Autologous stem cell transplantation for adult acute myelocytic leukemia in first remission-Better outcomes after busulfan and melphalan compared with busulfan and cyclophosphamide: A retrospective study from the Acute Leukemia Working Party of the European Society for Blood and Marrow Transplantation (EBMT)

Safety and Efficacy of High-Dose Chemotherapy with TreoMel 200 vs. TreoMel 140 in Acute Myeloid Leukemia Patients Undergoing Autologous Stem Cell Transplantation

(1) Background: Treosulfan and melphalan (TreoMel)-based high-dose chemotherapy (HDCT) has shown promising safety and efficacy as a conditioning regimen for acute myeloid leukemia (AML) patients undergoing autologous stem cell transplantation (ASCT). However, despite intensive first-line induction treatment and upfront consolidation with HDCT and ASCT, AML relapse rates are still high, and further efforts are needed to improve patient outcomes. The aim of this study was to compare two melphalan dose schedules in regard to the safety of TreoMel HDCT and patient outcomes. (2) Methods: We retrospectively analyzed the safety and efficacy of two melphalan dose schedules combined with standard-dose treosulfan in AML patients undergoing HDCT and ASCT at the University Hospital of Bern, Switzerland, between August 2019 and August 2023. Patients received treosulfan 42 g/m2 combined with either melphalan 140 mg/m2 (TreoMel 140) or melphalan 200 mg/m2 (TreoMel 200). Co-primary endpoints were progression-free survival (PFS), overall survival (OS), as well as safety profile. (3) Results: We included a total of 51 AML patients: 31 (60.8%) received TreoMel 140 and 20 (39.2%) TreoMel 200. The patients' basal characteristics were comparable between both cohorts. No significant differences in the duration of hospitalization or the adverse event profile were identified. There were no statistically significant differences in relapse (0.45 vs. 0.30, p = 0.381) and mortality rates (0.42 vs. 0.15, p = 0.064) between the melphalan 140 mg/m2 and 200 mg/m2 cohorts, nor for PFS (HR: 0.81, 95% CI: 0.29-2.28, p = 0.70) or OS (HR: 0.70, 95% CI: 0.19-2.57, p = 0.59) for the TreoMel 140 vs. TreoMel 200 cohort. (4) Conclusions: A higher dose of melphalan (TreoMel 200) was well tolerated overall. No statistically significant differences for patient outcomes could be observed, possibly due to the relatively small patient cohort and the short follow-up. A longer follow-up and prospective randomized studies would be required to confirm the safety profile and clinical benefit.

Autologous hematopoietic stem cell transplantation conditioning regimens and chimeric antigen receptor T cell therapy in various diseases

Conditioning regimens employed in autologous stem cell transplantation have been proven useful in various hematological disorders and underlying malig nancies; however, despite being efficacious in various instances, negative consequences have also been recorded. Multiple conditioning regimens were extracted from various literature searches from databases like PubMed, Google scholar, EMBASE, and Cochrane. Conditioning regimens for each disease were compared by using various end points such as overall survival (OS), progression free survival (PFS), and leukemia free survival (LFS). Variables were presented on graphs and analyzed to conclude a more efficacious conditioning regimen. In multiple myeloma, the most effective regimen was high dose melphalan (MEL) given at a dose of 200/mg/m2. The comparative results of acute myeloid leukemia were presented and the regimens that proved to be at an admirable position were busulfan (BU) + MEL regarding OS and BU + VP16 regarding LFS. In case of acute lymphoblastic leukemia (ALL), BU, fludarabine, and etoposide (BuFluVP) conferred good disease control not only with a paramount improvement in survival rate but also low risk of recurrence. However, for ALL, chimeric antigen receptor (CAR) T cell therapy was preferred in the context of better OS and LFS. With respect to Hodgkin's lymphoma, mitoxantrone (MITO)/MEL overtook carmustine, VP16, cytarabine, and MEL in view of PFS and vice versa regarding OS. Non-Hodgkin's lymphoma patients were administered MITO (60 mg/m2) and MEL (180 mg/m2) which showed promising results. Lastly, amyloidosis was considered, and the regimen that proved to be competent was MEL 200 (200 mg/m2). This review article demonstrates a comparison between various conditioning regimens employed in different diseases.

