Entasis Therapeutics has reported positive topline data from the international Phase III ATTACK clinical trial of sulbactam-durlobactam (SUL-DUR) drug in people with Acinetobacter baumannii-caused infections.

The gram-negative, opportunistic human pathogen Acinetobacter infects critically ill people and occasionally leads to severe pneumonia and infections in the bloodstream.

An intravenous (IV) experimental drug, SUL-DUR combines an IV β-lactam antibiotic, sulbactam, and a new broad-spectrum IV inhibitor of β-lactamase, durlobactam.

Commenced in April 2019, the two-part Phase III trial analysed the safety and efficacy of SUL-DUR versus colistin.

It enrolled 207 subjects at 95 trial centres in 17 nations.

The randomised, comparative Part A segment had subjects with documented Acinetobacter baumannii hospital-acquired bacterial pneumonia (HABP), ventilated pneumonia (VP) ventilator-associated bacterial pneumonia (VABP), or bacteremia.

Part B was the open-labelled segment and enrolled participants with ABC infections who are resistant to or did not respond to therapy with colistin or polymyxin B.

Findings showed that SUL-DUR met the primary goal of 28-day all-cause mortality in subjects with carbapenem-resistant Acinetobacter infections (CRABC) m-MITT population of Part A.

This data signifies the statistical non-inferiority of the treatment against colistin.

Mortality was 19% in the SUL-DUR arm versus 32.3% in subjects who received colistin.

SUL-DUR also met the primary safety goal of the trial attaining a statistically significant decline in nephrotoxicity.

Nearly 61.9% in the SUL-DUR group had a statistically significant difference in clinical cure at test of cure (TOC) versus 40.3% in the colistin group.

Furthermore, the 28-day all-cause death was 17.9% in the Part B segment which is in line with the Part A data.

Overall adverse events (AEs) in the safety population were similar across the treatment arms.

Entasis Therapeutics CEO Manos Perros said: “ATTACK was a landmark clinical trial, the first to successfully evaluate an investigational agent targeting a specific drug-resistant Gram-negative pathogen.

“SUL-DUR is the first investigational drug to demonstrate efficacy in a 28-day all-cause mortality trial focused on carbapenem-resistant Acinetobacter, an ‘Urgent’ threat as designated by the CDC.”

The company plans to include this data for new drug applications anticipated to be submitted mid-next year.