Does leukocytosis remain a predictive factor for survival outcomes in patients with acute promyelocytic leukemia receiving ATRA plus a chemotherapy-based regimen? A prospective multicenter analysis from TALWG

INTRODUCTION

Acute promyelocytic leukemia (APL) is a distinct subtype of acute myeloid leukemia (AML) with a unique clinical presentation and prognosis. This study aimed to investigate the epidemiology, clinical characteristics, treatments, and clinical outcomes of Thai APL patients dominantly treated with all-trans-retinoic acid (ATRA) combined with a chemotherapy-based therapy.

METHODS

This was an eight-year prospective, observational study from nine academic hospitals in the Thai Acute Leukemia Working Group (TALWG) of the Thai Society of Hematology, which included newly diagnosed Thai APL patients, aged 18 years or older. The web-based registration collected baseline charateristic, and clinical outcomes.

RESULTS

From 992 newly diagnosed AML patients, 79 APL patients were enrolled in this study. Almost all subjects were de novo APL (94.9%), while the others were therapy-related APL. The commonest clinical presentation was disseminated intravascular coagulation (38%). One-third of the patients were categorized as high risk according to the initial WBC. Almost all patients received ATRA combined with idarubicin regimen. The complete response rate was as high as 95.7%, which translated into excellent four-year overall survival (OS) (75.6%) and four-year leukemia-free survival (LFS) (75.4%). The multivariate analysis demonstrated that the older age and WBC count >20 × 10⁹/L conferred a significantly unfavorable OS with the hazard ratios of 3.03 (95% confidence interval [CI]: 1.14-8.05) and 4.18 (95%CI: 1.69-10.35), respectively. Similarly, these two parameters remained independent of the poor prognosis factors for LFS.

CONCLUSION

This report confirmed that APL had a favorable prognosis. However, advanced age and high WBC count >20 × 10⁹/L contributed to a worse outcome.

ABBREVIATIONS

APL; acute promyelocytic leukemia; ATRA; all-transretinoic acid; CR; complete remission; DS; differentiation syndrome; ECOG; Eastern Cooperative Oncology Group; ED; early death; HR; hazard ratio; IQR; interquartile range; LFS; leukemia-free survival; OS; overall survival; WBC; white blood cell.

Cardiac glycoside ouabain efficiently targets leukemic stem cell apoptotic machinery independent of cell differentiation status

BACKGROUND

Acute myeloid leukemia (AML) is an aggressive hematologic malignancy characterized by an accumulation of immature leukemic myeloblasts initiating from leukemic stem cells (LSCs)-the subpopulation that is also considered the root cause of chemotherapy resistance. Repurposing cardiac glycosides to treat cancers has gained increasing attention and supporting evidence, but how cardiac glycosides effectively target LSCs, e.g., whether it involves cell differentiation, remains largely unexplored.

METHODS

Digoxin, a user-designed digitoxigenin-α-L-rhamnoside (D6-MA), and ouabain were tested against various human AML-derived cells with different maturation phenotypes. Herein, we established two study models to specifically determine the effects of cardiac glycosides on LSC death and differentiation-one allowed change in dynamics of LSCs and leukemic progenitor cells (LPCs), while another maintained their undifferentiated status. Regulatory mechanisms underlying cardiac glycoside-induced cytotoxicity were investigated and linked to cell cycle distribution and apoptotic machinery.

