The main purpose of the study is to determine the correct dose of empasiprubart in adolescent participants. It also aims to evaluate if empasiprubart may work and how safe it is for the use in children living with CIDP.

The study consists of an open label treatment phase where participants will receive empasiprubart for up to 27 months approximately. After the final dose of empasiprubart, participants will enter a safety follow-up period for up to 14 months approximately.

The overall study duration for each participant is up to 43 months.

More information can be found here: clinicaltrials.argenx.com/emlight

Inclusion Criteria:

• Is aged 12 to <18 years.
• Meets criteria for CIDP based on EAN/PNS Task Force CIDP guidelines, second revision (2021).
• Has a diagnosis of either typical CIDP or 1 of the following CIDP variants: motor CIDP (including motor-predominant CIDP), multifocal CIDP (also known as Lewis-Sumner syndrome), focal CIDP, or distal CIDP.

Exclusion Criteria:

• Possible CIDP based on EAN/PNS Task Force CIDP guidelines, second revision (2021).
• Sensory CIDP (including sensory-predominant CIDP).
• Besides the indication under study, known autoimmune disease or any medical condition that would interfere with an accurate assessment of clinical symptoms of CIDP, or that puts the participant at undue risk.
• Prior use of other long-acting immunomodulatory treatment.