INSPIRED Symposium Part 3: Prevention and Management of Pediatric Chimeric Antigen Receptor T Cell-Associated Emergent Toxicities

Chimeric antigen receptor (CAR) T cell (CAR-T) therapy has emerged as a revolutionary cancer treatment modality, particularly in children and young adults with B cell malignancies. Through clinical trials and real-world experience, much has been learned about the unique toxicity profile of CAR-T therapy. The past decade brought advances in identifying risk factors for severe inflammatory toxicities, investigating preventive measures to mitigate these toxicities, and exploring novel strategies to manage refractory and newly described toxicities, infectious risks, and delayed effects, such as cytopenias. Although much progress has been made, areas needing further improvements remain. Limited guidance exists regarding initial administration of tocilizumab with or without steroids and the management of inflammatory toxicities refractory to these treatments. There has not been widespread adoption of preventive strategies to mitigate inflammation in patients at high risk of severe toxicities, particularly children. Additionally, the majority of research related to CAR-T toxicity prevention and management has focused on adult populations, with only a few pediatric-specific studies published to date. Given that children and young adults undergoing CAR-T therapy represent a unique population with different underlying disease processes, physiology, and tolerance of toxicities than adults, it is important that studies be conducted to evaluate acute, delayed, and long-term toxicities following CAR-T therapy in this younger age group. In this pediatric-focused review, we summarize key findings on CAR-T therapy-related toxicities over the past decade, highlight emergent CAR-T toxicities, and identify areas of greatest need for ongoing research.

Non-oral manifestations in adults with a clinical and molecularly confirmed diagnosis of periodontal Ehlers-Danlos syndrome

Introduction: Periodontal Ehlers-Danlos Syndrome (pEDS) is a rare autosomal dominant type of EDS characterised by severe early-onset periodontitis, lack of attached gingiva, pretibial plaques, joint hypermobility and skin hyperextensibility as per the 2017 International EDS Classification. In 2016, deleterious pathogenic heterozygous variants were identified in C1R and C1S, which encode components of the complement system. Materials and Methods: Individuals with a clinical suspicion of pEDS were clinically and molecularly assessed through the National EDS Service in London and Sheffield and in genetic services in Austria, Sweden and Australia. Transmission electron microscopy and fibroblast studies were performed in a small subset of patients. Results: A total of 21 adults from 12 families were clinically and molecularly diagnosed with pEDS, with C1R variants in all families. The age at molecular diagnosis ranged from 21-73 years (mean 45 years), male: female ratio 5:16. Features of easy bruising (90%), pretibial plaques (81%), skin fragility (71%), joint hypermobility (24%) and vocal changes (38%) were identified as well as leukodystrophy in 89% of those imaged. Discussion: This cohort highlights the clinical features of pEDS in adults and contributes several important additional clinical features as well as novel deleterious variants to current knowledge. Hypothetical pathogenic mechanisms which may help to progress understanding and management of pEDS are also discussed.

Abstract 4096: Assessing individual variability in efficacy and toxicity of autologous and allogeneic chimeric antigen receptor T-cell immunotherapy using a PBMC-humanized mouse model

Chimeric antigen receptor T-cell (CAR-T) therapy has emerged as a revolutionary therapeutic to fight cancer. However, side effects such as cytokine-release syndrome and neurotoxicity often accompany and remain unpredictable. While autologous CAR-Ts are FDA-approved, allogeneic CAR-Ts are in active development in pursuit of “off-the-shelf” availability and reduced manufacturing costs. However, the same concern for adverse events applies. Importantly, how the immune characteristics of the patient may predispose towards toxicity is not well modeled. Further, it is unclear how autologous versus allogeneic products interact with the patient immune system. Toxicity does not correlate with in vitro characterization of the CAR-Ts, adding unpredictability to the toxicity and efficacy. These highlight the need for in vivo mouse models to explore biological variation, predictive biomarkers, and therapeutic intervention. Therefore, we developed a humanized mouse model using NSG™-MHC Class I/II double knock-out (DKO) mice engrafted with human PBMCs to access individual variability in CAR-T-induced toxicity and efficacy. DKO mice are optimal for assessing human cytokine induction from CAR-Ts as they show delayed onset of GvHD and low baseline cytokine levels. To test donor variation in autologous CAR-T toxicity, we humanized mice and treated with autologous CD19 CAR-Ts containing the CD28 costimulatory domain and CD3z chain from two human PBMC donors (Donor A and B). CAR-T successfully eliminated human B cells from both PBMC donors in vivo. We observed drastic body weight loss and 83% of Donor A mice (engrafted with 17M PBMCs) reached the humane endpoint. In contrast, Donor B mice did not experience body weight loss. CAR-T induced human cytokines such as IFN-ꝩ, IL-2, IL-4, IL-6, IL-10, TNFα, MIG, MIP-1a, and IP-10, recapturing clinical data. To test donor variation in allogeneic CAR-T toxicity, we engrafted mice with 10M PBMCs from 6 healthy donors and treated with allogeneic CAR-Ts from Donor A or B. Allogenic efficacy was greater in Donor B CAR- than Donor A CAR-Ts. Donor-specific variability was observed; mice humanized with one of the six donors, experienced significant body weight loss only from the Donor B CAR-Ts but not from Donor A CAR-Ts. Principal component analysis of cytokine data revealed that Donor B CAR-Ts induced more distinguished cytokine responses than Donor A CAR-Ts, driven by IFN-ꝩ and IL-10. Lastly, the data indicates that the CAR-T cells show poor expansion in allogeneic treatment, corresponding to the current literature. PBMC-humanized mice provide an in vivo platform to assess the toxicity and efficacy of autologous and allogeneic CAR-T treatment. This platform can be used to preclinically assess cytokine induction from the interaction between the patient immune system and allogeneic CAR-Ts from healthy donors.

