Relapse Of Acute Leukemia Research Articles

Extramedullary Relapse of Acute Myelogenous Leukemia after Allogeneic Hematopoietic Stem Cell Transplantation.

The clinical significance of extramedullary relapse (EMR) of acute myelogenous leukemia (AML) after allogeneic hematopoietic stem cell transplantation (allo-HSCT) remains poorly defined. Here we report the clinical outcomes of patients who underwent allo-HSCT for AML at our institution between 2000 and 2012. A total of 293 patients with AML who underwent allo-HSCT were included. The median duration of follow-up in survivors was 1840 days. Disease status at the time of allo-HSCT was complete remission in 192 patients and nonremission in 101 patients. A total of 110 patients experienced AML relapse after allo-HSCT, including 18 with EMR only, 83 with bone marrow relapse (BMR) only, and 9 with both EMR and BMR. The 5-year cumulative incidence of EMR after allo-HSCT was 9.5%, whereas that of BMR only was 28.9%. In multivariate analysis, peripheral blood stem cell transplantation was associated with an increased risk of EMR. The 2-year overall survival after post-transplantation relapse was 7.5% in patients with BMR only, 11.1% in those with both EMR and BMR, and 27.5% in those with EMR only (P < .05). Although the short-term survival was better in patients with EMR only, they rarely achieved long-term survival. Appropriate strategies for both post-transplantation EMR and BMR are needed.

18F-FDG PET/CT Radiomic Analysis with Machine Learning for Identifying Bone Marrow Involvement in the Patients with Suspected Relapsed Acute Leukemia

18F-FDG PET / CT is used clinically for the detection of extramedullary lesions in patients with relapsed acute leukemia (AL). However, the visual analysis of 18F-FDG diffuse bone marrow uptake in detecting bone marrow involvement (BMI) in routine clinical practice is still challenging. This study aims to improve the diagnostic performance of 18F-FDG PET/CT in detecting BMI for patients with suspected relapsed AL.Methods: Forty-one patients (35 in training group and 6 in independent validation group) with suspected relapsed AL were retrospectively included in this study. All patients underwent both bone marrow biopsy (BMB) and 18F-FDG PET/CT within one week. The BMB results were used as the gold standard or real “truth” for BMI. The bone marrow 18F-FDG uptake was visually diagnosed as positive and negative by three nuclear medicine physicians. The skeletal volumes of interest were manually drawn on PET/CT images. A total of 781 PET and 1045 CT radiomic features were automatically extracted to provide a more comprehensive understanding of the embedded pattern. To select the most important and predictive features, an unsupervised consensus clustering method was first performed to analyze the feature correlations and then used to guide a random forest supervised machine learning model for feature importance analysis. Cross-validation and independent validation were conducted to justify the performance of our model.Results: The training group involved 16 BMB positive and 19 BMB negative patients. Based on the visual analysis of 18F-FDG PET, 3 patients had focal uptake, 8 patients had normal uptake, and 24 patients had diffuse uptake. The sensitivity, specificity, and accuracy of visual analysis for BMI diagnosis were 62.5%, 73.7%, and 68.6%, respectively. With the cross-validation on the training group, the machine learning model correctly predicted 31 patients in BMI. The sensitivity, specificity, and accuracy of the machine learning model in BMI detection were 87.5%, 89.5%, and 88.6%, respectively, significantly higher than the ones in visual analysis (P < 0.05). The evaluation on the independent validation group showed that the machine learning model could achieve 83.3% accuracy.Conclusions: 18F-FDG PET/CT radiomic analysis with machine learning model provided a quantitative, objective and efficient mechanism for identifying BMI in the patients with suspected relapsed AL. It is suggested in particular for the diagnosis of BMI in the patients with 18F-FDG diffuse uptake patterns.

Large Unstained Cell, Blast Suspect and Delta Neutrophil Index ll Analyzed with Automated Hematology Analyzer as Parameters for the Prediction of Acute Leukemia Relapse

Large Unstained Cell, Blast Suspect and Delta Neutrophil Index ll Analyzed with Automated Hematology Analyzer as Parameters for the Prediction of Acute Leukemia Relapse

Low-Dose Azacitidine with DNMT1 Level Monitoring to Treat Post-Transplantation Acute Myelogenous Leukemia or Myelodysplastic Syndrome Relapse.

