Observational StudyA Study of Patients' Preferences for Primary Immune Thrombocytopenia Treatment

Inclusion criteria:

1. Currently living in the US.
2. Aged 18 years and older on the day of providing informed consent.
3. A diagnosis of primary ITP:

a. For participants receiving first-line (1L) treatment for ITP: i. Diagnosed with primary ITP and started 1L corticosteroids within 3 months of diagnosis ii. Responded to 1L corticosteroid treatment \[with or without intravenous immunoglobulin (IVIg)\] b. For participants receiving second-line (2L) treatment for ITP: i. Assessed as needing or are taking thrombopoietin receptor agonist (TPO-RA) treatment for 2L treatment ii. Has previously been treated with a 1L corticosteroid (with or without IVIg) with insufficient response or relapse

Exclusion criteria:

1. For participants receiving 1L treatment for ITP only: Previous or current use of treatments different from corticosteroids and/or IVIg/anti-D immunoglobulin.
2. For participants receiving 2L ITP treatment: Previous or current use of treatments different from corticosteroids, IVIg/anti-D immunoglobulin or one TPO-RA (i.e. patients who have used any treatment in a third-line setting are ineligible).