Switch of TPO-Mimetics in Patients with Immune Thrombocytopenia

Background: Primary immune thrombocytopenia (ITP) is an immune-mediated condition characterized by isolated

thrombocytopenia, with peripheral blood platelet count of <100.000/μl in the absence of an identifiable underlying cause of thrombocytopenia. Clinical studies in patients with ITP demonstrated that thrombopoietin (TPO) mimetics increase platelet production and can outpace platelet destruction.

Aims: We evaluated patients treated with both TPO-mimetics.

Methods: From November 2008 and July 2017, 69 patients were treated with TPO-mimetics with a median follow up of 30 months (1-96): 39 patients underwent therapy with Romiplostim and 30 to Eltrombopag. In our study we evaluated 19 patients who received both therapies: among patients treated at first with Romiplostim, 10 patients (9F; 1 M) switched to Eltrombopag and 9 patients (4 M; 5 F) switched from Eltrombopag to Romiplostim. In the group of 10 patients treated at first with Romiplostim, 5 patients started Eltrombopag because were no responders, 3 for loss of response and 2 patients because of adverse events. In the group of 9 patients at first treated with Eltrombopag, 4 patients didn't obtain any response with Eltrombopag and switched to Romiplostim, 1 patient underwent to Romiplostim for loss of response and 4 patients because of adverse events.

Results: Among patients switched from Romiplostim to Eltrombopag, 2 achieved complete response, 4 response and 4 were no responders; among patients switched from Eltrombopag to Romiplostim, 5 obtained complete response, 3 response, 1 was no responder.

Summary/Conclusion: Romiplostim and Eltrombopag stimulate the TPO-R but have different mechanisms of action, therefore, in our limited experience switching from one thrombopoietic receptor agonist to the other could be beneficial in clinical practice for patients with severe chronic immune thrombocytopenia who failed to respond or experienced adverse events to the first treatment.