The Impact of Ethnicity on the Response to Eltrombopag in Patients With Immune Thrombocytopenia (ITP) in Qatar: A Single Institution Experience.

Background: Eltrombopag olamine (ELT) is a synthetic nonpeptide with a low molecular weight that has been investigated in various phase-3 studies and shown to be efficacious at a typical dose of 50 mg. Varied ethnic groups have reported different responses to ELT.

Aim: The aim is to examine the efficacy of ELT in Asian and Arab patients with immune thrombocytopenia (ITP) from the Indian subcontinent by starting with (12.5 mg, as a minimum dose) and gradually increasing to a maximum dose of 50 mg.

Methods: Between January 2015 and January 2019, we reviewed the electronic health records of non-Arab Asian (n = 17) versus Arab (n = 41) patients who were ≥18 years old, residing in Qatar, and with confirmed diagnoses with chronic ITP and under active treatment with a platelet count of 30,000/L, and bleeding symptoms. Following receiving ELT for three months or longer at various dosages, patients' response was examined.

Results: After three months of ELT therapy, the response rate (platelet count of 50,000/L) was equivalent in non-Arab (88.2%) versus Arab (87.5%) patients. However, to achieve an adequate response, 26% of Arab patients required a lower dose of 12.5 or 25 mg, and 41.5% required a higher dose of 50 mg.

Conclusion:  In adult chronic ITP patients, ELT is typically well-tolerated and delivers the desired outcomes. In 67.5% of Arab patients, smaller dosages of ELT (12.5-50 mg) were helpful in sustaining acceptable PLT levels. This helps patients get the most benefit at the lowest feasible dose, reducing toxicity and expense.