Ustekinumab (Stelara) is indicated for use in adult patients with moderately to severely active ulcerative colitis (UC) who have had an inadequate response, or were intolerant to either conventional therapy or a biologic, or have medical contraindications to such therapies. The recommended dose of ustekinumab is a single IV tiered infusion based on body weight (6 mg/kg) during the induction phase, followed by subcutaneous injections of 90 mg every eight weeks during the maintenance phase. The sponsor-submitted price is $2,079.84 per 130 mg/26 mL solution vial for IV infusion and $4,593.14 for a pre-filled syringe of 90 mg/1 mL for subcutaneous injection. The cost of treatment per patient with ustekinumab is estimated to be $33,798 in the first year and increases to $32,152 annually thereafter. CADTH has reviewed ustekinumab three times previously, but not for UC. The CADTH Canadian Drug Expert Committee (CDEC) has previously recommended listing (reimbursement of) ustekinumab for the treatment of adult patients with moderately to severely active Crohn disease (2017) and for the treatment of adult patients with chronic moderate-to-severe plaque psoriasis who are eligible for phototherapy or systemic therapy (2009). The clinical criterion for the active Crohn disease indication was that treatment should be discontinued if patients do not achieve clinical response within eight weeks of induction therapy, while the clinical criteria for the plaque psoriasis indication were: greater than 10% of body surface involvement or significant involvement of face, hands, feet, or genital regions; failed response, contraindications to, or intolerance to methotrexate and cyclosporine; failed response, intolerant to, or unable to access phototherapy. For the treatment of adult patients with active psoriatic arthritis (2014), CDEC recommended that ustekinumab not be listed at the submitted price. The sponsor submitted a cost-utility analysis comparing ustekinumab with other biologic therapies (infliximab, infliximab biosimilars, adalimumab, golimumab, vedol izumab, tofacitinib) or continuing conventional therapy (CT) (a mix of 5-aminosalicylates, corticosteroids, and immunomodulators) for Canadian adults with moderately to severely active UC and an inadequate, intolerant, or failed response to CT or biological drugs.