Patients with early relapse of acute myelogenous leukemia (AML) or myelodysplastic syndrome (MDS) after hematopoietic cell transplantation (HCT) have a poor prognosis, and no standard treatment. Twenty-nine patients with early disease recurrence post-transplantation were treated with azacitidine (AZA; median dose, 40 mg/m2/day for 5 to 7 days). At a median follow-up of 6.3 months (range, 1.3 to 41.1 months), 7 patients (27%) had a response to AZA, defined as complete remission, hematologic improvement, or improved donor chimerism. Response occurred after a median of 3 cycles, and the median duration of response was 70 days (range, 26 to 464 days). Median survival was 6.8 months (95% confidence interval, 3.8 to 11.1 months). Survival was similar in the patients receiving an AZA dose ≤40 mg/m2 and those receiving an AZA dose >40 mg/m2. Six patients receiving donor lymphocyte infusion with AZA had a response or stable disease without worsening graft-versus-host-disease. We retrospectively used a flow cytometry assay to explore DNA-methyltransferase-1 in blood mononuclear cells as a potential pharmacodynamic marker to assess intracellular drug targeting in 8 patients. No correlation with AZA dose or response was observed. Low-dose AZA appears to have comparable efficacy to higher-dose AZA post-HCT. A significant proportion of this poor-risk population responded to low-dose AZA, suggesting a dose-independent, noncytotoxic mechanism for antileukemic activity.

Aberrant Splicing of KMT2A As a Potential Molecular MRD Marker in Cytogenetically-Normal AML

Cytogenetically normal acute myeloid leukaemia (CN-AML) accounts for approximately 25%-30% of paediatric AML cases and carries a high risk of relapse. Minimal residual disease (MRD) is an essential factor in predicting relapse in acute leukaemia but is difficult to track for many CN-AML patients, due to the lack of a distinct and stable molecular marker. Consequently, new biomarkers are urgently required for MRD monitoring of the disease. Splicing variants, products of another hallmark of human cancers, aberrant splicing, have been shown informative in predicting responses to cancer treatment. Therefore, we characterized splicing events according to different cytogenetic features by targeted RNA-seq and interrogated the use of splicing variants in MRD monitoring of CN-AML.A total of 29 AML samples, collected from 18 de novo paediatric AML patients (median age 5.66 years, range 0.67 - 16.38 years) were analysed for this study. Among the 29 samples, 52% harboured a chromosome translocation, 21% were cytogenetically normal, and 28% showed a complex karyotype (defined as having 3 or more cytogenetic features). 100ng of total RNA, extracted from peripheral blood or bone marrow were subjected to library preparation using the Archer™ FusionPlex™ Heme and Myeloid panels, then sequenced using Illumina MiSeq® or NextSeq®. Novel splicing events and genetic mutations were identified by the Archer Dx analysis software in conjunction with normalisations against the library size and probe numbers. Splicing variants were validated using splicing junction-specific probe assays.Our results revealed 3249 novel splicing events in 29 AML samples. These events were classified into 4 major types (65% intron retention, 10% exon skipping, 8% exon out of order and 8% intra-exon gap), and 9 minor events that were combinations of the major types (9%). The number of splicing events per sample was not associated with the disease status or the presence of the mutations in the spliceosome encoding gene, SF3B1 or U2AF1. Instead, splicing variants were associated with cytogenetic features. Of note, an intron 13 retention of the KMT2A (MLL) gene was identified in all CN-AML samples, and was consistently expressed approximately 100 times higher in the CN-AML compared to other AML cases or remission samples. To assess whether KMT2A intron 13 retention could be a potential molecular MRD marker to monitor CN-AML, we measured its expression in samples from 5 independent CN-AML patients who had available samples for 3 time-points of disease progression. Our results demonstrated, with 95% detection power, that KMT2A intron 13 retention was differentially expressed at different time points (Figure 1). Moreover, the expression level of this splicing variant correlated with disease progression in every patient examined. In conclusion, these data suggest that intron 13 retention of KMT2A may be a novel molecular marker for MRD monitoring in CN-AML. [Display omitted] DisclosuresNo relevant conflicts of interest to declare.

Management of Relapse in Acute Promyelocytic Leukemia Treated with Upfront Arsenic Trioxide Based Regimens