Etoposide plus cytarabine versus cyclophosphamide or melphalan in busulfan-based preparative regimens for autologous stem cell transplantation in adults with acute myeloid leukemia in first complete remission: a study from the Acute Leukemia Working Party of the EBMT

We retrospectively compared the impact of the conditioning regimen in adult patients with acute myeloid leukemia (AML) in first complete remission (CR1) that received high-dose myeloablative chemotherapy followed by autologous stem cell transplantation (ASCT) from 2010 to 2021 with either high-dose cytarabine, etoposide and busulfan (BEA), busulfan with cyclophosphamide (BUCY) or busulfan and high-dose melphalan (BUMEL) registered in the EBMT database. Overall 1560 patients underwent ASCT, of which 156, 1143 and 261 received BEA, BUCY and BUMEL, respectively. Compared to BUCY and BUMEL, BEA patients were younger (p < 0.001) and less frequently had NPM1 mutations (p = 0.03). Transplant outcomes at 5 years with BEA, BUCY and BUMEL were: cumulative incidence of relapse 41.8%, 46.6% and 51.6%; non-relapse mortality (NRM) 1.5%, 5.2% and 7.3%; probability of leukemia-free survival (LFS) 56.7%, 48.2% and 41.1%; and overall survival (OS) 71.3%, 62.3% and 56%, respectively. In multivariable analysis the BEA regimen showed significant improvement in OS compared to BUCY (hazard ratio [HR] 0.65; 95% CI, 0.42-0.83; p = 0.048) and BUMEL (HR 0.59; 95% CI, 0.37-0.94; p = 0.029). In conclusion, high-dose myeloablative combination chemotherapy with BEA offered improved outcomes compared to classical BUCY or BUMEL in patients with AML in CR1 undergoing ASCT.

Low Incidence of Relapse with a Moderate Conditioning Regimen of Fludarabine, Busulfan, and Melphalan for Patients with Myeloid Malignancies: A Single-Center Analysis of 100 Patients

Relapse after allogeneic hematopoietic stem cell transplantation (allo-HSCT) with standard myeloablative conditioning regimens such as fludarabine (Flu) and busulfan (Bu) remains a major concern in patients with myeloid malignancies. A low relapse rate has been reported when thiotepa or melphalan (Mel) is added to Flu-Bu, but at a possible increased risk of nonrelapse mortality (NRM). Here we evaluated the outcomes of 100 patients (70 with acute myeloid leukemia, 23 with myelodysplastic syndrome, 4 with chronic myelomonocytic leukemia, and 3 with granulocytic sarcoma) who underwent their first allo-HSCT after a moderate-dose FBM conditioning regimen consisting of Flu 150 mg/m2, Bu 6.4 mg/kg, and Mel 140 mg/m2 (n = 69), with Mel 100 mg/m2 for patients age >55 years and/or with a Hematopoietic Cell Transplantation Comorbidity Index (HCT-CI) ≥3 (n = 31). Donors were HLA-matched siblings (n = 19), matched unrelated donors (n = 4), and haploidentical donors (n = 77). The majority of patients (88%) had an intermediate or high Disease Risk Index. Out of 96 evaluable patients, 94 achieved neutrophil engraftment and had full donor chimerism on day +30 post-transplantation. After a median follow-up of 468 days (range, 55 to 1039 days), only 4 patients relapsed, with a 2-year cumulative incidence of relapse (CIR) of 5.3% ± 3.6%. The 100-day and 2-year NRM were 6.8% ± 4.4% and 12.3% ± 3.6%, respectively. At the last follow-up, the 2-year disease-free survival (DFS) and overall survival (OS) were 82.4% ± 4.2% and 80.3% ± 6.0%, respectively. Comparing the transplantation outcomes between patients receiving Mel 100 mg/m2 and those receiving Mel 140 mg/m2, showed no significant differences in NRM and CIR between the 2 groups and similar 2-year DFS and OS in the 2 groups, although the Mel 100 group had a higher median age (58 years versus 42 years; P < .001) and a higher percentage of patients with an HCT-CI ≥3 (P = .005). In the total cohort, the sole independent factor associated with transplantation outcomes was HCT-CI ≥3, which correlated with higher NRM and inferior DFS and OS. Our study suggests that moderate-intensity FBM conditioning is feasible for patients with myeloid malignancies, with a low relapse rate without increased NRM. A lower Mel dose of 100 mg/m2 maintained the low risk of relapse without excess NRM in older adults. However, the FBM regimen should be used with caution in patients with high-risk HCT-CI (≥3).

