Table 1 Disease severity and definition of progression used in eligibility criteria for selected recently completed and ongoing clinical trials evaluating PF-ILD

Pirfenidone in unclassifiable ILD [15]

FVC ≥ 45%

DLCO ≥30%

6MWD ≥ 150 m

Fibrosis affecting > 10% of lung volume

6 months

FVC > 5% decline (absolute)

Worsening symptoms

Pirfenidone in progressive non-IPF ILD (RELIEF) [23]

FVC 40–90%

DLCO 25–75%

6MWD ≥ 150 m

12 months^a

FVC ≥ 5% decline (absolute)

Nintedanib in non-IPF PF-ILD (INBUILD) [14]

FVC ≥ 45%

DLCO 30–80%

Fibrosis affecting > 10% of lung volume

24 months

FVC ≥ 10% decline (relative)

FVC 5–10% decline (relative)

Worsening symptoms

Increasing extent of fibrosis

Pirfenidone in Patients With RA-ILD (TRAIL1) [24]

FVC ≥ 40%

DLCO ≥30%

Fibrosis affecting > 10% of lung volume

12 months

FVC ≥ 10% decline (relative)

or

FVC 5–10% decline (relative) and

DLCO ≥15% decline (relative)