Basiliximab Does Not Increase Efficacy of Corticosteroids in Patients With Steroid-Refractory Ulcerative Colitis

Background & AIMS Basiliximab is a chimeric monoclonal antibody that binds CD25 and thereby inhibits interleukin (IL)-2–mediated proliferation of lymphocytes. IL-2 might contribute to the resistance of T cells to corticosteroids. We investigated the efficacy and safety of basiliximab as a corticosteroid-sensitizing agent in patients with corticosteroid-refractory ulcerative colitis (UC). Methods We studied 149 patients with moderate to severe UC (Mayo score ≥6 and endoscopic subscore ≥2) despite treatment for at least 14 days with oral prednisone (40–50 mg/day). Subjects were randomly assigned to groups that were given 20 mg (n = 46) or 40 mg (n = 52) basiliximab or placebo (n = 51) at weeks 0, 2, and 4. All subjects received 30 mg/day prednisone through week 2; the dose was reduced by 5 mg each week to 20 mg/day, which was maintained until week 8. At week 8, we compared the rates of clinical remission (Mayo score ≤2, no subscore >1) for patients given basiliximab with the rate for patients given placebo. Results Twenty-eight percent of patients given placebo, 29% of those given the 40-mg dose of basiliximab, and 26% of those given the 20-mg dose of basiliximab achieved clinical remission ( P = 1.00 vs placebo for each dose). Basiliximab was generally well tolerated. Six subjects who received basiliximab had serious adverse events (6.1%) compared with 2 who received placebo (3.9%; P = .72). In subjects given basiliximab, incomplete saturation of CD25 (