This week saw the publication of the much anticipated clinical guideline on IPF and and PPF from the ATS, ERS, JRT and ALAT. The joint guideline provides recommendations on the definition of disease progression in fibrotic interstitial lung disease (F-ILD), using the term progressive pulmonary fibrosis (PPF) to describe non-IPF F-ILD in patients displaying and least two out of three criteria indicative of disease progression; namely worsening respiratory symptoms, physiological evidence of disease progression and radiological evidence of disease progression.
The guidelines define physiological evidence of disease progression as the presence of either of the following (if attributable to worsening fibrosis):
1. Absolute decline in FVC of >5% within 1 year of follow-up.
2. Absolute decline in DLCO (corrected for Hb) of >10% within 1 year of follow-up.
This new clinical guideline confirms the use of FVC in the physiological definition of disease progression in non-IPF F-ILDs. Whilst both DLCO and spirometry may be used to assess physiological evidence of progression, spirometry is a more commonly used test in clinical practice. FVC is the most often used physiological parameter in follow-up of IPF due to its association with prognosis, and it was also used to define disease progression in recent trials of patients with PPF.
So what are the implications of this guideline for home monitoring and its role in the identification of disease progression? The availability of home spirometry increases access to FVC assessment. One of the many advantages of home spirometry is that it can be conducted with greater frequency than clinic based spirometry, identifying changes in patients lung function earlier than possible with hospital spirometry conducted at schedule intervals. In IPF home spirometry data has been shown to be highly predictive of disease outcomes as early as three months, with greater sensitivity than hospital-based readings. Whilst the new joint guidelines provides a definition of physiological evidence of disease progression as absolute decline in FVC of >5% within 1 year it is possible that more aggressive disease progression may be identified at far earlier time points with home spirometry.
But is earlier identification of progression of a F-ILD clinical valuable? The recent approval of anti-fibrotic therapy (nintedanib) for the treatment of progressive fibrosing ILDs means that patients can now have access to disease modifying therapy, with implications for the timely initiation of treatment. The newly published joint guideline recommends that nintedanib is used for the treatment of PPF in patients who have failed “standard management” for fibrotic ILD, noting that the INBUILD trial demonstrated a statistically significant reduction in disease progression with nintedanib. The guidelines recognise that “standard management” for F-ILD differs patient to patient and evidence based guidance on care doesn't even exist for many F-ILDs, stating that research on the timing and sequencing of treatments (i.e. antifibrotics, corticosteroids, immunosuppressants) in the various types of ILD that can manifest PPF should be prioritised.
We’ll be speaking more about the use of home monitoring to identify disease progression in ILDs at the forthcoming ATS2022 Respiratory Innovation Summit. Our platform enables tracking of FVC (with tailored alerts which can identify FVC decline >5%) and respiratory symptoms (mMRC dyspnoea score and subjective patient diary). In this way, clinicians can track signs of physiological and symptomatic disease progression, enabling prioritised hospital based assessment (e.g. repeat HRCT) if home data is suggestive of patient decline.
We hope to see you at the ATS2022 Respiratory Innovation Summit, or to meet with us anytime over the rest of the ATS2022 conference please use the link below.