Autologous hematopoietic cell transplantation for AML in first remission – An abandoned practice or promising approach?

Multiple small-dose infusions of G-CSF-mobilized haploidentical lymphocytes after autologous haematopoietic stem cell transplantation for acute myeloid leukaemia

This retrospective study analysed 106 acute myeloid leukaemia (AML) patients undergoing autologous haematopoietic stem cell transplantation (ASCT) to assess the impact of multiple small-dose infusions of granulocyte-colony-stimulating factor (G-CSF)-mobilized haploidentical lymphocytes as post-ASCT maintenance therapy. Among them, 50 patients received lymphocyte maintenance therapy, 21 received alternative maintenance therapy, and 35 received no maintenance therapy. Patients receiving lymphocyte maintenance therapy demonstrated significantly higher overall survival (OS) and disease-free survival (DFS) compared to those without maintenance therapy, with 4-year OS and DFS rates notably elevated. While there were no significant differences in recurrence rates among the three groups, lymphocyte maintenance therapy showcased particular benefits for intermediate-risk AML patients, yielding significantly higher OS and DFS rates and lower relapse rates compared to alternative maintenance therapy and no maintenance therapy. The study suggests that multiple small-dose infusions of G-CSF-mobilized haploidentical lymphocytes may offer promising outcomes for AML patients after ASCT, particularly for those classified as intermediate-risk. These findings underscore the potential efficacy of lymphocyte maintenance therapy in reducing disease relapse and improving long-term prognosis in this patient population.

An Analysis of the Worldwide Utilization of Hematopoietic Stem Cell Transplantation for Acute Myeloid Leukemia

Acute myeloid leukemia (AML) has an aggressive course and a historically dismal prognosis. For many patients, hematopoietic stem cell transplantation (HSCT) represents the best option for cure, but access, utilization, and health inequities on a global scale remain poorly elucidated. We wanted to describe patterns of global HSCT use in AML for a better understanding of global access, practices, and unmet needs internationally. Estimates of AML incident cases in 2016 were obtained from the Global Burden of Disease 2019 study. HSCT activities were collected from 2009 to 2016 by the Worldwide Network for Blood and Marrow Transplantation through its member organizations. The primary endpoint was global and regional use (number of HSCT) and utilization of HSCT (number of HSCT/number of incident cases) for AML. Secondary outcomes included trends from 2009 to 2016 in donor type, stem cell source, and remission status at time of HSCT. Global AML incidence has steadily increased, from 102,000 (95% uncertainty interval: 90,200-108,000) in 2009 to 118,000 (104,000-126,000) in 2016 (16.2%). Over the same period, a 54.9% increase from 9659 to 14,965 HSCT/yr was observed globally, driven by an increase in allogeneic (64.9%) with a reduction in autologous (-34.9%) HSCT. Although the highest numbers of HSCT continue to be performed in high-resource regions, the largest increases were seen in resource-constrained regions (94.6% in Africa/East Mediterranean Region [AFR/EMR]; 34.7% in America-Nord Region [AMR-N]). HSCT utilization was skewed toward high-resource regions (in 2016: AMR-N 18.4%, Europe [EUR] 17.9%, South-East Asia/Western Pacific Region [SEAR/WPR] 11.7%, America-South Region [AMR-S] 4.5%, and AFR/EMR 2.8%). For patients <70 years of age, this difference in utilization was widened; AMR-N had the highest allogeneic utilization rate, increasing from 2009 to 2016 (30.6% to 39.9%) with continued low utilization observed in AFR/EMR (1.7% to 2.9%) and AMR-S (3.5% to 5.4%). Across all regions, total HSCT for AML in first complete remission (CR1) increased (from 44.1% to 59.0%). Patterns of donor stem cell source from related versus unrelated donors varied widely by geographic region. SEAR/WPR had a 130.2% increase in related donors from 2009 to 2016, and >95% HSCT donors in AFR/EMR were related; in comparison, AMR-N and EUR have a predilection for unrelated HSCT. Globally, the allogeneic HSCT stem cell source was predominantly peripheral blood (69.7% of total HSCT in 2009 increased to 78.6% in 2016). Autologous HSCT decreased in all regions from 2009 to 2016 except in SEAR/WPR (18.9%). HSCT remains a central curative treatment modality in AML. Allogeneic HSCT for AML is rising globally, but there are marked variations in regional utilization and practices, including types of graft source. Resource-constrained regions have the largest growth in HSCT use, but utilization rates remain low, with a predilection for familial-related donor sources and are typically offered in CR1. Further studies are necessary to elucidate the reasons, including economic factors, to understand and address these health inequalities and improve discrepancies in use of HSCT as a potentially curative treatment globally.

