Autologous stem cell transplantation is still a valid option in good- and intermediate-risk AML: a GITMO survey on 809 patients autografted in first complete remission

Autologous stem cell transplantation in adult patients with intermediate-risk acute myeloid leukemia in first complete remission and no detectable minimal residual disease. A comparative retrospective study with haploidentical transplants of the global committee and the ALWP of the EBMT

In patients with acute myeloid leukemia (AML) of intermediate-risk (IR) in first remission (CR1) with no measurable residual disease (MRD negative), the choice of the best consolidation is questionable. 1122 adult patients from 196 centers, transplanted in 2010-21 were analyzed: 547 received an autologous stem cell transplantation (ASCT) and 575 a Haploidentical donor transplant. Because of a significant interaction, comparisons were done separately for patients with wild-type FLT3 (FLT3-wt) and FLT3-ITD mutation (FLT3-ITD). In FLT3-wt patients, haploidentical transplants had two year lower relapse incidence (RI) (16.9% versus 32.6%; HR = 0.40, p < 0.001), higher NRM higher (17.2% vs 3.5%; HR = 7.02, p < 0.001), similar LFS (65.9% vs 63.8%; p = 0.37) and lower OS (73.2% vs 80.6%; HR = 1.69, p = 0.018). In FLT3-ITD patients, haploidentical transplants had two year lower RI (8.2% vs 47.8%; HR = 0.14, p < 0.001) higher NRM (20.2% vs 5.6%; HR = 3.43, p = 0.002), better LFS (71.5% vs 46.6%; HR = 0.53, p = 0.007) and similar OS (73.5% vs 61.9%; p = 0.44). In IR AML patients with FLT3-wt in MRD negative CR1, autologous stem cell transplantation is a valid option, while in patients with FLT3-ITD, haploidentical transplant is better. Whether autologous transplantation is superior to chemotherapy in FLT3-wt patients and the role of maintenance therapy with FLT3 inhibitors remain to be studied.

Safety and efficacy of a modified busulfan/cyclophosphamide conditioning regimen incorporating cladribine for autologous hematopoietic stem cell transplantation in acute myeloid leukemia

This is a small phase I study examining the safety and efficacy of a cladribine (CLAD)-containing conditioning regimen prior to autologous hematopoietic stem cell transplantion (auto-HSCT) for patients with acute myeloid leukemia (AML). All patients, aged 15-54 years (median 32 years), had favorable/intermediate risk AML (n = 20) or acute promyelocytic leukemia (APL; n = 2) and no evidence of minimal residual disease (MRD) prior to transplantation. Fourteen of the 22 patients received the conditioning regimen as follows: busulfan (Bu) + cyclophosphamide (Cy) + CLAD + cytarabine (Ara-c) or idarubicin. The conditioning regimen of 8 patients was without Cy nor idarubicin to reducing adverse cardiac reaction: the regimen of Bu + CLAD+ Ara-c for 6 patients; and the regimen of Bu + melphalan + CLAD + Ara-c for the other 2 patients. All 22 AML patients received peripheral blood stem cell transplantation. The number of infused mononuclear cells and CD34⁺ cells was 10.00 (2.88-20.97) × 10⁸/kg and 1.89 (1.52-10.44) × 10⁶/kg, respectively. Hematopoietic reconstitution was achieved in all patients, with a median time of 13 (10-34) days for neutrophils and 28 (14-113) days for platelets. Two patients suffered from pulmonary infection, 4 patients suffered from septicemia during the neutropenic stage, and the others suffered from infection or gastrointestinal reaction without exceeding grade 3 after conditioning, which were all alleviated by anti-infection and other supportive treatment. None of the patients died of transplantation-related complications. At a median follow-up of 29.5 (ranging from 4.0 to 60.0) months, three patients relapsed after auto-HSCT at a median time of 6 (ranging from 0.5 to 10.0) months. One patient died due to relapse at 18 months after auto-HSCT. The remaining 21 patients were all alive, including 19 patients with negative MRD. The other 2 patients achieved negative MRD after allogeneic HSCT or chemotherapy. The estimated 2-year survival, relapse, and Leukemia-free survival rates were 94.1 ± 5.7%, 14.7 ± 7.9% and 85.3 ± 7.9%, respectively. A CLAD-combination conditioning regimen is efficient and safe for auto-HSCT, indicating an effective approach for AML treatment.

