A Phase 2, Open-label, Proof-of-Concept Study to Investigate the Efficacy, Safety, and Tolerability of TAK-411 in Adult Subjects With Chronic Inflammatory Demyelinating Polyradiculoneuropathy (The CASCA Study)
CIDP is an autoimmune disease. This means that the body's germ fighting (immune) system attacks itself. In CIDP, the immune system attacks the protective covering around the nerves called myelin. Over time, these nerves lose their ability to send signals to the muscles in the body. This leads to muscle weakness and loss of sensation in arms and legs among other symptoms. Participants with CIDP can be treated with a protein called immunoglobulin (or IG). TAK-411 is a special type of immune globulin G (hsIgG) that has been chemically changed. It is made from IG that comes from human plasma. This study will test if TAK-411 can decrease inflammation and improve symptoms of CIDP. The main aim of this study is to check how TAK-411 affects the physical functioning of adults with CIDP when compared with results of the placebo group of a historical trial. Participants may be treated with TAK-411 for up to 1 year (51 weeks) and will be followed up for 3 weeks after last dose. During the study, participants may visit their study clinic up to approximately 21 times.
• The participant is at least 18 years of age, inclusive, at the time of signing the Informed Consent Form (ICF).
• The participant has a body weight of less than or equal to (\<=) 150 kilogram (kg).
• The participant has a documented diagnosis of typical CIDP, as confirmed by a neurologist specializing/experienced in neuromuscular diseases and consistent with the European Academy of Neurology/Peripheral Nerve Society (EAN/PNS) 2021 criteria.
• The participant has responded to IgG treatment in the past (documented partial or complete resolution of neurological symptoms and deficits).
• The participant has had disease activation within 18 months before screening, as documented in medical records and in the opinion of the investigator, defined as one of the following:
‣ Clinically meaningful deterioration of symptoms on interruption or dose reduction of IgG treatment.
⁃ Clinically meaningful deterioration of symptoms requiring IgG treatment dose increase with subsequent clinical improvement.
⁃ Clinically meaningful deterioration of symptoms at the end of IgG treatment dose interval with improvement after next dose administration.
• The participant is on a stable dose of immunoglobulin treatment intravenously (IGIV) treatment, defined as no change greater than 10 percentage (%) in frequency or dose of IGIV therapy within the 12 weeks before and throughout screening within the dose range of 0.4 to 2.4 grams per kilogram (g/kg) every 2 to 6 weeks (inclusive).
• The participant has an INCAT score greater than (\>) 2 at screening.