• Subjects voluntarily join this study, sign the informed consent form (ICF), and demonstrate good compliance;

• Male or female subjects aged 18 to 75 years (calculated based on the date of signing the informed consent form);

• Eastern Cooperative Oncology Group (ECOG) score of 0-1;

• Diagnosis of primary ITP prior to randomization, with a duration of ≥12 months;

• An average of at least three independent platelet counts (spaced more than 3 days apart) within the 3 months prior to randomization \<30×10\^9/L, with no count \>35×10\^9/L; and no severe bleeding within 4 weeks prior to screening;

• Previous treatment with glucocorticoids and at least one standard ITP therapy that was ineffective or resulted in relapse.

• Female subjects of childbearing potential must agree to use effective contraception during the study and for 6 months after the end of study treatment, with a negative serum or urine pregnancy test within 7 days prior to study enrollment; male subjects must agree to use effective contraception during the study and for 6 months after the end of study treatment, as detailed in Section 5.5.