What this trial measures

• Adherence to intervention based on the proportion of participants who received the assigned Adaptive Treatment Strategy (ATS) (without receiving added/removed therapy outside of assignment) during first stage of therapyDay 3

  Target ≥60%

• Adherence to intervention based on the proportion of participants who received the assigned Adaptive Treatment Strategy (ATS) (without receiving added/removed therapy outside of assignment) during second stage of therapyDays 4 through day 10 (maximum 7 days from initiation of second stage of treatment)

  Target ≥60%

• Proportion of eligible enrolled patients who were randomized during the first stage of intervention and who received treatment (regardless of ATS assignment)Randomized day 0 - up to day 3

  Target ≥ 80%

• Proportion of eligible enrolled patients initiated on first stage therapy who were randomized during second stage of intervention and who received their assigned treatment (regardless of ATS assignment)Days 4 through day 10

  Target ≥ 60%

• Proportion of eligible enrolled patients who initiated first stage therapy who successfully transitioned to the second stage of interventionDay 3 - Day 4

  Intervention (randomized and received treatment if deemed to be a non-responder or continued treatment/were discharged if deemed to be first stage responder) Target ≥ 50%.

• Proportion of eligible enrolled patients with complete data records for C-Reactive Protein (CRP) and Ulcerative Colitis Patient reported outcomes (UC-PRO) prior to second stage allocationDay 0 to Day 3 of intervention

  Target ≥ 60% with CRP and UC-PRO recorded on Day 3 or day of intervention phase completion if occurring before Day 3.

• Proportion of eligible patients who enroll (not including screen failures) in the trial throughout the enrollment period5 years

  Target ≥50%

• Proportion of eligible enrolled participants followed until discharge or colectomy (whichever comes first)up to approximately 10 days

  The proportion is regardless of ATS adherence (target ≥ 70%)

• Proportion of eligible enrolled participants without colectomy that were followed for 90 days with completion of one of the required study items90 days

  Participants followed for 90 days with completion of one of the required study items at Day 90 (UC-PRO, Complete Blood Count (CBC), Comprehensive Metabolic Panel (CMP), CRP, fecal calprotectin (FCP), research stool) (target ≥ 70%).

• Proportion of eligible enrolled participants without colectomy that were followed for 90 days with completion of all of the required study items at Day 9090 days

  Proportion of eligible enrolled participants without colectomy that were followed for 90 days with completion of all of the required study items at Day 90 (UC-PRO, CBC, CMP, CRP, FCP, research stool) (target ≥ 50%).

• Percentage of participants with complete colectomy status and safety data via 90-day chart review90 days

  Target ≥ 90%

• Proportion of eligible enrolled participants with complete UC-PROs on each day of hospitalization from enrollment to discharge or colectomy (whichever comes first regardless of intervention phase completion/ATS adherence)up to approximately 10 days

  Target ≥ 50% completion across all eligible days

• Proportion of eligible enrolled participants without colectomy that were followed for 90 days with completion of all requested study itemsDay 30, Day 60, Day 90

  Completion of all requested study items at Day 30, Day 60, and Day 90 (target ≥ 50%)

• Proportion of participants who were enrolled prior to receiving their first dose of intravenous (IV) methylprednisoloneBaseline

  Target ≥ 70%

• Proportion of participants who were enrolled who satisfied Truelove and Witts' disease severity criteria as measured by stool frequencyBaseline

  This is measured by stool frequency \> 6 Bowel Movements (BMs)/day with blood and 1 feature of systemic disturbance (fever \>37.8 Celsius, pulse \>90 beats/minute, hemoglobin \>10.5 grams per deciliter (g/dL), or erythrocyte sedimentation rate \>30 millimetres per hour (mm/h) or C-reactive protein \>30 mg/L) (target ≥ 50%).

• Proportion of eligible enrolled patients who initiated first stage therapy (regardless of ATS adherence) within 12 hours of randomizationup to 12 hours after randomization

  Target ≥ 50%

• Proportion of enrolled participants who completed endoscopic evaluation within 72 hours of enrollment and had an endoscopic Mayo score ≥ 2up to 72 hours

  This excludes those that did not complete endoscopic evaluation within 1 week of enrollment. Target ≥75%

• Proportion of eligible enrolled participants reporting trial design acceptable as measured by semi-structured interviewsup to approximately 10 days (prior to discharge)

  Interviews will assess perceptions of the ATS, trial burden, and willingness to participate in a similar study again (target ≥ 60%)

• Proportion of inpatient physicians interviewed reporting trial design acceptableUp to approximately 10 days

  Interviews assess the feasibility, practicality, complexity, workload imposed by the SMART design and clarity, and clinical appropriateness of the ATS (target ≥ 60%)