Study of Safety and Efficacy of MY008211A in Patients With Residual Anemia Despite Anti-C5 Antibody Treatment

Inclusion Criteria: 1. Male and female participants ≥ 18 years of age and BMI ≥ 18.0 kg/m2 with a diagnosis of PNH confirmed by high-sensitivity flow cytometry with clone size ≥ 10%. 2. Stable regimen of anti-C5 antibody treatment for at least 6 months before treatment, and Hb was still \< 100 g/L. 3. The average hemoglobin level of at least two tests in 4 months before screening \< 100 g/L. 4. The average hemoglobin level of two tests in the central laboratory during screening \< 100 g/L. 5. Vaccination against Neisseria meningitidis infection is required prior to the start of study treatment. If not received previously, vaccination against Streptococcus pneumoniae and Haemophilus influenzae infections should be given. Exclusion Criteria: 1. Patients with reticulocytes \<100x10\^9/L; platelets \<30x10\^9/L; neutrophils \<0.5x10\^9/L. 2. History of recurrent invasive infections caused by encapsulated organisms,e.g. meningococcus or pneumococcus. 3. Known or suspected hereditary complement deficiency. 4. Previous bone marrow or hematopoietic stem cell transplantation. 5. Previous splenectomy. 6. A history of malignancy within 5 years before screening, except cured local basal cell carcinoma of the skin and carcinoma in situ of the cervix.