Purpose

Related donor haploidentical hematopoietic cell transplantation (Haplo-HCT) using post-transplantation cyclophosphamide (PT-Cy) is increasingly used in patients lacking HLA-matched sibling donors (MSD). We compared outcomes after Haplo-HCT using PT-Cy with MSD-HCT in patients with lymphoma, using the Center for International Blood and Marrow Transplant Research registry.

Materials and Methods

We evaluated 987 adult patients undergoing either Haplo-HCT (n= 180) or MSD-HCT (n= 807) following reduced-intensity conditioning regimens. The haploidentical group received graft-versus-host disease (GVHD) prophylaxis with PT-Cy with or without a calcineurin inhibitor and mycophenolate. The MSD group received calcineurin inhibitor–based GVHD prophylaxis.

Results

Median follow-up of survivors was 3 years. The 28-day neutrophil recovery was similar in the two groups (95% v 97%; P=. 31). The 28-day platelet recovery was delayed in the haploidentical group compared with the MSD group (63% v 91%; P=. 001). Cumulative incidence of grade II to IV acute GVHD at day 100 was similar between the two groups (27% v 25%; P=. 84). Cumulative incidence of chronic GVHD at 1 year was significantly lower after Haplo-HCT (12% v 45%; P<. 001), and this benefit was confirmed on multivariate analysis (relative risk, 0.21; 95% CI, 0.14 to 0.31; P<. 001). For Haplo-HCT v MSD-HCT, 3-year rates of nonrelapse mortality (15% v 13%; P=. 41), relapse/progression (37% v 40%; P=. 51), progression-free survival (48% v 48%; P=. 96), and overall survival (61% v 62%; P=. 82) were similar. Multivariate analysis showed no significant difference between Haplo-HCT and MSD-HCT in terms of nonrelapse mortality (P=. 06), progression/relapse (P=. 10), progression-free survival (P=. 83), and overall survival (P=. 34).

Conclusion

Haplo-HCT with PT-Cy provides survival outcomes comparable to MSD-HCT, with a significantly lower risk of chronic GVHD.