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S1. Schematic diagram of NSD2 isoform indicating domains, the location of amino acid E1099 within the SET domain, and the targets of the shRNAs. S2. NSD2 Overexpression in B-ALL Cell Lines Does Not Impart Clonal Advantage. S3. Overexpression of REIIBP in B-ALL Cell Lines Does Not Impart Clonal Advantage. S4. Knockdown of WT NSD2 in B-ALL Cell Lines Does Not Lead to Phenotypic Differences. S5. Knockdown of NSD2 in RS4;11 and RCH-ACV lines leads to increased chemosensitivity. S6. Sensitivity to 6-MP Upon Knockdown of NSD2 in RS4;11 is Not Depedent of Level of Knockdown. S7. Knockdown of NSD2 in WT B-ALL Cell Lines Does Not Lead to Increased Sensitivity. S8. NSD2 WT and EK Overexpression in B-ALL Cell Lines Leads to Distinct Genetic Signature Unique to Each Cell Line. S9. NSD2 WT and EK Overexpression in B-ALL Cell Lines Leads to Distinct Epigenetic Signature Resulting in Gene Expression Changes. S10. NSD2 Knockdown in Mutant B-ALL Cell Lines Leads to Distinct Genetic Signature Unique to Each Cell Line. S11. ATAC peaks significantly correlate with gene expression for RS4;11 and RCH-ACV cell lines.

Cell line IC50 values

Supplementary materials and methods and supplementary figure legends.

A recent survey of pediatric hematology oncology (PHO) physicians identified that a majority believe fellows are struggling to find jobs that align with their goals. Career development for trainees has historically been home institution-specific, limiting fellows' exposures to career path possibilities. The "virtual-Symposium of Pediatric Hematology/Oncology of New York (v-SYMPHONY)" instituted a tristate Career Development Series for PHO trainees to better address their needs and increase awareness of the variety of PHO career opportunities.The v-SYMPHONY Career Development Series incorporated three sessions: (a) institutional perspective, (b) individual perspectives, and (c) nuts and bolts of job search. Pre- and post-series surveys were administered to participants to measure impact.Forty-one fellows registered for the series and completed a pre-survey. Over half (54%) were in their third or later year of fellowship. Careers with a clinical focus were the most commonly desired career path (59%). Most had received career development advice only from faculty within their institutions (90%). Post-surveys were completed by 11 PHO fellows. Overall, 100% of respondents reported benefiting from the career sessions and recommended the series should be repeated annually. Over 90% learned new information to prepare for the job search.The v-SYMPHONY Career Development Series for PHO fellows across multiple institutions was established and was extremely well received by its participants. PHO fellows agreed that these sessions were beneficial in helping prepare them for the job search process. An annual regional Career Development Series is feasible and is strongly suggested to support PHO fellows.

Background Pegaspargase (PEG‐ASP) is an integral component of therapy for acute lymphoblastic leukemia (ALL) but is associated with hepatotoxicity that may delay or limit future therapy. Obese and adolescent and young adult (AYA) patients are at high risk. Levocarnitine has been described as potentially beneficial for the treatment or prevention of PEG‐ASP‐associated hepatotoxicity. Methods We collected data for patients age ≥10 years who received levocarnitine during induction therapy for ALL, compared to a similar patient cohort who did not receive levocarnitine. The primary endpoint was conjugated bilirubin (c.bili) >3 mg/dl. Secondary endpoints were transaminases >10× the upper limit of normal and any Grade ≥3 hepatotoxicity. Results Fifty‐two patients received levocarnitine for prophylaxis (n = 29) or rescue (n = 32) of hepatotoxicity. Compared to 109 patients without levocarnitine, more patients receiving levocarnitine were obese and/or older and had significantly higher values for some hepatotoxicity markers at diagnosis and after PEG‐ASP. Levocarnitine regimens varied widely; no adverse effects of levocarnitine were identified. Obesity and AYA status were associated with an increased risk of conjugated hyperbilirubinemia and severe transaminitis. Multivariable analysis identified a protective effect of levocarnitine on the development of c.bili >3 mg/dl (OR 0.12, p = 0.029). There was no difference between groups in CTCAE Grade ≥3 hepatotoxicity. C.bili >3 mg/dl during induction was associated with lower event‐free survival. Conclusions This real‐world data on levocarnitine supplementation during ALL induction highlights the risk of PEG‐ASP‐associated hepatotoxicity in obese and AYA patients, and hepatotoxicity's potential impact on survival. Levocarnitine supplementation may be protective, but prospective studies are needed to confirm these findings., Patients who are adolescents or young adults and/or who are obese are at higher risk for pegaspargase‐induced hepatotoxicity. Levocarnitine supplementation may reduce the risk for hepatoxicity during induction therapy for acute lymphoblastic leukemia.

