Abrilumab (AMG 181) in Adults With Moderate to Severe Ulcerative Colitis

The study consisted of a 24-week double-blind, placebo-controlled treatment period followed by an open-label period of approximately 108 weeks. Participants were eligible to enter the open-label period of the study early if they did not achieve a response at week 8 and had an inadequate response at week 12 or later or if they experienced disease worsening after achieving response and/or remission at week 8. Failure to achieve response at week 8 was defined as failure to achieve a decrease from baseline in total Mayo Score ≥ 3 points and ≥ 30% decrease from baseline. Inadequate response at week 12 or later was defined as failure to achieve a 2-point decrease and 25% improvement in partial Mayo Score compared with screening and minimum partial Mayo Score ≥ 5 points. Disease worsening was defined as an increase in partial Mayo Score ≥ 3 points from the week 8 value and minimum partial Mayo Score ≥ 5 points with recto-sigmoidoscopy sub-score ≥ 2. Participants were planned to be randomized in a 2:1:2:2:2 ratio to placebo or abrilumab at 7 mg, 21 mg, 70 mg (on day 1, week 2, week 4, and every 4 weeks thereafter until week 24), or 210 mg (on day 1 followed by placebo in weeks 2 and 4 and every 4 weeks thereafter until week 24), respectively. Due to a consistent discrepancy between the investigational product (IP) instruction manual (IPIM) description of vial positions and the actual vial positions in the IP package participants were initially randomized to 3 arms (placebo, 70 mg, and 210 mg) with a randomization ratio of 4:3:2. The study was temporarily paused while this issue was investigated. Once the discrepancy was corrected, Protocol Amendment 3 implemented, and affected participants completed their double-blind treatment period, the study resumed enrollment and randomization per protocol. Neither the randomization nor study blind was compromised and therefore the intent-to-treat principle was maintained.