Endotype–phenotyping may predict a treatment response in progressive fibrosing interstitial lung disease

BACKGROUND: Some interstitial lung disease (ILD) patients develop a progressive fibrosing-ILD phenotype (PF-ILD), with similar persistent lung function decline suggesting common molecular pathways involved. Nintedanib, a tyrosine kinase inhibitor targeting the PDGF, FGF, VEGF and M-CSF pathways, has shown comparable efficacy in idiopathic pulmonary fibrosis (IPF) and systemic sclerosis-associated ILD (SSc-ILD). We hypothesize that Nintedanib targeted molecular pathways will be augmented to a similar degree across PF-ILD regardless of aetiology. METHODS: We collected explanted lung tissue at the time of lung transplantation from 130 PF-ILD patients (99 (76%) IPF, 14 (11%) SSc-ILD, 17 (13%) other PF-ILD), and wedge biopsies from 200 donor lungs and measured PDGF, FGF, VEGF and M-CSF concentrations by Luminex. FINDINGS: The concentrations of PDGF-AA, PDGF-BB, FGF-2, VEGF and M-CSF were significantly increased in PF-ILD lungs compared to donor lungs (PDGF-AA 93·0 pg/ml [±97·2] vs. 37·5 pg/ml [±35·4], p < 0·001; PDGF-BB 102·5 pg/ml [±78·8] vs. 61·9 pg/ml [±47·0], p < 0·001; FGF-2 1442·4 pg/ml [±426·6] vs. 1201·7 pg/ml [±535·2], p = 0·009; VEGF 40·6 pg/ml [±20·1] vs. 24·9 pg/ml [±29·5], p < 0·001; and M-CSF 25526 pg/ml [±24,799] vs. 6120 pg/ml [±7245], p < 0·001). There were no significant differences in these growth factor/angiogenic molecules/cytokine concentrations when segregated by IPF, SSc-ILD and other PF-ILDs. INTERPRETATION: Nintedanib specific targeted molecular pathways are augmented to a similar magnitude in all PF-ILD lung tissue as compared to controls, suggesting that Nintedanib treatment may be efficacious in PF-ILD regardless of aetiology. We speculate that clinical trials using Nintedanib for PF-ILD with or without IPF or SSc-ILD should show a similar relative reduction in FVC decline as seen in IPF and SSc-ILD (∼45–50%). FUNDING: Health Grant P01-HL108793 (JAB), South-Eastern Norway Regional Health Authority Grant 2018072 (AMHV).