Leukemia, most commonly B-cell acute lymphoblastic leukemia (B-ALL), accounts for about 30% of childhood cancer diagnoses. While there have been dramatic improvements in childhood ALL outcomes, certain subgroups-particularly those who relapse-fare poorly. In addition, cure is associated with significant short- and long-term side effects. Given these challenges, there is great interest in novel, targeted approaches to therapy. A number of new immunotherapeutic agents have proven to be efficacious in relapsed or refractory disease and are now being investigated in frontline treatment regimens. Blinatumomab (a bispecific T-cell engager that targets cluster of differentiation [CD]-19) and inotuzumab ozogamicin (a humanized antibody-drug conjugate to CD22) have shown the most promise. Chimeric antigen receptor T (CAR-T) cells, a form of adoptive immunotherapy, rely on the transfer of genetically modified effector T cells that have the potential to persist in vivo for years, providing ongoing long-term disease control. In this article, we discuss the clinical biology and treatment of B-ALL with an emphasis on the role of immunotherapy in overcoming the challenges of conventional cytotoxic therapy. As immunotherapy continues to move into the frontline of pediatric B-ALL therapy, we also discuss strategies to address unique side effects associated with these agents and efforts to overcome mechanisms of resistance to immunotherapy.

The NSD2 p.E1099K (EK) mutation has been shown to be enriched in patients with relapsed ALL and found to play a role in clonal fitness dependent on the underlying genetic/epigenetic landscape of the cells. To uncover 3D chromatin architecture-related mechanisms underlying drug resistance, we systematically integrated Hi-C, ATAC-seq, RNA-seq and ChIP-seq data from three B-ALL cell lines heterozygous for NSD2 EK (RS4;11, RCH-ACV, SEM) and assessed changes upon knockdown. NSD2 knockdown revealed widespread remodeling of the 3D genome, specifically in terms of compartmentalization. Systematic integration of these datasets revealed significant switches in A/B compartments with a strong bias towards B compartments upon knockdown, suggesting that NSD2 EK plays a prominent role in maintaining A compartments through enrichment of H3K36me2 epigenetic marks. In contrast, we identified few changes in intra-TAD activity suggesting that the NSD2 EK impacts transcriptional changes through a remarkable dependence on compartmentalization. Furthermore, EK-mediated reorganization of compartments highlights the existence of a common core of compacting loci shared across the three cell lines that explain previously described phenotypes as well as serve as targets for therapeutic intervention. This study offers a novel mechanism by which NSD2 EK drives clonal evolution and drug resistance.

Favorable histology (FH) Wilms tumor (WT) is one of the most curable of all human cancers, yet a small minority of patients fail treatment. The underlying biological pathways that lead to therapy resistance are unknown. We report a case of initially unresectable, FH WT which revealed limited necrosis and persistent blastemal predominant histology following neoadjuvant chemotherapy. Despite intensification of therapy and whole abdominal radiation, the patient relapsed and succumbed to her disease. In an effort to discover candidate drivers of drug resistance, whole exome sequencing and copy number analysis were performed on samples from all 3 tumor specimens. Sequencing results revealed outgrowth of clones with a dramatically different genetic landscape including dominant mutations that could explain therapy evasion, some of which have not been previously reported in WT. Our results implicate PPM1D, previously shown to be associated with drug resistance in other tumors, as the major driver of treatment failure.

