Rituximab Induced Remission in Patients With Chronic Inflammatory Demyelinating Polyneuropathy

Inclusion Criteria Group 1 (new/untreated patients): * CIDP according to the EAN/PNS criteria (1) * Untreated * Men and women aged between 18 and 80 years * Sufficient CIDP-related disability, as judged by treating physician to warrant IVIg and RTX treatment * Capable of giving signed informed consent Inclusion Criteria Group 2 (patients on maintenance treatment): * CIDP according to the European association of neurology/Peripheral nerve society (EAN/PNS) criteria (1) on maintenance treatment (stable dose/interval of at least 4 infusions or 3 months), including one of the following categories: 1. patients with wear-off symptoms before next IVIg infusion captured by at least the minimal clinical important difference (MCID) on at least one outcome measure (see below) 2. patients with a failed withdrawal attempt in the last 12 months captured by at least an MCID on at least one outcome measure (see below) 3. patients with an increase of IVIg/SCIg dose/interval in the last 12 months leading to improvement by at least the MCID on at least one outcome measure, see below. The most commonly used MCID criteria, namely: 1) one point on the aINCAT disability score (1-10); 2) 4 points on a centile score on I-RODS (disability, 1-100); 3) 2 points on the MRC sum score (muscle strength, 0-60) and 4) 8 kPa on Vigorimeter (grip strength, single or both arms, variable range). * Men and women aged between 18 and 80 years * Capable of giving signed informed consent Exclusion Criteria: * Paranodopathy with demonstrated (paranodal) antibodies, previously considered part of CIDP spectrum (in these cases rituximab is preferred treatment) * Use of drugs associated with a demyelinating neuropathy in the last six months. * Known serious adverse events with previous IVIg or RTX treatment. Hypersensitivity to RTX or any component of the formulation. Hypersensitivity to the human immunoglobulins or to any of the excipients. Known selective IgA deficiency patients who developed antibodies to IgA. * Positive hepatitis B and C serology suggesting active/untreated infection (HBsAg, anti-HB core en anti-HBs and HCV antibody (IgG)) * Ongoing immunosuppressive treatment for other indications. * Immunosuppressive treatment other than (already discontinued) corticosteroids in last 6 months. * IVIg interval of once every 6 weeks or more than 6 weeks (applies to Group 2 only) * Obesity (BMI \> 35) * Known active malignancy (not in remission), currently treated with chemotherapy or immunomodulatory drugs, or with a life expectancy of less than 1 year. * History of recurrent/chronic infections * Active, severe infections (such as tuberculosis, sepsis and opportunistic infections) * Patients in a severely immunocompromised state Severe heart failure (New York Heart Association Class IV) or severe, uncontrolled cardiac disease * Serious co-morbidity as judged by treating physician. * Pregnancy or nursing mother; intention to become pregnant during the course of the study; female patients of childbearing potential either not using or not willing to use a medically reliable method of contraception for the entire duration of the study. * No written informed consent