Entasis Therapeutics Holdings Inc. and Zai Lab Limited announced that patient enrollment in the ATTACK Phase 3 registrational clinical trial of sulbactam-durlobactam (SUL-DUR) is now complete, with top-line data readout anticipated early in the fourth quarter of 2021. ATTACK is a Phase 3 registrational trial that will evaluate the safety and efficacy of SUL-DUR in patients with confirmed carbapenem-resistant Acinetobacter infections. Part A of the trial, which evaluates the efficacy of SUL-DUR compared to colistin on a background of imipenem in patients with pneumonia and/or bloodstream infections, with 28-day all-cause mortality as the primary efficacy endpoint, has now enrolled over 120 patients, sufficient to complete the trial.

Approximately one-quarter of the patients in Part A, the primary efficacy arm of the trial, were enrolled in China. Part B of the trial, which enrolled over 25 patients, is a non-randomized cohort of patients with confirmed Acinetobacter infections that are treated with SUL-DUR but are not eligible for Part A due to factors that could include colistin resistance, colistin intolerance or Acinetobacter infection in another body site unresponsive to colistin therapy. SUL-DUR is an intravenous, or IV, investigational drug that is a combination of sulbactam, an IV ß-lactam antibiotic, and durlobactam, a novel broad-spectrum IV ß-lactamase inhibitor, or BLI, that the company is developing for the treatment of infections caused by Acinetobacter baumannii, including carbapenem-resistant strains.

The company initiated ATTACK, Phase?3 registration trial, in April 2019. ATTACK is a global Phase 3 registration trial that enrolled patients at clinical sites from 17 countries. Acinetobacter is a Gram-negative, opportunistic human pathogen that predominantly infects critically ill patients often resulting in severe pneumonia and bloodstream infections, but can also infect other body sites such as the urinary tract and the skin.

Acinetobacter is considered a global threat in the healthcare setting due in part to its ability to acquire multidrug resistance at rates not previously seen in other bacteria. Based on current carbapenem resistance rates, the company estimate there are in excess of 250,000 hospital-treated carbapenem-resistant Acinetobacter infections annually across the United States, Europe, the Middle East and China for which significant morbidity and mortality exists due to limited treatment options.