COVID‐19 has upended medical practice and education, but has also catalyzed enhancements in the field. Early on, a local group of researchers united to investigate the impact of the pandemic on pediatric hematology oncology (PHO). From this group, a regional educational series was established, “virtual‐Symposium of Pediatric Hematology/Oncology of New York” (v‐SYMPHONY). The implementation of these endeavors while PHO fellowship applications are declining has highlighted our perceptions that education, mentoring, and career expectations are not keeping up with the needs of current trainees. We describe our regional experience joining together to further education and research, and reflect on the current landscape of PHO training and workforce.

Purpose Pediatric oncology patients undergoing active chemotherapy are suspected to be at a high risk for severe disease secondary to severe acute respiratory syndrome coronavirus‐2 (SARS‐CoV‐2) infection; however, data to support this are lacking. We aim to describe the characteristics of coronavirus disease 2019 (COVID‐19) in this population and also its impact on pediatric cancer care in the New York region during the peak of the pandemic. Patients and Methods This multicenter, retrospective study included 13 institutions. Clinical and laboratory information on 98 patients ≤21 years of age receiving active anticancer therapy, who tested positive for SARS‐CoV‐2 by nasopharyngeal swab polymerase chain reaction (PCR), was collected. Results Of the 578 pediatric oncology patients tested for COVID‐19, 98 were positive, of whom 73 were symptomatic. Most experienced mild disease, 28 required inpatient management, 25 needed oxygen support, and seven required mechanical ventilation. There is a slightly higher risk of severe disease in males and obese patients, though not statistically significant. Persistent lymphopenia was noted in severe cases. Delays in cancer therapy occurred in 67% of SARS‐CoV‐2‐positive patients. Of four deaths, none were solely attributable to COVID‐19. The impact of the pandemic on pediatric oncology care was significant, with 54% of institutions reporting delays in chemotherapy, 46% delays in surgery, and 30% delays in transplant. Conclusion In this large multi‐institutional cohort, we observed that mortality and morbidity from COVID‐19 amongst pediatric oncology patients were low overall, but higher than reported in general pediatrics. Certain subgroups might be at higher risk of severe disease. Delays in cancer care due to SARS‐CoV‐2 remain a concern.

The NSD2 p.E1099K (EK) mutation is observed in 10% of acute lymphoblastic leukemia (ALL) samples with enrichment at relapse indicating a role in clonal evolution and drug resistance. To discover mechanisms that mediate clonal expansion, we engineered B-precursor ALL (B-ALL) cell lines (Reh, 697) to overexpress wildtype (WT) and EK NSD2, but observed no differences in proliferation, clonal growth, or chemosensitivity. To address whether NSD2 EK acts collaboratively with other pathways, we used short hairpin RNAs to knockdown expression of NSD2 in B-ALL cell lines heterozygous for NSD2 EK (RS4;11, RCH-ACV, SEM). Knockdown resulted in decreased proliferation in all lines, decreased clonal growth in RCH-ACV, and increased sensitivity to cytotoxic chemotherapeutic agents, although the pattern of drug sensitivity varied among cell lines implying that the oncogenic properties of NSD2 mutations are likely cell context specific and rely on cooperative pathways. Knockdown of both Type II and REIIBP EK isoforms had a greater impact than knockdown of Type II alone, suggesting that both SET containing EK isoforms contribute to phenotypic changes driving relapse. Furthermore, in vivo models using both cell lines and patient samples revealed dramatically enhanced proliferation of NSD2 EK compared with WT and reduced sensitivity to 6-mercaptopurine in the relapse sample relative to diagnosis. Finally, EK-mediated changes in chromatin state and transcriptional output differed dramatically among cell lines further supporting a cell context–specific role of NSD2 EK. These results demonstrate a unique role of NSD2 EK in mediating clonal fitness through pleiotropic mechanisms dependent on the genetic and epigenetic landscape. Implications: NSD2 EK mutation leads to drug resistance and a clonal advantage in childhood B-ALL.

Introduction: Although overall survival rates for children with acute lymphoblastic leukemia (ALL) are excellent, the prognosis for certain patients remains suboptimal. Risk-stratification has impr...

Ewing sarcoma (EWS) is a primitive neuroectodermal tumor arising in bone or soft tissue. It is the second most common primary bone malignancy of children and adolescents, with a peak incidence in the second decade of life. It most often arises in the long bones of the extremities and pelvis. Here, we present a novel case of EWS arising from the mastoid bone in a 5-year-old African American male who presented with symptoms of acute mastoiditis. This unique presentation highlights the importance of considering EWS in a patient who presents with atypical mastoiditis or a rapidly growing mass in the postauricular region.

