scholarly journals Single Cell Sequencing of Pediatric Acute Myeloid Leukemia Reveals Clonal Evolution to Relapse on Combination Chemotherapy with Sorafenib

Blood ◽  
2021 ◽  
Vol 138 (Supplement 1) ◽  
pp. 3470-3470
Author(s):  
Cheryl A C Peretz ◽  
Vanessa E Kennedy ◽  
Rhonda E. Ries ◽  
Soheil Meshinchi ◽  
Catherine C. Smith

Abstract Introduction: Relapse of pediatric acute myeloid leukemia (AML) remains a leading cause of childhood cancer mortality, and leukemias with activation of the Fms-like tyrosine kinase 3 (FLT3) are particularly susceptible to relapsed disease. Risk-directed therapy to prevent relapse is based both on genetic changes known to drive drug resistance, and measurable residual disease (MRD) at the end of induction therapy (EOI). In adult AML, resistance to type II FLT3-inhibitors, like sorafenib, is primarily driven by on-target FLT3 kinase domain (KD) mutations. However, the resistance mechanisms for pediatric leukemias, which are treated on combination therapies, have not been fully elucidated. MRD is considered the among the most predictive markers of future relapsed disease. It has been assumed that the major clone at the time of MRD assessment will predict the majority clone at relapse. However, this assumption has not been proven. The definition of the most specific genetic and MRD markers of relapse are essential to prognosticate and personalize therapy to prevent relapsed disease. Methods: We performed single cell sequencing (SCS) with a high-throughput DNA sequencing platform, Mission Bio Tapestri, on bone marrow or peripheral blood samples from 24 samples from 8 pediatric patients treated on COG AAML1031 with serial samples from diagnosis, EOI, and relapse. Results: We analyzed a total of 94,833 cells from 8 pediatric patients (median cells per patient 12,428) all treated on AAML1031. SCS revealed a sensitive and specific description of clonal evolution on the combination of sorafenib with cytotoxic chemotherapy. The FLT3 internal tandem duplication (ITD) was controlled by the therapy in only half of the patients. In five of the patients, the FLT3-ITD was present in multiple clones. The FLT3-ITD co-mutated with additional mutations (NRAS, SH2B3, WT1, TET2, or NPM1) in half of the patients. However, the presence of a co-mutation did not necessarily correlate with whether or not the ITD-containing clone persisted at the time of relapse. Of the leukemias whose relapse was not driven by FLT3, the most likely mutational driver of resistance was NRAS. Notably, however, despite the fact that FLT3 KD mutations make up the bulk of mutational resistance to type II FLT3i such as sorafenib in adult patients, there were no on-target FLT3 mutations found in any of these pediatric patients. Further, SCS allows for an unprecedented depth of analysis of the genetic complexity of pediatric AML. Phylogenic analysis revealed that the same mutations may arise independently in different cells (NPM1 W288fs, NRAS G60E). Additionally, the same gene may be mutated twice within the same cell (WT1, TET2). These data, consistent with our prior work, suggest that some leukemias may have a predilection to mutations within specific loci. Finally, although there is a standing assumption that the dominant MRD population will proliferate into relapsed disease, in 3/8 patients, the dominant MRD clone did not predict the dominant relapse clone. Conclusions: SCS allows for direct measurement of clonal hierarchy and evolution, phylogeny, co-mutational status, and zygosity, which can only be inferred through traditional bulk NGS. The mutational mechanisms of resistance seen in adult leukemias treated with sorafenib monotherapy are not necessarily relevant to the pediatric population; rather than on-target FLT3 mutations, off target mutations including NRAS are found. This corroborates prior findings that off-target RAS pathway mutations may drive resistance to FLT3i. Non-RAS off-target mutations found in this cohort do not necessarily predict sorafenib resistance, so may be passenger mutations. The lack of consistent resistance mutations suggests that other mechanisms of resistance such as epigenetic modifications may also drive resistance to combination chemotherapy with FLT3i in pediatric leukemia. Further, SCS exposes more genetic complexity in pediatric AML than has previously been appreciated: the same mutation may independently arise in more than one cell or the same cell may have multiple mutations within the same gene. Finally, the sensitivity of SCS reveals that the major clone at the time of MRD assessment is not necessarily the major clone at relapse. This suggests a benefit of more frequent MRD monitoring to track clonal evolution in real time. Disclosures Smith: Daiichi Sankyo: Consultancy; Revolutions Medicine: Research Funding; AbbVie: Research Funding; Amgen: Honoraria; FUJIFILM: Research Funding; Astellas Pharma: Consultancy, Research Funding.

Blood ◽  
2021 ◽  
Vol 138 (Supplement 1) ◽  
pp. 1170-1170
Author(s):  
Anilkumar Gopalakrishnapillai ◽  
Anne Kisielewski ◽  
Yang Zhang ◽  
Bruce Ruggeri ◽  
Peggy Scherle ◽  
...  

