An Open-label Extension Study of Canakinumab in Patients With Systemic Juvenile Idiopathic Arthritis and Active Systemic Manifestations Manifestations and Response Characterization Study in Canakinumab Treatment-naïve Patients With Active SJIA With and Without Fever.

Inclusion criteria: * Patients from study CACZ885G2305 or CACZ885G2301 who achieved an adapted ACR pediatric 30 response 15 days after their initial dose of canakinumab but clinically deteriorated afterwards or a minimum ACR Pediatric 30 response was not maintained after Day 15 and intervention is deemed necessary by the investigator, or Patients in study CACZ885G2301 who are not eligible to enter Part II (withdrawal part) because they were not able to meet the corticosteroid entry criteria , or Responder patients in Part I or Part II who had not flared when CACZ885G2301 was stopped, or CACZ885G2301 patients who were responders in Part I but experienced a flare in Part II. * Treatment-naïve patients need to meet the following criteria: * Confirmed diagnosis of systemic juvenile idiopathic arthritis as per ILAR definition that must have occurred at least 2 months prior to enrollment with onset of disease \< 16 years of age * Male and female patients aged ≥ 2 to \< 20 years of age * Active disease at the time of enrollment defined as having 2 or more of the following: * Documented spiking, intermittent fever (body temperature \> 38°C) for at least 1 day during the screening period and within 1 week before first canakinumab dose * At least 2 joints with active arthritis * AND C-reactive protein (CRP) \> 30 mg/L (normal range \< 10 mg/L) Rash Serositis Lymphadenopathy Hepatosplenomegaly * Naïve to canakinumab Other protocol-defined inclusion criteria may a…