The improvement in outcomes for children with acute lymphoblastic leukemia (ALL) is one of the greatest success stories of modern oncology however the prognosis for patients who relapse remains dismal. Recent discoveries by high resolution genomic technologies have characterized the biology of relapsed leukemia, most notably pathways leading to the drug resistant phenotype. These observations open the possibility of targeting such pathways to prevent and/or treat relapse. Likewise, early experiences with new immunotherapeutic approaches have shown great promise. Areas covered: We performed a literature search on PubMed and recent meeting abstracts using the keywords below. We focused on the biology and clonal evolution of relapsed disease highlighting potential new targets of therapy. We further summarized the results of early trials of the three most prominent immunotherapy agents currently under investigation. Expert commentary: Discovery of targetable pathways that lead to drug resistance and recent breakthroughs in immunotherapy show great promise towards treating this aggressive disease. The best way to treat relapse, however, is to prevent it which makes incorporation of these new approaches into frontline therapy the best approach. Challenges remain to balance efficacy with toxicity and to prevent the emergence of resistant subclones which is why combining these newer agents with conventional chemotherapy will likely become standard of care.

Introduction: Outcomes for children with relapsed acute lymphoblastic leukemia (ALL) remain poor. Mutations in epigenetic modifiers are commonly found at relapse, including the activating p.E1099K (EK) mutation within the conserved SET domain of NSD2, which has been reported in 10% of patients at relapse. NSD2 has 3 isoforms, two of which (Types II and REIIBP) contain the SET domain. Our aim was to determine the role of NSD2 in driving relapse and further elucidate the prevalence of NSD2 EK in patient samples. Methods: Whole genome/exome sequencing was performed on diagnosis/relapse ALL pairs and data were aggregated for somatic SNVs/indels. NSD2 EK positive cases at relapse were subject to ultra-deep targeted re-sequencing to determine the presence of small subclones at diagnosis. To investigate the role of NSD2 and its isoforms in mediating relapse, short hairpin RNAs (shRNAs) were used to knockdown (KD) NSD2 in three NSD2 EK mutant cell lines with non-targeting (NT) shRNA used as controls. Cells were treated with chemotherapy commonly used in pediatric ALL and assessed for cytotoxicity by CellTiter- Glo®. To determine NSD2's impact on gene expression and the epigenetic landscape, RNAseq, ChIPseq, ATACseq, and Hi-C were performed using standard techniques. Results: Examination of paired ALL patient samples revealed enrichment of NSD2 EK clones at relapse. B-ALL cell lines heterozygous for NSD2 EK (RS4;11, RCH-ACV, SEM) revealed that KD led to decreased proliferation in all lines and decreased clonal growth in RCH-ACV relative to NT. Furthermore, increased sensitivity to various chemotherapeutic agents was observed in the KD lines compared to NT controls, but the pattern of drug sensitivity varied among lines implying cell context specific drug responses. Simultaneous knockdown of Type II and REIIBP had a greater impact than Type II alone, indicating both SET containing EK isoforms contribute to phenotypic changes. When comparing gene expression changes in NT vs KD, minimal overlap in differential genes was noted among the three cell lines (4.4% upregulated, 1.7% downregulated) indicating significant diversity in transcriptional reprogramming. ATACseq of the NT and KD for all three lines revealed intergenic regions as the most affected by NSD2 with RCH-ACV and RS4;11 NT lines having more open chromatin compared to their KD whereas SEM NT displayed marked peak loss compared to its KD. Less than 2% of differential intergenic regions were shared among the lines. Hi-C analysis demonstrated disparity in chromosome architecture among NSD2 EK lines as well. Shifts in intergenic regions was further supported by ChIPseq, which revealed increased H3K36me2 across intergenic regions in RS4;11 NT compared to KD. Lastly, we noted a strong correlation of increased gene expression with increased H3K36me2, H3K9ac, and H3K27ac at promoters and gene bodies. Conclusions: NSD2 EK plays a unique role in mediating clonal fitness through pleiotropic mechanisms that are dependent on the underlying cellular context. Citation Format: Joanna Pierro, Jason Saliba, Sonali Narang, Gunjan Sethia, Shella Saint Fleur-Lominy, Ashfiyah Chowdhury, Takaya Moriyama, Kjeld Schmiegelow, Jun J. Yang, Mignon L. Loh, Patrick A. Brown, Jinghui Zhang, Xiaotu Ma, Aristotelis Tsirigos, Nikki A. Evensen, William L. Carroll. The NSD2 p.E1099K mutation is enriched at relapse and confers drug resistance in a cell context dependent manner in pediatric acute lymphoblastic leukemia [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr 5399.

