Patients diagnosed with Chronic Inflammatory Demyelinating Polyneuropathy were confirmed based on the European Federation of Neurological Societies/ Peripheral. Nerve Society Guideline. Patients who meet all inclusion criteria and do not conflict with the exclusion criteria will receive NPB-01 (intravenous immunoglobulin) 400mg/kg/day for five consecutive days. Subsequently, patients receive NPB-01 1g/kg every 3weeks and evaluate the Inflammatory Neuropathy Cause and Treatment（INCAT） score and INCAT sensory sumscore（ISS） et al.

As a safety endpoint, the safety of NPB-01 will be investigated the occurrence of adverse events by one year after the start of the study treatment.

Inclusion Criteria:

• 1. Patients with progressive or relapsing motor and sensory dysfunction of more than one limb resulting from neuropathy within 2 months prior to the date informed consent is obtained.
• 2. Patients who INCAT score between 2-9. (If the INCAT score is 1 in upper limb, the INCAT score of 2 must be exclusively from leg disability to qualify.)
• 3. Patients who need high-dose intravenous immunoglobulin therapy.
• 4. Patients who continued treatment for CIDP without addition or increase at 30 days before informed consent.
• 5. Patients with greater than or equal to twenty years old at informed consent.

Exclusion Criteria:

• 1. Patients with evidence of myelopathy or demyelination of central nerve
• 2. Patients with evidence of stroke, central nerve system trauma, or persistent neurological deficits due to peripheral neuropathy from other causes（diabetic neuropathy, IgM paraproteinaemia, uraemic neuropathy, toxic neuropathy, hereditary neuropathy）
• 3. Patients with evidence of neuropathy or alcoholic neuropathy or vitamin deficiency neuropathy due to myeloma, lymphoma, sarcoidosis, systemic lupus erythematosus, malignancy, vasculitis, Crow-Fukase syndrome, Sjögren syndrome.
• 4. Patients with multifocal motor neuropathy.
• 5. Patients treated with plasmapheresis at 3 months before informed consent.
• 6. Patients treated with rituximab at 6 months before informed consent.
• 7. Patients treated with high-dose intravenous immunoglobulin（greater than or equal to 1g/kg） at 8 weeks before informed consent.
• 8. Patients treated with intravenous immunoglobulin at 3 weeks before informed consent.
• 9. Patients with history of shock or hypersensitivity for NPB-01.
• 10. Patients with IgA deficiency.
• 11. Patients with malignancy at informed consent.
• 12. Patients with impaired liver function.
• 13. Patients with impaired renal function.
• 14. Patients with cerebro- or cardiovascular disorders.
• 15. Patients with high risk of thromboembolism.
• 16. Patients with hemolytic/hemorrhagic anemia.
• 17. Patients with decreased cardiac function.
• 18. Patients with decreased platelet.