Original article Economic evaluation of doripenem for the treatment of nosocomial pneumonia in the US: discrete event simulation

Objective: Patients with nosocomial pneumonia, particularly associated with ventilator use, are at an increased risk of death and further morbidity. Doripenem is a new broad-spectrum carbapenem that is approved for complicated intra-abdominal infection and complicated urinary tract infection and is under the Food and Drug Administration (FDA)’s review for nosocomial pneumonia and ventilator-associated pneumonia in the United States (US). The economic implications of this new antibiotic, relative to imipenem for treatment of nosocomial pneumonia, were investigated. Research design and methods: An economic model of the clinical course of nosocomial pneumonia after initiation of treatment was developed using discrete event simulation. Pairs of identical patients are generated; one receives doripenem and the other receives imipenem. Their clinical course is simulated using clinical trial data on treatment response, seizure rates, mortality, length of hospital and intensive care unit stays, days on mechanical ventilation, and emerging Pseudomonas aeruginosa (PsA) resistance; published treatment and hospital costs; and PsA transmission risk. Analyses of 10,000 patients per treatment for 100 replications were performed. From the perspective of a comprehensive payer, costs – in 2007 US Dollars (USDs) – were estimated for a treatment episode (35–49 days) without discounting. Study limitation includes clinical trial-driven design of the model in which some aspects may not represent actual practice; some assumptions around efficacy data due to data unavailability; and lack of consideration of factors that impact disease transmission such as hospital environment, hospital size, and hospital infection control as these analyses were not intended for any specific healthcare institution. Results: Doripenem yielded an average of approximately $7000 in savings per patient compared to imipenem, with 95% driven by reduction in hospital length of stay. The model predicted 63% fewer seizures, 52% fewer emerging PsA resistance, and 15% shorter stays leading to 46% fewer transmissions associated with doripenem.