Optimising carotegrast methyl use in ulcerative colitis: patient profiling, predictive biomarkers, and timing of efficacy evaluation (ASPECT study).

Background: Carotegrast methyl is approved for treating patients with moderately active ulcerative colitis with inadequate response to 5-aminosalicylic acid agents. However, real-world evidence to guide optimal use is limited. This retrospective study aimed to characterise suitable patient profiles, identify biomarkers predictive of carotegrast methyl efficacy, and determine the appropriate timing for treatment evaluation.

Methods: We analysed data from 186 patients enrolled in a phase 3 trial of carotegrast methyl (96 carotegrast methyl, 90 placebo). We assessed biomarkers (leucine-rich α-2 glycoprotein, C-reactive protein, faecal calprotectin, and anti-integrin αvβ6 antibody titres) alongside clinical outcomes and assessed symptom diaries and maintenance therapies.

Results: Low disease activity at baseline (partial Mayo score ≤ 5) was associated with higher remission rates (56.1 vs. 33.3%). Anti-integrin αvβ6 antibody titres of < 44.6 U/mL at baseline predicted higher clinical remission rates (49.1 vs. 26.8%). Symptom improvement was detectable from week 2. Faecal calprotectin correlated with the endoscopic subscore at the end of treatment (ρ = 0.566); a faecal calprotectin level of < 387.5 µg/g predicted Mayo endoscopic subscore 0/1. Most patients maintained remission with oral 5-aminosalicylic acid alone; the 1-year maintenance rate was 56.5%.

Conclusions: Carotegrast methyl appears most effective in patients with moderately active ulcerative colitis with low disease activity, with week 2 and beyond as an appropriate time point for assessing efficacy. Anti-integrin αvβ6 antibody titre shows promise in predicting response to carotegrast methyl. Faecal calprotectin may serve as a non-invasive surrogate for evaluating endoscopic healing.