The standard of care for patients with acute promyelocytic leukemia (APL) relapsing after frontline treatment with arsenic trioxide (ATO) based regimens remains to be defined. Available data on response and survival outcomes in patients who had received ATO as part of upfront therapy suggests that there is a high incidence of resistance to ATO and ATRA resulting in inferior response and survival (Zhu HH et al. N Engl J Med. 2014). We present our experience on management of relapse in APL patients treated with frontline ATO based therapy.Data on all consecutive patients with relapsed APL diagnosed and treated in the Depatment of Haematology, Christian Medical College, Vellore, from January, 1998-December, 2015 were included in this retrospective analysis.One hundred and four (29%) out of the total 358 APL patients diagnosed during the study period had relapsed. Out of these 73 (70%) patients received upfront ATO based therapy. Six out of 73 refused treatment and got discharged at request following the diagnosis of relapse, the remaining 67 (91.8%) were included in the analysis. Median age of patients was 28 years (range: 4-54), 44 (65.7%) were males. Median time to relapse from initial diagnosis was 19.6 months (range: 6 - 128). Relapses were isolated molecular in one, isolated CNS in 6 [9%], bone marrow + CNS in 13 [19.4%] and medullary only in 47 [70.1%] patients. All 67 patients received ATO based therapy (ATO ± ATRA +/- Anthracycline/Bortezomib) as re-induction. 63/67 (94%) achieved molecular remission post re-induction, while 3 (4.5%) died during re-induction and one discontinued treatment. An autologous SCT was offered to all patients who achieved molecular remission, however only a proportion of cases opted for SCT due to financial constraints. Those that did not opt for an autologous SCT were given ATO+ATRA maintenance therapy. 35/63 (55.6%) opted for autologous SCT while 28 (44.4%) continued on maintenance therapy alone. Median time to autologous SCT from relapse was 5.8 months (range: 2 - 32). There were no treatment related deaths following autologous SCT. At a median follow up of 46 months (range: 1-224), the 5 year estimate of OS and EFS (Fig 1) of the whole cohort (n=67) was 73.6% ± 5.7% and 67% ± 6.1%. The 5 year estimate of OS and EFS (Fig 2) of those who received autologous SCT vs those who were on chemotherapy were 90.3% ±5.3 vs 58.6±10.4 %, (P=0.004) and 87.1% ±6.0% vs. 47.7% ±10.3%, (P=0.001) respectively. In unadjusted analysis, those who received chemotherapy as post relapse consolidation had 5.73 (95%CI: 1.86 - 17.65) times risk of relapse as compared to those who received autologous SCT, which was statically significant (P=0.002). In the adjusted analysis (Table 1) those who received chemotherapy the risk of relapse was 7.6 (95%CI: 1.98 - 28.87) times compared to those who received autologous SCT, which was statically significant (P=0.003) after adjusting for age, total WBC at relapse and duration of CR1.Remission induction with ATO based regimens followed by an autologous SCT in patients with relapsed APL who were treated with frontline ATO based regimens is associated with excellent long term survival and should be considered the standard of care even in this setting. DisclosuresNo relevant conflicts of interest to declare.

Management of Relapse in Acute Promyelocytic Leukemia Treated with Upfront Arsenic Trioxide Based Regimens

Management of Relapse in Acute Promyelocytic Leukemia Treated with Upfront Arsenic Trioxide Based Regimens

Abstract CT137: Biomarkers of response to leukemia stem cell targeted therapy with low dose daunorubicin in relapsed/refractory acute leukemia

Abstract Patients with acute leukemia harbor chemotherapy-resistant leukemia stem cells (LSC) which ultimately lead to disease relapse in many patients. Clinical trial design of LSC targeted therapy is a challenge. The majority of leukemia cells are differentiated leukemia cells, with LSC comprising &amp;lt;1%. Clinical benefit of LSC targeted therapy is best measured by overall survival and difficult to measure in the short-term using the conventional endpoint of remission. Response to LSC targeted therapy may be confounded by lack of response of the bulk population. Optimal treatment strategies may ultimately include combined or sequential therapy targeted at both the LSC and bulk leukemia cell populations. However, this approach makes it difficult to measure effects on LSC specifically. In order to isolate specific effects of targeted therapy on LSC, we designed a clinical proof of concept study using serial bone marrow aspirates to measure the effects of LSC-targeted therapy in adults with relapsed acute leukemia. In pre-clinical models, we demonstrated that AKT-β-catenin interaction, indicated by Akt phosphorylation of β-catenin at serine 552 (pS552) is critical for LSC self-renewal. High throughput screening identified daunorubicin (DNR) as a potent inhibitor of pS552. To better understand the role of DNR in specifically targeting LSC, we experimented with lower doses, recognizing that most leukemia patients receive high dose DNR, yet LSC persist and result in disease relapse. In our murine model, low dose anthracycline inhibited LSC number and function. We hypothesized that low dose DNR treatment inhibits LSC number in patients with acute leukemia. Our pilot trial includes relapsed acute myeloid (AML) and lymphoblastic leukemia (ALL) patients (NCT02914977). Bone marrow aspiration was performed at study entry. Patients received DNR at 6.75 mg/m2/day x 5 days followed by repeat bone marrow aspiration on day 8. The plasma pharmacokinetics of low dose DNR was also characterized. Samples from pre- and post-treatment were analyzed by flow cytometry for the frequency (%) of total cells that are pS552-β-catenin positive LSCs (defined as CD34+ CD38- cells that express TIM3, which distinguishes LSCs from normal stem cells). Nine patients (8 AML, 1 ALL) have been treated. Seven patients had previous DNR treatment. Two patients had prior allogeneic stem cell transplant. Five of 9 patients had reduction in LSC number as measured by flow cytometry; 3/5 had prior DNR treatment. In this pilot proof of concept trial, we demonstrate the feasibility of serial bone marrow aspiration to measure biomarkers of LSC response. In our small series, 5/9 relapsed leukemia patients had reduction in LSC number after one cycle of low dose DNR. Future plans include incorporating low dose DNR following conventional chemotherapy in newly diagnosed patients with AML. This clinical proof of concept trial design with serial bone marrow aspirations may also be used to rapidly assess the validity of other LSC markers and targeted agents. Citation Format: Tara L. Lin, John M. Perry, Xi He, Gregory Reed, Na Zhang, Scott Weir, Joseph P. McGuirk, Linheng Li. Biomarkers of response to leukemia stem cell targeted therapy with low dose daunorubicin in relapsed/refractory acute leukemia [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr CT137.

