P1055 Intravenous to subcutaneous infliximab switch may reduce the risk of immunogenicity related treatment failure and can be used to facilitate immunomodulator withdrawal

Abstract

Abstract Background Infliximab (IFX) is an effective treatment option for many patients with inflammatory bowel disease. Immunogenicity mediated treatment failure (IMTF) is a common clinical problem usually tackled by addition of an immunomodulator (IMM) and/or IFX dose escalation. Switching stable patients on IV IFX maintenance therapy to SC IFX has been shown to be safe and effective.1 It is hypothesised that SC IFX may reduce the risk of IMTF but there is little data to support this. We aimed to explore whether switching selected patients at risk of IMTF from IV to SC IFX was safe and effective and assess whether this strategy can facilitate treatment de-escalation and IMM withdrawal. Methods The local IBD database was used to identify potentially suitable patients at higher risk of IMTF. This included those on escalated doses of IV IFX, those who had developed low level anti-drug antibodies (ADA), and those on combination therapy in whom it was felt desirable to withdraw IMM. Those who agreed to switch were commenced on SC IFX 120mg fortnightly and followed up clinically and with IFX drug levels (DLs) and ADA at week 8, 24 and 52. Results 29 eligible patients underwent IV to SC IFX switch. Two patients were excluded: one returned to IV IFX and the other stopped IFX completely within 8 weeks of switch. Outcomes for 27 patients were evaluated: 10 with UC, 14 CD, 3 IBD-unclassified. Median age was 38 (IQR 31-49). Median duration of IV IFX was 34 months (IQR 24-54 months). 17 patients were on accelerated IV IFX dosing. All 27 patients remained on SC IFX at one year. Two required a course of steroids for disease flare. Of the 19 patients who had faecal calprotectin (FCP) data available, the mean FCP prior to switch was 66.1 (30-317) and post initiation of SC IFX was 189.6 (30 – 1800), but this did not reach statistical significance (p=0.172). 12/27 patients were on IV IFX plus IMM therapy. 9/12 successfully stopped IMM after switch to SC IFX. Mean DL prior to switch was 7.13 (2.7-12.5) and post switch was 12.07 (1.6-14.5). In those who were on accelerated IV IFX dosing, 15/17 saw an increase in DLs post switch. In the 8 patients who had ADAs prior to switch, all saw a reduction, with 6 having no detectable ADAs post switch. Conclusion Switching from IV to SC IFX in this cohort was safe and effective. Most patients maintained steroid free remission at one year. All those who stopped IMM were successfully maintained on monotherapy at 1 year. 15/17 people treated with escalated IV dosing were successfully switched to standard SC IFX dosing with improvement in mean IFX DLs and without loss of clinical effect.