RESULTS

Primitive AML cells containing CD34+ LSCs/LPCs were very responsive to nanomolar concentrations of cardiac glycosides, with ouabain showing the greatest efficiency. Ouabain preferentially induces caspase-dependent apoptosis in LSCs, independent of its cell differentiation status, as evidenced by (i) the tremendous induction of apoptosis by ouabain in AML cells that acquired less than 15% differentiation and (ii) the higher rate of apoptosis in enriched LSCs than in LPCs. We sorted LSCs and LPCs according to their cell cycle distribution into G0/G1, S, and G2/M cells and revealed that G0/G1 cells in LSCs, which was its major subpopulation, were the top ouabain responders, indicating that the difference in ouabain sensitivity between LSCs and LPCs involved both distinct cell cycle distribution and intrinsic apoptosis regulatory mechanisms. Further, Mcl-1 and c-Myc, which were differentially expressed in LSCs and LPCs, were found to be the key apoptosis mediators that determined ouabain sensitivity in AML cells. Ouabain induces a more rapid loss of Mcl-1 and c-Myc in LSCs than in LPCs via the mechanisms that in part involve an inhibition of Mcl-1 protein synthesis and an induction of c-Myc degradation.

CONCLUSIONS

Our data provide new insight for repurposing cardiac glycosides for the treatment of relapsed/refractory AML through targeting LSCs via distinct cell cycle and apoptosis machinery. Video Abstract.

Simplified predictive scores for thrombosis and bleeding complications in newly diagnosed acute leukemia patients

BACKGROUND

Bleeding and thrombotic complications are the leading causes of death in acute leukemia patients. The Conventional International Society of Thrombosis and Haemostasis Disseminated Intravascular Coagulation (ISTH DIC) scoring system is utilized to assess DIC diagnoses in various conditions. Nevertheless, limited studies have tested the system's accuracy in predicting thrombo-hemorrhagic events in individuals with acute leukemia. This study aimed to (1) validate the ISTH DIC scoring system and (2) propose a new Siriraj Acute Myeloid/Lymphoblastic Leukemia (SiAML) bleeding and thrombosis scoring system for thrombohemorrhagic risk assessment in acute leukemia.

METHODS

We conducted a retro-prospective observational study of newly diagnosed acute leukemia patients between March 2014 and December 2019. We recorded thrombohemorrhagic episodes within 30 days postdiagnosis and DIC profiles, including prothrombin time, platelet level, D-dimer, and fibrinogen. The sensitivities, specificities, positive and negative predictive values, and areas under receiver operating characteristic curves for the ISTH DIC and SiAML scoring systems were calculated.

RESULTS

In all, 261 acute leukemia patients were identified: 64% with acute myeloid leukemia, 27% with acute lymphoblastic leukemia, and 9% with acute promyelocytic leukemia. Overall bleeding and thrombotic events were 16.8% and 6.1%, respectively. With a cutoff of 5 for the ISTH DIC score, the sensitivity and specificity for bleeding prediction were 43.5% and 74.4%, respectively, while the corresponding values for thrombotic prediction were 37.5% and 71.8%, respectively. D-dimer > 5000 µg FEU/L and fibrinogen ≤ 150 mg/dL were significantly associated with bleeding. A SiAML-bleeding score was calculated using these factors, with a sensitivity and specificity of 65.2% and 65.6%, respectively. Conversely, D-dimer > 7000 µg FEU/L, platelet > 40 × 10⁹/L, and white blood cell level > 15 × 10⁹/L were significant variables related to thrombosis. Using these variables, we established a SiAML-thrombosis score with a sensitivity and specificity of 93.8% and 66.1%, respectively.

CONCLUSIONS

The proposed SiAML scoring system might be valuable for prognosticating individuals at risk for bleeding and thrombotic complications. Prospective validation studies are needed to verify its usefulness.

Effects of different types of allogeneic hematopoietic stem cell transplantation donors on Philadelphia chromosome-positive acute lymphoblastic leukemia during the tyrosine kinase inhibitor era: A systematic review and meta-analysis

BACKGROUND

Matched donor (MD) allogeneic hematopoietic stem cell transplantation (allo-HSCT) is currently the preferred choice of treatment for Philadelphia chromosome-positive acute lymphoblastic leukemia (Ph+ ALL) patients who have achieved complete remission. This systematic review and meta-analysis was conducted to investigate the effects of allo-HSCTs from different donor types for Ph+ ALL patients who received tyrosine kinase inhibitors (TKIs).

