Outcomes of Haploidentical Haematopoietic Stem Cell Transplantation for Paroxysmal Nocturnal Haemoglobinuria

Background: Haematopoietic stem cell transplantation (HSCT) is the only curative therapy for paroxysmal nocturnal haemoglobinuria (PNH). Haploidentical HSCT (haplo-HSCT) is an alternative treatment method for PNH patients lacking suitable identical donors. The current study evaluated the feasibility of haplo-HSCT in PNH patients.

Methods: We retrospectively analysed the outcomes of 28 PNH patients who received haplo-HSCT between October 2010 and December 2018.

Results: The median age was 28 (range 6-54) years. One patient (underwent HSCT in December 2018) was not evaluable for engraftment or haematopoietic recovery because of early death on day +14 due to septicaemia. The 27 evaluable patients all achieved myeloid engraftment and complete chimerism, and one patient experienced secondary graft failure. Three patients demonstrated delayed platelet recovery, and one patient demonstrated platelet graft failure. The median time to neutrophil recovery was 12 (range, 9-26) days, and the median time to platelet recovery was 16 (range, 11-75) days. The cumulative incidences were 29.63% for grades I to IV acute graft-versus-host disease (aGVHD) and 14.82% for grades II to IV aGVHD. No patient experienced grades III to IV aGVHD. With a median follow-up time of 37 (range 4-78) months, the cumulative incidence of chronic graft-versus-host disease (cGVHD) was 28.81%, and the cumulative incidence of moderate-severe cGVHD was 11.73%. No patient relapsed during the follow-up period. The 12-month transplantation-related mortality (TRM) rate was 15.25%. The probabilities of 3-year overall survival (OS) and graft-versus-host disease-free, failure-free survival (GFFS) were 84.8 ± 7.1% and 77.0 ± 8.3%, respectively.

Conclusions: The preliminary results indicated that haplo-HSCT is a feasible option for PNH patients lacking suitable identical donors.