Efficacy and Safety of Abrilumab in a Randomized, Placebo-Controlled Trial for Moderate-to-Severe Ulcerative Colitis.

Background & Aims: The αβ integrin is a validated target in inflammatory bowel disease. This randomized, phase 2b, placebo-controlled, double-blind study evaluated the efficacy and safety of the anti-αβ antibody abrilumab in patients with moderate-to-severe ulcerative colitis despite treatment with conventional therapies.

Methods: Patients (total Mayo Score 6-12, recto-sigmoidoscopy score ≥2) with inadequate response or intolerance to conventional therapies were randomized to receive subcutaneous abrilumab (7, 21, or 70 mg) on day 1, weeks 2 and 4, and every 4 weeks; abrilumab 210 mg on day 1; or placebo. The primary end point was remission (total Mayo Score ≤2 points, no individual sub-score >1 point) for the 2 highest dosages at week 8. Key secondary end points were response and mucosal healing (centrally read) at week 8.

Results: For 354 patients who received ≥1 dose of investigational product (placebo, n = 116; 7 mg, n = 21; 21 mg, n = 40; 70 mg, n = 98; 210 mg, n = 79), non-adjusted remission rates at week 8 were 4.3%, 13.3%, and 12.7% for the placebo and abrilumab 70-mg and 210-mg groups, respectively (P < .05 for 70 and 210 mg vs placebo); odds of achieving remission were significantly greater with abrilumab 70 mg (odds ratio 3.35; 90% CI 1.41-7.95; P = .021) and 210 mg (odds ratio 3.33; 90% confidence interval 1.34-8.26; P = .030) than with placebo. Response and mucosal healing rates with these dosages also were significantly greater than with placebo. Higher baseline αβ levels on naïve CD4 T cells were a prognostic indicator for overall outcome, but not a predictive biomarker of abrilumab response. There were no cases of progressive multifocal leukoencephalopathy or deaths.

Conclusions: Abrilumab treatment for 8 weeks induced remission, clinical response, and mucosal healing in patients with moderate-to-severe ulcerative colitis. ClinicalTrials.gov, number NCT01694485.