In a Chinese phase II trial reported in the Journal of Clinical Oncology, Gao et al found that prophylactic recombinant human granulocyte colony-stimulating factor (rhG-CSF) and minimal-dose decitabine reduced the risk of relapse vs no intervention among patients with high-risk, minimal residual disease–negative acute myeloid leukemia (AML) after allogeneic hematopoietic stem cell transplantation.
The open-label, multicenter study included 204 patients who had undergone allogeneic hematopoietic stem cell transplantation 60 to 100 days before random assignment. Patients were randomly assigned between April 2016 and January 2017 to receive rhG-CSF plus decitabine (n = 102) or no intervention (control group, n = 102). Treatment consisted of rhG-CSF at 100 mg/m2 on days 0 to 5 and decitabine at 5 mg/m2 on days 1 to 5 every 6 to 8 weeks for up to six courses. The primary outcome measure was relapse after transplantation.
“Our findings suggest that rhG-CSF combined with minimal-dose decitabine maintenance after allogeneic hematopoietic stem cell transplantation can reduce the incidence of relapse, accompanied by changes in the number of lymphocyte subtypes.”— Gao et al
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Median follow-up was 28.0 months in the rhG-CSF/decitabine group and 26.4 months in the control group. The estimated 2-year cumulative incidence of relapse was 15.0% in the rhG-CSF/decitabine group vs 38.3% in the control group (hazard ratio [HR] = 0.32, 95% confidence interval [CI] = 0.18–0.57, P <.01).
The 2-year cumulative incidence of chronic graft-vs-host disease was 34.0% in the rhG-CSF/decitabine group vs 48.2% in the control group (HR = 0.62, P = .03). The 2-year cumulative incidence of chronic graft-vs-host disease without relapse was 23.0% vs 21.7% (HR = 1.07, P = .81). The 2-year rates of leukemia-free survival were 81.9% vs 60.7% (HR = 0.38, P < .01). The 2-year rates of overall survival were 85.8% vs 69.7% (HR = 0.45, P < .01).
In an analysis including 20 randomly selected patients from each group, it was found that the numbers of CD8-positive T, natural killer, and T regulatory cells increased by the second to third course of rhG-CSF/decitabine treatment (P < .05), with these increases being found to be significantly associated with reduced risk of relapse on univariate analysis. On multivariate analysis, the number of natural killer cells was independently associated with reduced relapse risk (HR = 0.96, P < .01)
The investigators concluded, “Our findings suggest that rhG-CSF combined with minimal-dose decitabine maintenance after allogeneic hematopoietic stem cell transplantation can reduce the incidence of relapse, accompanied by changes in the number of lymphocyte subtypes.”
Xi Zhang, MD, PhD, of Xinqiao Hospital, The Army Medical University, Chongqing, is the corresponding author for the Journal of Clinical Oncology article.
Disclosure: The study was supported by the National Key Research and Development Program of China, Chinese National Natural Science Foundation, and others. For full disclosures of the study authors, visit ascopubs.org.The content in this post has not been reviewed by the American Society of Clinical Oncology, Inc. (ASCO®) and does not necessarily reflect the ideas and opinions of ASCO®.