METHODS

Studies in EMBASE and MEDLINE between inception and December 2020 were identified using search terms related to "Ph+ ALL" and "HSCT." Eligible studies were studies with Ph+ ALL patients who received a TKI and allo-HSCT. The primary outcomes of interest-the overall survival (OS) or relapse-free survival (RFS)-needed to be reported. The Mantel-Haenszel method was used to combine the effect estimates and associated 95% confidence intervals (CIs) of each donor type.

RESULTS

Fourteen cohort studies were identified for the meta-analysis. Haploidentical (HID)-HSCT for Ph+ ALL patients resulted in a superior RFS to MD-HSCT, with a pooled odds ratio (OR) of 1.57 (95% CI, 1.05-2.32; I2 = 0%). However, HID-HSCT and MD-HSCT had comparable OS. Furthermore, HID-HSCT group had a significantly lower relapse rate than MD-HSCT group. On the other hand, the risks of graft-versus-host disease (GvHD) were higher for HID-HSCT and pooled OR of chronic GvHD rate. The OS and RFS of matched sibling-HSCT, matched unrelated-HSCT, and cord blood-HSCT were comparable with those of HID-HSCT.

CONCLUSION

This systematic review and meta-analysis showed that HID-HSCT is as effective as MD-HSCT in Ph+ ALL patients.

Characteristics and Outcomes of Secondary Acute Myeloid Leukemia and Acute Myeloid Leukemia With Myelodysplasia-Related Changes: Multicenter Study From the Thai Acute Leukemia Study Group

BACKGROUND

Secondary acute myeloid leukemia (sAML) and AML with myelodysplasia-related changes (AML-MRC) both result in dismal outcomes. This retrospective study aimed to determine whether these features are poor prognostic factors independent of older age and adverse cytogenetics, which are commonly associated with a poor prognosis.

METHODS

The characteristics and real-world outcomes of sAML and AML-MRC from the Thai AML registry database were investigated.

RESULTS

From a total of 992 newly diagnosed AML patients, 315 (31.8%) patients were classified into sAML or AML-MRC subtypes. Older age, low white blood cell (WBC) count, low bone marrow blast, and adverse cytogenetic risk were commonly present in sAML and AML-MRC compared to de novo AML. Complete remission after 7 + 3 induction therapy occurred in 42.3% of patients with sAML or AML-MRC and 62.4% of de novo AML (P < .001). The median overall survival (OS) of sAML, AML-MRC, and de novo AML were 6.9, 7.0, and 12.2 months, respectively (P < .001). The independent prognostic factors for inferior OS were older age, intermediate-risk or adverse-risk cytogenetics, WBC count > 100 × 10⁹/L, poor performance status, and a subgroup of AML-MRC with the morphologic criteria of multilineage dysplasia (AML-MRC-M). In addition, sAML, AML-MRC, and a WBC count > 100 × 10⁹/L were pre-treatment prognostic factors associated with poor relapse-free survival (P = .006, P = .017, and P < .001, respectively).

CONCLUSION

Both sAML and AML-MRC are independently associated with poor outcomes in Thai patients. Our study supports AML-MRC-M as an adverse prognostic factor for OS.

Comparison of Three Doses of Cytarabine Consolidation for Intermediate- and Adverse-risk Acute Myeloid Leukemia: Real World Evidence From Thai Acute Myeloid Leukemia Registry

BACKGROUND

Intermediate or high doses of cytarabine (IDAC or HiDAC) were recommended as postremission chemotherapy for acute myeloid leukemia (AML). This retrospective study investigated the real-world outcomes of 3-different cytarabine doses from the multicenter Thai AML registry database.

PATIENTS AND METHODS

The intermediate- and adverse-risk AML patients (N = 258) who achieved complete remission and proceeded to single-agent cytarabine consolidation were enrolled.

