Intravenous Immunoglobulin (IVIG, Bioven) Efficacy and Safety in Chronic Primary Immune Thrombocytopenia (ITP) in Adults

Inclusion criteria: * Signed Patient Informed Consent Form for participation in the study; * Men and women aged 18-65; * Confirmed primary chronic ITP (lasting \> 12 months since diagnosis); * A full blood count should be normal except for the isolated thrombocytopenia. Patients with low hemoglobin levels (but above 90 g / l) may be included if there are symptoms of bleeding; * If bleeding symptoms are diagnosed, the reticulocyte count should be measured; * Platelet count \<30 x 109 / L; * If the patient is taking corticosteroids, the treatment regimen/dose should be stable (at least 2 weeks prior to screening); * Negative pregnancy test (for women of child-bearing potential); * Willingness to use effective and reliable methods of contraception throughout the entire study period; * The results of physical, instrumental, and laboratory examination of patients should be within the normal range or deviations should be regarded by the researcher as clinically insignificant; * Ability, according to the researcher, to follow all the requirements of the study protocol; Exclusion criteria: * Known intolerance to plasma and immunoglobulin preparations; * Drug allergy or hypersensitivity to immunoglobulin preparations; * Confirmed deficiency of immunoglobulin A (IgA) and antibodies to IgA. * Contraindications to immunoglobulin administration according to the instructions for medical use; * Pregnancy and lactation; * Any clinically significant hepatic impairment (increase of serum transaminase levels by more than 3 times the upper limit of normal); * Serum creatinine levels are more than two times higher than the upper limit of normal for a given age and sex; * Severe cardiovascular insufficiency (HF III); * History of thrombosis or presence of significant risk factors for thrombosis. * Patients with preventive splenectomy; * Hemostatic disorders other than chronic thrombocytopenia; * Persons with acute or exacerbation of chronic diseases of the gastrointestinal tract associated with the risk of bleeding, acute infectious diseases, pathologies of the respiratory system; * Proven case of primary immunodeficiency; * Secondary immune thrombocytopenia; * Virus infections (Epstein-Barr, Cytomegalovirus, Parvovirus, Hepatitis B and C); * Documented HIV infection * Positive reaction of Wassermann (RW) test result; * Systemic immunopathological diseases (rheumatic diseases, nephritis, etc.); * Oncological diseases; * Diabetes mellitus; * Thyroid diseases; * History of mental illness; * Known drug addiction; * Any other concomitant decompensated diseases or acute conditions, the presence of which, according to the researcher, may significantly affect the results of the study; * The need to prescribe drugs that are incompatible with the administration of the drug in this study: other immunoglobulin preparations in addition to the study drug, cytostatic drugs, monoclonal antibodies, Avatrombopag); * Experimental treatment (e.g. Rituximab therapy) for 3 months prior to screening); * Blood transfusions or transfusions of blood products in the last 6 months prior to inclusion in the study; * Administration of IVIG 30 days prior to screening; * Participation in any other study currently or within the last 30 days; Criteria for exclusion of subjects (discontinuation of treatment with the study drug): * Patient's wish * Occurrence of severe and/or unexpected Adverse events (AE) or Adverse reactions (AR) in patient during the study, that require discontinuation of the drug; * The need to prescribe drugs prohibited in this study. * Significant deterioration of the patient's condition during the study period; * Failure of the patient to adhere to the treatment regimen; * Failure of the patient to follow the procedures established under the protocol;