Abstract 1040: Patient derived xenografts of hematologic malignancies for translational research

Abstract Acute leukemias and lymphomas represent a very heterogeneous group of hematologic malignancies and pose an important challenge in the clinical routine. They frequently develop resistance to the treatment with standard-of-care (SoC) drugs and have a high incidence of disease recurrence. Recent progress in molecular profiling has helped to identify new potential drivers for the different leukemia and lymphoma subtypes, with some of them being potential therapeutic targets. Further target validation and drug development projects are highly dependent on corresponding preclinical models representing the different clinical subtypes. Therefore, we started to establish and characterize new patient derived xenografts (PDX) of AML, ALL and lymphomas for drug development and translational research. AML- and ALL-PDX were derived from bone marrow aspirates or peripheral blood samples, from primary or relapsed acute leukemia patients. Purified cells were transplanted either intravenously (i.v.) and/or subcutaneously (s.c.) into immunodeficient mice. Some mice developed a systemic AML, which was monitored by flow cytometric analysis of blood samples. Non-Hodgkin- or Hodgkin lymphoma-PDX were derived from peripheral blood, lymph node extirpations or core needle biopsies, and were usually transplanted subcutaneously into immunodeficient mice. For further characterization, established PDX models were treated with SoC and investigational drugs. In parallel, gene expression profiles as well as mutations were analyzed within the first in vivo passages. More than 20 new PDX models from AML, ALL, NHL and HL have been successfully established and characterized. Highly individual response to the treatments were observed, correlation analyses with mutations and gene expression are ongoing. Our newly and extensively characterized PDX models from hematologic malignancies are suitable tools for preclinical drug development. They provide an exceptional platform for the identification and validation of new targets and allow the preclinical screening of new compounds and combinations for translational research projects. Citation Format: Antje Siegert, Bernadette Brzezicha, Stephan Fuhrmann, Leonid Karawajew, Martin Janz, Clemens Schmitt, Iduna Fichtner, Jens Hoffmann. Patient derived xenografts of hematologic malignancies for translational research [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 1040.

Relationship between the Therapeutic Dose of Arsenic Trioxide and Relapse in Acute Promyelocytic Leukemia

To analyze the correlation of ATO therapeutic dose with the relapse of patients with acute promyelocytic leukemia (APL) and to investigate the optimal dose and courses of ATO. The clinical data of 102 patients with APL from January 2008 to June 2015 were analyzed retrospectively. The clinical characteristics of APL patients in relapsed group and maintained remission group were compared. According to ATO dose in 2 years recommended in chinese guideline as criteria of grouping, the patients were divided into ATO high and low dose groups, then the relapse rate in groups was compared. The cut-off value of ATO dose was analyzed by ROC curve. Univariate analysis showed that the relapse rate in high ATO and low ATO groups on 2 year treatment was 2.5% and 17.7% respectively (P<0.05); multiple variate analysis demonstrated that the ATO dose>22.4 mg/kg on 2 year treatment was independent preventive factor for the relapse of APL (OR=0.119, P<0.05). The ROC curve showed that the cut-off value of ATO dose on 2 year treatment was 8.765 mg/kg. The relapse rate of APL in group of ATO dose >8.765 mg/kg group was significantly lower than that in group of ATO dose <8.765 mg/kg. The relapse of APL relates with used ATO dose, sufficient use of ATO dose can decrease the relapse rate of APL.

