Interferon-α Is Effective for Treatment of Minimal Residual Disease in Patients with t(8;21) Acute Myeloid Leukemia After Allogeneic Hematopoietic Stem Cell Transplantation: Results of a Prospective Registry Study

Background RUNX1-RUNX1T1 transcript levels were established as a powerful marker for predicting relapse in patients with t(8;21) acute myeloid leukemia (AML). We aimed to identify the efficacy of minimal residual disease (MRD)-directed interferon-alpha (IFN-alpha) treatment in patients with t(8;21) AML who were positive for MRD after allogeneic hematopoietic stem cell transplantation (allo-HSCT; n=42). Subjects, Materials, and Methods Results MRD-positive status was defined as a RUNX1-RUNX1T1 transcripts and/or the loss of a >= 4.5-log reduction after 3 months after HSCT. Patients with positive MRD received six cycles of IFN-alpha treatment (twice or thrice weekly of every 4 weeks cycle). The 1-year cumulative incidence of severe acute and chronic graft-versus-host disease after MRD-directed IFN-alpha treatment was 7.1% and 4.8%, respectively. After the treatment, 15 (35.7%), 5 (11.9%), 3 (7.1%), and 9 (21.5%) patients achieved MRD negativity at 1, 2, 3, and >3 months, respectively. Three patients relapsed after the IFN-alpha treatment, in which the 1-year cumulative incidence of relapse was 7.2%. One patient died of severe infection at 460 days after treatment. The 1-year probabilities of event-free survival, disease-free survival, and overall survival after treatment were 76.0%, 92.4%, and 92.5%, respectively. The clinical outcomes in patients who received MRD-directed IFN-alpha treatment were significantly better than those of the MRD-positive patients without any interventions in the historical cohort. Conclusion MRD-directed IFN-alpha treatment is effective for patients with t(8;21) AML who were MRD-positive after allo-HSCT. The study was registered at as NCT02027064.