OBJECTIVES: Bronchiolitis Obliterans Syndrome (BOS) is a rare, life-threatening disease where the immune system attacks the airways of the lungs. BOS is estimated to affect approximately 25,000 individuals worldwide and can occur after hematopoietic stem cell transplantation (HSCT) or lung transplantation, with up to half of all lung transplant recipients developing BOS within 5 years of transplantation. BOS is rapidly progressive and irreversible, leading to lung failure after diagnosis, and making it the leading cause of death. The aim of this analysis was to estimate the lifetime economic burden of illness for BOS patients from the perspective of a US Payer.

METHODS: A de-novo six-state natural history model was developed to estimate the lifetime costs of BOS. BOS patients flowed from the point of diagnosis to the end of life. The model leveraged published data on lung function loss in BOS patients who either had single-, double-lung transplants or HSCT. Modeled costs included drug acquisition and medical costs derived from a claims analysis. Published utility weights on chronic obstructive pulmonary disease were used as a proxy by mapping to the BOS health states based on forced expiratory volume in one second (FEV-1).

RESULTS: This model estimated that BOS patients survived for an average of 11.8 months (range depending on patient type is 5.4-13.1 months) or 9.2 months factoring in quality-of-life adjustment. The total economic impact over a lifetime was $83,500 on average ($27,900-$96,900 depending on patient type).

CONCLUSIONS: BOS patients have a significant morbidity leading to reduced life expectancy and high direct medical expenses. This early model highlights the magnitude of unmet medical need in this population and that BOS patients could benefit greatly from a therapy that could halt or slow the progression of disease and reduce healthcare resource use.