Reversal of T Cell Exhaustion by the First Donor Lymphocyte Infusion Is Associated with the Persistently Effective Antileukemic Responses in Patients with Relapsed AML after Allo-HSCT

Donor lymphocyte infusion (DLI) is an effective approach to treat acute myelogenous leukemia (AML) relapse after allogeneic hematopoietic stem cell transplantation (allo-HSCT) that significantly improves the survival of relapsed patients. However, the mechanism of an effective antileukemic response following DLI in AML relapse remains elusive. Here, we investigated the role of T cell exhaustion in AML relapse after allo-HSCT in prospective cohorts of 41 patients with the first AML relapse and 41 nonrelapsed AML control subjects after allo-HSCT and determined whether DLI exerts effective antileukemic effects by reversing T cell exhaustion in the relapsed cohorts by detecting the phenotypes and functions of T cells using flow cytometry. We found that both CD4+ and CD8+ T cells experienced exhaustion with upregulated coexpression of PD-1 and Tim-3, and functional impairments in cytokine production, proliferation, and cytotoxic potentials. The reversal of T cell exhaustion by the first DLI is associated with persistent complete remission in relapsed AML patients. In addition, the reversal of T cell–exhausted status after successful DLI in bone marrow was concurrent with the mitigated inversion of CD4/CD8 T cell ratio. In conclusion, our study shows a clinical correlation between T cell exhaustion and AML relapse after allo-HSCT, and uncovers the role of reversing T cell exhaustion in the antileukemic response by DLI and identifies possible immunological markers to evaluate and predict the graft-versus-leukemia effects induced by DLI.

Analysis of relapse after transplantation in acute leukemia: A comparative on second allogeneic hematopoietic cell transplantation and donor lymphocyte infusions

Relapse of acute leukemia (AL) after allogeneic hematopoietic cell transplantation (Allo-HCT) entails a dismal prognosis. In this scenario, donor lymphocyte infusions (DLIs) and second Allo-HCT are two major approaches. We compared outcomes of AL patients treated for relapse with DLI or second Allo-HCT after receiving debulking therapy. In total, 46 patients were included in the study; 30 (65%) had acute myeloid leukemia and 16 (35%) had acute lymphoblastic leukemia. The median age was 38 years (range 4-66). Twenty-seven patients received a second Allo-HCT and 19 patients received DLI. The median follow-up of the cohort was 273 days (range 9-7013). Overall survival (OS), disease-free survival (DFS), nonrelapse mortality, and cumulative incidence (CI) of relapse were calculated from DLI or second Allo-HCT date. In univariate analysis, second Allo-HCT was associated with higher OS (p = 0.021) and a trend to higher DFS (p = 0.097) and CI of relapse (p = 0.094) on univariate analysis. However, multivariate analysis showed comparable outcomes between DLI and second Allo-HCT, with the time interval to relapse before DLI or second Allo-HCT the only statistically significant factor with an impact on OS and DFS. Within the DLI cohort, T-cell-depleted Allo-HCT was associated with higher OS (p = 0.003) and DFS (p < 0.001) and lower CI of relapse (p = 0.002) than T-cell-replete Allo-HCT. Overall, in this cohort of AL patients, second Allo-HCT and DLI associated similar outcomes. As in other relapse studies, the length of remission (time to relapse) was identified as a factor with statistical impact on survival. Further studies are warranted.

155 A Unique Pediatric Case of Relapsing B- Acute Lymphoblastic Leukemia Presenting With Third-Degree Heart Block

Despite the steady improvement in outlook for children with acute lymphoblastic leukemia (ALL), 20%-25% of patients still experience relapse. Isolated extramedullary relapse of acute leukemia is a rare occurrence. Most common sites for relapse are central nervous system and testes; however, unusual other sites have been reported. We report an unusual pediatric presentation of an extramedullary relapse of acute lymphoblastic leukemia. A 13-year-old boy with a known history of B acute lymphoblastic leukemia status post stem cell transplantation was referred to our hospital, complaining of cardiac arrest secondary to third-degree complete atrioventricular dissociation. He had undergone emergent implantation of transvenous pacing leads and had Breinholt myocardial biopsy. Microscopic examination of the myocardial biopsy revealed heavy infiltration of myocardium and pericardium by leukemic cells with focal fibrotic scar. Immunohistochemical staining of paraffin embedded tissue showed strong positivity of the leukemic cells for CD19, PAX5, CD79a, and CD10, and focal positivity for TdT, while CD3 was positive in few scattered T-cells. Epstein-Barr virus-encoded RNA (EBER) in situ hybridization was also performed and revealed a negative result. CT-guided bone marrow aspirate and core biopsy were performed and revealed no leukemic cells involving the bone marrow. A diagnosis of relapsing B acute lymphoblastic leukemia was rendered. Leukemic relapses are more devastating to patients and families than the original diagnosis. Most cases of cardiac leukemic relapses were reported in postmortem examinations. However leukemic myocardial involvement at antemortem examination is a rare finding. Current therapy protocols for isolated extramedullary relapse use intensive re-induction systemic chemotherapy in addition to site-specific therapy. Although rare, the present case is noteworthy in highlighting the unusual pediatric third-degree heart block presentation of relapse B-acute lymphoblastic leukemia.

