General AML

A predictive model for prognosis in AML and MDS patients receiving haplo-SCT

Allogeneic Hematopoietic Cell Transplantation (HCT) is a curative option for Acute Myeloid Leukemia (AML) patients. However, remission status at the time of transplantation and disease status can vary the outcome of allogeneic HCT considerably.1 The potential interactions among these elements have not been explored.

In a Letter to the Editor of Blood, Bachegowda et al., from The University of Texas MD Anderson Cancer Center (MDACC), Houston, Texas, aimed to develop a model that can predict survival in AML and Myelodysplastic Syndrome (MDS) patients receiving Haploidentical Transplant (HaploSCT) using a combination of disease status, cytogenetics, and HCT Comorbidity Index (HCT-CI).2

In total, 105 AML (n = 77) and MDS (n = 28) patients (median age = 52 years) who received first HaploSCT using a post-transplant cyclophosphamide for GVHD prophylaxis between 09/2009–03/2015 at MDACC were retrospectively studied. Patients received HaploSCT when they were either in First or Second Complete Remission (CR1/2, n = 49) and had either favorable (n = 9), intermediate (n = 55) or unfavorable (n = 36) cytogenetics. The primary endpoint of the study was Progression Free Survival (PFS). The secondary endpoints were Overall Survival (OS) and disease progression. Median follow-up length of the study was 18 months.

The key results of the study were:
  • Using Classification and Regression Tree Analysis (CART), three mutually exclusive risk groups were identified; low-risk group (patients in CR1/2 with intermediate/favorable risk cytogenetics, irrespective of HCT-CI, n = 30), intermediate-risk group (patients with intermediate/favorable cytogenetics and HCT-CI score > 4, n = 57), and high-risk group (patients with at least one negative prognostic factor beyond CR1/2 and /or with adverse-risk cytogenetics and HCT-CI score > 4, n = 11)
  • 2-year OS for patients in low-risk, intermediate-risk, and high-risk group were 83% (HR reference), 30% (HR = 4.6, P = 0.002), and 12% (HR = 9.3, P < 0.001), respectively
  • 2-year PFS for patients in low-risk, intermediate-risk, and high-risk group were 77% (HR reference), 24% (HR = 5.2, P < 0.001), and 0% (HR = 12.2, P < 0.001), respectively
  • 2-year cumulative incidence of disease progression for patients in low-risk, intermediate-risk, and high-risk group were 5% (reference), 48% (P = 0.004), and 51% (P = 0.005), respectively

The authors concluded by stating “risk stratification models combining disease and patient characteristics could further refine prognosis for potential ASCT [allogenic HCT] patients” and could “better identify patients that could benefit from maintenance therapies post-transplant”. They further suggested that due to the small sample size and design used in developing the model to predict survival, a study with a larger sample size should be carried out for validation.

References
  1. Armand P. et al. A disease risk index for patients undergoing allogeneic stem cell transplantation. Blood. 2012 Jul 26; 120(4): 905–913. DOI: 1182/blood-2012-03-418202. Epub 2012 Jun 18.
  2. Bachegowda L.S. et al. Predictive model for survival in patients with AML/MDS receiving haploidentical stem cell transplantation. Blood. 2017 Mar 28. DOI: 1182/blood-2017-02-766154.