Comparison of umbilical cord blood allogeneic stem cell transplantation vs. auto-SCT for adult acute myeloid leukemia patients in second complete remission at transplant: a retrospective study on behalf of the SFGM-TC

Autologous hematopoietic stem cell transplantation followed by interleukin-2 for adult acute myeloid leukemia patients with favorable or intermediate risk after complete remission

High-dose chemotherapy followed by allogeneic hematopoietic stem cell transplantation (allo-HSCT) is generally the optimal option for patients with acute myeloid leukemia (AML). However, for favorable- and intermediate-risk patients, the regimen remains less understood due to graft versus host disease (GVHD) and increased non-relapsed mortality (NRM) caused by allo-HSCT. Additionally, the benefit of maintenance therapy has not yet been conclusively proven. Here, we conducted a retrospective study on the long-term outcome of AML patients with favorable or intermediate risk who underwent autologous hematopoietic stem cell transplantation (auto-HSCT) followed by interleukin-2 (IL-2) subcutaneous injection as maintenance therapy. A total of 49 patients from 2007 to 2019 were included in our study. They all received a daunorubicin + cytarabine regimen as induction chemotherapy followed by four to six cycles of consolidation therapy with medium- or high-dose cytarabine. Once patients achieved complete remission (CR1), they started receiving auto-HSCT followed by IL-2 injections. The results showed that no patients stopped receiving IL-2 injections on account of adverse side effects, and the 5-year overall survival (OS) and leukemia-free survival (LFS) rates were 85.6 ± 5.0% and 78.5 ± 6.1%, respectively. The multivariate analysis also suggested that age, gender, initial white blood cell (WBC) count, AML subtype, cytogenetic risk, and conditioning regimen did not affect the prognosis. In conclusion, auto-HSCT followed by IL-2 injection is an effective treatment that can improve the prognosis of AML for patients with favorable or intermediate risk.

Outcomes of Autologous Hematopoietic Cell Transplantation Compared With Chemotherapy Consolidation Alone for Non-High-Risk Acute Myeloid Leukemia in First Complete Remission in a Minority-Rich Inner-City Cohort With Limited Access to Allografts

INTRODUCTION

In the United States, autologous hematopoietic cell transplantation (autoHCT) has fallen out of favor over chemotherapy consolidation for non-high-risk acute myeloid leukemia (AML) when allogeneic hematopoietic cell transplantation (alloHCT) is unfeasible, which is common in racial minorities because of donor registry under-representation and socioeconomic challenges. We compared autoHCT consolidation outcomes with chemotherapy alone in a minority-rich cohort in the Bronx.

PATIENTS AND METHODS

We identified adults with favorable or intermediate cytogenetic risk AML in first complete remission after induction at Montefiore Medical Center from 1999 to 2015, and analyzed 81 patients who received consolidation with ≥2 cycles of chemotherapy, of whom 28 received autoHCT.

RESULTS

The cohort predominantly consisted of ethnic/racial minorities (69%). Age, sex, race, presenting white cell count, and cytogenetic risk were similar between groups. The autoHCT group had longer relapse-free (RFS; 43 vs. 11 months; P = .003) and overall (OS) survival (not reached vs. 36 months; P = .043). Adjusted multivariable analysis showed significant benefit of autoHCT over chemotherapy alone for RFS (hazard ratio [HR], 0.53; 95% confidence interval [CI], 0.37-0.75; P < .001) and OS (HR, 0.61; 95% CI, 0.40-0.95; P = .027).

CONCLUSION

In this inner-city non-high-risk AML cohort, autoHCT provided OS and RFS benefit compared with chemotherapy alone. AutoHCT might constitute a valuable option for ethnic/racial minorities affected by significant barriers to alloHCT, whereas integration of measurable residual disease can help select patients more likely to benefit.

Identification of leukemia stem cell expression signatures through Monte Carlo feature selection strategy and support vector machine

Acute myeloid leukemia (AML) is a type of blood cancer characterized by the rapid growth of immature white blood cells from the bone marrow. Therapy resistance resulting from the persistence of leukemia stem cells (LSCs) are found in numerous patients. Comparative transcriptome studies have been previously conducted to analyze differentially expressed genes between LSC⁺ and LSC^- cells. However, these studies mainly focused on a limited number of genes with the most obvious expression differences between the two cell types. We developed a computational approach incorporating several machine learning algorithms, including Monte Carlo feature selection (MCFS), incremental feature selection (IFS), support vector machine (SVM), Repeated Incremental Pruning to Produce Error Reduction (RIPPER), to identify gene expression features specific to LSCs. One thousand 0ne hudred fifty-nine features (genes) were first identified, which can be used to build the optimal SVM classifier for distinguishing LSC⁺ and LSC^- cells. Among these 1159 genes, the top 17 genes were identified as LSC-specific biomarkers. In addition, six classification rules were produced by RIPPER algorithm. The subsequent literature review on these features/genes and the classification rules and functional enrichment analyses of the 1159 features/genes confirmed the relevance of extracted genes and rules to the characteristics of LSCs.