Optimizing autologous hematopoietic stem cell transplantation for acute leukemia

Autologous hematopoietic stem cell transplantation (ASCT) remains an important postremission treatment for acute leukemia (AL). It is known that some prognostic factors, such as age, cytogenetic and molecular risk stratification, and minimal residual disease (MRD) status, are closely related to clinical outcomes following ASCT. Moreover, there are multiple measurements, including pretransplant treatment, stem cell mobilization and collection, conditioning regimens, and maintenance treatment after transplantation, that can affect prognosis after ASCT. Our clinical practice of ASCT should be better standardized to further improve patient outcomes. This review outlines optimization and quality control measures for ASCT developed at the Institute of Hematology and Blood Diseases Hospital of the Chinese Academy of Medical Sciences, the first established and largest autologous stem cell transplant center in China. These measures will enhance the development of best practices and strategies for AL ASCT therapies, thereby improving patient outcomes.

History and Development of Autologous Stem Cell Transplantation for Acute Myeloid Leukemia

This review describes the development of cryopreservation, the birth of autologous stem cell transplantation (ASCT) and its past and present use to consolidate adult patients with acute myelogenous leukemia (AML). It summarizes the first autografts in patients in relapse, the experience of autografting in complete remission (CR), using bone marrow unpurged or purged in vitro with cyclophosphamide-derivatives, and the important shift to peripheral blood stem cells. The review also discusses the results of recent studies in favor of the use of ASCT to consolidate good- and intermediate-risk patients who reach CR with no detectable minimal residual disease, and those which support the inclusion of maintenance therapy post autograft with hypomethylating agents, anti-BCL-2, and, possibly, in the future, anti AML chimeric antigen receptor-T cells. Carefully applied to well-selected patients, ASCT may regain interest, because of its simplicity, its reduced toxicity, lower non-relapse mortality and better quality of life.

Hematopoietic Cell Transplantation in the Treatment of Newly Diagnosed Adult Acute Myeloid Leukemia: An Evidence-Based Review from the American Society of Transplantation and Cellular Therapy

The role of hematopoietic cell transplantation (HCT) in the management of newly diagnosed adult acute myeloid leukemia (AML) is reviewed and critically evaluated in this evidence-based review. An AML expert panel, consisting of both transplant and nontransplant experts, was invited to develop clinically relevant frequently asked questions covering disease- and HCT-related topics. A systematic literature review was conducted to generate core recommendations that were graded based on the quality and strength of underlying evidence based on the standardized criteria established by the American Society of Transplantation and Cellular Therapy Steering Committee for evidence-based reviews. Allogeneic HCT offers a survival benefit in patients with intermediate- and high-risk AML and is currently a part of standard clinical care. We recommend the preferential use of myeloablative conditioning in eligible patients. A haploidentical related donor marrow graft is preferred over a cord blood unit in the absence of a fully HLA-matched donor. The evolving role of allogeneic HCT in the context of measurable residual disease monitoring and recent therapeutic advances in AML with regards to maintenance therapy after HCT are also discussed.

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.

The Role of Measurable Residual Disease (MRD) in Hematopoietic Stem Cell Transplantation for Hematological Malignancies Focusing on Acute Leukemia

The significance of measurable residual disease (MRD) in hematopoietic stem cell transplantation (HSCT) is well recognized in different hematological malignancies, but the evidence indicate that pre-transplant MRD status is of particular importance in acute lymphoblastic leukemia (ALL) and acute myeloid leukemia (AML). In ALL, inadequate response at the level of MRD is a commonly accepted risk factor for relapse and thus an indication for allogeneic HSCT. Similarly, growing evidence from the literature strongly suggest that MRD detected by multiparameter flow cytometry or molecular techniques should be also used for risk stratification in AML at the time of HSCT. Despite the well-defined association of MRD and outcomes of HSCT in acute leukemias, there are still many open issues such as the role of additional pre-transplant consolidation for MRD eradication, the ability of HSCT to overcome negative influence of MRD positivity on survival, the impact of conditioning regimen intensity on MRD clearance post HSCT, and transplantation outcomes or the selection of optimal donor with regards to MRD status. In addition, the role of MRD assessment in guiding post-transplant maintenance treatment should also be addressed in prospective trials. These open issues mostly awaiting further clinical studies will be discussed in our current review.

