P-1105. Effectiveness of Imipenem-Relebactam for Multidrug-resistant <i>Pseudomonas aeruginosa</i> in Pneumonia and Bloodstream Infections in the United States (MIRAGE)

Abstract Background Imipenem/relebactam (I/R) demonstrates potent in vitro activity against multidrug-resistant (MDR) Pseudomonas aeruginosa. The objective of this study is to evaluate the real-world effectiveness of I/R for treatment of MDR Pseudomonas infections across the U.S. Methods MIRAGE is a retrospective, multicenter, observational study describing the real-world effectiveness of I/R against MDR P. aeruginosa pneumonia and bloodstream infections. Patients were included if they received I/R for &amp;gt;48h initiated within 7 days of the index MDR P. aeruginosa culture. Clinical success was defined at day 7 and 30 as survival, resolution of signs and symptoms of infection, and the absence of a recurrent infection due to MDR P. aeruginosa. At day 30, patients had to have also completed the intended treatment course. Patients who died within 48 hours, and those with cystic fibrosis or COVID-19 were excluded. Results In a preliminary analysis, 32 patients from 4 centers met inclusion criteria (Table 1). The overall cohort was critically-ill; 53% and 81% were on vasopressors and mechanical ventilation at the time of I/R initiation, respectively. The median (IQR) SOFA score was 9 (5 – 12). 38% received treatment with a novel β-lactam for MDR P. aeruginosa infections prior to I/R. The median time to I/R initiation was 66.7 hours. Combination therapy with another in vitro active agent was used in 38%. The primary reason for I/R treatment was reported susceptibility results, which included resistance to other novel β-lactam agents (Table 2). 69% of patients completed the intended I/R treatment course. At day 7 and 30, 72% and 53% met criteria for clinical success, respectively (Table 3). The overall 30- and 90-day mortality rates were 22% and 31%, respectively. Recurrent infections were documented in 38% of patients within 90-days. Conclusion In this critically-ill patient population we found that I/R was often used following treatment with other novel β-lactams. Clinical outcomes were generally comparable to those previously reported in real-world studies for alternative β-lactam/β-lactamase inhibitor agents. Thus, the data demonstrate that I/R plays an important role in treatment of MDR P. aeruginosa infections, particularly when other gents are not available or test resistant. Disclosures jason M. Pogue, PharmD, Entasis: Advisor/Consultant|GSK: Advisor/Consultant|Melinta: Advisor/Consultant|Melinta: Grant/Research Support|Merck: Advisor/Consultant|Merck: Grant/Research Support|Shionogi: Advisor/Consultant|Shionogi: Grant/Research Support|Venatorx: Advisor/Consultant Yanbing Zhou, PhD, Merck: I am a full time Merck Employee and own stocks in the retirement plan provided by Merck.|Merck: Stocks/Bonds (Public Company) Emre Yucel, PhD, Merck: I am a full time Merck Employee and own stocks in the retirement plan provided by Merck.|Merck: Stocks/Bonds (Public Company) Ryan K. Shields, PharmD, MS, Allergan: Advisor/Consultant|Cidara: Advisor/Consultant|Entasis: Advisor/Consultant|GSK: Advisor/Consultant|Melinta: Advisor/Consultant|Melinta: Grant/Research Support|Menarini: Advisor/Consultant|Merck: Advisor/Consultant|Merck: Grant/Research Support|Pfizer: Advisor/Consultant|Roche: Grant/Research Support|Shionogi: Advisor/Consultant|Shionogi: Grant/Research Support|Utility: Advisor/Consultant|Venatorx: Advisor/Consultant|Venatorx: Grant/Research Support