RESULTS

The median relapse-free survival (RFS) using IDAC 1.5 g/m², high-dose cytarabine (HiDAC) 2 g/m², and HiDAC 3 g/m² were 12.6, 11.7, and 13 months, respectively. The median overall survival (OS) using IDAC 1.5 g/m², HiDAC 2 g/m², and HiDAC 3 g/m² were 34.9, 22.7, and 23.7 months, respectively. No significant difference in RFS and OS was detected between the 3 doses. Secondary AML, white blood cell > 100×10⁹/L and the adverse-risk AML were independent prognostic factors for inferior survival (P= .008, P < .001, P= .014). Patients who completed 3 to 4 cycles of consolidation had significantly superior RFS and OS (P< .001, P< .001). Febrile neutropenia occurred in 72.9% of IDAC, 73.8% of HiDAC 2 g/m², and 78.1% of HiDAC 3 g/m² without statistical significance. However, the incidence of septic shock was significantly higher after HiDAC 3 g/m² compared to IDAC regimen (8% vs. 3%, P= .037).

CONCLUSION

IDAC is an appropriate regimen for postremission chemotherapy for intermediate- and adverse-risk AML. The higher dosing levels may not produce any benefits to patients and may increase incidence of septic shock. The number of consolidation cycles may impact on survivals rather than the intensity of cytarabine.

Validation of Several Formulas to Differentiate Thalassemia from Iron Deficiency Anemia and Proposal of a Thalassemia–Iron Deficiency Discrimination (TID) Predictive Score

Objective: This study aimed to validate the sensitivity analysis of all the available formulas for their ability to differentiate between IDA and thalassemia and propose a novel formula to improve the sensitivity of all thalassemia subtypes screening.Material and Methods: We conducted a 5-year, single-center, Cohort study on 227 microcytic anemia patients diagnosed between June 2015 and September 2020 at Chaophraya Yommarat Hospital, Suphanburi, Thailand to validate the sensitivity of all the available formulas and invent the novel predictive score.Results: Approximately three-quarters of our cases were all subtypes of thalassemia diseases while 26.9% were IDA. The sensitivity of almost all the previous formulas for thalassemia prediction ranged between 13.9%-44.0%, while the specificity varied between 0%–98.4%. Nevertheless, the sensitivity of the formulas that had favorable sensitivity was quite low. Here, a novel thalassemia–iron deficiency discrimination (TID) predictive score is proposed, which demonstrated a sensitivity of 90.4% the specificity of 78.7%, the positive predictive value of 92.0 %, the negative predictive value of 75.0%, and the accuracy of 87.2%.Conclusion: The proposed TID predictive score is a novel uncomplicated formulation which offers high sensitivity for all thalassemia subtypes prediction.

Maintenance With Hypomethylating Agents After Allogeneic Stem Cell Transplantation in Acute Myeloid Leukemia and Myelodysplastic Syndrome: A Systematic Review and Meta-Analysis

Introduction

Hypomethylating agents (HMAs) seem to have a range of properties favorable to post-allogeneic hematopoietic stem cell transplantation (allo-SCT) maintenance in acute myeloid leukemia (AML) patients.

Materials and Methods

The Embase, MEDLINE, and Cochrane Central Register of Controlled Trials databases were independently searched by two investigators to identify relevant studies published inception to 18 November 2021. These trials compared HMA maintenance to observation following allo-SCT for AML or myelodysplastic syndrome.

Results

The meta-analysis eligibility criteria were fulfilled by 14 studies. The overall survival and relapse-free survival of the HMA maintenance group were superior to the observation group, with a pooled risk ratio (RR) of 1.38 and 1.46, respectively. Moreover, the cumulative incidence of relapse was significantly lower in those who received HMAs. The HMA group also had lower non-relapse mortality compared with the observation group. Overall, the incidences of grades III–IV acute graft-vs.-host disease (GVHD) and chronic GVHD did not differ in both groups. However, when looking specifically at those receiving decitabine maintenance, the rate of chronic GVHD seemed to be lower compared with observation alone.

