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.