Inclusion Criteria 

• Male or female patients, aged 18 to 80 years old
• Immune-related ITP
• Refractory or relapsed patients with no available and approved therapeutic options
• A history of response to at least one prior line of therapy
• Female patients who are of reproductive potential must agree for the duration of active treatment in the study to use a highly effective means of contraception

Exclusion Criteria 

• Pregnant or lactating women
• History of current, active malignancy requiring or likely to require chemotherapeutic or surgical treatment during the trial, with the exception of non-melanoma skin cancer
• Immunosuppressant drugs other than corticosteroids
• Treatment with rituximab or splenectomy 
• Planned or concomitant use of any anticoagulants and platelet aggregation inhibiting drugs
• Current drug or alcohol abuse 
• History of solid organ transplant 
• Positive screening for HIV, hepatitis B or hepatitis C
• History of serious infections requiring intravenous therapy
• Planned surgery in the time frame of the dosing period