P500 Real life 2 year experience with ustekinumab in a Spanish open-label cohort of ulcerative colitis patients

Background Ustekinumab has been recently approved for the treatment of moderately to severe ulcerative colitis (UC). Data from the UNIFI clinical trial are encouraging; nevertheless, real-world assessment is needed. We assess the effectiveness, safety and pharmacokinetics of ustekinumab in a cohort of refractory UC patients. Methods Multicentre and observational study of UC patients who received ustekinumab for active disease. Values for Partial Mayo Score (PMS), endoscopic activity, C reactive protein (CRP) and faecal calprotectin (FC) were recorded at baseline and at weeks 8, 24 and 52 weeks and at 18 and 24 months when was possible. Demographic and clinical data, previous treatments, adverse events (AEs), surgeries and hospitalizations were documented. Possible predictors of response were examined. Results One hundred and eight patients were analyzed (Table 1). Two patients only received the first IV dose. During follow-up, 58 patients (54%) required interval reduction (every 4 weeks (76%) and every 6 weeks (24%)) after a median of 22.3 weeks [11.6, 41.2]. Intravenous reinduction doses were administered to 20 (18.5%) after 27.7 weeks [6.64, 56.3]. Three patients required a maintenance therapy with IV administration. The clinical remission (PMS≤ 2) rates were 39.6%, 41%, 51% at 8, 24 and 52 weeks, respectively, and 61%, and 57.7% at 18 and 24 months, respectively. FC levels returned to normal ( Fewer previous anti-TNF agents and the loss of response to anti-TNF were associated with clinical response and with normalization of FC respectively. No variables at baseline (body mass index, serum albumin, and lymphocytes count) were associated with ustekinumab through levels. Of the 17 patients with endoscopy before and after treatment, 6 were in remission and 3 with mild activity. The AEs were recorded in 5 (4.6%) patients, 12 (11%) were hospitalized and 9 (8.3%) had surgery. A total of 23 patients (21%) discontinued ustekinumab over time, the persistence rates were 98%, 91%, 83% and 81% at 8, 24, 48 and 96 weeks respectively. Conclusion This is the first study to show the real-world long-term effectiveness, persistence, endoscopic improvement and safety of ustekinumab in a cohort of highly refractory UC patients. The clinical remission preceded the FC normalization. Ustekinumab through levels and their pharmacokinetic require further investigations.