Background Anti-TNF therapy (infliximab and adalimumab) is effective in the management of children with inflammatory bowel disease (IBD). In primary non-response or loss of response to anti-TNF, switching biologic class may be useful. Remission rates with ustekinumab (anti-IL2/23 monocloncal antibody) of 39%, and with vedolizumab (anti-a4b7 integrin monoclonal antibody with gut selective anti-inflammatory activity) of 39% (ulcerative colitis (UC)) and 24% (Crohn’s disease (CD)) have been reported.

Aims To evaluate remission rates in children with IBD in our tertiary centre after switching biologic class. We hypothesised that remission rates would be similar to published rates.

Subjects and Methods Children who had switched biologic class were identified from the IBD database and electronic patient records. Data was collected on gender, age at diagnosis, diagnosis, therapy including biologics, reason for switch and clinical and endoscopic response.

Results Of a total of 460 children with IBD, 165 (35.8%) were receiving biologics. Age at diagnosis ranged from 4–14 years. 15 had CD, 1 had UC and 1 had IBDU favouring CD. 17/165 (10%) switched class due to active disease; 5/17 (29.5%) to ustekinumab, 12/17 (70.5%) to vedolizumab.

All received immunomodulators prior to biologics. 16/17 received infliximab as first biologic. 15/17 are receiving concurrent immunomodulators; 2/17 are on biologic monotherapy.

All 5 patients switched to ustekinumab had initially switched within anti-TNF class; 80% received infliximab as initial anti-TNF therapy.

2/5 had primary non-response, 2/5 had antibody formation, 1/5 had secondary loss of response and psoriasis on anti-TNF.

40% of patients who switched from anti-TNF to ustekinumab showed clinical response but were yet to undergo endoscopic reassessment. 3/5 did not show clinical response, of which 2/3 were non-compliant with immunomodulators (both secondary non-response and antibody formation).

Of the patients 12 switched to vedolizumab, all received infliximab initially. 75% switched within anti-TNF class prior to switching to vedolizumab.

3/12 had primary non-response, 4/12 had secondary loss of response, 1/12 had secondary loss of response and psoriasis on anti-TNF. 2/12 had antibody formation, 1/12 had secondary loss of response to infliximab then antibodies to adalimumab, 1/12 had an adverse reaction to infliximab then antibodies to adalimumab.

Overall, 75% achieved clinical response with 16% confirmed endoscopic remission after switching. 25% had not achieved clinical response. 2/12 plan to switch from vedolizumab to ustekinumab aiming to achieve clinical response.

Summary and Conclusion 82% switched between anti-TNFs before switching class. Reasons for switching class were primary non-response (30%), antibodies to anti-TNF (35%) and secondary loss of response (35%) (1 patient developed antibodies to one anti-TNF and loss of response to another).

70% achieved clinical response on switching. Although most children are yet to have endoscopic assessment, all children assessed had achieved endoscopic remission.

Switching class may benefit children who do not respond to anti-TNF. The need to switch within several classes may be required for a select group of children with resistant disease.

3 children were non-compliant with immunomodulator therapy. Reasons for immunomodulator non-compliance should be explored.

Endoscopic re-evaluation is important to ensure mucosal healing particularly in this group of children.