P401 Association between induction vedolizumab drug levels and therapy outcome in inflammatory bowel disease
J. O'Connell1, M. S. Ismail2, M. McCormack3, P. McDonagh1, R. Argue4, N. Breslin2,5, V. Crowley3, G. Cullen5,6, G. A. Doherty5,6, C. Dunne1,5, K. Hartery1,5, F. MacCarthy5,7, S. McKiernan1,5, H. Mulcahy5,6, A. O'Connor2,5, C. O'Morain8, B. Ryan2,5, J. Sheridan5,6, M. Healy3, D. McNamara2,5, D. Kevans1,5
1St James's Hospital, Department of Gastroenterology, Dublin, Ireland, 2Tallaght University Hospital, Department of Gastroenterology, Dublin, Ireland, 3St James's Hospital, Department of Biochemistry, Dublin, Ireland, 4Trinty College Dublin, School of Medicine, Dublin, Ireland, 5INITIative, Investigator Network Inflammatory bowel disease Therapy in Ireland, Dublin, Ireland, 6St Vincent's University Hospital, Gastroenterology, Dublin, Ireland, 7St James's Hospital, Gastroenterology, Dublin, Ireland, 8Beacon Hospital, Gastroenterology, Dublin, Ireland
Vedolizumab (VDZ) is a monoclonal antibody which targets α4β7 integrin which has demonstrated efficacy in induction and maintenance of remission in both ulcerative colitis (UC) and Crohn’s disease (CD). We aim to determine the association between induction trough VDZ levels and therapy outcome at Week 14. We also assess the association between baseline patient characteristics and induction trough VDZ levels.
Patients were recruited prospectively from three Irish Academic Medical Centres. They were included if >18 years old, with an established diagnosis of UC or CD and due to initiate VDZ therapy for standard clinical indications. Partial Mayo score (PMS) and Harvey–Bradshaw index (HBI) were assessed as appropriate a Week 0 and 14. All patients received VDZ as per standard induction and maintenance protocol. Steroid-free clinical remission (CR) at Week 14 was defined as a PMS less than or equal to 1 or a HBI <5 and no requirement for corticosteroids. Serum was collected pre-VDZ infusion at Weeks 2, 6 and 14. VDZ trough levels were determined using IDKmonitor ELISA kit (Immunodianostik). Statistical comparisons were made with p values <0.05 considered significant.
32 patients were included,
VDZ is an effective induction therapy for UC and CD in a cohort with significant prior biologic exposure. Induction VDZ drug levels are not associated with therapy outcome at Week 14. Increased CRP and reduced albumin are associated with lower induction VDZ trough levels suggesting inflammatory burden may affect VDZ induction pharmacokinetics.