The goal of this clinical trial is to evaluate the efficacy and safety, of JYP0061 in acute NMOSD patients. The main questions it aims to answer are: efficacy and safety of JYP0061 in acute NMOSD patients. Participants will be treated with low-dose JYP0061 in combination with reduced dose glucocorticoids or standard dose glucocorticoids or high-dose JYP0061. Efficacy and safety evaluations will be conducted according to the protocol.

This study will be an open-label, multicenter phase 2 clinical trial. After being informed about the study and potential risks, all subjects giving written informed consent will undergo a 2-week screening period to determine eligibility for study entry. And then subjects will be treated with low-dose JYP0061 in combination with reduced dose glucocorticoids or standard dose glucocorticoids. The efficacy and safety measures will be conducted according to the protocol. If JYP0061 is effective and safe for acute NMOSD patients, then subjects will be treated with high-dose JYP0061 or standard dose glucocorticoid. The efficacy and safety measures will be conducted according to the protocol.

Inclusion Criteria:

• Neuromyelitis spectrum disease (NMOSD) patients according to 2015 International consensus diagnostic criteria.
• Positive Aquaporin 4 immunoglobulin G (AQP4-IgG)
• Patients with acute NMOSD
• Female serum pregnancy test results were negative at the time of screening, subject (including partner) had no child-rearing plan and voluntarily adopted double contraceptive (non-oral contraceptives) within 6 months from screening to the last study drug administration, and had no sperm/egg donation plan;
• Have fully understood this study, voluntarily participate in the experiment, and voluntarily sign the written informed consent.

Exclusion Criteria:

• Pregnant or lactating women;
• Suspected or clear allergy to similar ingredients or any ingredient in the study drug, or allergic constitution;
• Symptoms improved in the acute phase before the study drug was used;
• Unable to complete MRI or gadolinium enhanced examination;