Two cases of thrombosis in patients with antiphospholipid antibodies during treatment of immune thrombocytopenia with romiplostim, a thrombopoietin receptor agonist.

Abstract

Romiplostim is a thrombopeitin-receptor agonist approved for raising platelet counts in patients with immune thrombocytopenia (ITP). Several hematologic adverse effects have been reported including acute myeloid leukemia, myelofibrosis, and thrombosis. We report two cases, one pediatric and one adult patient, who had antiphospholipid antibodies and received romiplostim for ITP. Additionally, we conducted medline, Food and Drug Administration (FDA) Adverse Events reports website, and manufacturer's adverse events database. Both patients developed thrombosis with evidence for catastrophic antiphospholipid syndrome (CAPS) after treatment with romiplostim. No reports or events were found from literature and database searches in regards to thrombosis associated with romiplostim in patients with antiphospholipid syndrome. These cases illustrate the potential for thrombosis with the administration of romiplostim. The administration of this drug to patients with a history of an autoimmune disease, especially those with positive antiphospholipid antibodies, should be done with caution.