The challenge

Progressive fibrotic interstitial lung disease (PF-ILD) was clinically defined relatively recently, and the benefit of treatment for survival has only been studied over 12 months. We knew that a deeper understanding of survival, especially in the long term, would be needed to demonstrate a treatment’s value fully.

The approach

Our deep experience with idiopathic pulmonary fibrosis (IPF) and our thorough literature analysis pointed to the hypothesis that the survival of patients with PFI-ILD was likely similar to that of patients with IPF.

We used propensity score matching and combined long term evidence from an IPF cohort with a clinical trial of PF-ILD, using Bayesian survival analysis. This method is highly innovative and exploratory. It was well-received by reviewers and reimbursement agencies, which acknowledged that we were trying to reduce uncertainty in the survival estimates of patients with PF-ILD.

The outcome

Our survival data remain the most comprehensive estimate of medium- and long-term survival of patients with PF-ILD. It will play a pivotal role in future cost-effectiveness modelling in this disease area.