Impact of allogeneic stem cell transplantation comorbidity indexes after haplotransplant using post-transplant cyclophosphamide

Background: Three different scoring systems have been developed to assess pre-transplant comorbidity in allogeneic hematopoietic stem cell transplantation (Allo-HSCT): the Hematopoietic Cell Transplantation-Specific Comorbidity Index, the Comorbidity/Age index, and the Augmented Comorbidity/Age index. All were devised to predict overall survival (OS) and disease-free survival (DFS) survivals and non-relapse mortality (NRM) in patients receiving HLA-matched Allo-HSCT, but their performance has scarcely been studied in the haploidentical Allo-HSCT setting with post-transplant cyclophosphamide, a procedure in constant expansion worldwide.

Methods: To address this issue, their impact on survivals and NRM was examined in a cohort of 223 patients treated with haploidentical Allo-HSCT in four different centers.

Results: With a median follow-up of 35.6 months, 3-year OS, DFS, and NRM were 48.1% ± 4%, 46.3% ± 4%, and 30.0% ± 3%, respectively. No impact was found for any of the three comorbidity scores in univariate analysis. In multivariate analyses, the only three factors associated with lower OS were DRI (p < 0.001), an older age of recipients (≥55 years old, p = 0.02) and of donors (≥40 years old, p = 0.005). Older donor age was also associated with lower DFS and higher NRM.

Conclusion: The comorbidity scores do not predict survivals nor NRM in haploidentical Allo-HSCT with PTCY, suggesting that pre-transplant comorbidities should not be a contra-indication to this procedure.