Summary A subset of B cell acute lymphoblastic leukemia (B-ALL) patients will relapse and succumb to therapy-resistant disease. The bone marrow microenvironment may support B-ALL progression and treatment evasion. Utilizing single-cell approaches, we demonstrate B-ALL bone marrow immune microenvironment remodeling upon disease initiation and subsequent re-emergence during conventional chemotherapy. We uncover a role for non-classical monocytes in B-ALL survival, and demonstrate monocyte abundance at B-ALL diagnosis is predictive of pediatric and adult B-ALL patient survival. We show that human B-ALL blasts alter a vascularized microenvironment promoting monocytic differentiation, while depleting leukemia-associated monocytes in B-ALL animal models prolongs disease remission in vivo. Our profiling of the B-ALL immune microenvironment identifies extrinsic regulators of B-ALL survival supporting new immune-based therapeutic approaches for high-risk B-ALL treatment.

Introduction: While the outcome for children with acute lymphoblastic leukemia (ALL) has improved dramatically, the prognosis for those who relapse remains poor. One of the most common alterations found at relapse is the p.E1099K missense change within the SET domain of NSD2, a histone methyltransferase that di-methylates histone 3 lysine 36 (H3K36). NSD2 has 3 isoforms, two of which, Type II (canonical) and REIIBP (C-terminal), contain the SET domain, and another, Type I (N-terminal), that does not. The p.E1099K mutation leads to increased enzymatic activity, but pathways leading to a clonal advantage are unknown in ALL. Methods: We used short hairpin RNAs (shRNAs) to target knockdown of two combinations of NSD2 isoforms: shI/II targets Types I and II, shII/RE targets Type II and REIIBP. Three different B-cell lines (Reh, 697, and KOPN-8) with 2 wildtype (WT) copies of NSD2 were stably transduced with shII/RE. Two B-Cell lines, RS4;11 and RCH-ACV, heterozygous for the NSD2 p.E1099K mutation, were transduced with shI/II and shII/RE. As a control, each B-cell line was stably transduced with a scrambled non-targeting (NT) shRNA. NSD2 knockdown was confirmed by Western Blots. Cell lines were treated for 5 days with chemotherapy agents commonly used in pediatric ALL treatments (mercaptopurine (MP), cytarabine, methotrexate, prednisone, and doxorubicin). Cytotoxicity was assessed by CellTiter- Glo® and significance between IC50s was determined by ANOVA and post hoc Tukey test. Cell proliferation was measured by cell counting with trypan blue. Cell cycle progression in RS4;11 lines was monitored with Edu staining and flow cytometry with and without exposure to MP. Results: Similar to previously reported results, knockdown of NSD2 in the 3 WT B-cell lines had no effect on cell proliferation. However, shI/II reduced growth by 40% in RS4;11 and 20% in RCH-ACV, while shII/RE decreased proliferation by 45% in RS4;11 and 55% in RCH-ACV when compared to their NT control. In RS4;11, both shI/II and shII/RE led to a similar 10% decrease in cells progressing through S phase compared to NT, which could be due to either a slower progression through cell cycle or less cells entering the cell cycle. Knockdown of NSD2 resulted in sensitivity to 6MP compared to NT in both RS4;11 and RCH-ACV lines. RS4;11 shII/RE had an IC50 3.2-fold more sensitive ( p During a 120 hour exposure to MP, 34% more RS4;11 shII/RE cells were arrested in the G phase than NT controls, while 26% more RS4;11 shI/II cells were arrested in G phase relative to NT controls. This result indicates MP exposure leads to a reduced percentage of knockdown cells able to progress through the cell cycle. Overall, simultaneously reduced expression of Type II and REIIBP had a greater effect of on cell proliferation and MP response compared to the co-reduction of Types I and II NSD2 in the p.E1099K heterozygous cell lines. Conclusion: The p.E1099K mutation confers a growth advantage and resistance to MP, a cornerstone of ALL therapy. Concurrent reduction of Type II and REIIBP expression by shII/RE resulted in the largest impact on proliferation and MP sensitivity. Both of these isoforms include the SET domain containing the p.E1099K mutation, which indicates one or both isoforms could be responsible for changes in the chromatin state and other possible alterations that lead to a clonal advantage. Based on our findings, determining the mechanism of resistance to MP imparted by NSD2 p.E1099K is now a top priority. Disclosures No relevant conflicts of interest to declare.

