Merck's New Drug Approved! 15.9% Reduction in Pneumonia Mortality

On December 2, 2024, Merck's combination antibiotic injection, Imipenem/Cilastatin/Relebactam (containing 500mg imipenem, 500mg cilastatin, and 250mg relebactam), received marketing approval from China's National Medical Products Administration. Based on the latest advances in clinical trials, the approved indications may include ventilator-associated bacterial pneumonia (VABP) and hospital-acquired bacterial pneumonia (HABP).

Imipenem/Cilastatin/Relebactam contains three active ingredients with different mechanisms of action: imipenem, a carbapenem antibiotic; relebactam, a β-lactamase inhibitor; and cilastatin, a membrane dipeptidase inhibitor. The drug was first approved in the U.S. in July 2019 under the trade name Recarbrio for treating adult patients with complicated urinary tract infections (cUTI) and complicated intra-abdominal infections (cIAI) who have limited treatment options or no alternative therapies. In June 2020, the indications for this drug were expanded to include VABP and HABP.

According to public records, Merck initiated a global Phase III clinical trial (N=478) for Imipenem/Cilastatin/Relebactam in September 2018 in the EU, Japan, and China. This trial aimed to evaluate the efficacy, safety, and tolerability of Imipenem/Cilastatin/Relebactam compared to Piperacillin/Tazobactam (produced by Pfizer) in treating patients with HABP and VABP. The primary endpoint of the study was all-cause mortality related to treatment by day 28. The study successfully concluded in July 2022.

Results from the Phase III RESTORE-IMI 2 study conducted in the U.S., EU, and Japan indicated that Imipenem/Cilastatin/Relebactam could reduce all-cause mortality in patients with HABP and VABP by 15.9%, demonstrating non-inferiority to Piperacillin/Tazobactam (which reduced mortality by 21.3%).

Hospital-acquired bacterial pneumonia (HABP) and ventilator-associated bacterial pneumonia (VABP) are common types of bacterial pneumonia among hospitalized patients. HABP refers to pneumonia that develops within 48 hours of hospitalization in patients who have not received invasive mechanical ventilation and are not in the latent phase of a pathogenic infection. VABP refers to pneumonia occurring in patients who have undergone intubation or tracheostomy and were mechanically ventilated for 48 hours, as well as pneumonia that arises within 48 hours after extubation or ventilator removal. Both types of pneumonia can lead to symptoms such as fever, chills, cough, chest pain, and increased oxygen demand.