Outcome of autologous stem cell transplantation in patients with favorable-risk acute myeloid leukemia in first remission

OBJECTIVE

To evaluate the efficacy of autologous hematopoietic stem cell transplantation (auto-HSCT) in patients with favorable-risk acute myeloid leukemia in first remission.

METHOD

Twenty patients who received auto-HSCT at our center between January 2014 and January 2021 were retrospectively reviewed.

RESULTS

Until last follow-up, three patients in the cohort were dead due to relapse. The estimated 1-year and 5-year overall survival were 95.00% ± 4.87% and 83.82% ± 8.58%, respectively. The estimated 5-year RFS and CIR (cumulative incidence of relapse) were 85.00% ± 7.98% and 15.00% ±7.98%, respectively.

CONCLUSION

The outcome of auto-HSCT in patients with favorable-risk acute myeloid leukemia in first remission was excellent and auto-HSCT could be an effective treatment for these patients.

Risk stratification using FLT3 and NPM1 in acute myeloid leukemia patients autografted in first complete remission

FLT3-ITD and NPM1 mutation refine prognostic stratification in acute myeloid leukemia (AML) with intermediate-risk cytogenetics. However, data on their role in patients undergoing autologous stem cell transplantation (Auto-SCT) as post-remission therapy (PRT) are limited. We therefore sought to retrospectively evaluate the role of FLT3-ITD and NPM1 in a cohort of AML patients (n = 405) with intermediate-risk cytogenetics, autografted in first complete remission (CR1). Patients were transplanted between 2000 and 2014 and reported to the European Society for Blood and Marrow Transplantation (EBMT) registry. Leukemia-free survival (LFS) was the primary outcome. Median follow-up was 5.5 years. FLT3-ITD^neg/NPM1^WT was the leading molecular subtype (50%), followed by FLT3-ITD^neg/NPM1^mut (30%). In the univariate analysis, molecular subtype was associated with LFS, overall survival (OS), and relapse incidence (RI) (p < 0.001); 5-year LFS: FLT3-ITD^neg/NPM1^mut 62%, FLT3-ITD^pos/NPM1^mut 38%, FLT3-ITD^neg/NPM1^WT 32%, and FLT3-ITD^pos/NPM1^WT 21%. At 5 years, OS and RI in the FLT3-ITD^neg/NPM1^mut subtype were 74% and 35%, respectively. The corresponding OS and RI in other subtypes were below 48% and over 57%. In a Cox multivariable model, molecular subtype was the strongest predictor of LFS, OS, and relapse. In conclusion, AML patients with intermediate-risk cytogenetics and FLT3-ITD^neg/NPM1^mut experience favorable outcomes when autografted in CR1, suggesting that Auto-SCT is a valid PRT option.

Designing combination therapies using multiple optimal controls

Strategic management of populations of interacting biological species routinely requires interventions combining multiple treatments or therapies. This is important in key research areas such as ecology, epidemiology, wound healing and oncology. Despite the well developed theory and techniques for determining single optimal controls, there is limited practical guidance supporting implementation of combination therapies. In this work we use optimal control theory to calculate optimal strategies for applying combination therapies to a model of acute myeloid leukaemia. We present a versatile framework to systematically explore the trade-offs that arise in designing combination therapy protocols using optimal control. We consider various combinations of continuous and bang-bang (discrete) controls, and we investigate how the control dynamics interact and respond to changes in the weighting and form of the pay-off characterising optimality. We demonstrate that the optimal controls respond non-linearly to treatment strength and control parameters, due to the interactions between species. We discuss challenges in appropriately characterising optimality in a multiple control setting and provide practical guidance for applying multiple optimal controls. Code used in this work to implement multiple optimal controls is available on GitHub.

Is There Still a Role for Autologous Stem Cell Transplantation for the Treatment of Acute Myeloid Leukemia?

After intensive induction chemotherapy and complete remission achievement, patients with acute myeloid leukemia (AML) are candidates to receive either high-dose cytarabine-based regimens, or autologous (ASCT) or allogeneic (allo-SCT) hematopoietic stem cell transplantations as consolidation treatment. Pretreatment risk classification represents a determinant key of type and intensity of post-remission therapy. Current evidence indicates that allo-SCT represents the treatment of choice for high and intermediate risk patients if clinically eligible, and its use is favored by increasing availability of unrelated or haploidentical donors. On the contrary, the adoption of ASCT is progressively declining, although numerous studies indicate that in favorable risk AML the relapse rate is lower after ASCT than chemotherapy. In addition, the burden of supportive therapy and hospitalization favors ASCT. In this review, we summarize current indications (if any) to ASCT on the basis of molecular genetics at diagnosis and minimal residual disease evaluation after induction/consolidation phase. Finally, we critically discuss the role of ASCT in older patients with AML and acute promyelocytic leukemia.