IMVT-1402 in Adult Participants With Chronic Inflammatory Demyelinating Polyneuropathy (CIDP)

Inclusion Criteria: * Have met clinical diagnostic criteria for typical CIDP or one of the following CIDP variants: multifocal CIDP or motor CIDP per the 2021 European Academy of Neurology/Peripheral Nerve Society (EAN/PNS) Guideline on Diagnosis and Treatment of CIDP. * Have electrodiagnostic test results supporting the diagnosis of CIDP per the EAN/PNS guideline on diagnosis and treatment of CIDP. * Are currently on, and have been receiving chronic, stable doses of systemic corticosteroids (i.e., daily or every other day oral or pulse regimen), or immunoglobulin therapy (IVIg or SCIg) ± low dose oral corticosteroids for at least 3 months for the treatment of CIDP at the time of the Screening Visit. Additional inclusion criteria are defined in the protocol. Exclusion Criteria: * Have current or prior history of IgM paraproteinemia with or without anti-myelin-associated-glycoprotein antibodies. * Have distal, sensory, or focal CIDP, or have a diagnosis of autoimmune nodopathy per the EAN/PNS guideline on diagnosis and treatment of CIDP. * Have polyneuropathy of causes other than CIDP including but not limited to: * Multifocal motor neuropathy * Hereditary demyelinating neuropathy * Polyneuropathy, organomegaly, endocrinopathy, monoclonal protein and skin change syndromes (i.e., POEMS) * Lumbosacral radiculoplexus neuropathy * Systemic illnesses including vitamin deficiency syndromes and paraneoplastic neuropathies * Drug- or toxin-induced * Have diabetes mellitus (DM) and meets any of the following criteria: * Does not have both typical CIDP and strong evidence of demyelination on nerve conduction study. * In the opinion of the Investigator, there is evidence of poorly controlled DM preceding the diagnosis of CIDP. * In the opinion of the Investigator, there is evidence of poorly controlled DM at screening. * Have a history of myelopathy or evidence of central demyelination. Additional exclusion criteria are defined in the protocol.