended-for-Approval-by-FDA-Advisory-Committee.
  2. US Food and Drug Administration. FDA Briefing Document: Sulbactam-durlobactam for injection. Accessed April 17, 2023. https://www.fda.gov/media/167096/download.