The main purpose of this study is to assess the efficacy and safety of LIV-GAMMA SN Inj. in adult subjects with ITP. The primary objective of this study is to determine the responder rate. A response is defined as a platelet count of ≥30×10^9/L and at least a 2 fold increase of the baseline, confirmed on at least 2 separate occasions at least 7 days apart without bleeding. The secondary objectives are to evaluate the further efficacy assessments including duration of response, and the safety of LIV-GAMMA SN Inj.

Inclusion Criteria:

• Diagnosis of ITP
• Mean screening platelet count of <30×10^9/L from 3 qualifying platelet counts performed within 14 days before the start of treatment, with no individual platelet count above 35×10^9/L.
• No other factors inducing ITP
• Stable doses of ITP active treatment must not have modified the dose in the preceding 1 month and must maintain their prestudy dose during the study.

Exclusion Criteria:

• Known for hypersensitivity reactions to blood products, intravenous immunoglobulin (IVIg) or immunoglobulin G
• Immunoglobulin A (IgA) deficiency
• Therapy with live attenuated virus vaccines 3 months before the first administration of LIV-GAMMA SN Inj.
• Administration of other investigational product 1 month before the first administration of LIV-GAMMA SN Inj.
• Administration of Rituximab 3 months before the first administration of LIV-GAMMA SN Inj.
• Treatment with anti-coagulants, which may affect the function of platelet
• Positive HIV, HBV, HCV
• 3-fold increase of ALT or AST compared to normal upper limit
• eCFR < 30mL/min/1.73m^2
• History of deep vein thrombosis (DVT) or IVIg-induced thrombotic compliances
• Hemoglobin > 10g/dL