Abstract IA27: Deregulation and oncogenic functions of the NSD2/MMSET histone methyl transferase in hematologic malignancies

Abstract Epigenetic regulators of gene expression are among the commonest class of proteins mutated in human cancer. Most of these mutations lead to compete or total loss of function of the proteins leading to deregulated gene expression. Gain-of-function mutations in regulators are rare. The NSD2/MMSET histone methyltranferase is overexpressed in multiple myeloma associated with t(4;14) and leads to a global increase in histone 3 lysine 36 dimethylation, a chromatin mark associated with gene activation and a decrease of the inhibitory H3K27 methyl mark. As a result, gene expression is reprogrammed and many genes are aberrantly activated. Furthermore, the chromatin structure of cells with NSD2 overexpression is more “open.” In MM cells NSD2 overexpression increases MM cell growth and strikingly increases DNA repair processes making cells relatively resistant to chemotherapy, potentially explaining the poor prognosis of such patients. Proteomic studies show that NSD2 is associated with a variety of proteins involved in RNA metabolism, suggesting roles in both transcriptional and post-transcriptional processes. NSD2 is recurrently mutated in up to 15% of cases of relapsed childhood acute lymphocytic leukemia, in mantle cell lymphoma, and rarely in multiple myeloma and other tumors. This mutation increases the turnover rate of the enzyme in vitro and in vivo accelerates the conversion of unmodified histone to H3K36me1.The result is a global increase of H3K36me2 levels in cells with a concomitant decrease in H3k27me3 levels. Using CRISPR-mediated gene editing we eliminated this mutant allele, yielding reversal of histone methylation patterns, deceased growth, altered cellular adhesion, and increased susceptibility to chemotherapy. RNA-seq analysis showed that NSD2 mutation activated an aberrant program of cell adhesion resembling the epithelial-mesenchymal transition, increased motility, and augmented signaling and glucocorticoid and chemotherapy resistance likely associated with tumor progression. Mice harboring ALL cells with the E1099K mutation succumbed to disseminated leukemia faster than mice injected with cells in which the mutation was corrected. Furthermore, there was enhanced accumulation of cells with E1099K mutation in the brain, a common site of relapse in childhood ALL. Animal experiments suggest that knockdown of NSD2 could augment chemotherapy sensitivity motivating the search for NSD2 inhibitors. While modestly effective inhibitors have been identified to work in vitro, there are no inhibitors that are active in cells. A recently published crystal structure of an NSD2 structure is motivating our new in silico searches for candidate inhibitors. Citation Format: Jonathan D. Licht. Deregulation and oncogenic functions of the NSD2/MMSET histone methyl transferase in hematologic malignancies [abstract]. In: Proceedings of the Second AACR Conference on Hematologic Malignancies: Translating Discoveries to Novel Therapies; May 6-9, 2017; Boston, MA. Philadelphia (PA): AACR; Clin Cancer Res 2017;23(24_Suppl):Abstract nr IA27.

Progress in clinical studies of chimeric antigen receptor engineered T cells for treatment of childhood cancer

Nowadays, the 5-year survival rate of childhood cancer patients can be more than 80%, but some patients with relapse and refractory cancers have shown no good response to traditional strategies. Chimeric antigen receptor engineered T (CAR-T) cell therapy is promising for these patients. CAR-T cells recognize the tumor-associated antigens in a non-major histocompatibility complex-restricted manner, so their anti-tumor ability is enhanced. There are four generations of CAR-T cells now. The complete remission rate of pediatric patients with relapse and refractory acute lymphoblastic leukemia can be as high as 90% when treated with CD19-targeting CAR-T cells. Furthermore, CAR-T cell therapy can also be used to bridge to transplantation and donor CAR-T cell infusion can be a strategy to prevent relapse after hematopoietic stem cell transplantation. As to solid tumors, only patients with neuroblastoma present good response to the GD2-targeting CAR-T cell therapy. The toxic or side effects of CAR-T cell therapy include cytokine release syndrome, off-tumor effect, tumor lysis syndrome, and insertion mutation. Although the CD19-targeting CAR-T cell therapy for childhood cancer can result in a high remission rate, the relapse rate is high, including CD19+ and CD19- relapse. The mechanisms for relapse merit further investigatio.

