Pharmacologic Therapies to Prevent Relapse of Acute Myeloid Leukemia After Allogeneic Hematopoietic Stem Cell Transplantation

Randomized Phase III SIERRA Trial of 131I-Apamistamab Before Allogeneic Hematopoietic Cell Transplantation Versus Conventional Care for Relapsed/Refractory AML

PURPOSE

Older patients with relapsed or refractory AML (RR AML) have dismal prognoses without allogeneic hematopoietic cell transplantation (alloHCT). SIERRA compared a targeted pretransplant regimen involving the anti-CD45 radioconjugate 131I-apamistamab with conventional care.

METHODS

SIERRA (ClinicalTrials.gov identifier: NCT02665065) was a phase III open-label trial. Patients age ≥55 years with active RR AML were randomly assigned 1:1 to either an 131I-apamistamab-led regimen before alloHCT or conventional care followed by alloHCT if initial complete remission (CR)/CR with incomplete platelet recovery (CRp) occurred. Initial response was assessed 28-56 days after alloHCT in the 131I-apamistamab group and 28-42 days after salvage chemotherapy initiation; patients without CR/CRp or with AML progression could cross over to receive 131I-apamistamab followed by alloHCT. The primary end point was durable complete remission (dCR) lasting 180 days after initial CR/CRp. Secondary end points were overall survival (OS) and event-free survival (EFS), assessed hierarchically in the intention-to-treat (ITT) population.

RESULTS

The ITT population included 153 patients (131I-apamistamab [n = 76]; conventional care [n = 77]). In total, 44/77 conventional care arm patients crossed over and 40/77 (52%) received 131I-apamistamab and alloHCT, with six patients (13.6%) experiencing a dCR. In the ITT population, the dCR rate was significantly higher with 131I-apamistamab (17.1% [95% CI, 9.4 to 27.5]) than conventional care (0% [95% CI, 0 to 4.7]; P < .0001). The OS hazard ratio (HR) was 0.99 (95% CI, 0.70 to 1.41; P = .96), and the EFS HR was 0.23 (95% CI, 0.15 to 0.34), with HR <1 favoring 131I-apamistamab. Grade ≥3 treatment-related adverse events occurred in 59.7% and 59.2% of the 131I-apamistamab and conventional care groups, respectively.

CONCLUSION

The 131I-apamistamab-led regimen was associated with a higher dCR rate than conventional care in older patients with RR AML. 131I-apamistamab was well tolerated and could address an unmet need in this population.

Upregulation of lnc-FOXD2-AS1, CDC45, and CDK1 in patients with primary non-M3 AML is associated with a worse prognosis

Acute myeloid leukemia (AML) is a heterogeneous hematologic malignancy with an unfavorable outcome. The present research aimed to identify novel biological targets for AML diagnosis and treatment. In this study, we performed an in-silico method to identify antisense RNAs (AS-RNAs) and their related co-expression genes. GSE68172 was selected from the AML database of the Gene Expression Omnibus and compared using the GEO2R tool to find DEGs. Antisense RNAs were selected from all the genes that had significant expression and a survival plot was drawn for them in the GEPIA database, FOXD2-AS1 was chosen for further investigation based on predetermined criteria (logFC ≥|1| and P < 0.05) and its noteworthy association between elevated expression level and a marked reduction in the overall survival (OS) in patients diagnosed with AML. The GEPIA database was utilized to investigate FOXD2-AS1-related co-expression and similar genes. The Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analysis and gene ontology (GO) function analysis of the mentioned gene lists were performed using the DAVID database. The protein-protein interaction (PPI) network was then constructed using the STRING database. Hub genes were screened using Cytoscape software. Pearson correlation analysis was conducted using the GEPIA database to explore the relationship between FOXD2-AS1 and the hub genes. The transcription of the selected coding and non-coding genes, including FOXD2-AS1, CDC45, CDC20, CDK1, and CCNB1, was validated in 150 samples, including 100 primary AML non-M3 blood samples and 50 granulocyte colony stimulating factor (G-CSF)-mobilized healthy donors, using quantitative Real-Time PCR (qRT-PCR). qRT-PCR results displayed significant upregulation of lnc-FOXD2-AS1, CDC45, and CDK1 in primary AML non-M3 blood samples compared to healthy blood samples (P = 0.0032, P = 0.0078, and P = 0.0117, respectively). The expression levels of CDC20 and CCNB1 were not statistically different between the two sets of samples (P = 0.8315 and P = 0.2788, respectively). We identified that AML patients with upregulation of FOXD2-AS1, CDK1, and CDC45 had shorter overall survival (OS) and Relapse-free survival (RFS) compared those with low expression of FOXD2-AS1, CDK1, and CDC45. Furthermore, the receiver operating characteristic (ROC) curve showed the potential biomarkers of lnc -FOXD2-AS1, CDC45, and CDK1 in primary AML non-M3 blood samples. This research proposed that the dysregulation of lnc-FOXD2-AS1, CDC45, and CDK1 can contribute to both disease state and diagnosis as well as treatment. The present study proposes the future evolution of the functional role of lnc-FOXD2-AS1, CDC45, and CDK1 in AML development.