Citation Format: Won Lee, Destanie Rose, Katelyn Burleigh, Blair Armstrong, Heather Gustafson, Rebecca Gardner, James G. Keck, Jiwon Yang. Assessing individual variability in efficacy and toxicity of autologous and allogeneic chimeric antigen receptor T-cell immunotherapy using a PBMC-humanized mouse model. [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 4096.

The development of a mobile app-focused deduplication strategy for the Apple Heart Study that informs recommendations for future digital trials

An app-based clinical trial enrolment process can contribute to duplicated records, carrying data management implications. Our objective was to identify duplicated records in real time in the Apple Heart Study (AHS). We leveraged personal identifiable information (PII) to develop a dissimilarity score (DS) using the Damerau-Levenshtein distance. For computational efficiency, we focused on four types of records at the highest risk of duplication. We used the receiver operating curve (ROC) and resampling methods to derive and validate a decision rule to classify duplicated records. We identified 16,398 (4%) duplicated participants, resulting in 419,297 unique participants out of a total of 438,435 possible. Our decision rule yielded a high positive predictive value (96%) with negligible impact on the trial's original findings. Our findings provide principled solutions for future digital trials. When establishing deduplication procedures for digital trials, we recommend collecting device identifiers in addition to participant identifiers; collecting and ensuring secure access to PII; conducting a pilot study to identify reasons for duplicated records; establishing an initial deduplication algorithm that can be refined; creating a data quality plan that informs refinement; and embedding the initial deduplication algorithm in the enrolment platform to ensure unique enrolment and linkage to previous records.

Search for New Physics in Electronic Recoil Data from XENONnT

We report on a blinded analysis of low-energy electronic recoil data from the first science run of the XENONnT dark matter experiment. Novel subsystems and the increased 5.9 ton liquid xenon target reduced the background in the (1, 30) keV search region to (15.8±1.3)  events/(ton×year×keV), the lowest ever achieved in a dark matter detector and ∼5 times lower than in XENON1T. With an exposure of 1.16 ton-years, we observe no excess above background and set stringent new limits on solar axions, an enhanced neutrino magnetic moment, and bosonic dark matter.

Abstract 2816: A novel in vivo model to simultaneously assess efficacy and toxicity of chimeric antigen receptor T-cell immunotherapy

Over the past few years, chimeric antigen receptor T (CAR T)-cell therapy has emerged as a novel treatment option for certain hematologic malignancies. Several CAR T-cell therapies produced highly efficacious responses from patients with hematologic malignancies. However, wider adoption of CAR T-cell therapy is challenged due to the potential development of life-threatening toxicities including cytokine release syndrome (CRS). CRS symptoms can range from mild fever to life-threatening events, including death. Preclinical animal models to assess the efficacy and toxicity of CAR T-cell therapies have been lacking. Here, we developed a novel mouse model to assess the efficacy and toxicity of CAR T-cell therapy simultaneously. Two different PBMC humanized NSG™ variants were used. NSG-MHC Class I/II double knock-out strain is known to have a delayed onset of GvHD, and NSG-SGM3xIL15 strain shows a higher engraftment level of human NK and myeloid cells, in addition to human T cells. Mice were humanized using PBMCs and treated with autologous or allogeneic CAR T cells, and efficacy and toxicity were assessed. Compared to the control treatment, CD19 CAR T-cells caused a decrease in the human CD19+ cell population in the blood and spleen, and induced cytokine release. Both T-cell and myeloid cytokine releases, including IFNgamma, IL-10, RANTES, and MIP-1alpha, were induced in our animal models. The in vivo platform can also be used to determine individual PBMC/CAR T donor differences and show the extent of efficacy and toxicity of each PBMC donor treated with autologous and allogeneic CAR T-cell therapy. We further confirmed anticancer efficacy using luciferase-tagged human B-cell lymphoma Raji tumor cells, which express a high level of CD19. In summary, we have developed a novel in vivo model to test the efficacy and toxicity of both autologous and allogeneic CAR T-cell therapy simultaneously.

Citation Format: Jiwon Yang, Won Lee, Jing Jiao, Danying Cai, Heather Gustafson, Rebecca Gardner, Mingshan Cheng, James G. Keck. A novel in vivo model to simultaneously assess efficacy and toxicity of chimeric antigen receptor T-cell immunotherapy [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 2816.

Abstract 3581: Multi-omic analysis identifies mechanisms of resistance to CD19 CAR T-cell therapy in children with acute lymphoblastic leukemia

Background: Acute lymphoblastic leukemia (ALL) is the most common childhood cancer. Despite the survival rate of 90% for newly diagnosed children with ALL, the outcome for relapsed patients is historically poor with a less than 30% survival. CD19 CAR T-cell therapy (CART19) has shown remarkable response rates, between 80-90% in relapsed/refractory disease. Little is known about antigen-independent factors that predict initial resistance to CART19. We hypothesized that leukemias that are resistant to CART19 are distinct from sensitive leukemias and that these differences can be detected prior to therapy.

Methods: To interrogate differences between resistant and sensitive leukemias, we obtained pre-treatment bone marrow aspirates (BMAs) from patients enrolled in a clinical trial at Seattle Children’s Hospital (PLAT-02). Samples were categorized based on patient response, with non-response defined as not achieving and maintaining minimal residual disease negativity at Day +63. Our study included 7 resistant and 7 sensitive leukemias as controls. We performed whole exome sequencing, bulk RNA-seq, PacBio-seq of the CD19 locus, array-based methylation, ATAC-seq, scRNA-seq, and CyTOF.