Conclusions

The current systematic review and meta-analysis illustrated that AML and MDS patients receiving HMA maintenance after allo-SCT had better outcomes in regards to OS, RFS, NRM, CIR as well as a reduced incidence of chronic GVHD.

The Real-Life Efficacy of Fixed-Dose Hypomethylating Agents in Older Patients With Acute Myeloid Leukemia: A 10-Year Experience

BACKGROUND

Hypomethylating agent (HMA) is one of recommended treatment for elderly patients with acute myeloid leukemia (AML); however, their high cost precludes their general use, especially in developing countries. Therefore, the fixed-dose HMAs approach was adopted to reduce the expenses. This study focuses on the clinical outcome of various treatment protocols, including intensive chemotherapy, fixed-dose HMAs, and palliative treatment in Thai elderly patients with AML. Fixed-dose HMAs include 5-azacitidine given at 100 mg per day for seven days and decitabine given at 30 mg per day for 5 days.

PATIENTS AND METHODS

We conducted a 10-year cohort study focused on elderly AML patients aged over 60 years. The exclusion criteria were acute promyelocytic leukemia.

RESULTS

A total of 243 AML patients were enrolled. Comparing 3 groups of treatment regimens (intensive chemotherapy, fixed-dose HMAs, and palliative treatment), the proportions of patients in each category accounted for 23.5%, 21.4%, and 55.1%, respectively. The median overall survival (OS) in each therapeutic option was 7.7, 11, and 2.5 months, respectively. From multivariate analysis, palliative treatment was significantly inferior OS comparing to the fixed-dose HMAs and intensive treatment (hazard ratio [HR]: 0.42; 95% CI, 0.29-0.60; P value <.001 and HR: 0.41; 95% CI, 0.28-0.61; P value <.001, respectively). Nevertheless, the OS outcome in patients with fixed-dose HMAs was comparable to those who received intensive treatment.

CONCLUSION

Our study demonstrates that the fixed-dose regimen of HMAs is the reasonable treatment for these patients, and this approach is not inferior to intensive therapy. Thai Clinical Trials Registry identifier: TCTR20210514007.

Is stem cell transplantation still needed for adult Philadelphia chromosome-positive acute lymphoblastic leukemia receiving tyrosine kinase inhibitors therapy?: A systematic review and meta-analysis

Background

Hematopoietic stem cell transplantation (HSCT) is the current mainstay treatment for Philadelphia chromosome-positive acute lymphoblastic leukemia (Ph⁺ ALL). However, tyrosine kinase inhibitors (TKI) also play a significant role in the treatment of these patients. We conducted this systematic review and meta-analysis to compare the efficacy of allogeneic (allo-) HSCT, autologous (auto-) HSCT, and chemotherapy (CMT) alone–all in combination with TKIs in adult Ph⁺ ALL patients.

Materials and methods

This systematic review identified studies from the EMBASE and MEDLINE databases from inception to April 2021 using search terms related to “ALL” and “HSCT.” Eligible studies could be randomized controlled trials or cohort studies that included adult Ph⁺ ALL patients who received a TKI and either allo-HSCT, auto-HSCT, or CMT alone, and that reported the number of patients in each group for each of our primary outcomes of interest: overall survival (OS) or disease-free survival (DFS). Point estimates and associated 95% confidence intervals (CI) from each study were combined using the Hantel-Maenszel method.

Results

After two rounds of review, 26 cohort studies were determined to be eligible for the meta-analysis. Adult Ph⁺ ALL patients who received HSCT had better survival outcomes than those who did not receive any HSCT (pooled odds ratio [OR] for OS of 1.61, 95%CI: 1.08–2.40; I² = 59%, and for DFS of 3.23, 95%CI: 2.00–5.23; I² = 62% for allo-HSCT; and, pooled OR for OS of 7.04, 95%CI: 1.97–25.15; I² = 0%, and for DFS of 5.78, 95%CI: 1.04–32.19; I² = 42% for auto-HSCT). Allo-HSCT recipients had comparable OS and DFS, but lower relapse rate compared to auto-HSCT recipients. Funnel plot generally demonstrated no presence of publication bias.

