Early Economic Model of Extracorporeal Photopheresis and Other Treatments of Chronic Lung Allograft Dysfunction After...

Extracorporeal photopheresis (ECP) is a technology to treat chronic lung allograft dysfunction (CLAD) following lung transplantation. CLAD leads to significantly higher mortality rates.

The objective of this study was to develop an early economic model that can evaluate the potential cost-effectiveness of treatments for patients with a confirmed diagnosis of CLAD and to evaluate a plausible cost-effectiveness range for ECP.

The literature was reviewed and clinical experts were consulted to develop a Markov model with change in percent forced expiratory volume in 1 second (%FEV1) states, defining rates of lung function decline. The literature and clinical experts were also consulted to determine plausible transition probabilities between %FEV1 states and resource use. Probabilities of dying were estimated by calibrating the model to published survival curves. Treatment response was obtained from cohort studies. EQ-5D values and unit costs were obtained from published sources.

In the base case analysis, the incremental cost-effectiveness ratio (ICER) estimates for ECP ranged from £33 343/QALY to £88 278/QALY. This does not account for risk of bias in the implicit relative risk estimate in the model or for scenario combinations. The ICER was lower in the bronchiolitis obliterans syndrome population than in the restrictive allograft syndrome population and in earlier CLAD stages. The ICER was lower if ECP was provided for a course of treatment and there was a persistent protective effect from lung function decline after cessation of treatment.

There was very little quality evidence to inform the decision model. The results included a wide range of ICERs. Key determinants include the therapeutic benefit of ECP after treatment cessation, response rates with standard care, and CLAD stage mortality rates.The economic model can be updated as new evidence emerges from ongoing clinical trials. For the National Institute of Health and Care Excellence in England, ECP may qualify as a highly specialized technology, for which the cost-effectiveness threshold may be £100 000/QALY or higher.