Abstract Pediatric acute myeloid leukemia (AML) is the deadliest malignancy in children. Despite maximally intensive therapy, inclusive of chemotherapy and hematopoietic stem cell transplant, approximately 20% of patients experience recurrent disease. These patients are also burdened with treatment-related toxicities. Significant improvements in survival in pediatric AML patients necessitate the incorporation of rational targeted therapies with reduced toxicity. Recent studies demonstrate that PRMT5 knockout or inhibition in syngeneic mouse models of KMT2A (MLL) rearranged leukemic cells increased disease latency (Serio et al., Oncogene, 37:450, 2018; Kaushik et al., Leukemia, 32:499, 2018), indicating that PRMT5 is a potential therapeutic target in pediatric AML. However, there are no reports testing the efficacy of PRMT5 in PDX models of pediatric AML. We evaluated the preclinical efficacy of C220, a potent and selective PRMT5 inhibitor (PRMT5i) (Pastore et al., Cancer Discovery, 10:1742, 2020) in three distinct patient-derived xenograft (PDX) models of KMT2A rearranged AML. Based on the model used for the study, 3-5 million AML cells were injected intravenously in NSG-B2m mice. Disease progression was monitored by evaluating the percentage of human cells in mouse peripheral blood at periodic intervals by flow cytometry. At 2-3 weeks post transplantation, when human cells were detectable in peripheral blood, mice were randomly assigned to control (n=4-5) or treatment (n=2) groups. C220 was administered daily p.o. at a dose of 15 mg/kg for seven days with a break of two days. Mice were dosed with 2-3 additional cycles (indicated in the figure by shaded areas) based on their health status. Mice were monitored daily for experimental endpoints that included body condition score and human cell percentages in peripheral blood. Kaplan-Meier survival plots were generated based on the time when mice were euthanized because they met experimental endpoints. Chronic dosing of C220 prolonged survival and delayed the rise in percentage of human AML cells in mouse peripheral blood in all 3 PDX models (Fig. 1B, D, F). In the NTPL-146 model (KMT2A-MLLT1 fusion), a 135-day improvement in median survival was observed with C220-treatment (Fig. 1A). In the DF-2 (KMT2A-MLLT10 fusion) and DF-5 (KMT2A-MLLT4 fusion) models, which showed a faster engraftment compared to NTPL-146, there was a 5.5-day and 18-day improvement in median survival respectively (Fig. 1C, E). The improvement in median survival was statistically significant in all models (*P<0.05). In conclusion, C220 was effective in controlling leukemia progression and improving survival in KMT2A rearranged PDX models of pediatric AML. Figure 1 Figure 1. Disclosures Gopalakrishnapillai: Geron: Research Funding. Zhang: Prelude Therapeutics: Current Employment. Ruggeri: Prelude Therapeutics: Current Employment, Current equity holder in publicly-traded company. Scherle: Prelude Therapeutics: Current Employment, Current equity holder in publicly-traded company. Barwe: Prelude Therapeutics: Research Funding.


Blood ◽  
2016 ◽  
Vol 128 (22) ◽  
pp. 2850-2850
Author(s):  
Norio Shiba ◽  
Kenichi Yoshida ◽  
Yuichi Shiraishi ◽  
Shiraishi Yuichi ◽  
Yusuke Hara ◽  
...  

