Plasma, ELF and Intraperitoneal Pharmacokinetics of Ceftazidime/Avibactam in Critically Ill and Peritoneal Dialysis Patients

Ceftazidime/Avibactam (CAZ/AVI) is a novel antibiotic drug that has recently become available. It consists of a β-lactam/β-lactamase fixed drug combination with an almost exclusively Gram-negative spectrum and is indicated for the treatment of:

• complicated intra-abdominal infections (cIAI)
• complicated urinary tract infection (cUTI), including pyelonephritis
• hospital-acquired pneumonia including ventilator-associated pneumonia (VAP)
• infections due to aerobic Gram-negative organisms in patients with limited treatment options.

It is common knowledge that in anti-infective therapy, sufficient drug delivery to the target site is essential for antimicrobial efficacy and prevention of bacterial resistance. Based on this premise, the present exploratory trial will focus on the pharmacokinetics (PK) of CAZ/AVI in two patient populations:

PART A will investigate PK of CAZ/AVI in plasma and peritoneal dialysis fluid of patients undergoing automated peritoneal dialysis (APD). After a single intravenous dose of the drug PK sampling of CAZ/AVI will be performed in plasma and in peritoneal dialysis fluid, respectively. On the one hand, this will help to assess intraperitoneal exposure to CAZ/AVI after intravenous administration. This information might be of crucial importance for patients with infections localized in the peritoneal space. On the other hand, this study will show whether and to which extent CAZ/AVI is cleared from the bloodstream after intravenous administration in patients undergoing APD and receiving CAZ/AVI as treatment of other systemic infections, e.g. nosocomial pneumonia. Both aspects will improve current information on CAZ/AVI PK in peritoneal dialysis.

PART B will determine steady-state plasma and epithelial lining fluid (ELF) concentrations of CAZ/AVI in critically ill patients receiving the drug for treatment of nosocomial pneumonia (including VAP) at the discretion of their treating physicians. Penetration of CAZ/AVI into ELF has already been assessed in healthy volunteers and amounted roughly to 30% of plasma exposure. However, several physiological factors determining the amount of drug eventually recovered in ELF might be altered in critical illness (hemodynamics, binding to plasma and/or tissue proteins, local inflammation processes etc). Thus, PK of CAZ/AVI in lungs of critically ill patients might significantly differ from healthy volunteers, and deriving ELF exposure solely from plasma pharmacokinetics might not be entirely reliable in this circumstance. Still, considering the premise mentioned above, this issue is of crucial importance. The present study will help to assess whether CAZ/AVI reaches its target site (for the indication of nosocomial pneumonia) in critically ill patients to a sufficient degree.