Results: We found that non-response to CART19 is independent of leukemic subtype. Despite blasts being CD19+ in all patients by flow cytometry, we identified alternative splicing of CD19 in one non-responder, while the remaining non-responders expressed high levels of wildtype CD19. We discovered a distinctive DNA methylation pattern in the non-responders characterized by hypermethylation of PRC2 targets in embryonic and cancer stem cells (p = 8.15E-25) Furthermore, using gene set enrichment analysis of ATAC-seq data, we found increased accessibility of chromatin at regions associated with stem cell proliferation (NES = 2.31; p < 0.0001) and cell cycling (NES = 2.27; p < 0.0001). We found a greater similarity between accessibility patterns of non-responders to hematopoietic progenitors, including hematopoietic stem cells (p = 0.037) and common myeloid progenitors (p = 0.047). These findings were supported by an increased frequency of cell subpopulations expressing a multi-lineage phenotype (CD19, CD20, CD33, CD34; p = 0.009). Moreover, we find decreased expression of antigen presentation and processing pathways across all leukemic cells relative to responders (p = 0.0001).

Conclusions: This study, one of the most comprehensive multi-omic analyses of samples from patients treated with CAR T-cells, identified resistance mechanisms that can be detected prior to treatment. We report the novel association of a stem cell phenotype, lineage plasticity, and decreased antigen presentation with resistance. These results support further refinement of eligibility for CART19 for children with leukemia and highlights the need for alternative of complimentary approaches for these patients.

Citation Format: Katherine E. Masih, Rebecca Gardner, Hsien-Chao Chou, Abdalla Abdelmaksoud, Young K. Song, Luca Mariani, Vineela Gangalapudi, Berkley E. Gryder, Ashley Wilson, Serifat O. Adebola, Benjamin Z. Stanton, Chaoyu Wang, Xinyu Wen, Gregoire Altan-Bonnet, Michael C. Kelly, Jun S. Wei, Martha L. Bulyk, Michael C. Jensen, Rimas J. Orentas, Javed Khan. Multi-omic analysis identifies mechanisms of resistance to CD19 CAR T-cell therapy in children with acute lymphoblastic leukemia [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 3581.

LTBK-03. Targeted mass spectrometry of serial CSF and serum specimens from children with diffuse intrinsic pontine glioma treated with intracranial B7-H3 CAR T cells

Considering the high expression of B7-H3 (CD276) on diffuse intrinsic pontine glioma (DIPG) and preliminary evidence that repeated locoregional delivery of CAR T cells to patients with CNS tumors was feasible and tolerable, we open the phase 1 trial BrainChild-03 (NCT04185038). Children with DIPG in Dose Regimen 1 received 40 intraventricular B7H3CAR doses, with the two patients enrolling post-progression surviving >400 days from initial CAR T infusion. To evaluate for immune and tumor responses that may correlate with clinical and radiographic evaluations, we performed targeted proteomic analysis on serial CSF and serum biospecimens.

MRM-MS is a targeted mass spectrometry that provides sensitive measurement of proteins in cancer tissues and fluids. In 2 patients with longitudinal biospecimens, we identified 50 CSF and 59 serum proteins above level of detection. In general, there were fewer serum fluctuations compared to the CSF, supporting that intracranial delivery provides local immune activation. Sharp fluctuations of several immunoregulatory peptides were measured in the CSF at pre and post infusion timepoints, including BCL10, CXCL13, TIM-3, ICOSLG, and PD-L2. Notably, several analytes tracked consistently in the CSF of both patients, including markers of macrophage maturation and immune cell recruitment, including CD14, CD163, CD44, CSF-1, CXCL13 and VCAM-1. B7-H3 was detected in the CSF and serum of both patients. S005, who progressed on protocol therapy, had a sharp increase in B7-H3 in the CSF during Course 2, while S008, who had clinical improvement on protocol therapy, had consistently lower B7-H3 present. Notably, serum B7-H3 steadily declined in both patients over time, with the exception of a transient increase in S005 between Courses 4 and 5. Future work for all enrolled patients with DIPG will explore the correlation of these targeted proteomic measurements with clinical end points for potential use as markers of efficacy of therapy or adverse events.

Lessons learned in the Apple Heart Study and implications for the data management of future digital clinical trials

The digital clinical trial is fast emerging as a pragmatic trial that can improve a trial's design including recruitment and retention, data collection and analytics. To that end, digital platforms such as electronic health records or wearable technologies that enable passive data collection can be leveraged, alleviating burden from the participant and study coordinator. However, there are challenges. For example, many of these data sources not originally intended for research may be noisier than traditionally obtained measures. Further, the secure flow of passively collected data and their integration for analysis is non-trivial. The Apple Heart Study was a prospective, single-arm, site-less digital trial designed to evaluate the ability of an app to detect atrial fibrillation. The study was designed with pragmatic features, such as an app for enrollment, a wearable device (the Apple Watch) for data collection, and electronic surveys for participant-reported outcomes that enabled a high volume of patient enrollment and accompanying data. These elements led to challenges including identifying the number of unique participants, maintaining participant-level linkage of multiple complex data streams, and participant adherence and engagement. Novel solutions were derived that inform future designs with an emphasis on data management. We build upon the excellent framework of the Clinical Trials Transformation Initiative to provide a comprehensive set of guidelines for data management of the digital clinical trial that include an increased role of collaborative data scientists in the design and conduct of the modern digital trial.

