Symptom Improvement of ulceRative colitis after an Induction dose of UStekinumab in Japanese clinical practice (SIRIUS), measured using patient-reported outcomes: a prospective observational study

IntroductionUlcerative colitis (UC) is an idiopathic, chronic inflammatory disease of the large intestine. Ustekinumab is a monoclonal antibody against the p40 subunit of interleukin-12 and interleukin-23 and has proven efficacy in inducing and maintaining remission in adult patients with moderate-to-severe UC. In the Symptom Improvement of ulceRative colitis after an Induction dose of Ustekinumab study, we will document the initial treatment response (daily patient-reported outcomes for 8 weeks from first infusion) and treatment patterns of patients wih UC receiving an induction dose of ustekinumab in the real-world setting in Japan. We will also investigate the relationship between the treatment response at week 8 and early indicators of response and determine patient factors that may define the appropriate dosing interval for maintenance therapy.Methods and analysisFor this single-arm, prospective observational study at 24 centres in Japan with a follow-up period of 16/20 weeks, we aim to recruit 140 patients with moderate-to-severe UC between July 2021 and July 2022. All surveys will be conducted in Japanese and patient-reported outcomes relating to rectal bleeding, stool frequency, abdominal pain, nocturnal diarrhoea, tenesmus and perception of UC symptoms will be recorded using a smartphone application, where the patients can enter their initial response to ustekinumab induction therapy on a daily basis. Dosing intervals and the reasons for selecting this interval, and concomitant medications taken during treatment with ustekinumab will be collected by a physician questionnaire at the end of the study. On completion of primary end point (8-week patient-reported outcomes) data collection, results will be reported sequentially.Ethics and disseminationThe study has been approved by the ethics committee of each facility involved and the Institutional Review Board of the non-profit organisation MINS.Trial registration numberUMIN000043753, NCT04963725.