Conclusions

This systematic review and meta-analysis demonstrated superior results of HSCT in Ph⁺ ALL patients compared to CMT alone. Moreover, auto-HSCT could be implemented with comparable survival outcomes to allo-HSCT in patients with no available donor or when haploidentical HSCT is not feasible.

The effect of different types of allogeneic hematopoietic stem cell transplantation donors in Philadelphia chromosome-positive acute lymphoblastic leukemia during tyrosine kinase inhibitors era: A systematic review and meta-analysis

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Background: Matched donor (MD) allogeneic hematopoietic stem cell transplantation (allo-HSCT) is currently the preferred choice of treatment in Philadelphia chromosome-positive acute lymphoblastic leukemia (Ph+ ALL) who achieve complete remission. However, the unavailability of the appropriate donor remains a problem for a large group of patients. This systematic review and meta-analysis were conducted to investigate the effect of allo-HSCT from different types of the donor in Ph+ ALL patients who received tyrosine kinase inhibitors (TKIs). Methods: Studies from EMBASE and MEDLINE databases were identified from inception to December 2020 using search terms related to “Ph+ ALL” and “HSCT.” Eligible studies must be either randomized controlled trials or cohort studies with Ph+ ALL patients who received a TKI and allo-HSCT. The primary outcome of interest, consisting of overall survival (OS) or relapse-free survival (RFS), must be reported as the number of patients in each donor type. The Hantel-Maenszel method was implemented for combining effect estimates and associated 95% confidence interval (CI) from each. Results: Thirteen cohort studies were included for the meta-analysis. Haploidentical (HID)-HSCT for Ph+ ALL patients resulted in superior RFS than MD-HSCT with pooled odds ratio (OR) 1.64 (95%CI, 1.07–2.53; I2=0%) while had comparable OS (pooled OR 1.11 (95%CI, 0.74–1.69; I2=0%). Although HID-HSCT had significantly less relapse rate compared to the other group (pooled OR 0.53; 95%CI, 0.33–0.86; I2=0%), it also carried increased risks of graft-versus-host disease (GVHD) (pooled OR of acute GVHD rate 2.12; 95%CI, 1.05–4.31; I2=0% and chronic GVHD rate 1.63; 95%CI, 1.01–2.62; I2=0%). Matched sibling-HSCT, matched unrelated-HSCT, and cord blood-HSCT had the comparable OS and RFS to HID-HSCT. Conclusions: This systematic review and meta-analysis showed that HID-HSCT is as effective as MD-HSCT, and appears to be safe to implement in Ph+ ALL patients which could become useful in the case where there was no available donor.

High Incidence of Antiphospholipid Antibodies in Newly Diagnosed Patients With Lymphoma and a Proposed aPL Predictive Score

Given that the presence of antiphospholipid (aPL) antibodies has been proposed to be associated with thrombosis in newly diagnosed patients with lymphoma, we conducted a prospective cohort study on these patients. In all, 154 patients were enrolled. More than half were advanced-stage diffuse large B-cell lymphoma. Approximately one-third (35.7%) of the patients had the presence of aPLs, with single-, double-, and triple-aPL positivities of 29.9%, 5.2%, and 0.6%, respectively. Of the 154 patients, 8 (5.19%) developed symptomatic thrombosis during follow-up. There were no significant differences in the incidences of thrombosis for the aPL-positive and aPL-negative groups (5.5% vs 5.1%; P = 1.000). In a multivariate analysis, patients with male sex and lymphoma stage IV were significant risk factors for aPL positivity, with odds ratio [OR] = 2.22 (95% CI: 1.11-4.45), P = .025, and OR: 2.34 (95% CI: 1.17-4.67), P = .016, respectively. An aPL predictive score of ≥−1 was predictive of aPL positivity, with a sensitivity of 83.6% and specificity of 34.3%.

