This is an open-label, extension, Phase III study to evaluate the long-term safety, efficacy and PK of MRA in patients with pJIA who participated in Study MRA318JP.

Inclusion criteria

• Of the patients who received three infusions with MRA in the previous study and for whom a last observation was conducted
• the patients who did not have problems with safety in the previous study"

Exclusion criteria

• Patients who were not enrolled by 3 months after completion of the previous study

• Patients who received any of the following since completion of the previous study until initiation of treatment in the present study

  1. DMARDs or immunosuppressants
  2. Intravenous and intramuscular injection of corticosteroids
  3. Plasma exchange therapy
  4. Other drugs and therapies that may affect evaluation of drug efficacy