Efficacy and safety of ABT-874, a monoclonal anti-interleukin 12/23 antibody, for the treatment of chronic plaque psoriasis: 36-week observation/retreatment and 60-week open-label extension phases of a randomized phase II trial

Background: ABT-874, an anti-interleukin-12 and -23 antibody, was previously shown to be significantly more effective compared with placebo during a 12-week phase II study of psoriasis. We report here safety and efficacy data of ABT-874 during subsequent phases of this study. Objective: We sought to examine the preliminary efficacy and safety of ABT-874 for moderate to severe psoriasis beyond 12 weeks. Methods: Patients with chronic plaque psoriasis who responded to ABT-874 during the initial randomized, placebo-controlled, 12-week study phase were eligible for a 36-week observation/retreatment phase. During the subsequent 60-week, open-label extension phase, eligible patients were retreated with one of two ABT-874 dosages. Efficacy was measured using Psoriasis Area and Severity Index and physician global assessment scores; safety was monitored by adverse events (AEs), laboratory parameters, and vital signs. Results: During the observation/retreatment phase, 130 of 180 patients were eligible for retreatment. After 12-week retreatment with ABT-874, 55% to 94% of retreated patients (n = 58) achieved a 75% or greater reduction in Psoriasis Area and Severity Index score. Among patients receiving ABT-874 through the first 48 weeks, there were no deaths and 4 patients with serious AEs; one patient discontinued because of an AE. During the open-label extension (N = 105), there were no deaths or serious infections, and 3 serious AEs. Limitations: Lack of placebo or active comparator groups limited statistical analysis in later study phases. Dosing differences existed between groups, and only week-12 responders were eligible for retreatment. Conclusion: ABT-874 continued to show good efficacy and safety during withdrawal and reinitiation of therapy.