• Male or nonpregnant, nonlactating females, ≥ 18 years of age.

• An established diagnosis of CD or UC for at least 6 months based on standard clinical criteria, confirmed by the treating provider.

• Current treatment with an approved TIM for treatment of IBD, including biologic agents (e.g., TNFα antagonists, ustekinumab, vedolizumab) and small molecule inhibitors (e.g., Janus kinase inhibitors, ozanimod), including future TIMs that become commercially available during the conduct of the trial.

• Dose of TIM should be stable for 3 or more months prior to qualifying endoscopy/radiology. No treatment escalation of TIM or addition of IMM, corticosteroid, or mesalamines after the qualifying endoscopy/radiology procedure up to randomization is permitted. Dose de-escalation after qualifying procedure is permissible at the discretion of the treating provider.

• In corticosteroid-free symptomatic remission based on validated PROs (PRO2 score) and deemed to be experiencing no other IBD-related symptoms in the opinion of the treating provider. Includes patients who may be in medically induced remission (on index TIM); or surgically induced remission with post-op initiation of index TIM for prophylaxis and colonoscopy/imaging performed at least 3 months after initiation/optimization of TIM showing moderate-severe bowel inflammation. Validated PROs are defined as:

‣ CD: PRO2 (2-item patient reported outcome) mean daily score of abdominal pain score ≤1 and stool frequency score ≤ 3; or

⁃ UC: PRO2, with absence of rectal bleeding (rectal bleeding score = 0) and with stool frequency score ≤1.

• Evidence of moderate to severe bowel inflammation on local reading of colonoscopy, flexible sigmoidoscopy, balloon-assisted enteroscopy, capsule endoscopy or MR, CT enterography, or intestinal ultrasound, performed within 6 months prior to screening, defined at the investigator's discretion or as follows:

‣ CD: Colonoscopy showing moderately to severely active inflammation based on 1 of the following variables/scores:

• Simple Endoscopic Score for Crohn's Disease (SES-CD) score ≥7 or score ≥4 for those with isolated ileal disease, or

∙ Presence of mucosal ulcers \>5 mm in size if SES-CD has not been recorded, or

∙ Simplified Endoscopic Mucosal Assessment for Crohn's Disease (SEMA-CD) score ≥2, or

∙ Rutgeerts score i2b or higher for patients in surgically induced remission with post-operative endoscopic recurrence \[Note, either SES-CD or Rutgeerts score can be used for participants with post-operative recurrence\]; or

⁃ CD: MRE or CTE showing moderately to severely active inflammation based on 1 of the following variables:

• Increased bowel wall thickness, or

∙ Mural hyperenhancement, or

∙ Peri-enteric fat stranding, or

∙ Radiographic features of ulceration, or

∙ Intramural T2 signal on fat suppressed images; or

⁃ CD: Capsule endoscopy showing moderately to severely active small bowel disease based on Lewis score \>790 (in case the disease is not accessible via endoscopy), or per local endoscopist if Lewis score is not reported; or

⁃ CD: Gastrointestinal ultrasound showing at least 1 of the following variables:

• Increased bowel wall thickness \>5 mm, or

∙ Color doppler score \>5/cm2, or

∙ Bowel stenosis, or

∙ Bowel stratification, or

∙ Fatty wrapping; or

⁃ UC: modified MES score of 2 to 3, or documentation of any endoscopic feature that would define an MES of 2 to 3 (e.g., friability, ulceration, spontaneous bleeding, complete loss of vascular pattern), if an MES has not been recorded.

• Eligible to receive at least 1 alternative TIM (excluding their index TIM) for the treatment of their disease per approved drug label, based on clinical and reimbursement guidelines.

• Able to participate fully in all aspects of this clinical trial.

• Informed consent must be obtained and documented.