IMMU-09. Interim analysis from BrainChild-03: Seattle Children’s Locoregional B7-H3 CAR T Cell Trial for Children with Recurrent Central Nervous System Tumors and DIPG

BrainChild-03 is a phase 1 clinical trial delivering repeated locoregional 2nd generation B7-H3 CAR T cells with 4-1BB co-stimulation to children with central nervous system (CNS) tumors without lymphodepleting chemotherapy. The primary endpoints are feasibility and safety, with secondary endpoints of disease response and correlatives of CAR T cell activity. There are 3 arms: (A) – weekly delivery into the tumor cavity, (B) – weekly delivery into the lateral ventricle for metastatic disease, (C) – biweekly delivery into the lateral ventricle for diffuse intrinsic pontine glioma (DIPG). In total, 23/24 (96%) enrolled patients have had successful CAR T manufacturing. 16/24 patients are evaluable and have received a total of 141 intracranial CAR T cell doses. Unevaluable patients include 5 never treated and 3 who progressed prior to receiving the minimum doses to become evaluable. The most common adverse events have been headache (16/16, 100%), nausea/vomiting (12/16, 75%), and fever (10/16, 63%). There has been 1 DLT for an intratumoral hemorrhage and no cytokine release syndrome (CRS). 7 evaluable patients with DIPG (Arm C) have received a cumulative 50 infusions. 5/7 DIPG patients enrolled after progression and have a median survival of 246.5 days post-initial CAR T cell infusion, with 4/5 still alive. The 2 DIPG patients enrolled prior to progression had radiographic improvement, including 1 with improvement of a cranial nerve 6 palsy who self-withdrew from protocol therapy after 18 infusions over 12 months and 1 still on protocol therapy after 11 infusions over 6 months. DIPG patients have had increased CSF levels of proinflammatory mediators (e.g. CXCL10, CCL2, IFNg, GM-CSF, IL-12) without systemic cytokine changes. 5/7 DIPG patients had detectable CAR T cells in their CSF post-infusion. Ultimately, the preliminary experience suggests locoregional delivery of B7-H3 CAR T cells may be feasible and tolerable in children with CNS tumors, including DIPG.

CTIM-27. LOCOREGIONAL B7-H3-SPECIFIC CAR T CELLS FOR CHILDREN AND YOUNG ADULTS WITH DIPG: INTERIM REPORT OF BRAINCHILD-03 ARM C

Following preclinical optimization of B7-H3-specific CAR T cells against pediatric brain tumor models, we opened BrainChild-03 (NCT04185038), a phase 1 clinical trial of repeatedly dosed, outpatient, locoregional B7-H3-specific CAR T cells for children with recurrent/refractory central nervous system (CNS) tumors or diffuse intrinsic pontine glioma (DIPG). Here, we report the interim findings from patients enrolled on Arm C, dedicated to DIPG. The primary endpoints are feasibility and safety, with secondary endpoints of disease response. We utilize second-generation CAR T cells with a 4-1BB costimulatory domain and a methotrexate-resistant human DHFR mutein (huDHFRFS; L22F,F31S), allowing for methotrexate selection. We do not deliver conditioning chemotherapy. The first three evaluable patients with DIPG all met feasibility for generating a balanced CD4:CD8 CAR T cell product, with 3.85x109 CAR T cells generated for S005, 4.29x109 for S008, and 2.45x109 for S012, allowing for greater than 6 months of biweekly dosing for each patient. All subjects were treated at Dose Level 1 (1x107 CAR T cells). S005 received 10 doses before clinical progression greater than 2 years from diagnosis, S008 has received 10 doses and continues on therapy with decreased tumor volume, and S012 has received 5 doses and continues on study with stable disease. There have been no dose limiting toxicities (DLT). 3/3 patients exhibited post infusion fever, headache, and elevated serum CRP but no evidence of cytokine release syndrome (CRS) or systemic CAR T cells. 0/3 patients required PICU admissions. In the cerebrospinal fluid (CSF), 2/3 patients have had elevations of cytokines such as CXCL10 and CCL2, as well as circulating CSF CAR T cells. Advanced serial patient CSF proteomic and transcriptomic profiling are underway. Ultimately, this report provides preliminary evidence that outpatient locoregional B7-H3 CAR T cells for children with DIPG may be feasible and tolerable.

IMMU-11. CLINICAL UPDATES AND CORRELATIVE FINDINGS FROM THE FIRST PATIENT WITH DIPG TREATED WITH INTRACRANIAL CAR T CELLS

We report preliminary data for the first subject with diffuse intrinsic pontine glioma (DIPG) treated with intracranial CAR T cells. BrainChild-03 (NCT04185038) is a phase 1 trial of repetitively-dosed locoregional B7-H3-specific CAR T cells for children with recurrent/refractory central nervous system (CNS) tumors or DIPG. DIPG patients enroll on Arm C, on which B7H3CARs are delivered into the ventricular system via a CNS reservoir catheter. This study does not use lymphodepletion. Primary endpoints are feasibility and safety, with second endpoints of disease response. This 18-year-old female (BrainChild-03 S005) with radiographically-classic DIPG and biopsy-confirmed H3 K27M mutation enrolled on Arm C after progression 552 days from diagnosis following focal radiation and temozolomide, irinotecan, and bevacizumab. Apheresis and manufacturing produced 4.2x10⁹ second-generation B7H3CARs with a methotrexate-resistant human DHFR mutein (huDHFR^FS; L22F,F31S) in a single transcript in combination with the B7-H3-specific CAR and EGFRt, each separated by a T2A linker, allowing methotrexate selection and enrichment. At time of submission, she has received 10 every-other-week outpatient infusions of 1x10⁷ B7H3CARs (first dose on October 2, 2020). She has had no DLTs, but has experienced grade 2 fever and grade 2–3 headache peaking ~12–48 hours after each infusion. Following the 8^th CAR T cell infusion, she experienced increased focal weakness and dysarthria at ~72 hours with resolution after 48 hours. She has not experienced cytokine release syndrome (CRS). She has stable disease 138 days post-initial CAR T cell infusion. Frequently collected correlative studies have detected viable B7H3CARs in the CSF post-infusion via flow cytometry. CSF cytokine analysis has revealed elevations of CXCL10, GM-CSF, and G-CSF following B7H3CAR infusions, without correlation in the serum. A second evaluable subject with DIPG has also received 4 locoregional doses of 1x10⁷ B7H3CARs without a DLT. She also has stable disease and detectable viable B7H3CARs in the CSF.