Comparative analysis of hypomethylating agents as maintenance therapy after allogeneic hematopoietic stem cell transplantation for high-risk acute leukemia

We retrospectively analyzed the outcomes of 136 consecutive patients who received allogeneic hematopoietic stem cell transplantation (allo-HSCT) at our center. Among them, 76 cases used hypomethylating agents (decitabine, n = 40; azacitidine, n = 36) as post-transplant maintenance therapy, whereas 60 contemporaneous patients did not adopt maintenance therapy. The 3-year incidences of relapse in two groups were 16.6% and 39.2% (p = .001). The 3-year OS and DFS in maintenance group were 84.0% and 78.6%, which were remarkably improved than in control group (60.0% and 58.0%) (p = .004, p = .011). Moreover, the 3-year relapse rates for patients receiving decitabine and azacitidine therapy were 8.5% and 25.0%, respectively (p = .019). Patients utilizing decitabine had more common possibility of grade 3-4 neutropenia than azacitidine (20.0% vs. 2.8%, p = .031). These results indicate that maintenance therapies using hypomethylating agents could reduce the risk of post-transplant recurrence, resulting into remarkable superior survival. Decitabine might lower relapse after allo-HSCT with somewhat more severe myelosuppression when being compared to azacitidine.

FLT3 inhibitors as maintenance therapy post allogeneic hematopoietic stem cell transplantation in acute myeloid leukemia patients with FLT3 mutations: A meta-analysis

BACKGROUND

Acute myeloid leukemia (AML) patients with a Fms-like tyrosine kinase 3 (FLT3) mutation have a high incidence of relapse despite allogeneic hematopoietic stem cell transplantation (allo-HSCT) and a subsequent poor prognosis. FLT3 inhibitors (FLT3i) have been suggested to reduce the post-transplant relapse risk in recent studies. As more evidence is accumulated, we perform the present meta-analysis to assess the efficacy and safety of FLT3i as post-transplant maintenance therapy in AML patients.

METHODS

Literature search was performed in public databases from inception to December 31, 2021. Overall survival (OS), relapse-free survival (RFS), cumulative incidence of relapse (CIR), non-relapse mortality (NRM), graft-versus-host disease (GVHD) and adverse events were compared between FLT3i and control groups. Pooled hazard ratio (HR) or relative risk (RR) with corresponding 95% confidence interval (CI) were calculated.

RESULTS

We identified 12 eligible studies with 2282 FLT3-mutated AML patients who had received HSCT. There was no between-study heterogeneity and a fix-effect model was used. Post-transplant FLT3i maintenance significantly prolonged OS (HR = 0.41, 95%CI: 0.32-0.52, p < 0.001) and RFS (HR = 0.39, 95%CI 0.31-0.50, p < 0.001), and reduced CIR (HR = 0.31, 95%CI 0.20-0.46, p < 0.001) as compared with control. There were no significant risk differences in NRM (RR = 0.69, 95%CI 0.41-1.17, p = 0.169), acute GVHD (RR = 1.17, 95%CI 0.93-1.47, p = 0.175), chronic GVHD (RR = 1.31, 95%CI 0.91-1.39, p = 0.276) and grade ≥3 adverse events between both groups, except for skin toxicity (RR = 5.86, 95%CI 1.34-25.57, p = 0.019).

CONCLUSION

Post-transplant FLT3i maintenance can improve survival and reduce relapse in FLT3-mutated AML patients and is tolerable.

A Pediatric Case of Treatment-related Myelodysplastic Syndrome While on Therapy for Pre-B Acute Lymphoblastic Leukemia

BACKGROUND

Treatment-related myelodysplastic syndrome (t-MDS) is a rare late effect of cancer therapy. After alkylating agents, this typically occurs years after completion of therapy. Treatment of t-MDS in pediatrics is an allogeneic stem cell transplant, however, the prognosis remains poor.

OBSERVATIONS

This case demonstrates t-MDS developing in a patient receiving treatment for pre-B acute lymphoblastic leukemia. This patient was treated with a combination of hematopoietic stem cell transplant and hypomethylating agents.

