For pediatric and young adult patients who are ineligible for myeloablative transplant, non-myeloablative haploidentical bone marrow transplantation using post-transplant cyclophosphamide can be a safe and effective treatment, according to a single-center study of 40 transplant recipients.
Researchers at Johns Hopkins University analyzed outcomes of non-myeloablative haploidentical marrow transplants from 2003-2015 in patients conditioned with fludarabine, cyclophosphamide and total body irradiation. Post-transplant immunosuppression consisted of cyclophosphamide, mycophenolate mofetil and tacrolimus.
At a median follow-up of 20 months (range 3-148), 1-year overall and event-free survival were 56% and 43%, respectively. Despite a 1-year transplant-related mortality rate of 13%, the cumulative incidence of relapse at 2 years was high at 52%. In this high-risk group, researchers attributed the potential for significant minimal residual disease, active disease at HCT or pre-treatment regimens to the increased rate of relapse.
Cumulative incidences of acute GVHD grades II-IV and grades III-IV at day 100 were 33% and 5%, respectively. Cumulative incidence of chronic GVHD was 23%, with 7% of recipients developing moderate-to-severe chronic GVHD.
The researchers noted that the study size limited the comparison of outcomes for pediatric and young adult patients to published adult outcomes. However, they concluded that “this approach is a widely available, safe, and feasible option for pediatric and young adult patients with high-risk hematologic malignancies.”