Conditioning Regimens for Frail Patients with Acute Leukemia Undergoing Allogeneic Stem Cell Transplant: How to Strike Gently

Despite the recent dramatic progress in acute myeloid leukemia (AML) and acute lymphoblastic leukemia (ALL) therapy, allogeneic transplant remains a mainstay of treatment for patients with acute leukemia. The availability of novel compounds and low intensity chemotherapy regimens made it possible for a significant proportion of elderly and comorbid patients with AML or ALL to undergo curative treatment protocols. In addition, the expansion of donor availability and the recent dramatic progress in haploidentical stem cell transplant, allow the identification of an available donor for nearly every patient. Therefore, an increasing number of transplants are currently performed in elderly and frail patients with AML or ALL. However, allo-Hematopoietic stem cell transplant (HSCT) in this delicate setting represents an important challenge, especially regarding the selection of the conditioning protocol. Ideally, conditioning intensity should be reduced as much as possible; however, in patients with acute leukemia relapse remains the major cause of transplant failure. In this article we present modern tools to assess the patient health status before transplant, review the available data on the outcome of frail AML an ALL patients undergoing allo-HSCT, and discuss how preparatory regimens can be optimized in this setting.

Hematopoietic Cell Transplant-Composite Risk (HCT-CR): A Novel Predictor of Prognosis in Acute Leukemia Patients Undergoing Allogeneic Hematopoietic Stem Cell Transplantation

BACKGROUND

Allogeneic hematopoietic stem cell transplantation (allo-HCT) is a curable treatment modality for hematologic disorders. Transplant-related mortality remains high despite prominent scientific and technologic improvements. In consideration with the potential impact of patient- and disease-related factors on transplant outcome, this retrospective study was performed to investigate the predictive role of pretransplant HCT-composite risk (HCT-CR) score in allo-HCT recipients.

METHODS

A total of 313 patients with acute leukemia (male/female: 192/121; median age, 36 [18-71] years) were included in this study. The study cohort was divided into 2 subgroups based on pretransplant HCT-CR categories. The HCT-CR^lo group included low-risk patients, and the HCT-CR^int-hi group consisted of intermediate-, high-, and very high-risk patients.

RESULTS

In the whole cohort, overall survival (OS) and 5-year OS were found to be 32.2% and 45.1%, respectively. Probability of OS was significantly better in the HCT-CR^lo group compared with the HCT-CR^int-hi group (P < .001). Leukemia-free survival (LFS) and 3-year LFS were 59.5% and 65.1%, respectively. Probability of LFS was better in the HCT-CR^lo group compared with the HCT-CR^int-hi group (P = .001). Nonrelapse mortality (NRM) and 3-year NRM were estimated to be 38.1% and 27.5%, respectively. Probability of NRM was significantly higher in the HCT-CR^int-hi group compared with the HCT-CR^lo group (P = .012). In multivariate analysis, HCT-CR was shown to have significant prognostic impact in acute lymphoblastic leukemia patients (P = .023; hazard ratio, 2.613; 95% CI, 1.142-5.982).

CONCLUSION

Pretransplant evaluation of patient- and disease-related factors is essential for the accurate prediction of posttransplant survival. Further efforts to evolve current criteria for pretransplant risk assessment would eventuate in better transplant outcomes.

Comparison of Risk Scoring Systems in HLA-Matched Related Allogeneic Hematopoietic Stem Cell Transplantation: A Retrospective Cohort Study

Objective

Allogeneic hematopoietic stem cell transplantation (AHSCT) is a potentially curative treatment of choice for many hematological diseases. However, there are some transplantation-related risks. Predicting the risk-benefit ratio prior to AHSCT facilitates the choice of conditioning regimens and posttransplant follow-up. Hence, many risk models have been developed. The aim of the present study was to compare 6 different risk models that are clinically used.

Materials and Methods

A total of 259 patients were enrolled in this study. The European Society for Blood and Marrow Transplantation (EBMT), Hematopoietic Cell Transplantation Comorbidity Index (HCT-CI), Age-Adjusted Hematopoietic Cell Transplantation Comorbidity Index (HCT-CI-Age), revised Pretransplant Assessment of Mortality (rPAM), Acute Leukemia-EBMT (AL-EBMT), and Disease Risk Index (DRI) risk models were applied retrospectively.

