Savings in direct medical costs from the use of tobramycin solution for inhalation in patients with cystic fibrosis

Abstract

Two identical 24-week, double-blind, placebo-controlled trials of tobramycin solution for inhalation (TOBI [PathoGenesis Corporation, Seattle, Washington]) in cystic fibrosis patients with chronic Pseudomonas aeruginosa infection were conducted in the United States. The aim of the present study was to extrapolate the US trial data to a Canadian setting, using Canadian costs to estimate the savings in direct medical costs that might result from use of a similar 24-week TOBI regimen versus usual care in 2 Canadian provinces. Cystic fibrosis is a genetic disease in which persistent respiratory infection, usually due to P. aeruginosa infection, is the major cause of morbidity and mortality. The US trials demonstrated that TOBI produced significant improvements in pulmonary function test results, reduced sputum levels of P. aeruginosa, and resulted in a 26% reduction in the probability of hospitalization (95% CI, 2%-43% vs placebo in the clinical trials). Individual patient data from the US trials were used to calculate the mean number of days in hospital as well as the mean number of days of home intravenous or oral antibiotic therapy. To adjust for Canadian pricing, pertinent economic data were obtained from Statistics Canada and the Ontario and Quebec health ministries. Demographic and baseline data were obtained from health surveys conducted by the Canadian Cystic Fibrosis Foundation. Economic analysis showed that the use of TOBI for 24 weeks would result in estimated mean per-patient savings in direct medical costs (in Canadian dollars) of $4055 in Ontario and $4916 in Quebec, which would substantially offset the Canadian acquisition price of $8602 for the same 24-week period. Assuming that the percentage of reduction in hospital days observed in the US trials would also occur in the Canadian clinical setting, use of TOBI would reduce the use of health care services, particularly hospital days, and lead to substantial savings in direct medical costs that would offset its acquisition price. Whether this reduction actually occurs after TOBI enters the Canadian market is a subject for future investigation.