Increased proportion of physical child abuse injuries at a level I pediatric trauma center during the Covid-19 pandemic

BACKGROUND AND OBJECTIVES

The Covid-19 pandemic has forced mass closures of childcare facilities and schools. While these measures are necessary to slow virus transmission, little is known regarding the secondary health consequences of social distancing. The purpose of this study is to assess the proportion of injuries secondary to physical child abuse (PCA) at a level I pediatric trauma center during the Covid-19 pandemic.

METHODS

A retrospective review of patients at our center was conducted to identify injuries caused by PCA in the month following the statewide closure of childcare facilities in Maryland. The proportion of PCA patients treated during the Covid-19 era were compared to the corresponding period in the preceding two years by Fisher's exact test. Demographics, injury profiles, and outcomes were described for each period.

RESULTS

Eight patients with PCA injuries were treated during the Covid-19 period (13 % of total trauma patients), compared to four in 2019 (4 %, p < 0.05) and three in 2018 (3 %, p < 0.05). The median age of patients in the Covid-19 period was 11.5 months (IQR 6.8-24.5). Most patients were black (75 %) with public health insurance (75 %). All injuries were caused by blunt trauma, resulting in scalp/face contusions (63 %), skull fractures (50 %), intracranial hemorrhage (38 %), and long bone fractures (25 %).

CONCLUSIONS

There was an increase in the proportion of traumatic injuries caused by physical child abuse at our center during the Covid-19 pandemic. Strategies to mitigate this secondary effect of social distancing should be thoughtfully implemented.

Towards Real-World Applications of ServiceX, an Analysis Data Transformation System

One of the biggest challenges in the High-Luminosity LHC (HLLHC) era will be the significantly increased data size to be recorded and analyzed from the collisions at the ATLAS and CMS experiments. ServiceX is a software R&D project in the area of Data Organization, Management and Access of the IRIS-HEP to investigate new computational models for the HLLHC era. ServiceX is an experiment-agnostic service to enable on-demand data delivery specifically tailored for nearly-interactive vectorized analyses. It is capable of retrieving data from grid sites, on-the-fly data transformation, and delivering user-selected data in a variety of different formats. New features will be presented that make the service ready for public use. An ongoing effort to integrate ServiceX with a popular statistical analysis framework in ATLAS will be described with an emphasis of a practical implementation of ServiceX into the physics analysis pipeline.

IMMU-02. CHIMERIC ANTIGEN RECEPTOR (CAR) T CELL NEUROTOXICITY CORRELATES WITH PRETREATMENT AND ACUTE CSF NEUROFILAMENT LIGHT CHAIN (NFL) LEVELS

OBJECTIVE

Immunotherapy for hematologic malignancies with CD19-directed CAR T cells is complicated by neurotoxicity in approximately 40% of patients. We have previously reported evidence of glial injury in pediatric patients with CAR T neurotoxicity by elevated CSF levels of GFAP and S100b. We now hypothesize that NFL is also a useful biomarker of neuronal injury related to abnormal blood-brain-barrier and glial function.

METHODS

We used the Mesoscale Discovery platform to measure CSF and serum NFL levels in a consecutive cohort of 43 pediatric patients with B cell ALL who received CD19-directed CAR T cells. In addition, we will present expansion cohort measurements of NFL and GFAP (N=95).

RESULTS

CSF NFL levels prior to CAR T cell infusion positively correlated with the risk of subsequently developing severe neurotoxicity (no neurotoxicity, median 275pg/mL, mild 378pg/mL, severe 951pg/mL, P=0.0182 for severe vs none, P=0.0458 for severe vs mild). During neurotoxicity, mean CSF NFL levels increased to 1179pg/mL (mild neurotoxicity, P=0.0338) and 1345 pg/mL (severe neurotoxicity, P=0.0148), respectively. In serum, pretreatment NFL levels were highly abnormal in many patients (median 368pg/mL, range 10–56,321pg/mL; healthy control median 4pg/mL, range 1–7.5pg/mL). However, there was no correlation with neurotoxicity, history of CNS radiation, peripheral neuropathy, stem cell transplant, or number of prior chemotherapies. Day 7 serum NFL levels did not change significantly (median 439pg/mL, range 5–17,439pg/mL, P=0.3254).

CONCLUSION

We conclude that CSF NFL is promising biomarker of CAR T neurotoxicity risk and severity. The abnormal baseline serum NFL concentrations remain unexplained and require further study.

CAR T cells for other pediatric non-B-cell hematologic malignancies

As CAR T-cell therapy has advanced in B-cell acute lymphoblastic leukemia, research is now underway to develop similar therapies for other lymphoid and myeloid malignancies for pediatric patients. Barriers, including antigen selection and on-target/off-tumor toxicity, have prevented the rapid development of immune-based therapies for T-lineage and myeloid malignancies. More recently, unique strategies have been developed to overcome these barriers, with several products advancing to clinical trials. For T-lineage diseases, targets have focused on CD5, CD7, and CD38, whereas myeloid disease targets have predominately focused on CD123, CD33, and, more recently, CLL-1. This review provides a comprehensive overview of these targets and approaches to overcoming safety concerns in the development of CAR T-cell therapies for pediatric patients with T-lineage and myeloid malignancies.