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.

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.

Association Between Measurable Residual Disease in Patients With Intermediate-Risk Acute Myeloid Leukemia and First Remission, Treatment, and Outcomes

Importance

Measurable residual disease (MRD) is widely used as a therapy-stratification factor for acute myeloid leukemia (AML), but the association of dynamic MRD with postremission treatment (PRT) in patients with intermediate-risk AML (IR-AML) has not been well investigated.

Objective

To investigate PRT choices based on dynamic MRD in patients with IR-AML.

Design, Setting, and Participants

This cohort study examined 549 younger patients with de novo IR-AML in the South China Hematology Alliance database during the period from January 1, 2012, to June 30, 2016, including 154 who received chemotherapy, 116 who received an autologous stem cell transplant (auto-SCT), and 279 who received an allogeneic SCT (allo-SCT). Subgroup analyses were performed according to dynamic MRD after the first, second, and third courses of chemotherapy. The end point of the last follow-up was August 31, 2020. Statistical analysis was performed from December 1, 2019, to September 30, 2020.

Exposures

Receipt of chemotherapy, auto-SCT, or allo-SCT.

Main Outcomes and Measures

The primary end points were 5-year cumulative incidence of relapse and leukemia-free survival.

Results

Subgroup analyses were performed for 549 participants (314 male participants [57.2%]; median age, 37 years [range, 14-60 years]) according to the dynamics of MRD after 1, 2, or 3 courses of chemotherapy. Comparable cumulative incidences of relapse, leukemia-free survival, and overall survival were observed among participants who had no MRD after 1, 2, or 3 courses of chemotherapy. Participants who underwent chemotherapy and those who underwent auto-SCT had better graft-vs-host disease-free, relapse-free survival (GRFS) than those who underwent allo-SCT (chemotherapy: hazard ratio [HR], 0.35 [95% CI, 0.14-0.90]; P = .03; auto-SCT: HR, 0.07 [95% CI, 0.01-0.58]; P = .01). Among participants with MRD after 1 course of chemotherapy but no MRD after 2 or 3 courses, those who underwent auto-SCT and allo-SCT showed lower cumulative incidence of relapse (auto-SCT: HR, 0.25 [95% CI, 0.08-0.78]; P = .01; allo-SCT: HR, 0.08 [95% CI, 0.02-0.24]; P < .001), better leukemia-free survival (auto-SCT: HR, 0.26 [95% CI, 0.10-0.64]; P = .004; allo-SCT: HR, 0.21 [95% CI, 0.09-0.46]; P < .001), and overall survival (auto-SCT: HR, 0.22 [95% CI, 0.08-0.64]; P = .005; allo-SCT: HR, 0.25 [95% CI, 0.11-0.59]; P = .001) vs chemotherapy. In addition, auto-SCT showed better GRFS than allo-SCT (HR, 0.45 [95% CI, 0.21-0.98]; P = .04) in this group. Among participants with MRD after 1 or 2 courses of chemotherapy but no MRD after 3 courses, allo-SCT had superior cumulative incidence of relapse (HR, 0.10 [95% CI, 0.06-0.94]; P = .04) and leukemia-free survival (HR, 0.18 [95% CI, 0.05-0.68]; P = .01) compared with chemotherapy, but no advantageous cumulative incidence of relapse (HR, 0.15 [95% CI, 0.02-1.42]; P = .10) and leukemia-free survival (HR, 0.23 [95% CI, 0.05-1.08]; P = .06) compared with auto-SCT. Among participants with MRD after 3 courses of chemotherapy, allo-SCT had superior cumulative incidences of relapse, leukemia-free survival, and overall survival compared with chemotherapy (relapse: HR, 0.16 [95% CI, 0.08-0.33]; P < .001; leukemia-free survival: HR, 0.19 [95% CI, 0.10-0.35]; P < .001; overall survival: HR, 0.29 [95% CI, 0.15-0.55]; P < .001) and auto-SCT (relapse: HR, 0.25 [95% CI, 0.12-0.53]; P < .001; leukemia-free survival: HR, 0.35 [95% CI, 0.18-0.73]; P = .004; overall survival: HR, 0.54 [95% CI, 0.26-0.94]; P = .04). Among participants with recurrent MRD, allo-SCT was also associated with advantageous cumulative incidence of relapse, leukemia-free survival, and overall survival compared with chemotherapy (relapse: HR, 0.12 [95% CI, 0.04-0.33]; P < .001; leukemia-free survival: HR, 0.24 [95% CI, 0.10-0.56]; P = .001; overall survival: HR, 0.31 [95% CI, 0.13-0.75]; P = .01) and auto-SCT (relapse: HR, 0.28 [95% CI, 0.09-0.81]; P = .02; leukemia-free survival: HR, 0.30 [95% CI, 0.12-0.76]; P = .01; overall survival: HR, 0.26 [95% CI, 0.10-0.70]; P = .007).

