P797 Assessment of pharmacokinetics and clinical response in patients transitioning from intravenous to subcutaneous vedolizumab

Abstract

Abstract Background Vedolizumab is a humanized monoclonal antibody directed against α4β7 integrin used in inflammatory bowel disease (IBS) patients1. The usual dosage of Vedolizumab is 300 mg intravenously (iv). Recently the subcutaneous (sc) formulation (108 mg every 2 weeks) has been approved, which provides more independence for the patient, avoiding visits to the hospital and possible inconveniences associated with it2. Methods The aim of the study is to evaluate the clinical and biochemical response of IBS patients treated with vedolizumab, 16 weeks after transitioning from iv to sc. An observational, prospective, single-center cohort study was performed. Patients with IBS and maintenance treatment with vedolizumab, stable for at least 4 months, were offered to switch to sc formulation. At the same time of treatment administration a blood test was performed, with vedolizumab levels and fecal calprotectin. Clinical index as Harvey-Bradshaw Index (HBI)/Simple Clinical Colitis Activity Index (SCCAI) and questionaries (IBDQ-9 and TSQM) were performed on each visit. Results 43 patients were included, 12 of them (27.9%) chose to transition to sc formulation. Baseline characteristics of both groups are shown in Table 1. 34 (79.1%) patients were prescribed vedolizumab due to previous biologic failure, 7 (16.3%) in first line due to comorbidities and 2 (4.7%) because of adverse effects in prior treatment. All included patients remained in remission during follow-up. At week 16 (w16), no significant differences were found in calprotectin levels in patients on iv treatment (mean 146.6 ± SD 45.9) vs sc (159.26 ± 53.9) (p 0.9). Vedolizumab serum levels at w16 were higher in the sc group (22364.3 ± 5141.6) vs. iv (11425.9 ± 1514.2), with statistically significant differences (p 0.009). At w16, 9 (75%) of the patients in the SC group were highly satisfied with the medication and 11 (91.7%) considered it easy to administer. 1 patient (8.3%) in the sc group returned to iv treatment. 4 patients (12.9%) in iv and 2 (16.6%) in sc treatment presented mild adverse effects. The 2 cases (100%) of the sc group the adverse event was local inflammation at the injection site. Conclusion In our experience, vedolizumab sc is a safe and convenient alternative to iv administration. Vedolizumab serum levels in patients who transitioned to sc were higher than iv formulation. 1. Smith, Michael A et al. "Vedolizumab: an α4β7 integrin inhibitor for inflammatory bowel diseases." The Annals of pharmacotherapy vol. 48,12 (2014): 1629-35. 2. Vermeire, Séverine et al. "Efficacy and Safety of Subcutaneous Vedolizumab in Patients With Moderately to Severely Active Crohn's Disease: Results From the VISIBLE 2 Randomised Trial." Journal of Crohn's & colitis vol. 16,1 (2022): 27-38.