CONCLUSIONS

These agents should be considered for use in patients with t-MDS, before transplant to limit additional chemotherapy and as maintenance therapy post-transplant to reduce the risk of relapse.

Advances in Allogeneic Hematopoietic Stem Cell Transplantation for Acute Leukemia

In acute leukemia, advances have been made in therapeutic strategies centered on allogeneic hematopoietic stem cell transplantation (allo-SCT), three of which are presented here. The indication of allo-SCT for acute myeloid leukemia (AML) in 1st complete remission (CR1) has been debated. Genomic medicine has helped us gain a deeper understanding of this disease, some of which may serve as prognostic factors. Such genetic abnormalities could also help measure minimal residual disease (MRD) and provide additional clues to estimate the efficacy of chemotherapy. Combined with existing prognostic factors, these data can be used to construct a more accurate prognostic model, providing an optimal indication of allo-SCT for AML in CR1. Furthermore, overall treatment algorithms for high-risk AML after allo-SCT should include prophylactic and pre-emptive treatment to prevent relapse. These include immunotherapy using donor lymphocyte infusion (DLI), FLT3 inhibitors in FLT3-mutated AML, hypomethylating agents, or a combination of DLI with these agents. Clinical trials are currently ongoing to elucidate the role of these strategies, which will lead to a risk-adapted treatment for preventing relapse in high-risk AML. CD19-targeted chimeric antigen receptor (CAR) T-cell therapy induces a remarkable response in B-acute lymphoid leukemia (B-ALL); however, relapse remains a major problem. In this regard, allo-SCT as a consolidation treatment after CAR-T cell therapy for B-ALL is recommended for pediatric and adult patients. Achieving complete remission (CR) with CAR-T cell therapy is considered a promising bridging therapy to allo-SCT. Novel CAR-T treatment techniques are being developed to change their role as a pre-transplant treatment.

Acute myeloid leukemia relapse after allogeneic hematopoietic stem cell transplantation: a retrospective study from a single institution

Objective

The outcomes of patients with acute myeloid leukemia (AML) who relapse after allogeneic hematopoietic stem cell transplantation (allo-HSCT) are poor. However, the risk factors for relapse in this context remain unclear.

Methods

We retrospectively assessed 84 consecutive adult AML patients who underwent allo-HSCT and achieved complete remission (CR). These patients were dichotomized into non-relapse (n = 58) and relapse (n = 26) groups, and the cumulative relapse rates and associated risk factors were examined. We also examined the treatments for and outcomes of patients with AML relapse after allo-HSCT.

Results

Non-CR status before allo-HSCT and high-risk cytogenetics were significant risk factors for AML relapse in univariate analysis, and non-CR status was also identified as a risk factor in multivariate analysis. The cumulative AML relapse rates after allo-HSCT were significantly higher in patients with non-CR (70.0%) compared with patients with CR (25.6%). Only 2 of the 26 relapsed patients remained alive on the study-censored day.

Conclusions

Non-CR status before allo-HSCT was a significant risk factor for AML relapse after allo-HSCT. Patients with AML relapse after allo-HSCT had poor outcomes due to a lack of response to salvage remission-induction chemotherapy or treatment-related adverse events.

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.

Natural Killer Cell-Mediated Immunotherapy for Leukemia

Simple Summary

Conventional therapies such as chemotherapy and radiation in leukemia increase infection susceptibility, adverse side effects and immune cell inactivation. Natural killer (NK) cells are the first line of defense against cancer and are critical in the recognition and cytolysis of rapidly dividing and abnormal cell populations. In this review, we describe NK cells and NK cell receptors, functional impairment of NK cells in leukemia, NK cell immunotherapies currently under investigation including monoclonal antibodies (mAbs), adoptive transfer, chimeric antigen receptor-NKs (CAR-NKs), bi-specific/tri-specific killer engagers (BiKEs/TriKEs) and potential targets of NK cell-mediated immunotherapy for leukemia in the future.

Abstract

Leukemia is a malignancy of the bone marrow and blood resulting from the abnormal differentiation of hematopoietic stem cells (HSCs). There are four main types of leukemia including acute myeloid leukemia (AML), acute lymphoblastic leukemia (ALL), chronic myeloid leukemia (CML), and chronic lymphocytic leukemia (CLL). While chemotherapy and radiation have been conventional forms of treatment for leukemia, these therapies increase infection susceptibility, adverse side effects and immune cell inactivation. Immunotherapies are becoming promising treatment options for leukemia, with natural killer (NK) cell-mediated therapy providing a specific direction of interest. The role of NK cells is critical for cancer cell elimination as these immune cells are the first line of defense against cancer proliferation and are involved in both recognition and cytolysis of rapidly dividing and abnormal cell populations. NK cells possess various activating and inhibitory receptors, which regulate NK cell function, signaling either inhibition and continued surveillance, or activation and subsequent cytotoxic activity. In this review, we describe NK cells and NK cell receptors, functional impairment of NK cells in leukemia, NK cell immunotherapies currently under investigation, including monoclonal antibodies (mAbs), adoptive transfer, chimeric antigen receptor-NKs (CAR-NKs), bi-specific/tri-specific killer engagers (BiKEs/TriKEs) and future potential targets of NK cell-based immunotherapy for leukemia.