Background: Outcomes for children with acute lymphoblastic leukemia (ALL) have dramatically improved, but survival for patients who relapse remains poor. Mutations in genes encoding epigenetic modifiers are present in the majority of patients at relapse. In particular, activating mutations in NSD2 (MMSET, WHSC1), namely the glutamate to lysine substitution at amino acid 1099 (p.E1099K), are among the most common such mutations in epigenetic regulators. NSD2 converts histone 3 lysine 36 (H3K36) into its dimethylated form (H3K36me2) which in turn leads to stereotactic inhibition of EZH2 mediated H3K27me3. We and others have established that this leads to changes in chromatin state and gene expression. However, the pathways by which this leads to a clonal advantage remains elusive. Design/Method: We previously reported that overexpression of wild-type (WT) and p.E1099K mutant (EK) NSD2 in B-ALL cell lines led to unique cell context specific chromatin alterations and altered gene expression but did not lead to changes in proliferation or intrinsic drug resistance in vitro (Pierro et. al. Blood 2017 130:2474). We reasoned that these observations could be explained by the need for cooperating pathways that together with NSD2 EK lead to a clonal advantage. Thus we modulated expression of NSD2 using short hairpin RNAs (shRNAs) in the B-ALL cell line RS4;11 which harbors a heterozygous NSD2 EK mutation (NSD2 low). As a control, RS4;11 was also stably transduced with a non-targeting shRNA sequence (NSD2 high). Knockdown of NSD2 as well as decrease in H3K36me2 in NSD2 low lines was confirmed by Western Blot. Differences in gene regulation in NSD2 low cells were assessed by ChIPseq for CTCF, H3K9Ac, H3K27Ac, H3K36me2 and H3K27me3, and the results were correlated with RNAseq data. This data was then compared to RNAseq and ChIPseq data from REH and 697 NSD2 WT and EK overexpression cell lines in an effort to identify candidate genes or pathways preferentially regulated by the NSD2 EK mutation. Results: NSD2 low cells displayed a distinct gene expression profile compared to NSD2 high with 301 upregulated and 573 downregulated genes (LFC 0.58, P = 0.05). When compared to gene expression data from our previously reported NSD2 overexpression cell lines, there was minimal overlap across cell lines with only 15 differentially expressed genes shared between RS4;11 NSD2 knockdown and REH EK overexpression cell lines and only 24 genes shared between RS4;11 NSD2 knockdown and 697 EK overexpression cell lines. Across all cell lines (RS4;11, REH and 697), only three genes (NSD2, SCN8 and PCNXL2) overlapped, all of which were upregulated in NSD2 high cell lines. Using less stringent criteria (LFC 0.26, P = 0.1), we observed greater overlap with 34 shared up and downregulated genes among lines. Of the shared genes, only ZNF521 which is overexpressed in NSD2 high cell lines, is known play a role in leukemogenesis. Moreover, RS4;11 pathway analysis revealed several biologically relevant pathways modulated by the NSD2 EK mutation such as Ras, integrin signaling, cholesterol/steroid biosynthesis, apoptosis and cell proliferation. Significant differences were also observed across epigenetic marks between RS 4;11 NSD2 high and low cells. In accordance with previously published data, we observed a global decrease in the H3K36me2 mark in RS4;11 NSD2 low lines. When aligned with changes in histone marks, among genes downregulated in NSD2 low cells there was a clear correlation with acquisition of the repressive H3K27me3 mark (and a decrease in the H3K9Ac mark). However among genes upregulated in NSD2 low cells we saw paradoxical increases in the H3K36me2 mark and decreases in the H3K27me3. Furthermore, gene expression was also influenced by marks not directly regulated by NSD2, namely H3K27ac and H3K9ac, indicating that local NSD2 mediated epigenetic changes are not the sole regulator of gene expression. Conclusion: The activating p.E1099K substitution in NSD2 leads to a distinct gene expression profile in B-ALL cell lines that is cell context dependent. Moreover, while there is significant overlap in the transcriptional profile between WT and EK overexpression, there are distinct differences possibly indicating novel properties of the pE1099K substitution beyond enzyme hyperactivation. Our findings also imply that NSD2 EK collaborates with other leukemia associated alterations that result in clonal selection. Disclosures No relevant conflicts of interest to declare.

