P434 Clinical utility of routine measurement of Anti-TNF levels and their antibodies in inflammatory bowel disease (IBD)
S. Sarwar*, K. Foster, E. Corn, S. Moss
Diana Princes of Wales Hospital , Gastroenterology, Grimsby, United Kingdom
Anti-TNF therapy is an effective option for IBD. Anti-TNF levels and antibodies may help in decision making in these patients. The effectiveness of serial measurement of anti-TNF levels and their antibodies in these subjects is unknown. Therefore, we evaluated the clinical benefit of 2 monthly measurement of these parameters in patient with IBD on maintenance anti-TNF therapy
All patients receiving maintenance anti-TNF therapy between June 2013 and June 2014 were included in the study. The trough levels and antibodies for infliximab and adalimumab were measured every 2 months. The impact of monitoring on clinical management was reviewed.
Seventy nine (Inflximab n= 40, Adalimumab n=39) IBD patients were included in the study. Mean age was 39 ± 14 years. Median duration of disease was 72 months. Antibodies against infliximab and adalimumab were found in 7 patients. Only one patient with antibodies had a therapeutic level. Of these 7 patients, anti-TNF were switched to the other ant-TNF agent in 3 with partial response, 2 underwent surgery and 2 discontinued the drug as their disease was in remission. In patients with therapeutic levels (n=53), disease activity was present in 17 (32%). Of these 17 patients 11 (64%) underwent dose escalation to achieve higher therapeutic levels resulting in complete response in 6 and partial response in 5 patients. Subtherapeutic levels were found in 22 (27%) patients; other than 6 patients with antibodies, dose escalation in 5 resulted in complete response in 3 and partial response in 2 patients, one discontinued due to joint pains, anti-TNF was continued without any modification in 10 of these patients as their disease was in remission and subsequent levels normalized in 7 of these 10 patients.
Most patients with active disease with subtherapeutic and therapeutic levels but without anti-TNF antibodies may respond to dose escalation. Development of antibodies allows early discontinuation or switching of anti-TNF. Accordingly we suggest routine monitoring of infliximab and adalimumab levels and their antibodies as they impact management of IBD patients.