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.

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.

Hematopoietic stem cell transplantation for adult patients with isolated NPM1 mutated acute myeloid leukemia in first remission

Acute myeloid leukemia (AML) in first remission (CR1) with isolated NPM1 mutation (iNPM1m) is considered a good prognosis genotype, although up to one-third relapse. To evaluate the best transplant strategy, we retrospectively compared autologous stem cell transplantation (auto-SCT), related (MSD), and fully matched unrelated (MUD) allogeneic stem cell transplantation (allo-SCT). We identified 256 adult patients including 125 auto-SCT, 72 MSD, and 59 MUD. The 2-year leukemia-free survival (LFS) was 62% in auto-SCT, 69% in MUD, and 81% in MSD (P = .02 for MSD vs others). The 2-year overall survival (OS) was not different among auto-SCT, MUD, and MSD, reaching 83% (P = .88). The 2-year non-relapse mortality (NRM) was 2.5% in auto-SCT and 7.5% in allo-SCT (P = .04). The 2-year cumulative incidence of relapse (RI) was higher after auto-SCT (30%) than after MUD (22%) and MSD (12%, P = .01). In multivariate analysis, MSD versus auto-SCT but not MUD versus auto-SCT was associated with lower RI (P < .01 and P = .13, respectively) and better LFS (P = .01 and P = .31, respectively). Age correlated with higher NRM (P < .01). Allo-SCT using MSD appears as a reasonable transplant option for young patients with iNPM1m AML in CR1. Auto-SCT was followed by worse RI and LFS, but similar OS to both allo-SCT modalities.

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.

Allogeneic stem cell transplantation following relapse post autologous stem cell transplantation in adult patients with acute myeloid leukemia: A retrospective analysis of 537 patients from the Acute Leukemia Working Party of the EBMT

Patients with acute myeloid leukemia (AML) who relapse after autologous stem cell transplantation (ASCT) can be rescued by allogeneic SCT. We identified 537 adult patients with AML allografted in second complete remission (CR2) or first relapse after ASCT in the European Society for Blood and Marrow Transplantation (EBMT) registry. At 3 years post allograft, leukemia free survival (LFS) was 31.4% [95%CI 27.3-35.6], overall survival (OS) 39.5% [95%CI 35.1-43.9], relapse incidence (RI) 34.6% [95%CI 30.4-38.8], and nonrelapse mortality (NRM) 33.7% [95%CI 29.6-37.9]. RI was higher in patients transplanted in relapse in comparison to those transplanted in CR2 (HR 1.76, P = .004) and in patients who relapsed later after ASCT (HR 0.97 per month, P < 10^-3 ), both translating into better LFS/ OS. Relapse was also lower in patients undergoing allogeneic stem cell transplantation (allo-HSCT) from an unrelated donor (UD) in comparison to those transplanted from a matched sibling donor (MSD) (HR 0.49, P < 10^-3 ). NRM was increased in patients who received total body irradiation (TBI) pre-ASCT (HR 2.43; P < 10-4), translating into worse LFS/OS. LFS/OS did not differ between patients allotransplanted with reduced intensity (RIC) or myeloablative (MAC) conditioning. In conclusion, one third of adult patients with AML relapsing post ASCT can be rescued with allo-HSCT, with better LFS/OS in patients who relapsed later post ASCT, those transplanted in CR2 and those who had not received TBI pre-ASCT.

