Comparisons between Haploidentical Hematopoietic Stem Cell Transplantation and Eltrombopag Adding to Standard Immunosuppression in Patients with Severe Aplastic Anemia

Background:

Haploidentical hematopoietic stem cell transplantation (haplo-HSCT) becomes an alternative choice for patients in the absence of a matched donor¹. The use of eltrombopag (EPAG) combined with intensive immunosuppressive therapy (IST) as a front-line treatment has been shown to enhance both the rate and rapidity of hematologic response in SAA patients². However, no studies have compared the outcomes of IST + EPAG and haplo-HSCT for the treatment of SAA.

Methods:

The study was performed among 111 patients with SAA from 5 medical centers, including 51 patients in the IST+EPAG group and 60 patients in the haplo-HSCT group. The overall survival (OS), failure-free survival (FFS), GVHD-free FFS (GFFS)/ survival with CR status (CROS), overall response rate (ORR) as well as complications were compared between the two groups.

Results:

At 6 months post treatment, 91.67% patients in the haplo-HSCT group and 19.67% patients in the IST+EPAG group achieved normal blood routine (P=0.000). It turned out that the OS was comparable (92.16% vs 91.67%, P=0.775), while the FFS and GFFS/CROS in the haplo-HSCT group was superior to that in the IST+EPAG group (88.33% vs 72.55%, P=0.045 and 78.33% vs 25.49%, P=0.000). Being diagnosed with non-VSAA was a favorable factor for FFS, and the choice of haplo-HSCT was a favorable factor for GFFS/CROS in multivariate analysis. None of the evaluated factors was recognized as an independent favorable factor of OS. Multivariate analysis showed that being diagnosed with non-VSAA, patients aged <40years, and receiving hematopoietic stem cell transplantation were significantly associated with good therapeutic outcomes. Using propensity score matching (PSM), a comparative analysis was conducted to assess the treatment outcomes between patients treated with haplo-HSCT (n=28) and patients who underwent IST+EPAG therapy (n=28). In the PSM cohort, OS and FFS who underwent haplo-HSCT were comparable to those of the IST+EPAG group (89.29% vs 96.43%, P=0.278 and 85.71% vs 82.14%, P=0.785); However, there was still a significant difference between the 2 groups regarding GFFS/CROS (75.00 % vs 39.29%, P=0.024). The multivariate analysis showed that choosing haplo-HSCT was a favorable factor for GFFS/CROS, but did not affect FFS and OS in the PSM cohort。

Conclusions:

These results suggest that for the management of SAA patients, haplo-HSCT showed similar comparable long-term prognosis compared with IST+EPAG, whereas patients treated with haplo-HSCT could achieve faster hematopoietic reconstruction and higher CR rates.