Genetic alterations in Thai adult patients with acute myeloid leukemia and myelodysplastic syndrome-excess blasts detected by next-generation sequencing technique

Several molecular aberrations affect the prognosis of patients with acute myeloid leukemia (AML) and myelodysplastic syndrome (MDS) with excess blasts (EB). This study aimed to determine the incidence and clinical impact of molecular genetic aberrations in Thai patients with AML and MDS-EB, detected by the next-generation sequencing (NGS) technique. This prospective, observational study was conducted between 2018 and 2020 on newly diagnosed Thai AML or MDS-EB patients aged above 15 years. NGS was performed using a custom amplicon-based targeted enrichment assay for 42 genes recurrently mutated in myeloid neoplasms. The molecular results were correlated with baseline patient and disease characteristics as well as outcomes. Forty-nine patients were enrolled in this study. The median age was 56 years (interquartile range [IQR], 44-64), with nearly equal proportions of males and females. The median number of mutations was 3 (IQR, 2-4). The most frequent alterations were FLT3 internal tandem duplications (ITD) (28.6%), DNMT3A (24.5%), and WT1 (22.4%) mutations. FLT3-ITD was more frequent in the de novo AML group than in the MDS/secondary AML group, whereas in the MDS/secondary AML group, ASXL1, ETV6, and SRSF2 mutations were more frequent. Patients aged greater than 65 years and patients with mutated TP53 were more likely to have inferior overall survival from multivariate analysis. FLT3-ITD was the most common mutation among newly diagnosed Thai AML patients. TP53 mutation and advanced age were independent adverse factors for survival outcome. The genetic landscapes of AML patients vary between national populations. Thai Clinical Trials Registry identifier: TCTR20190227003.

FLAMSA-RIC for Stem Cell Transplantation in Patients with Acute Myeloid Leukemia and Myelodysplastic Syndromes: A Systematic Review and Meta-Analysis

Reduced-intensity conditioning (RIC) regimens are established options for hematopoietic stem cell transplantation (HSCT) for patients with acute myeloid leukemia (AML) and myelodysplastic syndrome (MDS). However, the efficacy of RIC regimens for patients with high-risk disease is limited. The addition of a fludarabine, amsacrine, and cytarabine (FLAMSA)-sequential conditioning regimen was introduced for patients with high-risk MDS and AML to combine a high anti-leukemic activity with the advantages of RIC. The current systematic literature review and meta-analysis was conducted with the aim of identifying all cohort studies of patients with AML and/or MDS who received FLAMSA-RIC to determine its efficacy and toxicity. Out of 3044 retrieved articles, 12 published studies with 2395 overall patients (18.1–76.0 years; 96.8% AML and 3.2% MDS; follow-up duration of 0.7–145 months; 50.3% had active AML disease before HSCT) met the eligibility criteria and were included in the meta-analysis. In the pooled analysis, the 1- and 3-year overall survival (OS) rates were 59.6% (95% confidence interval (CI), 47.9–70.2%) and 40.2% (95% CI, 28.0–53.7%), respectively. The pooled 3-year OS rate of the patients who achieved CR1 or CR2 prior to HSCT was 60.1% (95% CI, 55.1–64.8%) and the percentage of those with relapse or refractory disease was 27.8% (95% CI, 23.3–32.8%). The pooled 3-year leukemia-free survival (LFS) rate was 39.3% (95% CI, 26.4–53.9%). Approximately 29% of the patients suffered from grades 2–4 acute graft-versus-host disease (GVHD), while 35.6% had chronic GVHD. The pooled 1- and 3-year non-relapse mortality (NRM) rates were 17.9% (95% CI, 16.1–19.8%) and 21.1% (95% CI, 18.8–23.7%), respectively. Our data indicates that the FLAMSA-RIC regimen is an effective and well-tolerated regimen for HSCT in patients with high-risk AML and MDS.