Phase III Clinical Trial of NPB-01maintenance Therapy in Patients With Chronic Inflammatory Demyelinating Polyneuropathy.

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.