A phase I study of panobinostat in children with relapsed and refractory hematologic malignancies

Background: Panobinostat demonstrates activity against pediatric cancers in vitro. A phase I trial in children with refractory hematologic malignancies was conducted. Study design: The trial evaluated two schedules of oral panobinostat using 3 + 3 dose escalations in 28-day cycles. For children with leukemia, panobinostat was given once daily three days a week each week at 24, 30 and 34 mg/m2/day. For children with lymphoma, panobinostat was given once daily three days a week every other week at 16, 20 and 24 mg/m2/day. Cerebrospinal fluid (CSF) from Day 29 of the first cycle, when available, was evaluated for PK. The study was registered on clinicaltrials.gov (NCT01321346) Results: Twenty-two subjects enrolled with leukemia. Five enrolled at dose level 1, 6 at dose level 2, and 11 at dose level 3. There was one dose limiting toxicity (DLT) in the leukemia arm at dose level 3 (Grade 4 hypertriglyceridemia), but no maximum tolerated dose (MTD) was identified. No subjects required removal from protocol therapy for QTc prolongation. PK studies were available in 11 subjects with similar exposure in children as in adults. Four Day 29 CSF specimens were found to have panobinostat levels below the lower limit of quantification. Five subjects with lymphoma were enrolled and received study drug, and 4 were evaluable for DLT. A DLT was reported (Grade 3 enteritis) on the lymphoma arm. Conclusions: Panobinostat was tolerated in heavily pretreated pediatric subjects. Gastrointestinal effects were observed on this study. There were no cardiac findings. There were no responses.

Abstract 2298: Is smoking a risk factor for second primary lung cancer

Background: Lung cancer (LC) survivors in the U.S. are increasing in number, with 5-year survival rates improving by 26% over the past decade. Although LC survivors are at high risk of developing a second primary lung cancer (SPLC), risk factors for SPLC have not been established and the impact of tobacco smoking remains controversial. In this study, we examined risk factors for SPLC among participants in the Multiethnic Cohort (MEC) study, validated our findings with two epidemiologic cohorts–the Prostate, Lung, Colorectal, and Ovarian Cancer Screening Trial (PLCO) and the European Prospective Investigation into Cancer and Nutrition (EPIC)–and evaluated the impact of smoking cessation on SPLC risk.

Methods: We analyzed data from 7,299 initial primary lung cancer (IPLC) cases in MEC who were diagnosed from 1993-2017. Incident IPLC and SPLC were identified via linkage to SEER registries, with SPLC defined by Martini and Melamed criteria. Baseline smoking data were obtained at the time of enrollment (1993-1996) and updated with 10-year follow-up data close to IPLC diagnosis, if available. Fine-Gray regression was used to take into account competing risks and to evaluate the associations between risk factors and SPLC, adjusting for age at IPLC diagnosis and IPLC histology and stage. We conducted validation studies with PLCO (N=3,423 LC patients) and EPIC (N=4,605 LC patients) and evaluated the combined effects of risk factors from all three cohorts using meta-analysis.

Results: Among 7,299 MEC participants with IPLC, 167 (2.3%) developed a SPLC. Fine-Gray regression analyses identified several factors that were significantly associated with SPLC risk (P&lt;0.05), which included smoking pack-years (HR 1.12 per 10 pack-years (PY); P=0.004) and smoking intensity (HR 1.21 per 10 cigarettes per day (CPD); P=0.017). Individuals who met the U.S. Preventative Services Task Force's (USPSTF) screening criteria (i.e., aged 55-80, smoked ≥30 PY, and ≤15 years since smoking cessation) at the time of IPLC had a 68% increase in SPLC risk (HR 1.68; P=0.001). Validation studies with PLCO and EPIC showed consistent results; the combined effects based on meta-analysis showed a HR 1.15 per 10 PY (Pmeta=0.022) for smoking pack-years, HR 1.18 per 10 CPD (Pmeta=6.0x10-4) for smoking intensity, and HR 1.70 (Pmeta = 1.9x10-5) for meeting the USPSTF criteria. Subset analysis of MEC participants (N=156) who were current smokers at baseline, had 10-year follow-up smoking data, and were diagnosed with IPLC between baseline and 10-year follow-up showed that smoking cessation was associated with a reduced risk of SPLC (HR=0.25; P=0.005).

Conclusions: Smoking is a risk factor for SPLC among LC patients and the USPSTF criteria can potentially aid in identifying those at high risk of SPLC. Smoking cessation may reduce SPLC risk after IPLC diagnosis. Further analysis is required to stratify SPLC risk based on comprehensive risk factors and identify LC survivors at high risk of SPLC for CT screening.

Citation Format: Jacqueline V. Aredo, Sophia J. Luo, Rebecca Gardner, Thomas P. Hickey, Thomas L. Riley, Lynne R. Wilkens, Loic Le Marchand, Christopher I. Amos, Rayjean J. Hung, Mattias Johansson, Iona Cheng, Heather A. Wakelee, Summer S. Han. Is smoking a risk factor for second primary lung cancer [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 2298.

Pediatric Aggressive Mature B-Cell Lymphomas, Version 2.2020, NCCN Clinical Practice Guidelines in Oncology

Pediatric aggressive mature B-cell lymphomas are the most common types of non-Hodgkin lymphoma in children, and they include Burkitt lymphoma (BL) and diffuse large B-cell lymphoma (DLBCL). These diseases are highly aggressive but curable, the treatment is complex, and patients may have many complicated supportive care issues. The NCCN Guidelines for Pediatric Aggressive Mature B-Cell Lymphomas provide guidance regarding pathology and diagnosis, staging, initial treatment, disease reassessment, surveillance, therapy for relapsed/refractory disease, and supportive care for clinicians who treat sporadic pediatric BL and DLBCL.

