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PTH-104 Remission and recurrence in IBD after biological therapy

Introduction Biological agents have revolutionised the treatment of inflammatory bowel disease (IBD) with usage continually rising. Decisions regarding de-escalation of therapy require balancing the financial implications, risks of long-term immunosuppression against the risk of relapse, and the potential of unsuccessful re-challenge. Approximately one third of IBD patients relapse within 12 months of discontinuing biologics.1 We aimed to identify the factors associated with relapse and remission. Methods The IBD register at a single district general hospital was analysed for all patient who had received biologic therapy between 2015–2018. Details of current and previous biologic therapy and concurrent immunosuppression was recorded. Results 158 patients (69.6% Crohn’s disease (CD) 40.4% ulcerative colitis (UC)) required biologic treatment (BT) for IBD. 51.8% of these patients stopped BT over this time period. The median duration of BT was 16 months (IQR 6–35). Of these 60 and 11 patients required a second and third agent respectively. 96.2% of patients who stopped BT were on an anti-TNF agent (p=0.001). The reasons for changing therapies are detailed in Figure 1. Patients with CD were 2.82 times (95%CI 1.09–7.33, p=0.033) more likely to lose response to biological therapy than patients with UC. The odds ratio of losing response to BT in those patients on infliximab compared with alternative agents was 4.11 (95%CI 0.89–19.01, p=0.071). Patients on infliximab were 6.39 times (95%CI 0.80-51.13, p=0.081) more likely to lose response to BT than those on adalimumab. There were no other significant differences between biological agents and other reasons for stopping therapy. 32 cases (55.1%) were identified as having discontinued treatment due to clinical remission. Of these, 12 cases were thiopurine naïve previously. 24 cases had been followed up for over 12 months since discontinuation. The within 12 month relapse rate was 37.5% and the median time to relapse was 9 months (IQR 6–13.5). 93.3% of patients who relapsed were established on an immunomodulator prior to remission. There was no significant difference in the rate of relapse between step-up vs step-down therapy (p=0.647). Fifteen cases were re-challenged with the same biologic for relapse after successful remission, 80% of whom had a successful rechallenge.Abstract PTH-104 Figure 1 Rationale for cessation of biological therapy Conclusions Findings in our centre are comparable to the recognised rate of patients relapsing within a year of achieving remission and discontinuing therapy. There was no significant difference in the rate of relapse in patients who achieved remission between those who were stepped up or stepped down to biologics. The higher proportion of patients who lost response to infliximab may be a consequence of the drug’s higher immunogenicity. Reference Kennedy, et al. APT 2016;43(8):910–923.