Wilms Tumor 1 Expression and Pre-emptive Immunotherapy in Patients with Acute Myeloid Leukemia Undergoing an Allogeneic Hemopoietic Stem Cell Transplantation

Minimal residual disease (MRD) was monitored by Wilms tumor 1 (WT1) expression in 207 patients with acute myeloid leukemia (AML) after an allogeneic hemopoietic stem cell transplantation (HSCT) as a trigger to initiate pre-emptive immunotherapy (IT) with cyclosporin discontinuation and/or donor lymphocyte infusion. The trigger for IT was WT1 >= 180 copies/10(4) Abelson cells in marrow cells in the first group of 122 patients (WTI-180) and >= 100 copies in a subsequent group of 85 patients (WT1-100). Forty patients received IT. The cumulative incidence (CI) of relapse was 76% in WT1-180 (n = 17) versus 29% in WT1 - 100 patients (n = 23) receiving IT (P = .006); the leukemia-free survival from MRD positivity was 23% versus 74%, respectively (P = .003). We then looked at the entire AML patient population (n = 207). WT1-180 and WT1-100 patients were comparable for disease phase and age. The overall 4-year CI of transplantation related mortality was 13% in both groups; the CI of leukemia relapse was 38% in the WT1-180 and 28% in the WT1-100 patients (P = .05) and leukemia-free survival was 56% versus 48%, respectively (P = .07). In conclusion, we suggests that WT1-based pre-emptive immunotherapy is feasible in patients with undergoing an allogeneic HSCT. The protective effect on relapse is greater when IT is triggered at lower levels of WT1. (C) 2016 American Society for Blood and Marrow Transplantation.