(211) Safety and Efficacy of Romiplostim in Maintaining Chemotherapy Interval and Dose Intensity in Pediatric Patients with Solid Tumors and Chemotherapy Induced Thrombocytopenia (CIT)

Poster Abstract:

Background: Chemotherapy induced thrombocytopenia (CIT) is a complication of myelosuppressive chemotherapy that often results in delay or dose reduction of subsequent cycles of chemotherapy. CIT occurs in approximately 15-25% of patients receiving platinum, taxane, and/or gemcitabine-based chemotherapy regimens. As there are currently no FDA approved agents for the treatment of CIT, management of CIT is often solely platelet transfusions. In addition, the current standard of care is to dose-reduce or delay chemotherapy cycles which can lead to reduction in progression free survival as well as overall survival. Romiplostim is a thrombopoietin receptor agonist (TPO-RA) that binds to and activates the TPO receptor on megakaryocyte precursors, promoting cell viability, cell growth, and increased platelet production. TPO has been shown to be the most important growth factor for platelet production as it is involved in all stages of platelet production from stem cell though mature megakaryocyte. Although the National Comprehensive Cancer Network (NCCN) guidelines include the use of romiplostim for management of CIT, there is limited data to support its routine use. Literature to support the use of romiplostim and its application in the setting of CIT in pediatric patients is even further limited, with just one retrospective study in patients aged 3 to 33 years old with Ewing sarcoma from 2010-2020. At a large pediatric academic medical center, romiplostim is currently being utilized for CIT as an off-label indication based on literature demonstrating safety and efficacy in adult cohorts.

Objective: To evaluate the safety profile and efficacy of romiplostim in achieving and maintaining platelets > 75,000/mL to allow resumption of chemotherapy without recurrence of CIT in pediatric patients with solid tumors.

Methods: This is a single-center retrospective chart review of pediatric patients with solid tumors (≤ 21 years of age) in ambulatory oncology and neuro-oncology clinics who have received romiplostim for the treatment of chemotherapy induced thrombocytopenia (CIT) during the time frame of 07/01/2020 to 07/30/2023. The primary outcome of this study is to evaluate if romiplostim is effective in achieving and maintaining platelets > 75,000/mL to allow resumption of chemotherapy without recurrence of CIT in pediatric patients with solid tumors. Secondary outcomes that will be addressed include the occurrence of adverse effects (i.e., VTE, secondary malignancies) attributed to use of romiplostim, requirement of platelet transfusions, time to reach a platelet count >75,000/mL, as well as chemotherapy dose reductions or treatment delays due to CIT.

Results: Results pending.

Conclusion: Conclusion pending.

References (must also be included in final poster): 1. Al-Samkari H, Parnes AD, Goodarzi K, et al. A multicenter study of romiplostim for chemotherapy-induced thrombocytopenia in solid tumors and hematologic malignancies. Haematologica. 2021 Apr 1;106(4):1148-1157.
2. Bussel JB, Soff G, Balduzzi A, et al. A Review of Romiplostim Mechanism of Action and Clinical Applicability. Drug Des Devel Ther. 2021 May 26;15:2243-2268.
3. National Comprehensive Cancer Network (NCCN). Hematopoietic Growth Factors (Version 2.2023). https://www.nccn.org/professionals/physician_gls/pdf/growthfactors.pdf. Accessed July 20, 2023.
4. Wilkins CR, Ortiz J, Gilbert LJ, et al. Romiplostim for chemotherapy-induced thrombocytopenia: Efficacy and safety of extended use. Res Pract Thromb Haemost. 2022 May 10;6(3):e12701.
5. Soff GA, Miao Y, Bendheim G, et al. Romiplostim Treatment of Chemotherapy-Induced Thrombocytopenia. J Clin Oncol. 2019 Nov 1;37(31):2892-2898.
6. Parameswaran R, Lunning M, Mantha S, et al. Romiplostim for management of chemotherapy-induced thrombocytopenia. Support Care Cancer. 2014 May;22(5):1217-22.
7. Miao J, Leblebjian H, Scullion B, et al. A single center experience with romiplostim for the management of chemotherapy-induced thrombocytopenia. Am J Hematol. 2018 Aug;93(4):E86-E88.
8. Merjaneh N, Young J, Mangoli A, Olsen M, Setty B, Lane A, Nagarajan R, Pressey JG, Turpin B. Chemotherapy-induced thrombocytopenia in Ewing sarcoma: Implications and potential for romiplostim supportive care. Pediatr Blood Cancer. 2022 Jul;69(7):e29548.