Abstract A11: A comprehensive and integrative omic analysis of multiply relapsed refractory pediatric pre-B cell acute lymphoblastic leukemia predicts response to CD19 CAR T-cell therapy

Acute lymphoblastic leukemia (ALL) is the most common childhood cancer with a peak incidence at 3-5 years of age. Despite the improved survival rate of 90% for newly diagnosed children with ALL, the outcome for patients with relapsed disease is poor with a less than 30% overall survival. CD19 CAR T-cell therapy has shown remarkable response rates in relapsed/refractory disease. Long-term survival analysis has shown that initial response rates exceed 80%. However, durable response rates at one year are closer to 40%. Little is known about factors predicting durable response to CAR T therapy. We hypothesize that patients with CD19 CAR T-cell resistant ALL have a distinct disease compared to responders to therapy that can be identified in pretreatment leukemia. Utilizing advanced genomic, epigenetic, proteomic, and single-cell (sc) techniques, we characterized patient bone marrow aspirates (BMA) to identify mechanisms of resistance. Patients enrolled in PLAT-02 at Seattle Children’s Hospital were categorized according to the durability of their response to CD19 CAR T therapy. To characterize the molecular and genomic alterations specific to the therapy-resistant ALLs, we performed comprehensive analyses on pre-treatment therapy-resistant and sensitive BMAs using whole-exome sequencing, RNA- BMAs seq, scRNA-seq, sc B cell receptor (BCR)-seq, methylation array, H3K27ac ChIP-seq, ATAC-seq, and CyTOF. Additionally, we developed murine patient-derived xenografts (PDXs) for future studies. Initial mutation analyses revealed 5 hotspot mutations (ABL1, 2 x KRAS, IKZF1, and EP300) and actionable fusion (2 ABL1, 2 ETV6, 2 ETV5, KMT2A). Interestingly, we identified a KMT2A-AFF1 fusion in a sensitive leukemia, which has been demonstrated to predispose patients to CD19 CAR T resistance through lineage switching. Additionally, we identified a novel CREBBP-fusion in leukemias resistant to CD19 CAR T-induced B-cell aplasia. Alterations of CREBBP have previously been associated with ALL that is refractory to conventional therapies. Integrated gene expression and epigenetic analyses are ongoing to identify genes or pathways associated with resistant disease. scRNA- and scBCR-seq data are being analyzed and integrated with CyTOF analyses to detect mixed lineage and gene expression-based heterogeneity that may predict clonal selection by CAR T pressure. Finally, we developed and genetically analyzed murine PDXs for 64% of the patient samples, establishing a valuable resource for future studies and developing novel therapies for resistant leukemias. This study is one of the most integrative and comprehensive genomic profiling approaches to identify the molecular traits of therapy-resistant ALL in patient samples. We hope to identify and develop crucial biomarkers predicting responsiveness to CAR T-cell therapy.

Citation Format: Katherine E. Masih, Rebecca Gardner, Berkley E. Gryder, Abdalla Abdelmaksoud, Ashley Wilson, Serifat Adebola, Benjamin Z. Stanton, Young K. Song, Justin Lack, Chaoyu Wang, Xinyu Wen, Zachary Rae, Adam Cheuk, Gregoire Altan-Bonnet, Michael Kelly, Jun S. Wei, Michael C. Jensen, Rimas J. Orentas, Javed Khan. A comprehensive and integrative omic analysis of multiply relapsed refractory pediatric pre-B cell acute lymphoblastic leukemia predicts response to CD19 CAR T-cell therapy [abstract]. In: Proceedings of the AACR Special Conference on the Advances in Pediatric Cancer Research; 2019 Sep 17-20; Montreal, QC, Canada. Philadelphia (PA): AACR; Cancer Res 2020;80(14 Suppl):Abstract nr A11.

Decitabine and Vorinostat with Chemotherapy in Relapsed Pediatric Acute Lymphoblastic Leukemia: A TACL Pilot Study

PURPOSE

Treatment failure from drug resistance is the primary reason for relapse in acute lymphoblastic leukemia (ALL). Improving outcomes by targeting mechanisms of drug resistance is a potential solution.

PATIENTS AND METHODS

We report results investigating the epigenetic modulators decitabine and vorinostat with vincristine, dexamethasone, mitoxantrone, and PEG-asparaginase for pediatric patients with relapsed or refractory B-cell ALL (B-ALL). Twenty-three patients, median age 12 years (range, 1-21) were treated in this trial.

RESULTS

The most common grade 3-4 toxicities included hypokalemia (65%), anemia (78%), febrile neutropenia (57%), hypophosphatemia (43%), leukopenia (61%), hyperbilirubinemia (39%), thrombocytopenia (87%), neutropenia (91%), and hypocalcemia (39%). Three subjects experienced dose-limiting toxicities, which included cholestasis, steatosis, and hyperbilirubinemia (n = 1); seizure, somnolence, and delirium (n = 1); and pneumonitis, hypoxia, and hyperbilirubinemia (n = 1). Infectious complications were common with 17 of 23 (74%) subjects experiencing grade ≥3 infections including invasive fungal infections in 35% (8/23). Nine subjects (39%) achieved a complete response (CR + CR without platelet recovery + CR without neutrophil recovery) and five had stable disease (22%). Nine (39%) subjects were not evaluable for response, primarily due to treatment-related toxicities. Correlative pharmacodynamics demonstrated potent in vivo modulation of epigenetic marks, and modulation of biologic pathways associated with functional antileukemic effects.

CONCLUSIONS

Despite encouraging response rates and pharmacodynamics, the combination of decitabine and vorinostat on this intensive chemotherapy backbone was determined not feasible in B-ALL due to the high incidence of significant infectious toxicities. This study is registered at http://www.clinicaltrials.gov as NCT01483690.

