How can idiopathic pulmonary fibrosis (IPF) trials capture a more complete picture of treatment benefits? This was a question that came up consistently throughout the 2026 IPF Summit.
Forced vital capacity (FVC) remains a key endpoint in IPF studies, but sponsors are considering how additional measures can help them understand treatments effects on disease progression and quality of life. The program reflected this focus, with sessions on symptom assessments, biomarkers, and imaging alongside FVC.
Our main takeaway: FVC remains central to IPF trials, but the choice of measures alongside it deserves careful consideration.
Understanding what FVC does not capture
FVC provides evidence about changes in lung function, but it does not fully describe how patients feel or how the disease affects their daily lives. Complementary measures can help assess symptoms, physical limitations, and other aspects of treatment response.
Some options for additional measures include objective cough frequency, patient-reported outcomes (PROs), and serum biomarkers. Each addresses a different question. Symptom assessments help measure improvements in patients’ quality of life, while biomarkers may help researchers understand biology and biological responses to treatment.
Connecting cough with quality of life
Patients consistently describe cough, alongside breathlessness, as among the most burdensome symptoms of IPF.¹ Yet objective cough measurement has not been consistently included in IPF trials, leaving a gap between what matters to patients and the outcomes being assessed.
Objective cough monitoring provides the ground truth about how often or how intensely patients cough, while PROs capture how symptoms affect their lives. Collecting both gives sponsors complementary evidence on whether changes in cough frequency are accompanied by improvements in patient-reported burden.
The Summit program also addressed variation in PRO use across trials and the importance of selecting instruments that more consistently capture symptoms and quality of life.
Exploring additional measures alongside FVC
Our team also heard renewed interest in the six-minute walk test (6MWT), questions about slow vital capacity (SVC), and exploration of oscillometry. Some participants questioned whether SVC could offer a more meaningful measure in certain study settings.
Quantitative high-resolution CT (HRCT) imaging was another focus, including its potential to assess structural changes and complement lung function data. Sessions addressed regulatory acceptance and the standardization of collection and analysis.
There is no single agreed path beyond FVC. Questions remain about which additional measures offer the most useful evidence and what would be required for regulatory acceptance of an alternative primary endpoint. For now, FVC remains central, while sponsors work to determine how best to strengthen the evidence around it.
What this means for trial designs going forward
For sponsors, the question is which measures will add the most useful evidence alongside FVC. That decision should start with what the therapy is intended to change and what each assessment can demonstrate.
The summit reinforced the need to connect lung function with other dimensions of treatment response. A carefully chosen endpoint strategy can help IPF sponsors assess changes in disease trajectory and how patients feel and function.
References:
1. Graham CS, et al. Perspectives of people living with idiopathic pulmonary fibrosis. BMC Pulm Med. 2025;25(1):221