Use of Intravenous Anti-RhD Immunoglobulin (RhIG) in the Treatment of Primary Immune Thrombocytopenia

Abstract

Commercialized intravenous immunoglobulin (IVIG) products have been used since the early 1980s for various patient treatment options, specifically to induce an immunomodulatory and therapeutic effect. IVIG, a pooled immunoglobulin G (IgG) preparation, is used for patients with immune deficiencies, inflammatory conditions, and autoimmune disorders such as primary immune thrombocytopenia (ITP). Front-line therapies for ITP include corticosteroids, IVIG, or anti-RhD immune globulin (RhIG). WinRho SDF (Cangene Corporation, Winnipeg, Manitoba, Canada), a RhIG preparation, was FDA-approved for use in 2005 and is used for treatment of patients with ITP through what is called a Fc blockade mechanism. After intravenous WinRho administration, patient platelets are spared from clearance by the spleen and with a good response to treatment, the patient's platelet count increases. WinRho is not without potential side effects and also impacts the transfusion service pre-transfusion testing in the event that the patient undergoing treatment requires red cell transfusion. In 2010, a work group of experts reviewed the warnings associated with RhIG and concluded that assuming that patients are appropriate candidates for RhIG, monitored in a clinical setting for 8 hours after administration, RhIG products such as WinRho are considered a very effective front-line therapy for ITP.¹ Effective first line therapies can circumvent the necessity for less-desirable second line therapies such as an invasive splenectomy or life-long treatment with thrombopoietin-receptor agonists (TPO-RAs) to increase platelet counts.

ABBREVIATIONS: IVIG – intravenous immunoglobulin, ITP – primary immune thrombocytopenia, RhIG – Rh immune globulin, TPO-RAs – thrombopoietin-receptor agonists, MPV – mean platelet volume, RBC – red blood cell, HUS – hemolytic uremic syndrome, TTP – thrombotic thrombocytopenic purpura, DIC – disseminated intravascular coagulation, CBC – complete blood count, PT – prothrombin time, APTT – activated partial thromboplastin time, FDA – Food and Drug Administration