Abstract Background: Pediatric acute myeloid leukemia (AML) comprises approximately 20% of pediatric leukemia, representing one of the major therapeutic challenges in pediatric oncology with a current overall survival rate of less than 70%. The pathogenesis of AML is heterogeneous and can be caused by various chromosomal aberrations, gene mutations/epigenetic modifications, and deregulated/overregulated gene expressions, leading to increased proliferation and decreased hematopoietic progenitor cell differentiation. Recurrent chromosomal structural aberrations [e.g., t(8;21), inv(16), and MLL-rearrangements] have been well established as diagnostic and prognostic markers of AML. Furthermore, recurrent mutations in FLT3, KIT, NPM1, and CEBPA have been reported in both adult and pediatric AML. Recently, massively parallel sequencing enabled the discovery of recurrent mutations in DNMT3A, TET2, and IDH, which are clinically useful for the prediction of the prognosis. However, these mutations are rare in pediatric AML, suggesting that other genetic alterations exist in pediatric AML. In contrast, recent reports have described NUP98-NSD1 fusion as an adverse AML prognostic marker and PRDM16 (also known as MEL1) as the representative overexpressed gene in patients harboring NUP98-NSD1 fusion. Intriguingly, PRDM16 overexpression occurs in nearly one-quarter of all children, with AML involving NUP98-NSD1-negative patients. Moreover, this overexpression is enriched in specimens with other high-risk lesions (e.g., FLT3-ITD, NUP98-NSD1, and MLL-PTD). Patients and Methods: To reveal a complete registry of gene rearrangements and other genetic lesions in pediatric AML with a normal karyotype, we performed transcriptome analysis (RNA sequencing) of 61 of 70 de novo pediatric AML patients with a normal karyotype using Illumina HiSeq 2000. We could not perform RNA sequencing in nine patients because of a lack of RNA quantity or quality. Among the 70 AML patients with a normal karyotype, 33 patients overexpressed PRDM16, which was found to be strongly associated with a poor prognosis in our previous studies. All patients were enrolled and treated with AML-05 in the study conducted by the Japan Pediatric Leukemia/Lymphoma Study Group (JPLSG). We also analyzed the known genetic mutations associated with these patients using the data derived from RNA sequencing. Results: A total of 144 candidate gene rearrangements, which were not observed in normal samples, were identified in 51 of 61 samples. Many of the recurrent gene rearrangements identified in this study involved previously reported targets in AML, including NUP98-NSD1, NUP98-JARID1A, CBFA2T3-GLIS2, MLL-MLLT10, and MLL-MLLT3. However, several gene rearrangements were newly identified in the current study, including MLL-SEPT6, HOXA10-HOXA-AS3, PRDM16-SKI, and CUL1-EZH2. We have also performed the validation of these novel gene rearrangements using Sanger sequencing. Most of these gene rearrangements were found in patients with a high expressionof PRDM16. In contrast, CEBPA mutations were frequently observed in patients with a low expression of PRDM16. Known gene alterations, such as FLT3-ITD and MLL-PTD, and mutations of the RAS, KIT, CEBPA, WT1, and NPM1genes were also detected using RNA sequencing. Conclusion: RNA sequencing unmasked a complexity of gene rearrangements and mutations in pediatric AML genomes. Our results indicate that a subset of pediatric AML represents a discrete entity that could be discriminated from adult counterparts, regarding the spectrum of gene rearrangements and mutations. In the present study, we identified at least one potential gene rearrangement or driver mutation in nearly all AML samples, including some novel fusion genes. These findings suggest that gene rearrangements in conjunction with mutations also play essential roles in pediatric AML. Disclosures Ogawa: Kan research institute: Consultancy, Research Funding; Takeda Pharmaceuticals: Consultancy, Research Funding; Sumitomo Dainippon Pharma: Research Funding.


2017 ◽  
Vol 4 (5) ◽  
pp. 1890
Author(s):  
Juliana C. Abreu ◽  
Raissa M. Fontes ◽  
Jesamar C. Matos ◽  
Fátima G. Jorge ◽  
Diego S. Lima

Acute myeloid leukemia (AML) is characterized by clonal expansion of undifferentiated myeloid precursors that results in the bone marrow (BM) failure. Some cytogenetic alterations can be used to predict the prognosis of the disease. AML with t(8;21), presenting RUNX1/RUNX1T1 gene fusion, is associated to favorable prognosis and it is one of most prevalent structural abnormalities in pediatric AML. Variants of t(8;21) has been described, though the prognostic value of these changes remains controversial, especially in pediatric patients. Thereby, we report a pediatric patient with AML with RUNX1/RUNX1T1 fusion presenting the variant t(1;21;8). The diagnosis was confirmed by myelogram, immunophenotyping, cytogenetics and molecular biology. After the diagnosis, the patient was subjected to chemotherapy and submitted to related allogeneic BM transplant. Until this date, the patient has no clinical complaints, predicting a favorable outcome. The register of variants and its proper follow up contributes to a better understanding of the mechanisms involved in these rearrangements and provides information that may be relevant for an appropriate classification and risk stratification of these patients.


Blood ◽  
2020 ◽  
Vol 136 (Supplement 1) ◽  
pp. 6-7
Author(s):  
Mareike Rasche ◽  
Martin Zimmermann ◽  
Emma Steidel ◽  
Todd A. Alonzo ◽  
Richard Aplenc ◽  
...  

