Comparison of eltrombopag and avatrombopag in the treatment of refractory/relapsed aplastic anemia: a single-center retrospective study in China

Abstract

Background: Eltrombopag (ELT), a thrombopoietin receptor agonist (TPO-RA), has been approved for relapsed/refractory aplastic anemia (AA). However, data on avatrombopag (AVA), another TPO-RA, are limited, and the comparisons between the two TPO-RAs are lacking.

Objectives: We aimed to compare the efficacy and safety between ELT and AVA in relapsed/refractory AA patients.

Design: In this retrospective study, patients with relapsed/refractory AA who had been treated with ELT (N = 45) or AVA (N = 30) alone and had compatible baseline hematological parameters were compared.

Methods: Data from patients diagnosed with acquired AA were retrospectively collected. All patients were refractory/relapsed to standard immunosuppressive therapy (IST) for at least 6 months before ELT or AVA. Patients had to be treated with ELT or AVA alone for at least 6 months before evaluation if they did not respond. Baseline characteristics, overall response (OR), complete response (CR), relapse, adverse events, and factors that may affect efficacy were analyzed.

Results: Of the 75 patients enrolled, 45 received ELT and 30 received AVA. Patients with AVA had a higher percentage of abnormal liver or renal function than those with ELT (p = 0.036). No significant difference was found in the OR/CR rate in the first/second/third/sixth month between the two cohorts (p > 0.05). Patients treated with AVA had a shorter median time to response than those treated with ELT (p = 0.012) and had a higher platelet level in the second month (p = 0.041). AVA had fewer adverse events than ELT (p = 0.046). Under compatible follow-up time (p = 0.463), no difference was found between the ELT and AVA cohorts in relapse (p = 1.000) or clone evolution (p = 0.637). No predictive factors for OR and CR in the sixth month were found for either ELT or AVA.

Conclusion: With worse liver or renal function, AVA had a similar OR/CR rate but a shorter median time to response and fewer adverse events for patients with relapsed/refractory AA.

Keywords: aplastic anemia; avatrombopag; effects; eltrombopag; relapsed/refractory.

Figure 1.

Response to ELT/AVA at different time points. The 100% stacked column was constructed by the number of CR, PR, and NR each month to show the percentages of CR, PR, and NR patients. (a) The percentages of patients who responded in the first, second, third, sixth months, and in the last follow-up in the ELT cohort and (b) the percentages of patients who responded in the first, second, third, sixth months, and in the last follow-up in the AVA cohort. No difference was found between the two cohorts in ORR or CRR at any time. Analysis visits were shown according to months (m). ELT, eltrombopag; AVA, avatrombopag; CR, complete response; PR, partial response; NR, no response; ORR, overall response rate; PR, partial response; CRR, complete response rate.

Figure 2.

Changes in median platelet level over time in platelet responders. The median platelet level values over time (from baseline to the last follow-up) of platelet responders of the ELT cohort (blue) and avatrombopag cohort (orange) were constructed. The difference in median platelet level between the two cohorts reached the highest in the second month [30 × 10⁹/L (range, 9–171) versus 95 × 10⁹/L (range, 10–202), p = 0.041] but was compatible at other time points. Error bars indicate the interquartile range. Analysis visits were shown according to month (m). *p < 0.05 in patients treated with ELT and AVA. ELT, eltrombopag; AVA, avatrombopag; m, month.