Results

The AL-EBMT, HCT-CI, and HCT-CI-Age scoring systems were found to be predictive for 2-year overall survival (OS) and 2-year non-relapse mortality (NRM) (2-year OS: AL-EBMT, reference vs. score 8.5-10, HR: 1.3, p=0.035; AL-EBMT, reference vs. score >10, HR: 3.8, p=0.001; HCT-CI: reference vs. score 1-2, HR: 1.4, p=0.018; HCT-CI: reference vs. score ≥3, HR: 2.5, p<0.001; HCT-CI-Age: reference vs. score 1-2, HR: 1.3, p<0.001; HCT-CI-Age: reference vs. score ≥3, HR: 3.2, p<0.001) (2-year NRM: AL-EBMT: reference vs. score 8.5-10, HR: 1.61, p<0.001; AL-EBMT: reference vs. score >10, HR: 3.3, p<0.001; HCT-CI: reference vs. score 1-2, HR: 1.3, p=0.028; HCT-CI: reference vs. score ≥3, HR: 2.3, p=0.011; HCT-CI-Age: reference vs. score 1-2, HR: 1.3, p=0.01; HCT-CI-Age: reference vs. score ≥3, HR: 2.4, p=0.003). In terms of the Kaplan-Meier estimates of 2-year OS and 2-year NRM, the risk scoring system with the highest predictive power was found to be AL-EBMT (2-year AUC: 0.59 and 0.60, respectively). The other scores were not found to be predictive for 2-year OS and NRM.

Conclusion

In the present study at our bone marrow and stem cell transplant center, it has been demonstrated that the HCT-CI, HCT-CI-Age, and AL-EBMT are good predictors of 2-year NRM and OS.

European Group for Blood and Marrow Transplantation score correlates with outcomes of older patients undergoing allogeneic hematopoietic stem cell transplantation

BACKGROUND

Acute myeloid leukemia (AML) and myelodysplastic syndrome (MDS) are hematological diseases predominantly occurring in older patients. Although allogeneic hematopoietic stem cell transplantation (allo-HSCT) remains the curative therapy for refractory AML or high-risk MDS, old age is often a hurdle to the procedure. We conducted a retrospective study to analyze the prognostic factors predicting outcomes of older patients undergoing allo-HSCT for acute leukemia and MDS.

METHODS

We collected data from patients diagnosed with acute leukemia or MDS, who underwent allo-HSCT at >50 years of age and reviewed clinical characteristics, including age, sex, underlying disease, European Group for Blood and Bone Marrow Transplantation (EBMT) risk score, and presence of acute graft-versus-host disease (aGVHD) or chronic GVHD (cGVHD). The Cox proportional hazard model was adopted to explore the independent prognostic factors for overall survival (OS), progression-free survival (PFS), and non-relapse mortality (NRM).

RESULTS

A total of 85 older patients were included, with the median age at allo-HSCT being 55 years. The significant prognostic factors for worse OS or PFS were an EBMT risk score > 3 and grade III-IV aGVHD, while patients with moderate to severe cGVHD would have better OS or PFS. Interestingly, it is not cGVHD but grade III-IV aGVHD that significantly correlated with NRM.

CONCLUSION

This cohort study suggests that an EBMT risk score >3 and grade III-IV aGVHD predict poor outcomes, and careful management of GVHD may allow better survival for older patients undergoing allo-HSCT.

Prognostic Scoring Systems in Allogeneic Hematopoietic Stem Cell Transplantation: Where Do We Stand?

Allogeneic hematopoietic stem cell transplantation is a potentially curative treatment for many hematologic disorders. Maximizing the benefit of transplantation for disease control while minimizing the risk for associated complications remains the field's leading challenge. This challenge has prompted the development of multiple prognostic scoring systems over the last 2 decades. Prognostic scores can be used for informed decision making, better patient counseling, design of interventional trials, and analysis of prospective and retrospective data. They are also helpful in treatment allocation and personalization according to predicted risk. A better understanding of the molecular and cytogenetic features of the disease, along with the advent of novel therapies, has increased the need for reliable prognostication of which patients will benefit most from transplantation. Here we review the clinical role of the prognostic systems currently in clinical use, examining both their strengths and their limitations.