The Effect of Cytomegalovirus Reactivation on Relapse in Acute Myeloblastic Leukemia after Allogeneic Hematopoietic Stem Cell Transplantation

The Effect of Cytomegalovirus Reactivation on Relapse in Acute Myeloblastic Leukemia after Allogeneic Hematopoietic Stem Cell Transplantation

Epidemiology of Clostridium difficile infection Among Patients with Newly Diagnosed or Relapsed Acute Leukemia: A Single-center Experience

BackgroundPatients undergoing treatment for hematologic malignancy are at a higher risk for developing Clostridium difficile infection (CDI). We sought to determine the epidemiology of toxigenic C. difficile (TCD) carriage and CDI incidence among patients undergoing with newly diagnosed or relapsed acute leukemia.MethodsSerial stool samples were collected from 92 patients with new or relapsed acute leukemia admitted at Memorial Sloan Kettering Cancer Center between August 26, 2011 to January 22, 2013. Only the first hospitalization during this time period was included. Screening was performed by toxigenic culture and polymerase chain reaction for tcdB gene regardless of symptoms of diarrhea. Genotyping was done by Multi Locus Sequence Typing (MLST). Acquisition of TCD, development of CDI, and associated clinical variables were recorded.ResultsA total of 92 patients were enrolled in the study. The mean age was 54.3 (median 57.5, range 21–86), 51 were male (55%). The majority (86, 93%) had newly diagnosed acute leukemia and 7% had relapsed disease. 60 patients (65%) had recent healthcare-related exposure, among these were 35 (38%) patients newly referred another facility. The most common chemotherapy regimen was Daunorubicin + Cytarabine in 71 subjects (77%). Systemic antibiotics of any duration during the same hospitalization were used in 89 patients (97%). Median length of stay (LOS) was 30.5 days (range 6–140 days).Among the 92 subjects, 17 developed CDI within 90 days (18%), 12 (71%) had CDI during the index admission. Five among these 12 had known TCD colonization, genotyping of colonizing and CDI strains from the same patients were identical for all patients. CDI in subsequent hospitalizations occurred in 5 patients, 4/5 were new acquisitions. One patient with TCD colonization never developed CDI.53 subjects (58%) underwent stem cell transplant at a median time of 4 months (range 2–19 months), 8 (15%) developed CDI within 30 days of the transplant admission.ConclusionCDI is exceedingly common among patients with acute leukemia. Acquisition of TCD and CDI occurs early in the treatment course. Approximately half of infections occur in patients with known TCD colonization. Extended LOS and high antibiotic usage are contributors to the high burden of CDI among this population.Disclosures All authors: No reported disclosures.

Bone Marrow WT1 Levels in Allogeneic Hematopoietic Stem Cell Transplantation for Acute Myelogenous Leukemia and Myelodysplasia: Clinically Relevant Time Points and 100 Copies Threshold Value