Conclusions and Relevance

This study suggests that clinical decisions based on dynamic MRD might be associated with improved therapy stratification and optimized PRT for patients with IR-AML. Prospective multicenter trials are needed to further validate these findings.

Comparison of post-remission strategies in acute myeloid leukemia: Autologous hematopoietic stem cell transplantation versus consolidation chemotherapy

Autologous Hematopoietic Stem Cell Transplantation (auto-HSCT) has become a therapeutic option for first-line consolidation in Acute Myeloid Leukemia (AML) patients with favorable and intermediate risk features. A total of 101 AML patients in first complete remission, who were not eligible for allogeneic HSCT, were randomized to receive intensive cytarabine-based chemotherapy or to undergo auto-HSCT. The probability of LFS was significantly better in auto-HSCT recipients compared to chemotherapy arm (43% vs 4.8%, p=0.008). At the end of 915 (30-4470) days of followup, the probability of overall survival was better in auto-HSCT group compared to chemotherapy, without statistical significance (79.2% vs 38.8%, p=0.054). Multivariate analysis revealed a significant predictive impact of cytogenetic risk status on OS (p=0.002, HR: 2.824, 95% CI: 1.445-5.521). Auto-HSCT is considered as an effective consolidation approach in favorable and intermadiate risk AML patients.

Somatostatin receptor mediated targeting of acute myeloid leukemia by photodynamic metal complexes for light induced apoptosis

Acute myeloid leukemia (AML) is characterized by relapse and treatment resistance in a major fraction of patients, underlining the need of innovative AML targeting therapies. Here we analysed the therapeutic potential of an innovative biohybrid consisting of the tumor-associated peptide somatostatin and the photosensitizer ruthenium in AML cell lines and primary AML patient samples. Selective toxicity was analyzed by using CD34 enriched cord blood cells as control. Treatment of OCI AML3, HL60 and THP1 resulted in a 92, and 99 and 97% decrease in clonogenic growth compared to the controls. Primary AML cells demonstrated a major response with a 74 to 99% reduction in clonogenicity in 5 of 6 patient samples. In contrast, treatment of CD34⁺ CB cells resulted in substantially less reduction in colony numbers. Subcellular localization assays of RU-SST in OCI-AML3 cells confirmed strong co-localization of RU-SST in the lysosomes compared to the other cellular organelles. Our data demonstrate that conjugation of a Ruthenium complex with somatostatin is efficiently eradicating LSC candidates of patients with AML. This indicates that receptor mediated lysosomal accumulation of photodynamic metal complexes is a highly attractive approach for targeting AML cells.

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.

Superior outcome of patients with favorable-risk acute myeloid leukemia using consolidation with autologous stem cell transplantation

Autologous stem cell transplantation (ASCT), intensifying anti-leukemic effects without significant treatment-related mortality (TRM), is particularly appealing in AML with favorable genetic/molecular profile. This study retrospectively evaluated the outcomes of post-remission treatment in consecutive favorable-risk AML patients. Sixty-six patients were included: 32 had mutated NPM1/wild-type FLT-ITD, 16 had t(8:21) and 18 - inv(16). Forty patients received chemotherapy alone, 26 underwent ASCT upfront. In time-dependent analysis, the ASCT group demonstrated higher relapse-free (RFS) (p = .001) and overall survivals (OS) (p = .0007). The 1-year RFS and OS were 44.2% vs 88% and 71% vs 96% for chemotherapy and ASCT, respectively. The corresponding TRM was 4/40 (10.0%) and 0/26 (0%), with relapse rates of 70.0% and 19.2% (p = .0002). In multivariate analysis, ASCT was associated with superior OS and RFS. In conclusion, ASCT offers significantly superior RFS and OS in favorable-risk AML in first complete remission. These data support the recent resurgence of interest in ASCT for AML.

