Novel approaches in management of immune thrombocytopenia

Platelets play the key role in primary haemostasis. The number of platelets that can be recruited for these first steps of haemostasis is important, as platelets maintain vascular integrity. Therefore severe thrombocytopenia is associated with a high risk for bleedings. The overall incidence of chronic autoimmune thrombocytopenia (cAITP) is 1 to 10 per 100 000 in industrialized countries. Like most other autoimmune disorders, cAITP is more common among adults, and thereby women are more often affected than man. It is relatively benign and rarely requires treatment. Furthermore, most treatment modalities are associated with severe adverse effects that may outweigh the benefits. Therefore, currently treatment is considered appropriate only for symptomatic patients and for those at high risk of bleeding, either because of a surgical procedure or because of very low platelet counts. Short-term treatment aims to increase platelet counts in patients with acute bleeding symptoms or in those undergoing surgery. Long-term treatment may be considered to increase the quality of life, if patients are affected by low platelet counts in the form of bleeding or anxiety. Recently, two new substances have been shown to increase platelet counts in cAITP, romiplostim and eltrombopag. Both bind to the thrombopoietin receptor thereby inducing an increase of platelet formation. Remarkably, the rate of treatment success was independent of any stratification modalities like previous response to drugs or splenectomy, and was associated with rather few and mild adverse effects. Further, it was previously assumed that thrombopoiesis is already turned on to compensate increased platelet sequestration in cAITP. The treatment success shows that thrombopoiesis can be increased to enhance platelet production, strongly supporting impaired thrombopoiesis in cAITP. It is likely that romiplostim and eltrombopag will significantly add to the treatment armaments for bridging certain situations of increased risk of bleeding in cAITP, mainly if corticosteroids are contraindicated, or for non-responders to first-line treatment modalities. Their role in long-term treatment and in deferring splenectomy will be determined by their price and foremost by their proven safety in long-term observational studies.