Allogeneic hematopoietic stem cell transplantation for the treatment of BCR-ABL1-negative atypical chronic myeloid leukemia and chronic neutrophil leukemia: A retrospective nationwide study in Japan

Abstract

Atypical chronic myeloid leukemia (aCML) and chronic neutrophilic leukemia (CNL) are rare BCR-ABL1 fusion gene-negative myeloid neoplasms with a predominance of neutrophils. Since no standard therapeutic strategy currently exists for these diseases, we retrospectively evaluated the outcomes of allogeneic hematopoietic stem cell transplantation (allo-HSCT) for aCML and CNL. Data from 14 aCML and 5 CNL patients as their diagnoses were collected using a nationwide survey. Allo-HSCT was performed between 2003 and 2014. Preconditioning regimens included myeloablative (n=15), reduced-intensity (n=3), and non-myeloablative (n=1) regimens. Transplanted stem cells were obtained from HLA-matched related donors (n=5) and alternative donors (n=14). Neutrophil engraftment was successfully achieved in 17 patients. One-year overall survival rates (OS) were 54.4% (95% confidence interval [CI], 24.8 to 76.7%) and 40.0% (95% CI, 5.2 to 75.3%) in patients with aCML and CNL, respectively. Among aCML patients, 1-year OS were 76.2% (95% CI, 33.2 to 93.5%) and 20.0% (95% CI, 0.8 to 58.2%) in patients with <5% myeloblasts (n=9) and ≥5% myeloblasts (n=5) in peripheral blood before allo-HSCT, respectively. These results suggest that allo-HSCT achieves long-term survival in patients with aCML and CNL. Better pre-transplant management is required to improve the outcomes of aCML patients with ≥5% blasts in peripheral blood.

Hydroxyurea- a cost effective treatment in developing countries for Atypical Chronic Myeloid Leukemia (aCML): Case Report of Two Patients

“…Currently, the only known treatment that has relatively better outcomes in disease free survival in aCML patients is allogeneic hematopoietic stem cell transplantation (HSCT). 27 Unfortunately, HSTC cannot be an option for all patients in LMICs because of lack of suitable donor, advanced age, socioeconomic constraints and specialized medical teams. 8,17,28,29 Additionally the cost of stem cell transplant and immunosuppressant drug costs (taken after transplant) approximates to 3–4 million Pakistani rupees (on average) and becomes an additional challenge for economically deprived populations.…”

Atypical Chronic Myelogenous Leukemia, BCR-ABL1 Negative: Diagnostic Criteria and Treatment Approaches

“…A myeloablative regimen was used in 11/14 patients. Among patients with neutrophil engraftment, 9/13 achieved a CR and the 1-year OS was 54.4%, being higher in univariate analysis in patients with related donors, <5% myeloblasts in the peripheral blood, and a Karnofsky performance status of ≤80% ( 48 ).…”

Chronic neutrophilic leukemia: 2022 update on diagnosis, genomic landscape, prognosis, and management

“…124 A contemporary retrospective study of allo-HSCT in Japan reported data from 14 aCML and five CNL patients transplanted between 2003 and 2014. 142 The majority received myeloablative preconditioning regimens. Transplants were principally from alternative donors (n = 14) versus HLA-matched related (n = 5).…”