OBJECTIVES: The National Institute for Health and Care Excellence (NICE) makes funding recommendations based on whether new clinically effective treatments are good value for money for the English and Welsh National Health Service. To date, two antifibrotic (AF) medicines have been recommended by NICE: pirfenidone for the treatment of idiopathic pulmonary fibrosis (IPF), and nintedanib for the treatment of IPF and progressive fibrosing interstitial lung disease (PF-ILD). The aim of our analysis was to review cost-effectiveness modelling methods used in NICE Technology Appraisals (TAs) of AF medicines to identify the strengths and limitations of the economic modelling approaches submitted over the past ten years.

METHODS: Data was extracted from the TAs of AF medicines from the NICE website, including the economic models, inputs, assumptions, and NICE committee deliberations.

RESULTS: Five TAs were identified, two each for pirfenidone and nintedanib in IPF, and one for nintedanib in PF-ILD. Outcomes modelled included lung function decline, mortality, acute exacerbations, and treatment discontinuation. Pirfenidone was recommended for patients with 50-80% forced vital capacity percentage predicted (FVC%pred). A limitation of the pirfenidone economic analysis was that it inadequately captured the progressive nature of IPF. Nintedanib was recommended for IPF patients across different FVC%pred categories and PF-ILD, although with similar model limitations. Due to the lack of suitable data, all five TAs included the limitations of mortality risk being modelled independently from lung function decline and acute exacerbation outcomes, as well as uncertainties in survival data extrapolation and treatment benefit over time.

CONCLUSIONS: Our review identified difficulties in modelling the interdependency of key outcomes like mortality, disease progression, acute exacerbations and treatment discontinuation. It highlighted uncertainties in extrapolating survival data and treatment benefits from trials, indicating areas for improvement in future economic models for IPF and PF-ILD treatments, if the relevant data is available.