P962 Clinical and endoscopic remission at 3 months after Acute Severe Ulcerative Colitis is predictive of maintenance therapy outcomes at 12 months - Results from PREDICT UC
Authors: Li Wai Suen C , Choy M C , Con D , Boyd K , Pena R , Burrell K , Rosella O , Proud D , Brouwer R , Gorelik A , Liew D , Connell W R , Wright E K , Taylor K , Pudipeddi A , Sawers M , Christensen B , Ng W , Begun J , Radford-Smith G , Garg M , Martin N , Van Langenberg D R , Ding N S , Beswick L , Leong R W , Sparrow M P , De Cruz P 
Published: January 2024

Abstract

Background
The optimal maintenance regimen after rescue therapy for Acute Severe Ulcerative Colitis (ASUC) is unknown. We aimed to evaluate prospectively the impact of different maintenance regimens after successful infliximab (IFX) rescue, along with factors associated with Month 12 remission.

Methods
Clinical responders at 3 months from PREDICT UC, a randomised trial (NCT02770040) comparing standard and intensified IFX rescue strategies, were evaluated in this prospective cohort study up to Month 12. Maintenance therapies were as follows: (1) Thiopurine monotherapy (azathioprine or mercaptopurine) for thiopurine naïve patients or prior suboptimal thiopurine therapy (TP); (2) Combination thiopurine and IFX therapy 5mg/kg 8-weekly for thiopurine-experienced patients (IFX+TP combo); (3) IFX monotherapy 5mg/kg 8-weekly for thiopurine-intolerant patients (IFX mono). All patients received oral 5-aminosalicylates. Clinical and endoscopic assessments were performed at baseline (Month 3) and Month 12. Clinical remission was defined as a partial Mayo score of 0-1 and endoscopic remission as Mayo Endoscopic Score (MES) of 0-1.

Results
Of 138 patients randomised, 79 entered the maintenance phase. Of these, 56 (71%) received TP, 16 (20%) received IFX+TP combo and 7 (9%) received IFX mono. Baseline characteristics were similar across the 3 maintenance groups. At 12 months, 42 patients (53%) were in clinical remission, 44 patients (56%) were in endoscopic remission, and one patient underwent colectomy. The 3 maintenance groups had similar rates of clinical remission (TP 55%, IFX+TP combo 56%, IFX mono 29%; P=0.39) and endoscopic remission (TP 55%, IFX+TP combo 56%, IFX mono 57%; P=0.99) at 12 months.

Clinical Remission
On univariable and multivariable analysis, no factors were associated with clinical remission at 12 months, including baseline CRP, albumin, partial Mayo score, MES, UCEIS or maintenance strategy.

Endoscopic Remission
Factors associated with endoscopic remission at 12 months included baseline partial Mayo score of 0 (OR 3.36, 95% CI 1.24-9.10, P=0.017), MES of 0-1 (OR 3.48, 95% CI 1.08-11.27, P=0.037) and UCEIS of 0-1 (OR 3.30, 95% CI 1.24-8.76, P=0.016). However, a partial Mayo score cut-off of 0-1 did not reach significance (OR 3.46, P=0.09). No factors associated with endoscopic remission were identified on multivariable analysis.

Conclusion
In steroid-refractory ASUC patients who received IFX rescue, clinical and endoscopic remission at Month 3 were associated with endoscopic remission at Month 12, particularly among patients with greater depth of remission. Month 3 assessment helps identify patients at higher risk of disease progression for whom more intensive treatment may be required.