Entasis Therapeutics has initiated the pivotal Phase III ATTACK clinical trial of ETX2514SUL to treat pneumonia and bloodstream infections caused due to carbapenem-resistant Acinetobacter baumannii.

Acinetobacter baumannii is a gram-negative bacterium known to cause severe infections and exhibit increasing rates of antibiotic resistance.

ETX2514SUL is a fixed-dose combination of the company’s broad-spectrum β-lactamase inhibitor ETX2514 with sulbactam. ETX2514 is designed to inhibit class A, C, and D β-lactamases.

A generic β-lactam, sulbactam is known to exhibit intrinsic antibacterial activity against acinetobacter baumannii but is associated with β-lactamase-mediated resistance.

Preclinical studies demonstrated that ETX2514 could restore sulbactam antibacterial activity against the bacteria.

“ETX2514SUL has great potential for the treatment of patients with carbapenem-resistant A. baumannii infections.”

The global, two-part ATTACK trial will assess the safety and efficacy of ETX2514SUL given intravenously in a total of 300 patients across 18 countries.

Part A of the Phase III study will involve patients with acinetobacter baumannii-calcoaceticus complex (ABC) hospital-acquired bacterial pneumonia, ventilator-associated bacterial pneumonia or bacteremia.

The second part will recruit subjects with ABC infections who have failed colistin therapy.

The company intends to use its collaboration with Zai Lab to enrol patients in China. Entasis also hopes to offer early access in Asia-Pacific countries.

The trial will leverage the BioFire FilmArray Pneumonia Panel for patient enrolment.

Entasis Therapeutics CEO Manos Perros said: “It is the culmination of extensive preclinical development and multiple Phase I and II clinical trials, which have shown that ETX2514SUL has great potential for the treatment of patients with carbapenem-resistant A. baumannii infections.”

The company expects that ATTACK data, which is anticipated to be available in the second half of next year, will be enough to support its regulatory submissions in the US and Europe.

Previously, ETX2514 with sulbactam was studied in single and multi-ascending dose Phase I trials and a Phase II trial for complicated urinary tract infections.