Zanuburutinib in Relapsed and Refractory iMCD: a Prospective, Single-center, Single-arm Trial

Inclusion Criteria: * fulfilled the CDCN (Castleman Disease Collaborative Network) diagnostic criteria of iMCD * relapsed or refractory disease. Relapsed = patients who ever achieved overall partial response (PR) or complete response (CR) with prior lines of therapy suffered from progressive disease (PD); refractory = iMCD patients who never achieved PR or CR with the first-line treatment but suffered from PD during treatment. * Eastern Cooperative Oncology Group performance status (ECOG-PS ≤ 2) * Neutrophil count ≥ 0.75×10\^9/L, hemoglobin ≥ 70 g/L and platelet count \> 30×10\^9/L * Total bilirubin ≤ 2 x ULN (upper limit of normal), AST（aspartate aminotransferase） or ALT（Alanine aminotransferase）≤ 2.5 x ULN * INR （international normalized ratio) and APTT(activated partial thromboplastin time) ≤ 1.5 x ULN；eGFR\>25ml/min/1.73m2 * estimated survival ≥ 3 months * agree to take birth control methods during study period for women of reproductive age * agree to provide informed consent Exclusion Criteria: * concurrent malignancies * prior history of receiving any kind of BTK (Bruton's tyrosine kinase) inhibitors * patients with SLE (systemic lupus erythematosus), HHV-8 (human herpesvirus-8) infection or POEMS syndrome * History of major surgery or radiation therapy within 4 weeks before initiation of study drug * history of myocardial infarction within 1 years * patient with history of heart failure (NYHA 3 or 4) would be excluded unless his LVEF(left ventricular ejection fraction) ≥ 50% within 1 months * primary cardiomyopathy; Qtc \> 450ms for men and \> 470ms for women * breast feeding or pregnant women * intolerance for oral regimen due to gastro-intestinal disorders * uncontrolled infection * positive HBV(hepatitis B virus)-DNA titers or positive HbsAg; positive HCV(hepatitis C virus)antibody; patients with HIV infection * patients with history of bleeding disorders * cerebral infarction or intracranial bleeding within 6 months * active bleeding disorders within 2 months * taking anti-platelet or anticoagulation drugs * taking drugs which strongly inhibit P450 CYP3A * patients or their relatives fail to understand the purpose of the study * any other conditions that the investigators consider to be not appropriate for inclusion