Ilaris® Effects in Schnitzler Syndrome (ILESCH)

This is a multi-center double-blind placebo-controlled study to assess the efficacy and safety of canakinumab (trade name Ilaris®), a high-affinity monoclonal antibody that neutralizes IL-1β, in patients with Schnitzler syndrome. Efficacy is assessed by physician's global assessment (a combined clinical symptom score) and inflammation markers. Following a baseline period of 1-4 weeks, patients will be randomized to receive single s.c. injections of either 150 mg canakinumab or placebo (day 0). Treatment response will be assessed on day 7. Patients will then be eligible to enter the 16-week open-label phase and receive canakinumab injections (150-300mg, dose depends on clinical response on day 7) upon relapse of symptoms. Visits for investigator's assessments will be scheduled at 4-weekly intervals following day 7. Overall a max. of 20 subjects with Schnitzler syndrome will be enrolled. 1. Amendment: After successful completion of the 16-week open-label phase patients will be eligible to enter a one-year open-label extension of the study. During this part of the study patients will be scheduled at bi-monthly intervals. Canakinumab dosing will be performed upon relapse of symptoms comparable to the 16-week open-label phase. 2. Amendment: After successful completion of the 1-year open-label study extension patients will be eligible to enter another 3-year open-label extension. Patients will be scheduled at 3-month-intervals and Canakinumab dosing will be performed on an individual basis with optimized dosing intervals to ensure a constant low disease activity.