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.

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.

Outcomes of Intermediate Risk Karyotype Acute Myeloid Leukemia in First Remission Undergoing Autologous Stem Cell Transplantation Compared With Allogeneic Stem Cell Transplantation and Chemotherapy Consolidation: A Retrospective, Propensity-score Adjusted Analysis

INTRODUCTION

Optimal post-remission therapy (PRT) for intermediate risk acute myeloid leukemia remains an area of ongoing research. We aimed to retrospectively compare outcomes following autologous stem cell transplantation (autoSCT) with allogeneic SCT (alloSCT) and consolidation chemotherapy (CMT) in patients with intermediate-risk karyotype AML in first complete remission.

PATIENTS AND METHODS

We compared overall survival (OS) and leukemia-free survival (LFS) using propensity score (PS)-adjusted analysis of patients receiving PRT with autoSCT, matched sibling (MSD) alloSCT, unrelated/mismatch (UD/MM) alloSCT, and CMT. We included patients diagnosed between 1984 and 2003 (period of autoSCT at our center) in CR1 following induction CMT and received at least 2 consolidative cycles.

RESULTS

We identified 190 patients (62 MSD-alloSCT, 18 UD/MM-alloSCT, 30 autoSCT, and 80 CMT). Baseline characteristics were used for PS calculation and were well-balanced after weight adjustment. The median follow-up for patients surviving beyond 1 year was 8.7 years. We excluded 55 patients based on PS calculation. Adjusted multivariate hazard ratio (HR), 95% confidence interval (CI) and P-value for OS, considering CMT as reference, were: MSD-alloSCT (HR, 0.4; 95% CI, 0.2-0.8; P = .009), UD/MM-alloSCT (HR, 1.5; 95% CI, 0.6-3.9; P = .363), and autoSCT (HR, 1.2; 95% CI, 0.5-3.1; P = .666), respectively. Adjusted multivariate HR, 95% CI and P-value for LFS were MSD-alloSCT (HR, 0.3; 95% CI, 0.2-0.6; P < .001), UD/MM-alloSCT (HR, 1.1; 95% CI, 0.4-2.7; P = .854), and autoSCT (HR, 0.8; 95% CI, 0.3-2.2; P = .697), respectively.

CONCLUSION

Patients with intermediate risk-karyotype acute myeloid leukemia who underwent MSD-alloSCT in first complete remission had the best outcomes. There were no survival differences between autoSCT, UD/MM-alloSCT, and CMT. Further study incorporating molecular changes and minimal residual disease status is warranted to select appropriate patients for autoSCT.

Prospective randomization of post-remission therapy comparing autologous peripheral blood stem cell transplantation versus high-dose cytarabine consolidation for acute myelogenous leukemia in first remission

We prospectively compared outcomes of autologous stem cell transplantation (ASCT) versus high-dose cytarabine (HiDAC) consolidation as post-remission therapy for favorable- and intermediate-risk acute myelogenous leukemia (AML) in first complete remission (CR1). Two-hundred-forty patients under 65 years with AML-M1, M2, M4, or M5 subtypes were enrolled. After induction, 153 patients did not undergo randomization, while the remaining 87 who achieved CR1 were prospectively randomized to HiDAC (n = 45) or ASCT arm (n = 42). In the HiDAC arm, 43 patients completed three cycles of HiDAC, whereas in ASCT arm 22 patients completed two cycles of consolidation consisting of intermediate-dose cytarabine plus mitoxantrone or etoposide followed by ASCT. The three-year disease-free survival (DFS) rate was 41% in HiDAC and 55% in ASCT arm (p = 0.25). Three-year overall survival (OS) rates were 77 and 68% (p = 0.67). Incidence of relapse was 54 and 41% (p = 0.22). There was no significant difference in nonrelapse mortality between two arms (p = 0.88). Patients in the ASCT arm tended to have higher DFS rates and lower relapse rates than patients in HiDAC; however, there was no significant improvement in OS in patients with favorable- and intermediate-risk AML in CR1. Patients with AML are not benefited by the intensified chemotherapy represented by ASCT.