The Elephant in The Room: AML Relapse Post Allogeneic Hematopoietic Cell Transplantation

Relapsed acute myeloid leukemia (AML) following allogeneic hematopoietic cell transplantation (allo-HCT) is an unfavorable event associated with a poor prognosis, particularly for patients with early relapses. It usually arises from resistant leukemic blasts that escaped both preparative chemotherapy regimen and the graft-versus-leukemia (GVL) effect. Independent from the choice of salvage treatment, only minority of patients can achieve durable remissions. In recent years, better understanding of the disease relapse biology post allo-HCT allowed the application of newer strategies that could induce higher rates of remission, and potential longer survival. Those strategies aim at optimizing drugs that have a direct anti-leukemia activity by targeting different oncogenic mutations, metabolism pathways or surface antigens, and concurrently enhancing the immune microenvironment to promote GVL effect. This review discusses the current treatment landscape of AML relapse post allo-HCT.

Maintenance therapy after allogeneic hematopoietic transplant for acute myeloid leukemia: a systematic review and meta-analysis

BACKGROUND

For patients undergoing allogeneic hematopoietic stem cell transplant (HSCT) for acute myeloid leukemia (AML), disease relapse remains the most common reason for transplant failure and patient death. Recent randomized controlled trials (RCTs) have aimed to reduce the risk of relapse by means of post-transplant maintenance therapy.

METHODS

We performed a systematic review and meta-analysis of RCTs comparing the efficacy and safety of maintenance with observation or placebo in patients with AML after allogeneic HSCT. We searched Cochrane Library, PubMed and conference proceedings up to Febuary 2021.

RESULTS

Our search yielded five trials including 736 patients. Maintenance therapy consisted of tyrosine kinase inhibitors (TKIs) in 3 studies (sorafenib 2 studies; midostaurin 1 study) and hypomethylating agents (HMAs) in 2 studies (decitabine and azacytidine 1 study each). Maintenance therapy was associated with an improved overall survival (OS), HR = 0.61 (95% CI 0.47-0.80). Subgroup analysis revealed advantage in OS with either TKI or HMA maintenance. Relapse free survival (RFS) was also improved in the maintenance arm compared with the control arm HR = 0.51(95% CI 0.40 - 0.66). There was no difference between the two arms in overall grade 3/4 adverse events or overall infections, in grade 3/4 infections, or in acute and chronic graft versus host disease.

CONCLUSIONS

Our meta-analysis shows that post-transplant maintenance therapy in AML patients is effective in improving RFS and OS, with a satisfactory safety profile.

CDC45 modulates MCM7 expression and inhibits cell proliferation by suppressing the PI3K/AKT pathway in acute myeloid leukemia

Acute myeloid leukemia (AML) is a heterogenous hematologic disease that has a poor prognosis. This study aimed to identify new targets for the diagnosis and treatment of AML. The GSE65409 and GSE90062 were selected from the AML database of the Gene Expression Omnibus and compared using the GEO2R tool to identify differentially expressed genes (DEGs). The Database for Annotation, Visualization, and Integrated Discovery was used to perform gene ontology and Kyoto Encyclopedia of Genes and Genomes analyses of the DEGs. Protein-protein interactions were visualized using the Search Tool for the Retrieval of Interacting Genes, which identified two potential hub genes that encode CDC45 and MCM7. Relative to AML specimens, normal specimens had higher expression levels of CDC45 and MCM7 based on the Gene Expression Omnibus and The Cancer Genome Atlas databases. Furthermore, Pearson's correlation analysis revealed a significant relationship between CDC45 and MCM7. High expression of CDC45 was positively correlated with complete remission and negatively correlated with white blood cell count, hemoglobin concentration, platelet count, and bone marrow blasts. Moreover, high expression of MCM7 was negatively correlated with white blood cell count, hemoglobin concentration, platelet count, bone marrow blasts, and unfavorable cytogenetics. Overexpression of CDC45 increased the expressions of CDC45 and MCM7, while overexpression of MCM7 increased the expression of MCM7 but not CDC45. Overexpression of CDC45 or MCM7 led to impaired AML cell proliferation and blockage at the G1/S phase transition. Overexpression of CDC45 or MCM7 also attenuated the phosphorylation of PI3K, AKT, and mTOR, while simultaneous down-regulation of MCM7 expression abolished the effects of CDC45 overexpression. These findings suggest a functional relationship between CDC45 and MCM7, which might have use in the diagnosis and treatment of AML.

