Allogeneic transplantation versus non-transplant treatment for classical paroxysmal nocturnal haemoglobinuria without...

To describe outcomes after haematopoietic stem cell transplantation (HSCT) and non-transplant treatment in patients with classical paroxysmal nocturnal haemoglobinuria (cPNH) without access to complement inhibitors, we analysed 227 patients with cPNH treated at 10 centres between January 1976 and April 2022. Among them, 51 underwent HSCT and 176 received non-transplant treatment without complement inhibitors. At 6 months post-treatment, 96.08% of HSCT patients achieved normal complete blood count, compared to 3.41% in the non-HSCT cohort (p < 0.001). Estimated 5-year overall survival (OS) did not differ significantly between HSCT and non-HSCT cohorts (92.16% vs. 98.83%, p = 0.097). Five-year failure-free survival (FFS) was 92.16% in the HSCT cohort and 0.57% in the non-HSCT cohort (p < 0.001). Delayed platelet engraftment-free, graft-versus-host disease-free, failure-free survival did not differ significantly between HSCT performed within 12 months after diagnosis and later transplantation (83.33% vs. 62.34%, p = 0.136). In addition, alternative donor HSCT achieved OS and FFS comparable to matched sibling donor HSCT. This study reports outcomes after HSCT and non-transplant treatment in a historical setting without access to complement inhibitors. However, further studies are needed to clarify the role and indications for HSCT in cPNH in the complement inhibitor era.