
A retrospective study of patients with carbapenem non-susceptible infections and limited treatment options at 24 US hospitals found that imipenem/cilastatin/relebactam (IMI/REL) was effective and well-tolerated, researchers reported yesterday in Open Forum Infectious Diseases.
IMI/REL is a beta-lactam/beta-lactamase inhibitor combination that was approved by the Food and Drug Administration (FDA) in 2019 for treating complicated infections caused by multidrug-resistant (MDR) gram-negative pathogens. While FDA approval was based on data from randomized controlled trials that showed IMI/REL was efficacious, well-tolerated, and noninferior to comparator antibiotics, the type of patients who have MDR gram-negative infections typically aren't eligible for such trials.
The aim of the study, which was led by researchers at Wayne State University, was to assess the performance of IMI/REL in real-world settings. The primary outcome was clinical success, defined as improvement or resolution of infection-related signs/symptoms while receiving IMI/REL.
Clinical success in 70% of patients
A total of 151 patients (median age, 60; 54.3% male) received IMI/REL for 48 hours. The most common source of infection was the lower respiratory tract, which accounted for 52.3% of cases. Most patients (85.4%) had a carbapenem non-susceptible organism, and 72.2% received IMI/REL for targeted treatment of Pseudomonas aeruginosa. There was a high burden of comorbid conditions among the patients, including diabetes (39.1%), heart failure (28.5%), and chronic kidney disease (25.8%).
Clinical success was achieved in 70.2% of patients, and adverse events occurred in 6%, with three instances of IMI/REL discontinuation. Multivariable analysis found that heart failure, receipt of antibiotics within the past 90 days, intensive care unit admission at time of index culture collection, and isolation of difficult-to-treat P aeruginosa were independently associated with reduced odds of clinical success.
The study authors say the findings offer valuable insights into the demographics and clinical characteristics of patients prescribed IMI/REL.
"Our findings highlight the potential of IMI/REL as a valuable therapeutic option in challenging clinical scenarios," they wrote. "Continued investigation into its application among specific situations, including comparative analyses, will be important to more completely understand its place in therapy to combat the escalating threat of MDR Gram-negative infections."