BACKGROUND: Children with high risk acute myeloid leukemia (AML) still experience consistently high rates of relapse. Survival after first relapse increased from 21% between 1987 and 1997 up to 39% in recent studies. However, since 2009, there have been no publications on subsequent large pediatric AML relapse trials. As the indications for HSCT during first-line treatment have been extended since then, the current survival of these patients at relapse remains unclear. Herein, we report outcome results from the BFM and COG study group, which represents the largest available dataset analyzed for post-relapse survival. PATIENTS AND METHODS: Pediatric patients with first relapse of AML (no Down syndrome, secondary leukemia or FAB M3) have been analyzed from two large study groups with patients from the United States, Canada, Australia, New Zealand, Germany, Austria, Czech Republic and Switzerland. Out of 1222 patients in the BFM cohort (AML-BFM study 2004, registry 2012 and study 2012), 350 experienced at least one relapse and 197 of those had a first relapse after closure of the last I-BFM relapse trial (04/2009 through 2017). Within the Children's Oncology Group (COG) Phase 3 trials (AAML0531 and AAML1031, n=2119) 852 pediatric patients suffered a relapse. Five-year probability of overall survival (pOS) and event-free survival (pEFS) were calculated according to Kaplan-Meier. EFS was calculated for the BFM cohort as time from relapse to the next event (second relapse, death, failure to achieve a second remission or secondary malignancy) or until last follow-up, while OS reflects the time from relapse until death or last follow-up. The Cox proportional hazards model was used for multivariate analysis of outcomes. Living patients were censored at last follow-up with a median follow-up after relapse of 4·2 years (BFM) and 4·8 years (COG). Data have been frozen at 03/27/2020 (BFM) and 03/31/2020 (COG). RESULTS: In the 197 patients with relapse after closure of the last BFM relapse trial (04/2009 through 2017) the pOS at 5 years was 42±4% (BFM). The 5-year pOS in patients relapsing after COG trials 2006-2018 was 35±2% (n=852). Patients experiencing a relapse between 2014 to 2017 had a pOS of 49±6% (BFM, n=78) and 40±3% (COG, n=333). Risk classification at initial diagnosis and a short time from diagnosis to relapse predicted a diminished survival probability in both cohorts (see Table 1). However, the absence of full hematopoietic regeneration of the bone marrow after re-induction did not predict survival: Within the BFM dataset, a subgroup analysis in all patients receiving DNX-FLA (n=156) have been performed. Initial characteristics are comparable to the total cohort. Among these patients 147 were evaluable for response (7 excluded due to early death before evaluation, 2 for insufficient data). Eighty-nine (57%) achieved a CR (n=69) or CRp (n=20) and 52 (33%) no response. Overall survival was superior for patients with a CR/CRp (54±6% (CR/CRp) vs. 32±7% (No CR/CRp); p=0·0064), but long-term survival was still possible even with a poor re-induction response. Patients with a CRp had a comparable survival to those with a CR after a second re-induction (pOS 60±11% (CRp) vs. pOS 52±7% (CR); p=0·57). Patients with >5% leukemic blasts (n=32) had the lowest survival (pOS 27±9%). The 5-year pEFS for this cohort was 29±4% (pEFS 50±6% (CR) vs. pEFS 50±11% (CRp)). The analysis of post-relapse treatment showed that the vast majority of patients who survive had a HSCT following relapse. By landmark analysis, survival was significantly higher in patients with subsequent HSCT compared to that of non-transplanted patients (BFM: pOS 53±4%, n=154 vs. pOS 5±5%, n=21; p(Mantel-Byar)=0·0002). CONCLUSION: This is the largest report to date on post relapse survival in children with AML. Our analysis confirmed previously described risk factors for poor survival while also highlighting new findings contrary to established standards. Strikingly, the absence of full hematopoietic regeneration of the bone marrow after re-induction did not predict survival at first relapse, thereby questioning the current value of the established International Working Group Criteria published by Cheson et al for response-evaluation in pediatric AML. As the international pediatric AML community embarks on collaborative efforts to evaluate new therapies in children with relapsed AML, a comprehensive review of post relapse survival is critical. Disclosures Bourquin: Servier: Other: Travel Support. Reinhardt:Novartis: Membership on an entity's Board of Directors or advisory committees; CLS Behring: Research Funding; bluebird bio: Membership on an entity's Board of Directors or advisory committees; Janssen: Membership on an entity's Board of Directors or advisory committees; Roche: Research Funding; Celgene Corporation: Membership on an entity's Board of Directors or advisory committees, Research Funding.


Blood ◽  
2020 ◽  
Vol 136 (Supplement 1) ◽  
pp. 31-32
Author(s):  
Jacob Higgins ◽  
Fang Yin Lo ◽  
Michael J. Hipp ◽  
Charles C. Valentine ◽  
Lindsey N. Williams ◽  
...  

