Allogeneic Hematopoietic Cell Transplantation in Patients With Aplastic Anemia and Paroxysmal Nocturnal Hemoglobinuria Clones: Time for a Change

Abstract

Dear Editor, Acquired severe aplastic anemia (SAA) remains a diagnostic and therapeutic challenge, despite advances in the field that have led to improved survival rates. 1 Allogeneic hematopoietic cell transplantation (alloHCT) is a cornerstone in the therapeutic algorithm of the disease even in patients with coexisting paroxysmal nocturnal hemoglobinuria (PNH) clones. Nevertheless, literature on patients with SAA and PNH clones post alloHCT is scarce.Complement inhibition with eculizumab has shown effectiveness in patients with PNH and high disease activity, with or without aplastic anemia. 2 However, the role of eculizumab in the transplant setting has not been clarified yet. Recently, DeZern et al reported successful outcomes with eculizumab bridging before alloHCT in 8 SAA patients. 3 Two recent studies have also explored outcomes of patients with PNH clones in the age of eculizumab. 4,5 Although both studies present the potential benefits of eculizumab post alloHCT in 8 and 2 patients respectively, there is no clear comparison with a historical control group that did not receive eculizumab. 4,5 This comparison would clarify the role of complement inhibition, given that alloHCT mortality in SAA patients with PNH clones has been reported at approximately 30%. 6 Given the renewed interest in the field, we conducted a retrospective analysis of alloHCT outcomes in patients transplanted for SAA with or without PNH clones.

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“…VSAA patients usually exhibit higher chances of relapse and clonal evolution when compared with SAA patients (43). Therefore, for young VSAA patients, haplo-HSCT is an attractive option when MSD is not available (44), while for young SAA patients, treatment should be balanced depending on the related mortality and the long-term disease outcomes.…”