Introduction The efficacy of anti-TNF therapy, Infliximab (IFX) and Adalimumab (ADA) has been established in pivotal trials for induction and maintenance of remission of inflammatory bowel disease (IBD). Despite this a proportion of patients lose response and require dose intensification. The aim of our study was to assess the efficacy and durability of dose intensification with IFX/ADA.
Methods A retrospective review of patients with IBD receiving IFX/ADA infusions from October 2011 until April 2012 at our institution was conducted through electronic and case note review, endoscopy, radiology and pathology reports. Patients losing response after 6 months or more of IFX/ADA maintenance therapy and in whom treatment was intensified were included. Dose intensification was defined as an increase in IFX dose per infusion from 5mg to 10mg/kg or increase in frequency of infusions from 8 weeks to 5 – 6 weeks. For ADA this was defined as increasing the dose from 40 mg to 80mg or increasing the frequency from biweekly to weekly.
A positive response was defined by clinician assessment after 3 infusions. Non-response or loss of response was defined as persistent disease related symptoms requiring steroid therapy, hospitalisation, surgery or discontinuation of IFX/ADA.
Results Of 208 patients receiving anti TNF therapy (IFX = 157, ADA = 51), 15 patients (12 female) received dose intensification (IFX = 12, ADA = 3). 6 had Ulcerative Colitis (UC) (4 pan-colonic, 2 left sided) and 9 had Crohn’s Disease (CD) with non stricturing, non penetrating disease (3), active stricturing (3), penetrating (1) and peri-anal (2) disease respectively. Disease location was ileal (1), colonic (2) and ileo-colonic in 6. The median age was 40 years (range 18–72 yrs).
Response to intensification after approximately median duration of follow up of 12 months was noted in 8/9 CD and 2/6 UC patients. 9 patients (60%) remained on dose intensification and 5 lost response (33%). In 1 patient treatment was discontinued in the third trimester of pregnancy. Two patients (UC) reverted to their previous dose, 2 non-responders underwent surgery and 1 received Methotrexate. 2 patients are being evaluated for dose intensification. CRP was elevated in 5 patients prior to intensification. Endoscopic assessment of disease was performed in 4 patients with UC showing active colitis in 3. Four patients underwent enterography showing active disease in three.
Conclusion A significant proportion of patients with CD respond to dose intensification but thorough disease assessment does not always appear to precede such critical decision. Anti-TNF trough and antibody levels, an astute assessment for active disease and search for alternative mechanistic explanations for symptoms are imperative prior to embarking on expensive therapy with its inherent risks.
Disclosure of Interest None Declared