Sensitive and specific detection of measurable residual disease (MRD) after treatment in pediatric acute myeloid leukemia (AML) is prognostic of relapse and is important for clinical decision making. Mutation-based methods are increasingly being used, but are hampered by the limited number of common driver gene mutations to target as clone markers. Additional targets would greatly increase MRD detection power. However, even in cases with many AML-defining mutations, it is the limited accuracy of current molecular methods which establishes the lower bounds of sensitivity. Here we describe an ultrasensitive approach for disease monitoring with personalized hybrid capture panels targeting hundreds of somatic mutations identified by whole genome sequencing (WGS), and using extremely accurate Duplex Sequencing (DS) in longitudinal samples. In a pilot cohort of 13 patients we demonstrate detection sensitivities several orders of magnitude beyond currently available single locus testing or less accurate sequencing. With multi-target panels, overall power for MRD detection is cumulative across sites. For example, if a patient has MRD at a true frequency of 1/30,000, sequencing a single mutant site to 10,000x molecular depth would be unlikely to detect MRD. However, sequencing 10 sites each to 10,000x would effectively total 100,000x informative site depth, increasing power to >95%. However, standard sequencing assays are insufficiently accurate to achieve this theoretical limit of detection (LOD). DS enables accurate detection of individual variants to <10-5 with an error rate <10-7 and, thus, can achieve MRD sensitivities below one-in-one-million. Marrow aspirates were collected from 13 uniformly treated pediatric AML patients at time of diagnosis (TOD), during treatment (end of induction, EOI), in remission (end of therapy, EOT), and at relapse. 9/13 patients relapsed. DNA from TOD was analyzed by WGS. Germline variants were excluded and somatic single nucleotide variants (SNVs) were targeted by a custom probe panel designed for each patient. An average of 170 SNVs were targeted per patient (range 53-200). More than 90% of the SNVs were noncoding. Longitudinal samples were then analyzed with DS, which compares sequences from both strands of each DNA molecule to eliminate technical noise and reveal biological mutation signal with extreme accuracy and sensitivity. A median of 82% of WGS SNVs were validated by DS in the TOD DNA, and the vast majority of those were also present at relapse. Relapsers had more SNVs at diagnosis than non-relapsers. EOT samples were sequenced to an average Duplex molecular depth of 29,400x, with a maximum of 61,283x. The figure below shows time course plots tracking SNVs at diagnosis, EOT and relapse for 2 patients. Among mutations validated in TOD samples, a median of only 8 (5%) were detected per EOT sample (range 0-66 mutations). MRD was detected in 8/9 relapsers. Targeting 1 or even 10 SNVs would therefore have missed MRD in the majority of these patients. Among relapsers, median EOT SNV VAF was 0.069%. The lowest single VAF detected per EOT sample ranged from 0.036% to 0.002%. The presence of an SNV at diagnosis and relapse implies that it must truly be present at EOT, whether or not it is detected. Therefore, if a small minority of leukemic mutations are detected at EOT, the true overall MRD frequency is much lower than the LOD at any single site. In the only relapser where MRD was not detected, targeted SNVs were present at diagnosis and relapse, so additional sequencing depth at EOT would eventually reveal ultra-low frequency mutations. Among patients that did not relapse by the end of the study, median VAF at EOI (the latest time point DNA available) was 0.0258%. Therefore, non-relapsers have a lower median VAF at EOI than relapsers do even later at EOT, potentially indicating very early on that treatment is more successful. This study shows excellent performance of DS-based assays for detecting MRD with patient-specific panels. We have demonstrated that among large panels of validated somatic SNVs present at time of diagnosis, a median of 5% are identified at EOT in eventual relapsers. DS detected MRD in 8/9 patients, and at a median VAF well below the limit of detection of any other sequencing technology. Comprehensive personalized hybrid selection panels coupled with DS represents a powerful option for MRD monitoring in pediatric AML and potentially other cancers. Figure Disclosures Higgins: TwinStrand Biosciences: Current Employment. Lo:TwinStrand Biosciences: Current Employment. Hipp:TwinStrand Biosciences: Current Employment. Valentine:TwinStrand Biosciences: Current Employment. Williams:TwinStrand Biosciences: Current Employment. Radich:TwinStrand Biosciences: Research Funding. Salk:TwinStrand Biosciences: Current Employment.


2021 ◽  
Vol 2021 ◽  
pp. 1-14
Author(s):  
Feng Jiang ◽  
Xin-Yu Wang ◽  
Ming-Yan Wang ◽  
Yan Mao ◽  
Xiao-Lin Miao ◽  
...  

Objective. The aim of this research was to create a new genetic signature of immune checkpoint-associated genes as a prognostic method for pediatric acute myeloid leukemia (AML). Methods. Transcriptome profiles and clinical follow-up details were obtained in Therapeutically Applicable Research to Generate Effective Treatments (TARGET), a database of pediatric tumors. Secondary data was collected from the Gene Expression Omnibus (GEO) to test the observations. In univariate Cox regression and multivariate Cox regression studies, the expression of immune checkpoint-related genes was studied. A three-mRNA signature was developed for predicting pediatric AML patient survival. Furthermore, the GEO cohort was used to confirm the reliability. A bioinformatics method was utilized to identify the diagnostic and prognostic value. Results. A three-gene (STAT1, BATF, EML4) signature was developed to identify patients into two danger categories depending on their OS. A multivariate regression study showed that the immune checkpoint-related signature (STAT1, BATF, EML4) was an independent indicator of pediatric AML. By immune cell subtypes analyses, the signature was correlated with multiple subtypes of immune cells. Conclusion. In summary, our three-gene signature can be a useful tool to predict the OS in AML patients.


