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

AbstractBackground.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‐α) 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.MRD‐positive status was defined as a <4.5‐log reduction from diagnosis in 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‐α treatment (twice or thrice weekly of every 4 weeks cycle).Results.The 1‐year cumulative incidence of severe acute and chronic graft‐versus‐host disease after MRD‐directed IFN‐α 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‐α 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‐α treatment were significantly better than those of the MRD‐positive patients without any interventions in the historical cohort.Conclusion.MRD‐directed IFN‐α treatment is effective for patients with t(8;21) AML who were MRD‐positive after allo‐HSCT. The study was registered at https://ift.tt/KkipBP as NCT02027064.Implications for Practice.In patients with t(8;21) acute myeloid leukemia (AML), the presence of post‐allogeneic hematopoietic stem cell transplantation (allo‐HSCT) minimal residual disease (MRD), measured by RUNX1‐RUNX1T1 transcript levels, has been established as a powerful marker for predicting relapse. Interferon‐alpha (IFN‐α) could exert a relatively strong graft‐versus‐leukemia effect, and MRD‐directed IFN‐α treatment is effective for patients with t(8;21) AML who were MRD‐positive after allo‐HSCT.

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