651. Ceftazidime/avibactam utilization in the national Veterans Affairs (VA) Healthcare System
Authors: Caffrey Aisling R , Appaneal Haley J , Lopes Vrishali V , LaPlante Kerry L 
Published: December 2022

Abstract

Background
Multidrug-resistant infections are challenging to treat, due to underlying patient conditions, pathogen characteristics, and high resistance rates to antibiotic treatments. Ceftazidime/avibactam (CAZ-AVI, approved in 2015) is approved to treat complicated intra-abdominal infections, complicated urinary tract infections, hospital-acquired bacterial pneumonia, and ventilator-associated bacterial pneumonia. As newer antibiotic therapies come to market, limited data exist about their use in real-world practice. Therefore, we sought to describe the utilization of CAZ-AVI in clinical practice.

Methods
This national retrospective cohort study included hospitalized VA patients receiving CAZ-AVI from 2015 through 2021. Cultures, infection diagnoses, demographics, comorbidities, treatments, and clinical outcomes were assessed in this cohort.

Results
During the study period, 1,048 unique patients received CAZ-AVI, with a mean age of 71.5 (±11.9) years. The study cohort was predominantly male (98.3%) and White (66.2%, Black 27.7%). The most common organism-culture site combinations were Klebsiella-urine (19.6%), Pseudomonas aeruginosa-respiratory (14.0%), Pseudomonas aeruginosa-urine (10.1%), Escherichia coli-urine (6.9%) and Klebsiella-blood (6.9%). The median time to CAZ-AVI initiation from admission was 6 days, with a subsequent median 14-day hospital stay. Median length of CAZ-AVI therapy was 8 days. Most patients changed antibiotic therapy 3 times before starting CAZ-AVI. Treatment heterogeneity was high both prior to CAZ-AVI initiation (89.6%) and during CAZ-AVI treatment (85.6%). The most common concomitant antibiotic therapies during CAZ-AVI treatment were vancomycin (41.4%), meropenem (24.1%), cefepime (15.2%), and piperacillin/tazobactam (15.2%). Inpatient mortality in this cohort was 23.6%, and about one-third of patients had a subsequent hospitalization with CAZ-AVI treatment (35.1% in 2021).

Conclusion
Utilization of CAZ-AVI increased from 2015 to 2018 and has since stabilized in the national VA Healthcare System. CAZ-AVI has been utilized in complex, difficult-to-treat patients with substantial treatment heterogeneity and variation in causative organism-culture site.

Disclosures
Aisling R. Caffrey, PhD, M.S., AbbVie Inc.: Grant/Research Support|Gilead Sciences Inc.: Grant/Research Support|Merck & Co., Inc: Advisor/Consultant|Merck & Co., Inc: Grant/Research Support|Shionogi Inc.: Grant/Research Support Haley J. Appaneal, PharmD, Ph.D., Shionogi Inc: Grant/Research Support Kerry L. LaPlante, Pharm.D., FCCP, FIDSA, FIDP, AbbVie Inc.: Grant/Research Support|Gilead Sciences, Inc.: Grant/Research Support|Melinta Therapeutics, Inc.,: Grant/Research Support|Merck & Co., Inc.: Advisor/Consultant|Merck & Co., Inc.: Grant/Research Support|Nabriva Therapeutics US, Inc.,: Grant/Research Support|Ocean Spray Cranberries, Inc.: Grant/Research Support|Pfizer Pharmaceuticals: Grant/Research Support|Shionogi, Inc.: Grant/Research Support|Tetraphase Pharmaceuticals.: Grant/Research Support.