eltrombopag

A thrombopoietin receptor agonist (TPO-RA) used to treat thrombocytopenia and severe aplastic anemia.
Thrombopoietin (TPO) is a glycoprotein hormone produced by the liver and kidney which regulates platelet production by binding to and activating TPO receptors on the megakaryocyte cell surface, thereby inducing intracellular signalling cascades that lead to the production and differentiation of megakaryocytes, that bud off large numbers of platelets.
(Indicatoins)
• immune thrombocytopenic purpura (ITP): As second line treatment in patients who have had an insufficient response to corticosteroids, immunoglobulin therapy, or splenectomy, and only whose clinical condition increases bleeding risk. Initial dose, 50 mg PO qDay. Adjust dose to achieve and maintain platelet count more than 50 · 109 /L to reduce risk of bleeding, but not to exceed 75 mg/day. Discontinue if it fails to achieve and maintain the platelet count after 4 weeks at the maximum of 75 mg/day.
• cirrhosis due to hepatitis C: Thrombocytopenia may be a contraindication for interferon treatment. Initial dose, 25 mg PO qDay.
• severe aplastic anemia (SAA): As first line treatment, in combination with standard immunosuppressive therapy. Initial dose, 150 mg PO qDay for 6 months. (Do not exceed total duration of 6 months.)
• sefractory SAA: In patients who fail to respond adequately to at least 1 prior immunosuppressive therapy. Initial dose, 50 mg PO qDay. Discontinue in case no hematologic response occurred after 16 weeks of therapy or consider if new cytogenetic abnormalities are observed.
(Treatment for ITP)
First line treatment: to increase platelet counts
• oral corticosteroids
• intravenous immunoglobulin
• anti-D immunoglobulin
Second line treatment:
• splenectomy: In the patients, immune system treats platelets as foreign and destroys them. The spleen is responsible for removing these damaged platelets. Therefore, removal of the spleen can help to keep more platelets circulating in the body.
• rituximab: A monoclonal antibody drug to treat certain autoimmune diseases and types of cancer.
• thrombopoietin receptor agonists: E.g. romiplostim, eltrombopag, avatrombopag, lusutrombopag.
(Comparisons between TPO-RAs: Dose regimen)
• romiplostim: 1 mcg/kg, once weekly, subcutaneous injection.
• eltrombopag: 50-75 mg, once daily, orally. It can be taken without a meal or with a meal low in calcium (less than 50 mg). It should be taken 2 hours before or 4 hours after taking medications like antacids, mineral supplements, or foods that are high in calcium such as dairy products, calcium-fortified juices, and certain fruits and vegetables.
• avatrombopag: 20 mg, once daily, orally.
• lusutrombopag: 3 mg, once daily, orally with or without food for 7 days.