Blood ◽  
2005 ◽  
Vol 106 (11) ◽  
pp. 3263-3263
Author(s):  
Luca Lo Nigro ◽  
Laura Sainati ◽  
Anna Leszl ◽  
Elena Mirabile ◽  
Monica Spinelli ◽  
...  

Abstract Background: Myelomonocytic precursors from acute or chronic leukemias can differentiate to dendritic cells in vitro, but leukemias with a dendritic cell immunophenotype are rare, have been reported mainly in adults, and their molecular pathogenesis is unknown. Dendritic cells are classified as Langherans, myeloid and lymphoid/plasmacytoid cells, but leukemias arising from dendritic cells are unclassified in the FAB system. We identified a new entity of pediatric acute myeloid leukemia (AML) presenting with morphologic and immunophenotypic features of mature dendritic cells, which is characterized by MLL gene translocation. Methods and Results: Standard methods were used to characterize the morphology, immunophenotype, karyotype and MLL translocations in 3 cases of pediatric AML. The patients included two boys and one girl diagnosed with AML between 1–6 years old. Their clinical histories and findings included fever, pallor, abdominal and joint pain, adenopathy, hepatosplenomegaly, normal WBC counts but anemia and thrombocytopenia. and no evidence of CNS disease. The bone marrow aspirates were hypocellular and replaced completely by large blasts with irregular nuclei, slightly basophilic cytoplasm, and prominent cytoplasmic projections. There were no cytoplasmatic granules or phagocytosis. Myeloperoxidase and alpha napthyl esterase reactions were negative, excluding FAB M5 AML, and the morphology was not consistent with any standard FAB morphologic diagnosis. The leukemic blasts in all three cases were CD83+, CD86+, CD116+, consistent with differentiated myeloid dendritic cells, and did not express CD34, CD56 or CD117. MLL translocations were identified in all 3 cases. In the first case FISH analysis showed t(10;11)(p12;q23) and RT-PCR identified and a ‘5-MLL-AF10-3’ fusion transcript. In the second case FISH analysis showed t(9;11)(p22;q23) and RT-PCR identified and a ‘5-MLL-AF9-3’ fusion transcript. In the remaining case, the MLL gene rearrangement was identified by Southern blot analysis and RT-PCR showed an MLL-AF9 fusion transcript. The fusion transcripts in all 3 cases were in-frame. Remission induction was achieved with intensive chemotherapy, and all three patients have remained in durable remission for 30–60 months after hematopoietic stem cell transplantation. Conclusions. We have characterized a new pediatric AML entity with features of mature dendritic cells, MLL translocation and an apparently favorable prognosis. The in-frame MLL fusion transcripts suggest that chimeric MLL oncoproteins underlie its pathogenesis. The partner genes in all 3 cases were known partner genes of MLL that encode transcription factors. This study increases the spectrum of leukemias with MLL translocations. Comprehensive morphological, immunophenotypic, cytogenetic and molecular analyses are critical for this diagnosis, and will reveal its frequency and spectrum as additional cases are uncovered.


Blood ◽  
2009 ◽  
Vol 114 (22) ◽  
pp. 2290-2290
Author(s):  
Joseph A. Pidala ◽  
Jongphil Kim ◽  
Claudio Anasetti ◽  
Melissa Alsina ◽  
Ernesto Ayala ◽  
...  

