This is a Phase 2, open-label, randomized, multicenter study to assess the efficacy and safety of DZD8586 in patients with primary immune thrombocytopenia (ITP). The target population of this study is patients with primary ITP who had failed to respond or relapsed after receiving at least one standard therapy. Participants who meet the inclusion criteria and do not meet the exclusion criteria will be randomized to different dose groups.

Inclusion Criteria:

1. Male and female participants ≥ 18 years of age.
2. Diagnosed with persistent or chronic primary ITP, and an average of two platelet counts < 30 × 10⁹/L.
3. Have failed at least one standard treatment for ITP (glucocorticoids and/or IVIG).
4. Adequate bone marrow reserve and organ functions.
5. Willing to comply with contraceptive restrictions.

Exclusion Criteria:

1. Have evidence of secondary causes of immune thrombocytopenia.
2. Have a history of coagulation disorders other than ITP, such as disseminated intravascular coagulation, hemolytic uremic syndrome, or thrombotic thrombocytopenic purpura.
3. Any of previous or current treatment prohibited by protocol.
4. Any of severe cardiac abnormalities.
5. Active infection.
6. Poorly controlled gastrointestinal disorder, inadequate absorption of medication or other systemic diseases.
7. Known allergy to DZD8586 drug excipients or other chemical analogues.
8. Pregnant or breastfeeding female participants.