P1065 Rapid onset of action of ustekinumab in patients with moderate to severe Ulcerative Colitis (RAUCU Study)
Authors: Bastón Rey I , García Alvarado M , García Morales N , Fernández Suárez B , Latras-Cortés I , Ferreiro-Iglesias R , Santos Fernández J , Tejido Sandoval C , Vázquez Rey M T , García Alonso F J , Guerrero Montañés A , Molina Arriero G , Velayos Jimenez B , Ruíz Barcia M J , Ibáñez García M , Porto Silva M S , Tejerizo García L , Ucha Abal P , Martí Marqués E , Nieto García L , Gómez Hidalgo R , Muñoz Núñez F , Barreiro-de Acosta M 
Published: January 2025

Abstract

Background
Real-world data on the speed of onset of ustekinumab (UST) in patients with ulcerative colitis (UC) are limited. Current information regarding early response in these patients comes from the UNIFI trial. The primary outcome of this study was to evaluate the response to UST in patients with moderate-to-severe UC by assessing PRO2 at 14 days after the first intravenous dose (6mg/kg).

Methods
A multicenter, prospective observational study was designed in patients ≥18 years old with moderate-to-severe UC (partial Mayo score ≥6) who initiated UST 6mg/kg between June 2023 and September 2024. Patients received a diary to record the stool frecuency and rectal bleeding during first 14 days after first dose of induction. The proportion of patients achieving the combined outcome of rectal bleeding score = 0 and stool frequency score ≤ 1 (PRO-2: patient-reported outcome 2 remission) was assessed. FC was measured at baseline and at day 7 and 14. Health-Related Quality of Life was evaluated using the disease-specific shortened Spanish version of the IBDQ (SIBDQ-9) at baseline and at 4 weeks. Patients with previous panproctocolectomy with ileostomy or pouch and those who had received cyclosporine within one month prior to starting UST were excluded. Descriptive statistics are presented as frequencies with percentages for categorical variables.

Results
A total of 54 patients were included across 14 hospitals in Spain. Of these, 29 (53.7%) were men, with a mean age of 54 (± SD 16.1) years. Thirty (55.6%) patients had pancolitis, 20 (37%) had left-sided colitis, and 4 (7.4%) had proctitis. Five (9.3%) patients were bio-naïve, 32 (59.3%) had previously received one biological therapy, 10 (18.5%) had received two, and 7 (13%) had received three biologics prior to starting UST. Mean decreases in stool frequency and rectal bleeding are shown in Figure 1. By day 14, 26% of patients had achieved clinical remission. No significant differences in clinical remission were observed based on disease extent (p = 0.11) or the number of prior biologics (p = 0.39). By day 7, 12/31 (38.7%) patients with baseline bloody stools had achieved a rectal bleeding score = 0. A reduction in FC &gt;50% was observed in 14/48 (29%) patients by day 7 and in 20/47 (43%) patients by day 14. The SIBDQ9 average score was 54.9 (± SD 6.2) at baseline and 61.3 (± SD 7.4) at week 4.

Conclusion
One-quarter of patients with moderate-to-severe UC achieved clinical remission by day 14 following the first induction dose of UST. Nearly 40% of patients achieved a rectal bleeding score = 0 (PRO2) by day 7. A reduction in FC &gt;50% was observed in 43% of patients by day 14.