P0589 High treatment persistence following infliximab dose escalation in Inflammatory Bowel Disease: A real world study

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Abstract Background Biologic dose escalation is frequently employed in inflammatory bowel disease (IBD) patients who lose response to standard dosing regimens. Infliximab (IFX), the most commonly used biologic in IBD, has a well-established role in inducing and maintaining remission in IBD, particularly in fistulising Crohn's disease (CD).¹ Secondary loss of response to IFX can occur due to low serum drug levels, primarily from immunogenicity.² We investigated the effectiveness and treatment persistence of IFX dose escalation in IBD patients with inadequate response to standard dosing after initial clinical response. Methods We conducted a retrospective analysis of IBD patients who underwent IFX dose escalation between 2020-2024 at a tertiary IBD centre. Dose escalation was defined as increase in dose (>5mg/kg) and/or frequency [>every 8 weekly (Q8W)]. Primary outcomes included clinical disease activity scores (Simple Clinical Colitis Activity/SCCAI Index for UC, Harvey-Bradshaw Index/HBI for CD), biochemical markers (CRP, faecal calprotectin) and treatment persistence, evaluated at 3-12 months, 12 months, and annually up to 36 months post-escalation. Results The cohort included 47 patients (mean age 29 years, 52% female), comprising 33 CD (70%) and 14 UC (30%) patients. Primary indication for dose escalation was low drug levels (76%), followed by loss of response despite adequate levels (24%). Dose escalation led to significant improvements in disease activity scores (HBI: p=0.01; SCCAI: p=0.04) and CRP (p=0.02) at 3-12 months. These improvements were sustained at 12 months for CRP (p=0.04) but not for clinical scores. Treatment persistence at 36 months was notably high at 100% for biologic-naïve patients and 92% for biologic-exposed patients. Mild adverse events occurred in 5 patients (11%) including psoriasiform rash (n=3), transient liver enzyme derangement (n=1) and shingles (n=1). No serious adverse events occurred. Conclusion IFX dose escalation demonstrates significant improvements in clinical and biochemical parameters in the short term, with high treatment persistence up to 36 months. While both groups showed excellent outcomes, biologic-naïve patients achieved superior persistence (100% vs 92%). These findings support dose escalation as a viable therapeutic option for maintaining response in IBD patients, with an acceptable safety profile. Prospective studies are needed to identify predictive factors for successful dose escalation and optimal timing of intervention.