Abstract Abstract 2290 Poster Board II-267 Reduced and intermediate intensity conditioning with allogeneic hematopoietic cell transplantation (HCT) offers promise to effectively control hematologic malignancies, while limiting treatment related toxicity and mortality (TRM). We aimed to examine the efficacy of IV targeted Busulfan and Fludarabine (IV-Bu/Flu) in a large series of adults with exclusively acute myelogenous leukemia (AML). One hundred adults (median age 48) with AML (CR1 49, CR2 25, REL1 8, REL2 1, PIF 16, untreated 1) were treated with Busulfan 130-145 mg/m2/day for four days with pharmacokinetic targeting on the final two days to achieve an area under the curve (AUC) of 5300 (+/-10%) μmol*min/L/day and Fludarabine 40mg/m2/day for 4 days, followed by transplantation of G-CSF mobilized peripheral blood stem cells (PBSC) (N=98) or unstimulated bone marrow (BM) (N=2) from allogeneic donors (MRD 38, MUD 38, MMUD 24). Acute GVHD prophylaxis consisted of tacrolimus/methotrexate (N = 77), tacrolimus/mycophenolate mofetil (N = 22), or tacrolimus/sirolimus (N = 1). Median time to neutrophil and platelet engraftment was 16 and 12 days, respectively. Non-relapse mortality was 3% at 100 days, and 15% by 1 year. The cumulative incidence of relapse was 41%. Overall survival (OS) was 59% (95% CI: 48.1 – 67.5) at 1 year, and 42% (95% CI: 30.8-53.3) at 4 years. OS at 4 years for primary AML in CR1, secondary AML in CR1, CR2, and PIF were 52.9%, 40.1%, 41.2%, and 57.5% respectively; none with relapsed disease survived to 4 years (log-rank p = 0.0014). Progression-free survival (PFS) was 53% (95% CI: 42.8 – 62.2) at 1 year, and 32.3% (95% CI: 21.8 – 43.2) at 4 years. PFS at 4 years for primary AML in CR1, secondary AML in CR1, CR2, and PIF were 44.1%, 33.4%, 33.9%, and 33.1%, respectively, while none with relapsed disease at transplant reached this endpoint (p = 0.0264). On multivariable modeling, remission status at HCT (relapsed disease HR 14.85 (95% CI: 2.12 - 104.2), p = 0.007), moderate/severe cGVHD (HR 0.281, 95% CI: 0.10 - 0.76; p = 0.013), and day 90 bone marrow (BM) chimerism ≥ 90% (HR 0.245, 95% CI: 0.08 - 0.79; p = 0.018) predicted overall survival, and day 90 BM chimerism ≥ 90% (HR of 0.18 (95% CI: 0.08 - 0.45), p = 0.0002) predicted PFS. The following were not significantly related with OS or PFS: age, cytogenetics, donor relation, number of induction cycles, aGVHD prophylaxis regimen, maximum aGVHD grade, WBC at diagnosis, time in first CR, or % BM blasts prior to transplant. Day 90 BM chimerism and cGVHD were significantly related with relapse. Maximum grade of aGVHD predicted non-relapse mortality. These data support the low TRM and efficacy of IV-Bu/Flu in a large series of exclusively AML patients, and demonstrate the impact of day 90 bone marrow chimerism as an important prognostic factor. Further efforts to mitigate relapse risk after HCT are warranted, particularly in those with advanced disease at time of transplant. Disclosures: Off Label Use: IV busulfan and fludarabine for the treatment of acute myeloid leukemia. Alsina:Ortho Biotech: Research Funding, Speakers Bureau; Millenium: Research Funding, Speakers Bureau. Field:PDL BioPharma: Research Funding. Fernandez:Otsuka: Honoraria.


Blood ◽  
2011 ◽  
Vol 118 (21) ◽  
pp. 5239-5239
Author(s):  
Hala Abalkhail ◽  
Hassan El-Solh ◽  
Amal Alseraihy ◽  
Asim F Belgaumi ◽  
Abdullah Al-Jefri ◽  
...  

Abstract Abstract 5239 Background: Acute myeloid leukemia (AML) is biologically heterogeneous with significant molecular and clinical variation. Most of the recent studies suggest that AML in pediatric population differs significantly clinically and biologically from adult AML. Numerous newly described molecular abnormalities in AML have been described in adult patients, but except for rare publications, a little is known about the molecular abnormalities and their clinical relevance in pediatric AML, especially in early childhood and when the patients are treated with intensive chemotherapy followed by hematopoietic stem cell transplant (HSCT). The Saudi Arabian population is known to be genetically homogenous due to high consanguinity. Higher incidence of inherited diseases including certain types of cancer has been reported in Saudi Arabia. We attempted to compare the molecular abnormalities and their clinical relevance in pediatric AML patients from Saudi Arabia with adult AML from the same population. Methods: Samples from 87 adult patients with AML and samples from 40 pediatric AML patients were analyzed for FLT3-ITD and FLT3-D835, IDH1, IDH2, NPM1, and DNMT3A mutations by direct sequencing and by fragment length analysis (FLT3 and NPM1). The prevalence of mutations was compared between the adult and pediatric groups. They included patients with intermediate-risk cytogenetics (N=66 adults, N=26 pediatrics) and adverse cytogenetics (N=21 adults, N=14 pediatrics). The median age of the pediatric patients is 7 years, with a range from less than one year to 14 years. All patients were treated with intensive chemotherapy, followed by HSCT in first remission. Results: FLT3-ITD mutation was detected in 18 patients (21%) of the adult group, but detected only in 3 patients of the pediatric group (7.5%). Two of the 3 patients in the pediatric group carrying the FLT3 mutation died within the first year after the transplant. The FLT3-D835 mutation was detected in 6 patients (7%) of the adult group, while none of the pediatric patients showed this mutation. In addition, the pediatric patients showed no mutations in IDH1 or IDH2, while the adult patients showed IDH1 and IDH2 mutations in 6 (7%) and 7 (8%), respectively. Mutations in the DNMT3A gene were detected in three patients (3%) in the adult group, but were not detected in any of the pediatric AML. NPM1 mutations were detected in 9 (10%) of the adult AML patients, but none of the pediatric patients showed NPM1 mutation. Conclusion: This data suggests that the biology of AML in pediatric patients is significantly different from that in the adult patients. Mutations in FLT3, IDH1, IDH2, NPM1, and DNMT3A genes are very rare in pediatric patients. However, our data involves early childhood (90% younger than 13 years of age) and there is a possibility that older children may have higher incidence of mutations. Most of the currently used molecular markers in risk-stratifying adult AML patients are difficult to use in stratifying pediatric AML patients. Disclosures: No relevant conflicts of interest to declare.


