Generalized Myasthenia gravis (gMG) is a rare autoimmune disease in which the body’s defense system attacks the connection point between nerves and muscles. This can cause double vision, drooping of the eyelids, and difficulty swallowing, talking, breathing, and using the arms and legs.

The Adapt Junior SC study is designed to evaluate how the investigational study drug^* may work (also known as efficacy) and how safe it is for the use in children living with gMG.

* The investigational study drug, efgartigimod PH20 SC, is not approved by any regulatory agency for use in pediatric patients living with gMG as efficacy and safety have not been established.

Your child may be eligible to participate if they:

• Are between the ages of 2 and 18 (for US ages between 12 – 18)
• Are diagnosed with gMG

Additional criteria to participate will apply which the study doctor will discuss with you.

The study consists of 3 phases:

Sceening phase (2 weeks): up to 2 weeks before starting the study treatment, the study team will assess if your child meets the eligibility criteria.

Treatment phase (4 weeks): the investigational study drug will be given once per week (4 times) as an injection through a needle under the skin. The standard therapy for gMG will also be continued during the study.

Follow up phase (8 weeks): for approximately 8 weeks after the last dose of the investigational study drug. The study team will continue to monitor your child for safety. This will include physical check-ups, blood work and urine tests, and answering health-related questions.

Study participants who complete the Adapt Jr SC may choose to enroll in the open label extension safety study, where the study participant will receive the investigational study drug and continue to be monitored for safety.