P91 Withdrawal of immunomodulatory therapy is feasible in anti-TNF treated patients with negative HLA-DQA105 – an observational study

BackgroundCombination therapy with immunomodulators and anti-TNFs were recommended following the results of the SONIC study. It was determined the main benefit for combination therapy was due to reduction in the risk of anti-drug antibodies. The PANTS study indicated that patients at higher risk of antidrug antibodies to anti-TNF agents could be identified with HLADQA1*05 allele carriage. A HLADQA1*05 stratified withdrawal of immunomodulators has not been evaluated before.MethodsWe included IBD patients on combination immunomodulaotrs and anti TNF agents from a prospective database who had HLADQA1 *05 status determined retrospectively after treatment of minimum 12 months. Patients with Crohn`s disease -perianal fistula or those on immunomodulators due to non-IBD indications were excluded. Immunomodulator withdrawal was offered to all patients in clinical and biomarker remission with a negative HLADQA1805 status. Patients were followed up with structured clinical and biomarker assessment. Therapeutic drug monitoring was performed at 3–6 month intervals. The primary outcome was development of anti-drug antibodies.ResultsThree hundred and eighteen patients on anti-TNF agents had HLA-DQA1*status determined. Among these 248 patients were on combination therapy. Withdrawal of immunomodulaotrs was suggested to 146 (59%) of the HLA-DQA1*05 negative patients. None of the patients declined attempt at withdrawal but five patients preferred dose reduction rather than complete cessation and these were not included in analysis. Median follow up among the remaining 141 patients was 13 months (range 3–27 months). Antidrug antibodies developed in 11 patients (7.8%) including in three patients with undetectable drug levels necessitating switch of agent. An additional 16 patients lost clinical response without development of antibodies.ConclusionIn anti TNF treated IBD patients in long-term remission, withdrawal of immunomodulators is feasible in majority of patients not carrying HLA-DQA1*05 with limited risk of development of antidrug antibodies.