Autologous Hematopoietic Stem Cell Transplantation in Acute Myelogenous Leukemia

The clinical outcomes of autologous hematopoietic stem cell transplantation (ASCT) in acute myelogenous leukemia (AML) have improved over time. Indeed, numerous studies have demonstrated that ASCT is associated with a lower relapse rate and acceptable nonrelapse mortality compared with chemotherapy alone in patients with AML. In addition, ASCT is also associated with comparable overall survival outcomes to those of allogeneic hematopoietic stem cell transplantation in some patients with AML. To date, age, cytogenetic and molecular risk stratification, and minimal residual disease (MRD) status have been shown to be closely related to clinical outcomes following ASCT. ASCT is recommended for patients with favorable-risk and intermediate-risk AML in first complete remission and patients with acute promyelocytic leukemia in second complete remission for whom a matched sibling donor is not available. MRD status pre-ASCT is the most important factor to consider when determining whether a patient is eligible for ASCT and can effectively predict clinical outcomes after ASCT. Advanced age is not an absolute contradiction for ASCT. In this review, we describe the literature and clinical trials evaluating the outcomes of ASCT in patients with AML and discuss the indications for ASCT therapy. Because the greatest concern in ASCT recipients is early relapse, important factors that should be monitored before ASCT and future perspectives in this area are also presented.

Revisiting autologous transplantation in acute myeloid leukemia

PURPOSE OF REVIEW

Autologous hematopoietic cell transplantation (auto-HCT) has been evaluated as a consolidation treatment for acute myeloid leukemia (AML) in the 1980s and 1990s. These prospective studies from large trials compared auto-HCT with chemotherapy. A comparison was made also with allogeneic hematopoietic cell transplantation (allo-HCT). These studies reported a lower relapse rate with auto-HCT compared with chemotherapy, but without impact on the overall survival. A high transplant-related mortality in that era confounded the relevance of these data.

RECENT FINDINGS

Several prospective studies and a plethora of retrospective registry data have confirmed the potent antileukemic therapy of auto-HCT compared with chemotherapy and, in some instances, have even challenged the presumed superiority of allo-HCT as the definitive therapy for certain patients with AML.

SUMMARY

The aggregate of recent data, prospective and retrospective, strongly suggests an important role for auto-HCT, at least as the most potent nonimmunologic antileukemia therapy. The transplant-related mortality in 2017 is close to that expected from standard consolidation therapy leading to the conclusion that the role of auto-HCT needs to be rigorously revisited, preferably in prospective studies, to establish its precise role in the current era.

Should autotransplantation in acute myeloid leukemia in first complete remission be revisited?

PURPOSE OF REVIEW

Despite numerous studies, the best postremission therapy in acute myeloid leukemia (AML) is a subject of intense controversy. Major prognostic factors for disease outcome are the genetic alterations of AML, patient's age, and performance status. AML is more common in older adults, with a median age of 72 years. However, in this age group the unfavorable cytogenetics dominates at a time when biologically it may be most difficult to administer optimal intensive therapy.

RECENT FINDINGS

Autologous stem cell transplantation (ASCT) enables the administration of high-dose therapy supported by stem cell infusion with a treatment-related toxicity not significantly higher than that associated with chemotherapy and significantly lower than in allogeneic stem cell transplantation. The dilemma of best postremission therapy has not been resolved because of the paucity of randomized controlled studies, especially in various cytogenetic risk and age groups. Instead, the use of genetic randomization by donor availability, analysis of outcome based on intention-to-treat, and mixed populations in the registry data produce variable results.

SUMMARY

ASCT has been associated with prolonged disease-free survival as compared to chemotherapy, especially in the favorable and intermediate risk groups. Advances in immunotherapy in AML may propel ASCT as a platform for various immunologic maneuvers.

Autologous stem cell transplantation versus alternative allogeneic donor transplants in adult acute leukemias

The availability of alternative sources of stem cells including most recently T-replete haploidentical marrow or peripheral blood, and the increasing use of reduced-intensity conditioning (RIC), renders feasible an allogeneic transplant to almost all patients with acute leukemia up to 70 years of age. Autologous stem cell transplantation (ASCT) for consolidation of complete remission (CR), however, offers in some circumstances an alternative option. Although associated with a higher relapse rate, autologous transplant benefits from a lower non-relapse mortality, the absence of graft-versus-host disease (GVHD), and a better quality of life for long-term survivors. The recent use of intravenous busulfan (IVBU) with high-dose melphalan, better monitoring of minimal residual disease (MRD), and maintenance therapy post autografting bring new interest. Few retrospective studies compared the outcome following alternative donor versus autologous transplants for remission consolidation. Genoidentical and phenoidentical allogeneic stem cell transplantations are undisputed gold standards, but there are no data showing the superiority of alternative allogeneic donor over autologous transplantation, at the time of undetectable MRD, in patients with good- and intermediate-1 risk acute myelocytic leukemia (AML) in first complete remission (CR1), acute promyelocytic leukemia in second complete remission (CR2), and Philadelphia chromosome-positive (Ph(+)) acute lymphocytic leukemia (ALL).