Blood ◽  
2012 ◽  
Vol 120 (21) ◽  
pp. 1483-1483 ◽  
Author(s):  
Walter Fiedler ◽  
Sabine Kayser ◽  
Maxim Kebenko ◽  
Jürgen Krauter ◽  
Helmut R. Salih ◽  
...  

Abstract Abstract 1483 Background: Activating FLT3 mutations including internal tandem duplications (FLT3-ITD) and tyrosine-kinase domain mutation (FLT3-TKD) occur in approximately one third of patients with acute myeloid leukemia (AML) and are particularly associated with a poor outcome in case of FLT3-ITD. Sunitinib is a multitargeted FLT3 inhibitor approved for the treatment of advanced/metastatic renal cancer and metastatic/unresectable malignant GIST after failure of imatinib. Sunitinib has been evaluated in refractory AML as single agent treatment resulting in transient blast count reduction and in several cases of partial response in AML with activating FLT3 mutations. Aims: To evaluate the feasibility of a standard induction and consolidation therapy in combination with orally administered sunitinib in elderly AML patients with activating FLT3 mutations. Methods: Patients aged 60 years or higher with AML with activating FLT3 mutations (FLT3-ITD, FLT3-TKD) and fit enough for intensive chemotherapy were eligible. Induction therapy included cytarabine 100 mg/m2 per continuous infusion on days 1–7 and daunorubicin 60 mg/m2 i.v. on days 1–3 (DA). A second course was allowed in responding patients, who did not achieve a complete remission (CR). In patients achieving a CR after induction therapy three consolidation cycles were intended (cytarabine 1 g/m2 i.v. bid, on days 1,3,5). A 3+3 dose escalation/de-escalation scheme was used to define the dose and scheduling of sunitinib. The first cohort of three patients received oral sunitinib continuously starting from day 1 in a dose of 25 mg/day (level 1). Dose escalation to level 2 with sunitinib 37.5 mg/day continuously or dose de-escalation to level −1 with 25 mg day 1 to 7 had been defined in the protocol. After definition of the maximally tolerated dose (MTD) an extension of the cohort at that dose was intended. Results: A total of twenty-two patients were enrolled between January 2009 and March 2011. The median age was 70 years (range 60–78), 13 were female. The type of AML was de novo in 16 pts., s-AMLin one patient and t-AML in 4 pts. Fifteen patients had a FLT3-ITD (68%) and 7 a FLT3-TKD (32%) mutation. A NPM1 mutation was present in 11 patients (50%), 15 patients exhibited a normal karyotype, 3 an intermediate-2 risk karyotype according to ELN guidelines and 2 a complex karyotype and 2 had no evaluable metaphases. In the first cohort 5 patients were treated and two experienced dose-limiting toxicity (DLT), i) prolonged hematological recovery beyond day 35 in a patient achieving a CR and ii) a hand-foot-syndrome grade III. Four of the 5 patients achieved a CR. According to the protocol the following patients received treatment at dose level −1 with sunitinib 25mg days 1 to 7. In this cohort only one DLT occurred, again prolonged hematological recovery. Thus the MTD was defined at dose level −1. Response to induction therapy in all patients was CR in 13 pts. (59%), partial remission in 1 pt. (4.5%), refractory disease in 5 pts. (23%), death in 3 pts. (13.5%). CR rate in AML with FLT3-ITD was 53% (8/15) and 71% (5/7) in those with FLT3-TKD. All 13 patients achieving CR received repetitive cycles of high-dose cytarabine consolidation therapy and 7 proceeded to single agent sunitinib maintenance therapy (median 11 months, range 1–24 months). In these patients relapse occurred in 10, one patient died due to severe colitis during consolidation therapy and two patients are in sustained CR. Two patients not achieving a CR after induction therapy underwent allogeneic stem cell transplantation form matched unrelated donors. Twelve of the 22 patients died leading to a median survival of 18.8 months and a 2 year survival of 36% (95%-CI, 19–70%). Median relapse-free survival was 11 months. Conclusion: Combination of intensive induction and consolidation therapy with oral sunitinib in AML with activating FLT3 mutations is feasible with 25 mg sunitinib given during intensive therapy on days 1 to 7 and continuously during maintenance. Disclosures: Fiedler: Novartis: Consultancy, Research Funding; Pfizer Inc.: Consultancy, Research Funding.


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