Multifocal motor neuropathy (MMN) is a rare but serious chronic disorder that affects the nerves responsible for controlling muscle movement, mainly in the hands, forearms, and lower legs. Over time, it causes progressive muscle weakness that could eventually lead to considerable disability. This may result in irreversible functional impairment and fatigue, which often impacts a person’s physical health, psychological health, social life, and occupation.

The Empasound study is designed to evaluate how the investigational study drug*, empasiprubart, may work (also known as efficacy) and how safe it is for the use in adults living with MMN.

The study aims to evaluate if the investigational study drug affects the thickness of the nerves, muscle strength, movement, and how well participants can grip and handle objects.

*The investigational study drug, empasiprubart, is not approved by any regulatory agency for use in MMN as efficacy and safety have not been established.

MMN patients may be eligible to participate if they are:

• Diagnosed with MMN
• Vaccinated against certain bacterial infections. If not yet vaccinated, willing to be vaccinated before receiving the investigational study drug
• At least 18 years old
• Not pregnant, or actively trying to get pregnant

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

Screening phase: Tests will be run to find out if the participant can join the study. The study doctor may ask for tests to confirm the MMN diagnosis. Participants will receive vaccines against certain bacterial infections if they have not had them already. Regular immunoglobulin treatment (IVIg or SCIg) may continue until the end of the screening phase.

Treatment phase: The participant will receive the investigational study drug monthly for up to 12 months. The study drug is given through a vein in the arm (intravenously). Immunoglobulin treatment is not allowed during this phase.

Follow up phase: For up to 15 months after the final study drug administration, the study team will continue to monitor the participant for safety. This will include a physical check-up, blood work, urine tests, and answering health related questions.