Autologous Transplantation for Older Adults with AML

While the majority of patients with acute myeloid leukemia (AML) are above the age of 65 years at diagnosis, the outcome of older AML patients remains disappointing. Even if standard intensive chemotherapy induces morphologic complete remission (CR1), relapses in older AML patients are common leading to poor long-term survival outcomes. Since autologous hematopoietic stem cell transplantation (HCT) offers distinct anti-leukemic effectiveness while avoiding graft-versus-host disease associated with allogeneic transplantation, it represents an option for consolidation treatment in selected older AML patients. However, prospective studies in older AML patients assessing the benefit of autologous HCT compared to chemotherapy consolidation or allogeneic transplantation are lacking. Consequently, clinicians face the dilemma that there is considerable ambiguity on the most appropriate consolidation treatment for older AML patients in CR1. This review highlights the possible role of autologous HCT for consolidation in older AML patients reaching CR1 after induction treatment.

Optimizing the pretransplant regimen for autologous stem cell transplantation in acute myelogenous leukemia: Better outcomes with busulfan and melphalan compared with busulfan and cyclophosphamide in high risk patients autografted in first complete remission: A study from the acute leukemia working party of the EBMT

Autologous stem cell transplantation remains a clinical option to consolidate some adult patients with acute myelogenous leukemia (AML) in first complete remission (CR1). In a small cohort of patients, we have previously shown better outcomes following Busulfan and Melphalan (BUMEL) over Busulfan and Cyclophosphamide (BUCY). To identify the subpopulations that might get the highest benefit with BUMEL, we designed a larger study. All adult patients with primary AML and available cytogenetics, autografted from January 2000 to December 2016 in CR1, were included: 1137 patients received BUCY and 512 BUMEL. All factors differing in distribution between the 2 conditioning groups were introduced in multivariate analyzes. In a primary analysis, we found an interaction between conditioning and the poor risk group defined as poor cytogenetics and/or presence of the FLT3-ITD mutation. During analysis of the poor risk group, 176 patients received BUCY and 62 BUMEL. BUMEL was associated with a lower RI at 5 years (53% versus 69%, HR: 0.52, P = .002), a better Leukaemia-free survival (LFS) (42% versus 25%, HR: 0.54, P = .002) and a better OS (54% versus 36%, HR: 0.61, P = .02). During analysis of the non poor risk group, 961 patients received BUCY and 450 BUMEL. At 5 years, the RI was 50% and 47%, the LFS 45% and 48% and the OS 56% and 60% respectively, with no significant difference. We conclude that BUMEL is the preferable conditioning regimen for the poor risk leukemic patients, while in AML patients without poor risk cytogenetics or FLT3 both conditioning regimens are valid.

High-dose melphalan-based sequential conditioning chemotherapy followed by allogeneic haematopoietic stem cell transplantation in adult patients with relapsed or refractory acute myeloid leukaemia

Considering the unsatisfactory results of salvage therapies for patients with relapsed/refractory acute myeloid leukaemia (R/R-AML), their value before allogeneic haematopoietic stem cell transplantation (HSCT) remains questionable. However, direct allogeneic HSCT following established conditioning regimens applied in patients with R/R-AML during active disease has been equally disappointing. In this retrospective observational study, high-dose melphalan, as part of a sequential preparative regimen, followed by a total body irradiation (4 × 2 Gy)-based or a treosulfan-based dose-adapted conditioning therapy for allogeneic HSCT was administered to 292 adult patients (median age 56 years, range 17-74) with primary refractory (144 patients), secondary refractory (97 patients) or relapsed AML (51 patients). Overall survival rates at 3 years were 34%, 29% and 41%, respectively. Risk factors associated with an inferior survival were higher age, transplantation from a human leucocyte antigen-mismatched donor and high disease burden. Patients transplanted with blast infiltration <20% showed a notable survival rate of 51% at 3 years. In particular, patients with primary refractory AML showed a more favourable outcome when transplanted early during their disease course. Thus, high-dose melphalan-based sequential conditioning chemotherapy followed by an allogeneic HSCT is feasible and enables long-term remission to be achieved in a substantial proportion of patients with active R/R-AML.

