Real-world experience of treatment with thrombopoietin receptor agonists in anti-thymocyte globulin-naïve patients with aplastic anemia: an observational retrospective analysis in a single institution

Abstract

Objective: To explore the efficacy and safety of thrombopoietin receptor agonists (TPO-RAs) without anti-thymocyte globulin (ATG) in ATG-naïve patients with aplastic anemia (AA) in a real-world setting. Methods: We retrospectively evaluated treatment outcomes in 45 consecutive ATG-naïve patients with AA who received TPO-RAs between 2017 and 2021 at our hospital. Results: ATG ineligibility was due to advanced age (≥ 70 years), n = 22; not recommended under Japanese guidelines due to mild symptoms, n = 13; patient preference, n = 6; uncontrolled heart failure, n = 2; uncontrolled diabetes mellitus, n = 2; chronic renal failure, n = 2; invasive aspergillosis, n = 1. Twenty-eight patients (62%) achieved hematologic response in at least unilineage after 6 months’ treatment, while 38 (84% in unilineage response-eligible patients) and four (25% in trilineage response-eligible patients) patients achieved at least unilineage and trilineage responses, respectively, at any point during the follow-up period. Five patients switched from eltrombopag to romiplostim because of adverse events or lack of efficacy, and two developed hematologic malignancies. Eltrombopag was effective even in elderly ATG-ineligible patients with severe AA. The 2-year overall survival rate was 84.3%, with a median 26.3-month follow-up. Time from diagnosis to eltrombopag treatment initiation tended to affect the response (p = 0.0727), but no factors that significantly predicted hematologic response were identified. Conclusions: We found eltrombopag to be effective even in elderly ATG-naïve patients with severe AA, indicating that TPO-RA treatment should be considered in patients ineligible for ATG treatment because of age, complications, or severe AA.