{
  "abstract": "Introduction Infliximab (IFX) improves outcomes in Inflammatory Bowel Disease; however secondary loss of response (LOR) occurs in up to 60% of patients at 3 years. Data on long–term outcomes following proactive therapeutic drug monitoring (TDM) combined with IFX dose escalation (DE) is limited.Methods At a tertiary centre, IFX and antibodies to IFX (ATI) trough levels were measured at every intravenous infusion following the first dose. ATI >10 mg/L is considered positive. A retrospective analysis was performed of IBD patients who underwent IFX DE between 1 January 2020 and 1 October 2025. DE was defined as a reduction in infusion interval to <8 weeks and/or dose increase up to 10 mg/kg. During this period, 998 patients received IFX, of whom 334 patients received DE. Data from 100 randomly selected patients are presented.Results Among the 100 patients, 55 had Crohn’s disease (CD), 38 ulcerative colitis (UC) and 7 with IBD-unclassified. DE strategies included: IFX dose increase to 10 mg/kg every 8 weeks (n=16), interval reduction up to every 4 weeks at 5 mg/kg (n=34), combined dose and interval escalation to 10mg/kg every 4 weeks (n=21), and multiple DE Methods (n=29).Median IFX trough level prior to DE was 1.9mg/L (range <0.8 - 17.4) rising to 11.5mg/L (range <0.8 - 44.9) after three escalated doses of IFX.60 patients received proactive DE (pDE) to optimise drug levels and/or suppress positive ATI, and 40 received reactive DE (rDE) for LOR. In the pDE group, 46/60 were on concomitant immunosuppression (CI). Positive ATI were present in 36/60 at pDE (median 42.5mg/L, range 11-255); following pDE, 22/36 achieved ATI ≤10mg/L with a median post-pDE of 7mg/L (range 1-85).Figure 1 shows that at 70 months’ follow up, >80% of patients receiving pDE and >60% receiving rDE remained on IFX. Persistence was significantly higher in the pDE group (p=0.03) compared to the rDE group. 19 patients were subsequently switched and maintained on subcutaneous IFX.In the rDE group, 33/40 were on CI. Positive ATI were detected in 10/40 at rDE (median 39 mg/L range 13-296; following rDE, 7/10 achieved ATI ≤10mg/L with a median post-rDE ATI of 6 mg/L (range 2-53). Baseline disease assessment was available in 32/40 rDE patients (calprotectin/endoscopy/imaging), with active disease identified in 23. Post rDE reassessments in 31 patients demonstrated normalisation or improvement in 22. 70% of rDE patients remained on IFX; one discontinued due to recurrent infections.Conclusions Proactive TDM combined with IFX DE enables effective optimisation of IFX therapy. Both pDE and rDE strategies are associated with high rates of IFX persistence at 5 years follow up.Abstract P255 Figure 1Persistence of IFX treatment in patients who received proactive dose escalation to optimise therapeutic drug monitoring and reactive dose escalation for loss of response",
  "authors": [
    {
      "affiliations": [
        "Sheffield Teaching Hospitals, Sheffield, United Kingdom"
      ],
      "name": "James Hassall"
    },
    {
      "affiliations": [
        "Sheffield Teaching Hospitals, Sheffield, United Kingdom"
      ],
      "name": "Thean Chew"
    },
    {
      "affiliations": [
        "Sheffield Teaching Hospitals, Sheffield, United Kingdom"
      ],
      "name": "Melissa Hale"
    },
    {
      "affiliations": [
        "Sheffield Teaching Hospitals, Sheffield, United Kingdom"
      ],
      "name": "Anupam Rej"
    },
    {
      "affiliations": [
        "Sheffield Teaching Hospitals, Sheffield, United Kingdom"
      ],
      "name": "Alenka Brooks"
    },
    {
      "affiliations": [
        "Sheffield Teaching Hospitals, Sheffield, United Kingdom"
      ],
      "name": "Anne Phillips"
    },
    {
      "affiliations": [
        "Sheffield Teaching Hospitals, Sheffield, United Kingdom"
      ],
      "name": "Alan Lobo"
    },
    {
      "affiliations": [
        "Sheffield Teaching Hospitals, Sheffield, United Kingdom"
      ],
      "name": "Kerry Robinson"
    },
    {
      "affiliations": [
        "Sheffield Teaching Hospitals, Sheffield, United Kingdom"
      ],
      "name": "Alison Wright"
    },
    {
      "affiliations": [
        "Sheffield Teaching Hospitals, Sheffield, United Kingdom"
      ],
      "name": "Laura Marshall"
    },
    {
      "affiliations": [
        "Sheffield Teaching Hospitals, Sheffield, United Kingdom"
      ],
      "name": "Gloria Tun"
    }
  ],
  "title": "P255 Proactive therapeutic drug monitoring and dose escalation are associated with sustained intravenous infliximab persistence beyond five years",
  "uid": "68f72d0b-4fbe-5edb-99df-9a8a5b96dd44"
}