DOP011TRANSPIRE: TRANSperineal ultrasound Parameters for Identifying steroid non-response in patients with acute seveRE ulcerative colitis: an interim analysis

Background Transperineal ultrasound (TPUS) has emerged as a non-invasive method for assessing rectal inflammation in ulcerative colitis (UC) and overcomes the limitations of standard intestinal ultrasound in evaluating distal colonic disease. However, TPUS has never been studied in acute severe UC (ASUC). The TRANSPIRE study aimed to determine whether early TPUS parameters can identify steroid non-response in ASUC. Methods In this prospective study, adults admitted with ASUC (per Truelove and Witts criteria) underwent TPUS on admission (T1) and 48±24 hours later (T2). Parameters assessed included rectal bowel wall thickness (BWT) and Doppler activity. Steroid non-response (SNR) was defined as the need for medical rescue therapy. Predictive performance was assessed using comparative statistics and ROC analysis. Results Twelve patients were included, median age 40 years, 66.7% were female. Two patients had proctitis and the remainder had left-sided or pancolitis. Five (41.7%) patients required rescue therapy. Rectal BWT was higher in non-responders at both T1 and T2. Median T1BWT was 7.0mm in responders and 8.4mm in non-responders (p=0.09). T1BWT ≥8.4mm predicted steroid non-response (sensitivity 60%, specificity 100%, AUROC 0.80) and outperformed admission UCEIS (AUROC 0.59). Median T2BWT was 5.6mm in responders and 6.6mm in non-responders (p=0.02). T2BWT ≥6.6mm similarly predicted steroid non-response (sensitivity 60%, specificity 100%, AUROC 0.80). A 20% reduction in BWT from T1 to T2 identified SNR (sensitivity 80%, specificity 85.7%, PPV 80%, NPV 85.7%, OR 24 (1.0-45), AUROC 0.83). Doppler activity did not significantly differ between groups or enhance prediction beyond BWT. Conclusion TRANSPIRE is the first study to evaluate TPUS in ASUC. T1 and T2 rectal BWT can be used to identify corticosteroid non-response, supporting TPUS as a promising rectal-focused, non-invasive bedside tool in ASUC. Larger studies are needed to validate these findings. Conflict of interest: Subhaharan, Deloshaan: No conflict of interest Sagami, Shintaro: Shintaro Sagami has served as an advisory board member, consultant, or speaker for AbbVie, Alimentiv, Bristol Myers Squibb, Celltrion, EA Pharma, Eli Lilly, Ferring Pharmaceuticals, Gilead Sciences, Janssen Pharmaceuticals, Kyorin Pharmaceutical, Mitsubishi Tanabe Pharma, Mochida Pharmaceutical, Nippon Kayaku, Pfizer, Takeda, and Zeria Pharmaceutical, and has received research funding from Bristol Myers Squibb, EA Pharma, Gilead Sciences, Helmsley Charitable Trust, JIMRO, Kyorin Pharmaceutical, Miyarisan, Mochida Pharmaceutical, Nippon Kayaku, Pfizer, Sekisui Medical, Samsung, Takeda, and Zeria Pharmaceutical. Haig, Adam: No conflict of interest Mohsen, Waled: No conflict of interest Kakkadasam Ramaswamy, Pradeep: None