Unrelated matched versus autologous transplantation in adult patients with good and intermediate risk acute myelogenous leukemia in first molecular remission

Patients with Acute Myelogenous Leukemia have a better outcome if reaching molecular remission. We compared the outcome of 373 patients autografted and 335 patients allografted with a 10/10 compatible unrelated donor in first molecular remission. Patients were stratified using the ELN European Leukemia Net classification. ELN favorable group: (234 auto and 70 unrelated transplants). By univariate analysis, in the auto group, the Non Relapse Mortality (NRM) was lower (3.7% versus 19%; P < 10^-4 ), Relapse Incidence (RI) higher (29% versus 17%, P < 10^-4 ), Leukemia Free Survival (LFS) identical (67% versus 64%) and Overall Survival (OS) better than in the allogeneic group (83% versus 62%; P = .008). By multivariate analysis, autologous transplantation was associated with a lower NRM (HR: 4, P = .01) and a better OS (HR: 2.08, P = .04). ELN intermediate group 1: (87 autologous and 172 unrelated transplants). By univariate analysis, in the auto group, NRM was lower (2.5% versus 11.8%; P = .03), RI higher (59% versus 18%, P < 10^-6 ), LFS lower (39% versus 70%; P < 10^-6 ) and OS lower than in the unrelated donor group (61% versus 74%; P = .005). By multivariate analysis, unrelated donor was superior to autologous transplantation for LFS (HR: 0.36, P < 10^-5) and OS (HR: 0.53, P = .01). ELN intermediate group 2: (52 autologous and 93 unrelated donors). The outcome was identical. We conclude that good risk patients get higher benefit from autologous transplantation. Intermediate risk 2 patients have the same outcome and Intermediate risk 1 patients get higher benefit from unrelated donor transplants.

Matched and mismatched unrelated donor compared to autologous stem cell transplantation for acute myeloid leukemia in first complete remission: a retrospective, propensity score-weighted analysis from the ALWP of the EBMT

BACKGROUND

Optimal post-remission strategy for patients with acute myeloid leukemia (AML) is matter of intense debate. Recent reports have shown stronger anti-leukemic activity but similar survival for allogeneic stem cell transplantation (allo-HSCT) from matched sibling donor compared to autologous transplantation (auto-HSCT); however, there is scarcity of literature confronting auto-HSCT with allo-HSCT from unrelated donor (UD-HSCT), especially mismatched UD-HSCT.

METHODS

We retrospectively compared outcome of allogeneic transplantation from matched (10/10 UD-HSCT) or mismatched at a single HLA-locus unrelated donor (9/10 UD-HSCT) to autologous transplantation in patients with AML in first complete remission (CR1). A total of 2879 patients were included; 1202 patients received auto-HSCT, 1302 10/10 UD-HSCT, and 375 9/10 UD-HSCT. A propensity score-weighted analysis was conducted to control for disease risk imbalances between the groups.

RESULTS

Matched 10/10 UD-HSCT was associated with the best leukemia-free survival (10/10 UD-HSCT vs auto-HSCT: HR 0.7, p = 0.0016). Leukemia-free survival was not statistically different between auto-HSCT and 9/10 UD-HSCT (9/10 UD-HSCT vs auto-HSCT: HR 0.8, p = 0.2). Overall survival was similar across the groups (10/10 UD-HSCT vs auto-HSCT: HR 0.98, p = 0.84; 9/10 UD-HSCT vs auto-HSCT: HR 1.1, p = 0.49). Notably, in intermediate-risk patients, OS was significantly worse for 9/10 UD-HSCT (9/10 UD-HSCT vs auto-HSCT: HR 1.6, p = 0.049), while it did not differ between auto-HSCT and 10/10 UD-HSCT (HR 0.95, p = 0.88). In favorable risk patients, auto-HSCT resulted in 3-year LFS and OS rates of 59 and 78 %, respectively.

CONCLUSIONS

Our findings suggest that in AML patients in CR1 lacking an HLA-matched sibling donor, 10/10 UD-HSCT significantly improves LFS, but this advantage does not translate in better OS compared to auto-HSCT. In intermediate-risk patients lacking a fully HLA-matched donor, auto-HSCT should be considered as a valid option, as better survival appears to be provided by auto-HSCT compared to mismatched UD-HSCT. Finally, auto-HSCT provided an encouraging outcome in patients with favorable risk AML.

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).