Chemotherapy-induced thrombocytopenia in Ewing sarcoma: Implications and potential for romiplostim supportive care

Update on the Use of Thrombopoietin-Receptor Agonists in Pediatrics

This review summarizes the rationale and current data on the use of thrombopoietin receptor agonists (TPO-RAs) for treating severe thrombocytopenia in infants, children, and adolescents. It focuses on substances that have been approved by the U.S. Food and Drug Administration (FDA) and European Medicines Agency (EMA) for pediatric patients. Romiplostim and eltrombopag are already established as second-line treatment for persistent or chronic immune thrombocytopenia (ITP). As in adults, TPO-RAs are currently also evaluated in severe aplastic anemia (SAA), chemotherapy-induced thrombocytopenia (CIT), myelodysplastic syndromes (MDS), and poor engraftment after hematopoietic stem cell transplantation in pediatric and adolescent patients. Moreover, studies on the implication of TPO-RA in treating rare inherited thrombocytopenias, such as Wiskott-Aldrich syndrome (WAS), congenital amegakaryocytic thrombocytopenia (CAMT), or MYH9-associated thrombocytopenia, deserve future attention. Current developments include testing of avatrombopag and lusutrombopag that are approved for the treatment of thrombocytopenia associated with chronic liver disease (CLD) in adult patients. In pediatric and adolescent medicine, we expect in the near future a broader use of TPO-RAs as first-line treatment in primary ITP, thereby considering immunomodulatory effects that increase the rate of sustained remission off-treatment, and a selective use in rare inherited thrombocytopenias based on current clinical trials.

Optimal management of chemotherapy-induced thrombocytopenia with thrombopoietin receptor agonists

Chemotherapy-induced thrombocytopenia (CIT) is a common complication of antineoplastic therapy, resulting in antineoplastic therapy dose reductions, treatment delays, treatment discontinuation, and morbid bleeding events. Despite several decades of research into thrombopoietic growth factors in CIT, there are presently no available U.S. FDA- or EMA-approved agents to treat CIT. However, a respectable body of evidence has been published evaluating the thrombopoietin receptor agonists (TPO-RAs) for the management and prevention of CIT in patients with solid tumors, and critical studies are ongoing with the TPO-RAs romiplostim and avatrombopag. When employed in the appropriate patient population and used properly, TPO-RAs can successfully and safely manage CIT for extended periods of time with minimal apparent risks. This comprehensive review discusses the evidence for TPO-RAs in CIT in patients with solid tumors, provides detailed guidance for their use in the clinic, and discusses ongoing essential clinical trials in management of CIT.

Thrombopoietin receptor agonists for chemotherapy-induced thrombocytopenia: a new solution for an old problem

Chemotherapy-induced thrombocytopenia (CIT) is common, resulting in increased bleeding risk and chemotherapy delays, dose reduction, and treatment discontinuation, which can negatively affect oncologic outcomes. The only agent approved by the US Food and Drug Administration to manage CIT (oprelvekin) was voluntarily withdrawn from the market by the manufacturer, leaving few options for patients. Therefore, patients experiencing CIT present a significant clinical challenge in daily practice. The availability of thrombopoietin receptor agonists has led to formal clinical trials describing efficacy in CIT as well as a rather extensive body of published observational data from off-label use in this setting but no formal regulatory indications for CIT to date. The accumulated data, however, have affected National Comprehensive Cancer Network guidelines, which now recommend consideration of TPO-RA clinical trials as well as off-label use of romiplostim. This review article details the evidence to date for the management of CIT with thrombopoietin receptor agonists (TPO-RAs), discussing the efficacy data, the specific circumstances when treatment is warranted (and when it is generally unnecessary), and safety considerations. Specific recommendations regarding patient selection, initiation, dosing, titration, and discontinuation for TPO-RA therapy in CIT are given, based on published data and expert opinion where evidence is lacking.

Dual enzyme therapy improves adherence to chemotherapy in a patient with gaucher disease and Ewing sarcoma

This case reports concomitant use of enzyme and substrate reduction therapy to improve chemotherapy adherence in a pediatric patient diagnosed with Ewing sarcoma (ES) and type 1 Gaucher disease (GD). The 17-year-old female presented with 5 months of right knee pain with associated mass on exam. She was diagnosed with ES with pulmonary metastasis. The patient was treated with 17 alternating cycles of vincristine-doxorubicin-cyclophosphamide and ifosfamide and etoposide chemotherapy followed by tumor resection and radiation per standard protocol. As part of her staging work-up, bone marrow biopsy was performed, significant for Gaucher cells. After the second cycle of chemotherapy the patient began to experience severe delays averaging 30 days between cycles compared to 17.29 days observed in Children's Oncology Group data. Given her bone marrow biopsy findings and chemotherapy delays GD screening was obtained and the patient was diagnosed with GD following genetic confirmation. Due to delays in chemotherapy decreasing chance of remission, the patient was referred to Genetics for aggressive management with imiglucerase and eliglustat. After initiation of therapy the period between chemotherapy cycles decreased to 23 days on average, with a 21% increase in platelet count during therapy. The patient was able to complete ES therapy achieving remission. GD is associated with an increased risk of malignancy, as seen in our patient with ES. GD patients experience prolonged hematologic cytopenia during cancer treatment. Combining Enzyme and Substrate Reduction Therapies should be investigated as an option to improve chemotherapy adherence in GD patients.