Objective To compare the effectiveness of antiepileptic drugs (AEDs) for use in older adults with epilepsy. Design Retrospective review. Setting Columbia Comprehensive Epilepsy Center, New York, New York. Patients Four hundred seventeen outpatients 55 years and older newly taking any of the 10 most commonly prescribed AEDs between 2000 and 2005. Main Outcome Measure The percentage of patients who remained taking the AED for 12 or more months (12-month “retention”). We also measured efficacy (12-month seizure freedom) and adverse effects leading to dose change. Retention and seizure-freedom rates were analyzed by pairwise comparisons using χ 2 for the overall group and patients with refractory and nonrefractory disease as well as patients newly taking their first AED. Results The 10 AEDs newly taken by 10 or more patients were analyzed. There were no significant non-AED predictors of retention. Without controlling for severity, lamotrigine had the highest 12-month retention rate (79%), significantly higher than carbamazepine (48%), gabapentin (59%), oxcarbazepine (24%), phenytoin (59%), and topiramate (56%). The retention rate for levetiracetam (73%) was second highest and significantly higher than carbamazepine and oxcarbazepine. Oxcarbazepine had the lowest retention rate, significantly lower than all other AEDs. Lamotrigine had the highest 12-month seizure-freedom rate (54%), followed by levetiracetam (43%). When stratified into patients with nonrefractory and refractory disease, relative rates of seizure freedom and retention remained comparable with the overall group. Imbalance, drowsiness, and gastrointestinal symptoms were the most common intolerable adverse effects. Conclusion In this study of older adults with epilepsy, lamotrigine was the most effective AED as measured by 12-month retention and seizure freedom, with levetiracetam a close second. Oxcarbazepine was consistently less effective than most other AEDs.

Subjective cognitive side effects (CSEs) are common in patients taking antiepileptic drugs (AEDs). The objective of this study was to predict which patients are at risk for CSEs, and compare the CSE profiles of all commonly used AEDs. In this nonrandomized retrospective study, medical records of 1694 adult outpatients with epilepsy seen at our center over a 5-year period who had taken one or more AEDs were examined. Non-AED predictors of CSEs were investigated, and rates of AED-related CSEs were compared in 1189 patients (546 on monotherapy) newly started on an AED at our center. The average rate of AED-related intolerable CSEs (leading to dosage change or discontinuation) was 12.8%. On multivariate analysis, no significant non-AED predictors of CSEs were found. Significantly more intolerable CSEs were attributed to topiramate (21.5% of 130 patients) than to most other AEDs, including carbamazepine (9.9%), gabapentin (7.3%), levetiracetam (10.4%), lamotrigine (8.9%), oxcarbazepine (11.6%), and valproate (8.3%). CSE rates with zonisamide (14.9%) were significantly higher than those for gabapentin and lamotrigine. After exclusion of CSEs during the first 8 weeks of therapy, rates of CSEs were lower, but relative differences remained unchanged. In monotherapy, significantly more intolerable CSEs occurred with topiramate (11.1% of 18 patients) than with carbamazepine or valproate, and both phenytoin and zonisamide were associated with more CSEs than valproate. From this study, it can be concluded that intolerable patient-reported CSEs are most common with topiramate, followed by zonisamide, phenytoin, and oxcarbazepine. They are least likely to be reported with gabapentin, valproate, lamotrigine, carbamazepine, and levetiracetam.