DOP119 Predicting response to anti-tumour necrosis factor-alpha therapy-α in fibrostenotic Crohn’s disease using infra-red microspectroscopy
Authors: Keung C , Correia J , Longano A , Schulberg J D , Wright E K , Hamilton A L , Kamm M A , Lim R , Sievert W , Wood B , Moore G T 
Published: January 2025

Abstract

Background
Fibrostenotic strictures are common in Crohn’s disease, have limited treatment options and lack validated biomarkers to predict treatment response. Fourier-transform infra-red (FTIR) spectroscopy provides reproducible biochemical information from biospecimens using a rapid, label-free, non-destructive technique via molecular vibrations. We previously completed a proof-of-concept study that identified spectral biomarkers for inflammation in a model of colitis.1 The aim of this study was to investigate whether the tissue biochemical "fingerprint" using FTIR spectroscopy can predict patient clinical response to anti-tumour necrosis-factor-α (anti-TNFα) therapy, and identify spectral biomarkers for treatment response.

Methods
Hyperspectral images were acquired using the Agilent Cary 670 FPA-IR coupled with the Agilent Cary 620 microscope in transflection mode in the wavenumber region 1800 – 800 cm-1 from fixed ileo-colonoscopic biopsies from 62 patients with Crohn’s disease and 12 healthy controls. A subset of patients (n = 24) were included from STRIDENT2, a randomised study assessing adalimumab therapy for intestinal Crohn’s strictures. Thousands of spectra were obtained per sample, pre-processed via transformation to the second derivative, normalised and reduced to 25 spectra per sample prior to analysis using partial least squares discriminant analysis (PLSDA) with internal cross-validation. Spectral biomarkers were identified by the most contributive infra-red bands from the latent variables (LV) and significant variable importance in projection (VIP) scores of &gt;1. Adjacent histological sections were stained with H&E, Masson’s trichrome and α-smooth muscle actin with inflammation and fibrosis scored by a clinical pathologist.

Results
Spectra from baseline biopsies from the 24 patients in the STRIDENT study demonstrated excellent performance using PLSDA in discriminating between responders and non-responders in relation to the 12 month clinical outcomes, defined by area under the receiver operating characteristic curve (AUC) &gt;0.9 for MRI and IUS responses, normalisation of faecal calprotectin and CRP, CDAI and pain responses (Table 1). Spectral biomarkers of interest for stricture response to anti-TNFα are shown in Figure 1 and include the amide I and II protein bands (peaks at 1651 and 1543 cm-1, respectively), the carboxylate group of proteins (1454 cm-1), lipid bands (1750 and 1395 cm-1), collagen band (1236 cm-1), glycoprotein bands (1081 and 1030 cm-1), and nucleic acid bands (1236, 1081 and 966 cm-1).

Conclusion
The novel technique of FTIR spectroscopy detects tissue biochemical "fingerprints" in fibrostenotic Crohn’s disease that demonstrate excellent discrimination for predicting clinical response to adalimumab therapy.

References
1.Keung C, Heraud P, Kuk N, et al. Fourier-Transform Infra-Red Microspectroscopy Can Accurately Diagnose Colitis and Assess Severity of Inflammation. Int J Mol Sci. 2022;23(5).
2.Schulberg JD, Wright EK, Holt BA, et al. Intensive drug therapy versus standard drug therapy for symptomatic intestinal Crohn's disease strictures (STRIDENT): an open-label, single-centre, randomised controlled trial. Lancet Gastroenterol Hepatol. 2022;7(4):318-331.
3.Rimola J, Ordas I, Rodriguez S, et al. Magnetic resonance imaging for evaluation of Crohn's disease: validation of parameters of severity and quantitative index of activity. Inflamm Bowel Dis. 2011;17(8):1759-1768.