P615 Clinical efficacy of accelerated 4-weekly vs. Conventional 8-weekly ustekinumab dosing in Inflammatory Bowel Disease: A single centre experience

Abstract

Abstract Background 8-weekly dosing regimen of ustekinumab in the treatment of moderate-to-severe Inflammatory Bowel Disease (IBD) is the current standard of care. Accelerated 4-weekly dosing has been suggested to be efficacious, however not licensed, in ‘non-responders’. The aim of this study is to determine how 4-weekly accelerated dosing regimen in ustekinumab drug levels correlate with response to treatment in patients with IBD. Methods Patients for inclusion were identified retrospectively utilising online prescription records at Mercy University Hospital, Cork. Inclusion criteria consisted of IBD patients commenced on ustekinumab with a treatment duration of at least 6 months. Participants were separated into 4-weekly and 8-weekly treatment groups. Faecal calprotectin (FCP) levels/ustekinumab drug levels were recorded from the 12-week check in post initiation and at the 2nd assessment. Symptoms were scored at these visits and further quantified using the Harvey Bradshaw index for Crohn’s Disease and the partial mayo score for Ulcerative Colitis. Results 101 patients at the Mercy University Hospital Cork were identified utilising a database of prescriptions and physical charts (4-weekly: 27; 8-weekly: 74). A statistically significant decrease in FCP levels at 2nd assessment was noted in patients with 4-weekly dosing (p=0.028). There was no statistically significant relationship between dosing interval and symptoms (p=0.735). Individual patient factors including age, gender, type of IBD, and concurrent IBD medications did not have a statistically significant effect on faecal calprotectin levels or symptoms. Conclusion The greater percentage decrease in faecal calprotectin provides objective evidence supporting the escalated dosing interval at the Mercy University Hospital IBD centre. However, further study is necessary to justify increasing the dosing interval for all patients treated with ustekinumab for IBD.