Use of Romiplostim to Facilitate Platelet Engraftment in Allogeneic Hematopoietic Transplantation

Thrombocytopenia requiring platelet transfusions is a constant in the hematopoietic transplantation (HT). In some situations, like the adult non-related donor and cord blood HT, the platelet engraftment is delayed for a long time. Hemorrhagic cystitis, venooclusive disease, graft-vs-host disease could to worse these procedures with a very high risk of bleeding and to increase the transplantation morbi-mortality. The agonists of thrombopoietin receptor (TRAs) have demonstrated to increase the platelet production in different pathological situations, like in the ITP and MDS patients. Thus, these new drugs could have a potential benefit in other clinical situations with low platelet production.

We describe our experience in seven patients with Allogeneic HT using Romiplostim (NPlate®, Amgen Inc.), a parenteral TRA peptide, to accelerate the platelet engraftment or to increase the platelet level in the thrombocytopenia induced by HT conditioning or HT related complications. We have administrated Romiplostim in a compassionate basis (off-label). In all cases the drug was administered subcutaneously at a dose of 250 mcg. Most of the patients received only one dose, with the exception of patients #1 and 7, whom received two doses separated by seven days. The first case, a woman diagnosed as Acute Lymphoblastic Leukemia (ALL) with severe HLA platelet refractoriness acquired in the induction and consolidation chemotherapy treatments previous to HT, received two doses of 250 mcg of Romiplostim on days +4 and +12 after peripheral blood progenitor cells infusion from an HLA matched brother.

In the first case, a rapid and sustained platelet level increase was obtained, without platelet transfusional support. Encouraged by this successful result, we have used Romiplostim in six more patients with platelet refractoriness to platelet transfusions with or without bleeding. In all the patients the spleen was present. The patient #6, obtained a previous platelet engraftment that was loosed with the beginning of severe cGVHD. (see table)

The use of Romiplostim could be very useful in HT complicated by severe platelet transfusions refractoriness. Our data encourages the realization of a randomized prospective study with this drug in HT.

Graphic evolution of platelet count over time is depicted in the next figure:

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Days after Romiplostim administration. Number of platelets x10⁹/L.

Ojeda:Amgen Inc.: Consultancy, Honoraria. Off Label Use: Romiplostim (Nplate)is an agonist of thrombopoietin receptor (TRAs) that have demonstrated to increase the platelet production in different pathological situations, like in the ITP and MDS patients.