To evaluate the efficacy and safety of B001 injection in aquaporin-4 antibody positive patients with neuromyelitis optica spectrum disorder.

Inclusion Criteria:

1. Confirmed NMOSD patients;
2. Experienced at least 1 recurrence of NMOSD within 1 year or at least 2 recurrence within 2 years prior to screening;
3. The blood pregnancy tests were negative within 7 days before the first dose in fertile female subjects. The fertile subjects and the male subjects whose partner are fertile woman agree to use reliable contraception during the study period and within 6 months after the study drug discontinuation;
4. Volunteer to participate in clinical research; Fully understand and know the study and sign the informed consent; Willing to follow and able to complete all test procedures.

Exclusion Criteria:

1. Subjects with severe NMOSD were judged by the researcher to be unfit to participate in this study;
2. Subjects with chronic active immune system diseases undergoing systematic treatment;
3. Received anti-CD20 or other cell depletion therapy within 6 months before first dose;
4. Received the prescribed drug treatment at the prescribed time before first dose;
5. Subjects who have participated in any drug clinical trials within 28 days prior to the first dose;
6. Received hematopoietic stem cell transplantation、 lymphatic irradiation before first dose;
7. Pregnant or lactating women; Subjects with birth plans during the trial;
8. Subjects who had undergone major surgery within 2 months prior to screening or were scheduled to undergo major surgery during the trial;
9. Subjects with severe, progressive, or uncontrolled disease who have been assessed by the investigator to be at increased risk of participating in the study;
10. A history of gastrointestinal perforation and/or fistula within 6 months prior to screening;
11. Subjects who received a live or attenuated vaccine within 4 weeks prior to initial administration, or who plan to receive vaccination during the study period;
12. Subjects with severe or persistent infection currently or within the 1 months prior to screening;
13. Subjects with positive gamma interferon release test;
14. Subjects who currently have active hepatitis or have a history of severe liver disease;
15. Uncontrolled systemic disease, or any other reason the investigator deems inappropriate for inclusion;
16. Abnormal laboratory test results;
17. Subjects with a history of alcohol or drug abuse in the 6 months prior to screeing, or who are abusing;
18. Subjects with symptoms of severe mental illness who are clinically uncooperative;
19. Subjects who were unable to undergo magnetic resonance imaging during the study and who had other conditions that the investigator considered inappropriate to enroll.