A Study to Assess Adults with CIDP Transitioning from IVIg to Efgartigimod PH20 SC

Inclusion Criteria:

• Is at least 18 years of age and the local legal age of consent

• Is diagnosed with CIDP (confirmed or possible CIDP) according to the criteria of theEuropean Academy of Neurology/Peripheral Nerve Society

• Is being treated with IVIg every 3-6 weeks, on a stable dose and dosing interval (between 0.5-2 g/kg) for at least 3 doses

• If receiving oral corticosteroids, this should be at a stable dose of less than 20mg a day or less than 40 mg every other day, for at least a month.

• If receiving nonsteroidal immunosuppressive medication, this should be at a stabledose for at least 3 months

Exclusion Criteria:

• Besides the indication under study, known autoimmune disease or any medicalcondition that would interfere with an accurate assessment of clinical symptoms ofCIDP or puts the participant at undue risk

• Types of other polyneuropathy other than CIDP