Study of the Safety and Immunogenicity of Long-term GNR-069 Therapy in ITP Patients

It is an extension study in patients with ITP who completed participation in RMP-ITP-III clinical trial.

The study will be conducted in three stages:

* Transition visit - 1 day (transition of clinical trial participants from the RMP-ITP-III study to the RMP-ITP-III-X study);
* Treatment period - minimum 26 weeks;
* Follow-up period - 1 week. Patients will then be provided with the study therapy till the product market access with only safety data collection.

• GNR-069 (Biological), also known as romiplostim: Once a week as a subcutaneous injection.

Primary outcomes

• Frequency and severity of adverse events associated with the use of the GNR-069 [up to 29 weeks]: Adverse events will be assessed based on complaints, physical examination and laboratory data.
• Number of undesirable events of particular interest in the study (Bleeding;Thrombotic/thromboembolic events) [up to 29 weeks]: The event of particular interest in this study are bleeding and thrombotic/thromboembolic events of any location.
• Number of clinically significant bleeding on Visits 1-5 [up to 29 weeks]: The clinically significant bleeding will be considered events ≥ grade 2 according to CTCAE 5.0.
• Number and proportion of the patient with antidrug antibodies. [up to 29 weeks]: The antidrug antibodies willl be characterized by their type, titer and neutralizing activity.

Secondary outcomes

• Frequency of the loss of the treatment response [up to 27 weeks]: Loss of the treatment response is assessed as absense of platelet increase ≥ 50,0 х 109/L on the 4 weeks treatment with maximal study drug dose.
• Platelet count dynamics at Visits 1-5 [up to 5 weeks]: The platalets must be counted till week 5
• Сhange in ITP-BAT bleeding scores from baseline to week 27 [up to 27 weeks]: ITP-specific bleeding assessment tool (ITP-BAT) will be calculated at baseline and at week 27.

Sex: All, ages: 18 Years to 75 Years

Inclusion Criteria:

* Completion of participation in the study RMP-ITP-III while maintaining the clinical effectiveness of romiplostim therapy

Exclusion Criteria:

* Hypersensitivity to the components of the study drug or E. Coli proteins;
* Pregnancy or breastfeeding;
* Any diseases and conditions that, in the opinion of the Investigator, may hinder the patient's participation in the study

• Oksana A. Markova, MD, MSc, Study chair, AO GENERIUM