Prophylactic or Preemptive Low-Dose Azacitidine and Donor Lymphocyte Infusion to Prevent Disease Relapse following Allogeneic Transplantation in Patients with High-Risk Acute Myelogenous Leukemia or Myelodysplastic Syndrome

Because of the persistently high rates of relapse of patients with high-risk acute myelogenous leukemia (AML) and myelodysplastic syndrome (MDS) following allogeneic hematopoietic stem cell transplantation (allo-HSCT), post-transplantation maintenance therapy has been proposed. We previously initiated a Phase II trial in which epigenetic therapy was combined with immunotherapy in an attempt to reduce disease relapse. In that study, low-dose azacitidine (AZA) and escalating doses of donor lymphocyte infusion (DLI) were given as post-allo-HSCT maintenance treatment. In the present study, we retrospectively analyze a larger cohort of patients receiving post-transplantation maintenance therapy and provide updates on some patients of the earlier study. The objectives of the present study were to analyze the cumulative incidence of relapse (CIR), overall survival (OS), and progression-free survival (PFS) and the incidence of acute and chronic graft-versus-host disease (GVHD) of patients with high-risk AML or MDS receiving post-transplantation maintenance treatment with AZA with or without DLI. We retrospectively analyzed 77 patients (54 with AML, 23 with MDS) considered at high risk based on either their genomic or clinical status at transplantation. Following allogeneic transplantation, they received at least 1 cycle of prophylactic or preemptive low-dose AZA with or without escalating doses of DLI to prevent disease relapse. Almost one-half of the patients (47%) were able to receive the full 12 cycles of scheduled AZA, and a majority (79%) received at least 1 DLI. With a median follow-up of 24 months, 19 patients (25%; 16 with AML, 3 with MDS) relapsed, at a median of 9.8 months (range, 4 to 58.6 months), giving a 22% CIR at 24 months. OS and PFS at 24 months were 70.8% and 68.3%, respectively. The cumulative incidences of grade II-IV acute GVHD and chronic GVHD were 27.4% and 45%, respectively. Only a minority of patients (11%) required delayed administration of AZA. These findings confirm that AZA-DLI maintenance is both tolerable and effective in reducing the risk of post-transplantation relapse.

Risk adapted therapeutic strategy in newly diagnosed acute myeloid leukemia: Refining the outcomes of ELN 2017 intermediate-risk patients

INTRODUCTION

Despite advances in the treatment of acute myeloid leukemia (AML), cytotoxic chemotherapy remains the standard induction regimen.

PATIENTS AND METHODS

In this single center retrospective study, we assessed outcomes of 99 consecutive adult AML patients treated with a risk-adapted strategy with a median follow-up of 35.5 months.

RESULTS

We identified 24 (24 %), 55 (56 %) and 20 (20 %) patients classified as favorable-, intermediate-, and adverse- risk group respectively, according to the European LeukemiaNet (ELN) 2017 classification. Patients either received idarubicin and cytarabine induction chemotherapy with or without FLT3 inhibitors or hypomethylating agents based on age and comorbidity. The complete response (CR) rate was 76 % (82 % and 61 % in patients aged < 60 and ≥ 60, respectively). For the whole cohort, the 3-year overall survival (OS) was 53 %, being 62 % and 30 % in patients aged < 60 and ≥ 60, respectively. The 3-year leukemia-free survival (LFS) was 54 %, with 56 % and 45 % in patients aged < 60 and ≥ 60, respectively. The 3-year LFS were 58 %, 62 % and 25 % for patients within ELN favorable-, intermediate-, and adverse-risk groups respectively. Twenty-seven (36 %) out of 75 patients with intermediate- and adverse-risk disease underwent allogeneic hematopoietic cell transplantation (allo-HCT) in first CR with 92 % of them receiving post-transplant maintenance consisting of azacitidine in 19 (76 %) patients or sorafenib in 6 (24 %) patients. Of these patients younger than 60 years, the 3-year OS and LFS were 85 % and 69 %, respectively.

CONCLUSION

These results indicate an improved OS for AML patients especially in intermediate-risk category who were treated with a total therapy consisting of induction chemotherapy followed by allo-HCT and post-transplant maintenance.