Background: Immunosuppressive therapy with horse antithymocyte globulin and cyclosporine currently remains the standard therapy for children with severe aplastic anemia (SAA) who lack human leukocyte antigen (HLA)-identical sibling. The thrombopoietin receptor agonist eltrombopag has been recently approved for SAA patients 2 years and older. However, there are limited data on its safety and efficacy in pediatric cohorts.
Methods: We conducted a retrospective study of patients ≤18 years old consecutively diagnosed with SAA between 2000 and 2018. Patients received either standard immunosuppressive therapy (IST-Std) or IST with eltrombopag (IST-Epag). The primary outcome was the objective response (OR), including partial and complete response (CR), at 6 and 12 months after starting therapy.
Results: We identified 16 patients receiving IST-Std and nine IST-Epag treatment (seven of nine as upfront therapy and two of seven after previously failed IST). The OR at 6 and 12 months in IST-Std arm was 71% and 100%, with CR in 29% and 58%, respectively. Seven patients receiving upfront IST-Epag had OR at 6 and 12 months, with two of seven (29%) achieving CR at 6 and 12 months. Two patients who previously failed standard IST did not respond to eltrombopag. No significant differences were observed in both cohorts with regard to infections. One IST-Epag-treated patient developed transient grade 3 transaminitis. Finally, no changes in paroxysmal nocturnal hemoglobinuria (PNH) clone size and cytogenetic abnormalities were seen in either cohort.
Conclusion: The addition of eltrombopag to standard IST was well tolerated and resulted in satisfactory hematological response at 6 and 12 months in this single-institution experience. A larger cohort with longer follow-up is required to assess response durability.