met minimum enrollment goal, however, enrollment was slow due to the pandemic, therefore, the study was terminated

Evaluate patient characteristics, treatment patterns, clinical outcomes and safety of fostamatinib as second-line therapy in real-world clinical practice, for the treatment of ITP in adult patients who have an insufficient response to prior therapy (steroids ± immunoglobulins).

Evaluate patient characteristics, treatment patterns, clinical outcomes and safety of fostamatinib as second-line therapy in real-world clinical practice, for the treatment of ITP in adult patients who have an insufficient response to prior therapy (steroids ± immunoglobulins).

Inclusion Criteria:

1. Willing and able to provide written informed consent
2. Diagnosis of ITP in adult patients (≥ 18 years of age) with an insufficient response to steroids ± immunoglobulins and requiring a change in therapy
3. For Cohort 1, intent to initiate fostamatinib at enrollment as change in therapy
4. For Cohort 2, currently undergoing treatment with fostamatinib as second line therapy for at least 12 weeks, with the intent to continue, at the time of enrollment

Exclusion Criteria:

1. Any prior ITP therapy/treatment other than steroids ± immunoglobulins (e.g. rituximab, thrombopoietin receptor agonists (TPO), splenectomy)
2. Participation in any interventional study during the course of this study
3. Lack of historical platelet counts, at time of fostamatinib initiation for those entering Cohort 2
4. Pregnant and/or nursing

This two-cohort study will enroll approximately 45 patients diagnosed with ITP. Cohort 1 will enroll approximately 30 ITP patients who will begin treatment with fostamatinib as second-line therapy. Cohort 2 will enroll approximately 15 patients who have a record of at least 12 weeks of fostamatinib treatment as second-line therapy, with the intent to continue, at time of enrollment.