Study of Efficacy, Safety and Immunogenicity of GP40141 (GEROPHARM, Russia) in Patients With Immune Thrombocytopenia

• Signed informed consent to participate in the study.
• male or female
• Age ≥18 years
• Diagnosis of primary immune thrombocytopenia (PIT).
• Duration of PIT at the Screening Visit: for cohort 1: ≥3 months; for cohort 2: ≥6 months.
• PIT therapy with glucocorticosteroids (GCS) for cohort 1: duration of continuous therapy ≥3 months at the Screening Visit or ≥2 courses of pulse therapy during the year before the Screening Visit;
• TPO-RA therapy: for cohort 1: no history of TPO-RA use; for Cohort 2: Use of TPO-RA for ≥12 weeks at the Screening Visit;
• No increase in TPO-RA dose during the 4 weeks preceding the end of screening.
• Blood platelet count: for cohort 1: mean platelet count ≤30×10*9/L, based on the last two measurements 7±2 days apart, each of which had a platelet count ≤35×10*9/L OR steroid dependence, defined as the use of prednisolone at a daily dose of >5 mg (or another corticosteroid at an equivalent dose) for ≥2 months before the Screening Visit to maintain a platelet count ≥30×10*9/L OR to prevent bleeding; for cohort 2: platelet count ≥50×10*9/ml for ≥6 weeks out of the last 8 weeks of follow-up with platelet counts every 7±2 days and no emergency treatment for severe hemorrhagic syndrome in the last 12 weeks before the Screening Visit.
• Consent and ability to comply with the procedures of the Protocol, as well as the prohibitions and restrictions provided for by the Research Protocol.

Exclusion Criteria:

• Hypersensitivity to romiplostim.
• History of TPO-RA use: for cohort 1: any TPO-RA; for cohort 2: any TPO-RA, with the exception of romiplostim and eltrombopag.
• Unpromising treatment with romiplostim in the opinion of the Researcher
• Splenectomy \<24 weeks prior to the Screening Visit or planned splenectomy during the study.
• Treatment with rituximab within the 14 weeks preceding the Screening Visit, or planned treatment with rituximab during the study.
• Treatment with intravenous immunoglobulin or anti-D immunoglobulin during the 2 weeks preceding the Screening Visit, or planned use during the study.
• Therapy with hematopoietic growth factors during the 4 weeks preceding the Screening Visit, or their planned use during the study.
• Therapy with alkylating chemotherapy drugs during the 8 weeks preceding the Screening Visit, or their planned use during the study.
• Use of other medicines listed in section 5.3.3. of this study protocol.
• Participation in a clinical trial of an investigational drug or investigational medical device within 4 weeks or 5 half-lives (whichever is longer) preceding the Screening Visit.
• Secondary immune thrombocytopenia in the following diseases: autoimmune thyroiditis, systemic lupus erythematosus (SLE), antiphospholipid syndrome (APLS), lymphoproliferative diseases, drug-mediated, viral origin (herpes viruses, HIV, chronic viral hepatitis).
• Hereditary thrombocytopenia.
• Diseases of the hematopoietic system accompanied by thrombocytopenia (for example, acute leukemia, aplastic anemia, myelodysplastic syndrome, lymphoproliferative diseases).
• Metastatic bone marrow lesions.
• Uncontrolled concomitant diseases of internal organs.
• Arterial thrombosis (for example, myocardial infarction, acute cerebrovascular accident) within 1 year preceding the Screening Visit.
• History of venous thrombosis.
• High risk of venous thrombosis and thromboembolism, defined as the presence of at least three of the following risk factors:
• diabetes;
• smoking;
• use of combined oral contraceptives or menopausal hormone therapy;
• positive titer of antiphospholipid antibodies;
• hypercholesterolemia (>240 mg/dl or >13 mmol/l);
• hypertriglyceridemia;
• arterial hypertension requiring therapy.
• HIV infection.
• Viral hepatitis B or C.
• Oncological and/or oncohematological disease beyond the stage of complete 5-year remission at the Screening Visit.
• Major surgery ("major surgery") within 8 weeks preceding the Screening Visit, or incomplete recovery from surgery at the Screening Visit.
• Pregnancy or lactation in women.
• Hospitalization for any reason planned during the patient's participation in the study.
• A history of mental disorders that do not allow you to adequately assess your behavior and follow the conditions of the study protocol.
• Alcoholism. Alcoholism or consumption of alcohol in quantities exceeding for men: 14 units. per week (on average); for women: 7 units. per week (on average).