The outcome of allogeneic hematopoietic stem cell transplantation (HCT) in patients with myeloid malignancies is better in those without minimal residual disease (MRD) than in those with MRD+, as assessed by multiparametric flow cytometry (MPFC). WT1 quantitation also has been used to assess the probability of relapse in acute myelogenous leukemia (AML) treated with chemotherapy. We analyzed the clinical value of normalized bone marrow WT1 levels as a measure of the expanded myeloid progenitor compartment in a consecutive series of 193 adult patients with myeloid malignancies who underwent HCT. Bone marrow WT1 levels before the HCT, at the first bone marrow aspirate after infusion, and in the follow-up samples after HCT were determined by means of real-time PCR using the European LeukemiaNet normalized method. We sought to clarify the prognostic relevance in terms of overall survival (OS), progression-free survival (PFS), and cumulative incidence of relapse (CIR). Based on earlier experience in AML, we selected a threshold of 100 copies, defining 2 groups: patients with <100 WT1 copies and those with ≥100 copies. Patients with <100 WT1 copies before HCT (median time, 36 days; range, 4 to 268 days) had a better OS, PFS, and CIR than those with ≥100 copies (40 ± 1 versus 29 ± 6 days, P = .004; 35 ± 9 versus 26 ± 6 days, P = .002; and 29 ± 7 versus 37 ± 6 days, P = .051). In the first bone marrow study after the HCT (median time, 42 days; range 14 to 157 days, respectively), patients with <100 WT1 copies also had better outcomes in terms of OS, PFS, and CIR (40 ± 7 versus 31 ± 9 days, P = .025; 36 ± 7 versus 30 ± 8 days, P = .004; and 29 ± 6 days versus 54 ± 9, P < .001, respectively). At this time point, bone marrrow samples with >100 copies also included patients who were negative for MRD as assessed by MPFC (19 of 32). During the HCT follow-up, patients with sustained WT1 levels <100 copies showed a marked benefit in terms of OS, PFS, and CIR even compared with those with only a single measurement >100 copies (mean, 68 ± 11 versus 26 ± 7 days, P < .001; 63 ± 11 versus 20 ± 8 days, P < .001; and 20 ± 8 vs. 71 ± 8 days, P < .001, respectively). Standardized bone marrow WT1 levels using a 100-copy threshold in samples obtained before HCT, at leukocyte recovery, and during follow-up provided relevant prognostic information in patients with myeloid malignacies submitted to HCT.

Traumatic stress in patients with acute leukemia: A prospective cohort study.

Acute leukemia (AL) is associated with an immediate threat to life, an unpredictable clinical course, and substantial physical suffering. Traumatic stress symptoms that may meet criteria for acute stress disorder (ASD) may be common and disabling in this context, but have received little clinical attention. We investigated the incidence over time and risk factors for traumatic stress symptoms and ASD in the 3months following diagnosis or relapse of AL. Individuals with AL were recruited at a tertiary cancer center in Canada within one month of diagnosis or relapse. Participants (N=230) completed self-report measures, including the Stanford Acute Stress Reaction Questionnaire, at baseline and monthly over 3months. The incidence of traumatic stress symptoms over time was examined, and a generalized logistic model was used to identify factors associated with ASD. Participants were 60% male, with a mean age of 48.9±15.2years. Symptoms of ASD were identified on ≥1 assessment over the study period in 24.4% of participants at baseline and in an additional 12.6% at a subsequent follow-up. Of these, 55.3% reported symptoms on ≥2 assessments. ASD was associated with having young children, being unmarried, acute lymphocytic leukemia, and greater physical symptom burden. Persistent or recurrent ASD was associated with female sex, acute lymphocytic leukemia, greater attachment anxiety, less spiritual well-being, and less satisfactory patient-clinician communication. Symptoms of ASD are common and often persist or recur following diagnosis or relapse of AL. Research is urgently needed to determine the impact of interventions to prevent and treat psychological distress in this population.

Significance of Monitoring Minimal Residual Disease by Flow Cytometry in Acute Leukemia Patients Underwent Nonmyeloablative Allo-HSCT

To explore the value of dynamically monitoring minimal residual disease (MRD) by flow cytometry before and after non-myeloablative allo-HSCT (NST) for prediction of acute leukemia(AL) relapse after transplantation. The clinical data of 51 AL patients underwent NST were analyzed retrospectively in Department of Hematology of Affiliated Hospital of Academy of Military Medical Sciences from January 2011 to December 2015. All AL patients achieved the morphologic complete remission of bone marrow before transplantation. The bone marrow samples were collected for monitoring of MRD within 35 days before transplant, every month till 3 months after transplant, every 3 months till 24 months after transplant, and then every 6 months after 2 years of transplant. According to the MRD cutoff value of 0.2%, the AL patients were divided into high level MRD group (18 cases) which was defined as MRD≥0.2% after transplantantion at least for 1 time, and low level MRD group (33 cases) which was defined as MRD<0.2% after transplant all the time. 2 year cumulative relapse rate in 2 groups were compared. Two-year relapse rates were 6.1% and 50% in low-level MRD group and high-level MRD group post NST(P=0.001)respectively. Multivariate analysis indicated that the risk of relapse in high level MRD group was 5.84 times of low level MRD group(P=0.036). MRD≥0.2% post transplant was an independent risk factor for leukemia relapse post NST. The mortality rate was 81.8% and 46.3%(P<0.05) in relapse and non-relapse groups respectively. Dynamically monitoring MRD by FCM is a crucial tool for early relapse estimation of acute leukemia in adult patients after allogeneic nonmyeloablative hematopoietic stem cell transplantation. MRD≥0.2% after transplant can be used as a early valuable evidence for predicting relapse and guiding active medical intervention.