ServiceX A Distributed, Caching, Columnar Data Delivery Service

We will describe a component of the Intelligent Data Delivery Service being developed in collaboration with IRIS-HEP and the LHC experiments. ServiceX is an experiment-agnostic service to enable on-demand data delivery specifically tailored for nearly-interactive vectorized analysis. This work is motivated by the data engineering challenges posed by HL-LHC data volumes and the increasing popularity of python and Spark-based analysis workflows.

ServiceX gives analyzers the ability to query events by dataset metadata. It uses containerized transformations to extract just the data required for the analysis. This operation is colocated with the data to avoid transferring unnecessary branches over the WAN. Simple filtering operations are supported to further reduce the amount of data transferred.

Transformed events are cached in a columnar datastore to accelerate delivery of subsequent similar requests. ServiceX will learn commonly related columns and automatically include them in the transformation to increase the potential for cache hits by other users.

Selected events are streamed to the analysis system using an efficient wire protocol that can be readily consumed by a variety of computational frameworks. This reduces time-to-insight for physics analysis by delegating to ServiceX the complexity of event selection, slimming, reformatting, and streaming.

Mechanisms of and approaches to overcoming resistance to immunotherapy

Immunotherapies have been successfully developed for the treatment of B-cell acute lymphoblastic leukemia (B-ALL) with FDA approval of blinatumomab, inotuzumab, and tisagenlecleucel for relapsed or refractory patients. These agents target either CD19 or CD22, which are both expressed on the surface of the leukemic blasts in the majority of patients. The use of these agents has greatly transformed the landscape of available treatment, and it has provided curative therapy in some patients. As the field has matured, we are learning that for most patients, the currently available immunotherapies are not curative. Leukemic resistance to both CD19 and CD22 pressure has been described and is a major component of developed resistance to these therapies. Patients with B-ALL have developed CD19- or CD22-negative B-ALL, and in more rare cases, they have undergone lineage switch to acute myeloid leukemia. Current efforts are focusing on overcoming antigen escape, either by forced antigen expression or by dual-targeting therapies. A functional immune system is also required for maximal benefit of immunotherapy, particularly with chimeric antigen receptor (CAR) T-cell therapies. Data are now being produced that may allow for the prospective identification of patients whose immune deficits may be identified up front and predict failure. Preclinical work is focusing on additional engineering of CAR T cells to overcome these inherent immune deficits. Last, with improved knowledge of which patients are likely to benefit from immunotherapy as definitive treatment, those patients who are predicted to develop resistance may be prospectively recommended to undergo a consolidative hematopoietic cell transplant to lessen the recurrence risk.

Impact of dual-eligible status on survival in Medicare patients with lung cancer

149

Background: Dual-eligible (DE) patients are insured by both Medicaid and Medicare and are known to have complex medical and social needs. While DE patients with cancer have been shown to be less likely to undergo definitive surgical resection of early stage disease and more likely to be diagnosed at a later stage, they have also been shown to be more likely to adhere to cancer treatment due to lower copays with Medicaid. Lung cancer (LC) is the most common cancer diagnosed in the DE population, but little is known about the outcomes of DE patients with LC compared to non-DE patients. Our study sought to assess the impact of DE status on overall survival in lung cancer patients. Methods: We conducted a cross-sectional secondary analysis of data extracted from the Medicare-SEER database, including Medicare patients diagnosed with LC where complete survival data was available. Patients were defined as “DE” if they were designated as DE status during the month they were diagnosed with LC. Categorical variables were compared between DE and non-DE patients using the chi2 test. A Cox regression analysis was performed to evaluate the association between mortality and dual-eligibility, adjusting for demographic and clinical factors including age, ethnicity, gender, stage at time of diagnosis, type of lung cancer, and place of residence (urban vs. rural). Results: A total of 118,816 patients were included in the analysis, of which 81% were non-DE and 19% were DE. DE patients were more likely than non-DE patients to be female, non-white, younger, have squamous cell carcinoma, and be diagnosed at a later stage (P-values all < 0.001). After adjusting for all demographic and clinical characteristics included in the analysis, the hazard ratio for mortality was 1.243 (95% confidence interval: 1.222-1.264, p < 0.001) for DE patients compared to non-DE patients. Conclusions: DE patients with LC have a significantly higher mortality rate than non-DE patients in the Medicare population after adjusting for confounding factors. Future studies should explore the factors that influence this survival differential and consider targeted interventions at the policy level to improve outcomes in this population.

Abstract LB-056: An integrated genomic, epigenetic, proteomic, and single cell analysis of pediatric B cell acute lymphoblastic leukemia to elucidate resistance mechanisms to CD19 CAR T cell therapy

Background

Acute lymphoblastic leukemia (ALL) is the most common childhood cancer with a peak incidence at 3-5 years of age. Despite the improved survival rate of 90% for newly diagnosed children with ALL, the outcome for patients with relapsed disease is poor with a less than 30% overall survival. CD19 CAR T cell therapy has shown impressive response rates in relapsed/refractory disease. However, long-term survival analysis has shown that despite initial response rates exceeding 80%, durable response rates at one year are closer to 40%. Currently, little is known about molecular factors predicting durable response to CAR T therapy. We hypothesized that patients with CD19 CAR T therapy resistant ALL have a molecularly distinct disease compared to patients who respond to therapy, which can be identified in pre-treatment leukemia samples. Utilizing advanced genomic, epigenetic, proteomic, and single-cell techniques, we characterized the bone marrow of patients that were resistant or sensitive to therapy to identify mechanisms of resistance.

Methods

Patients enrolled in a phase I clinical trial at Seattle Children’s Hospital (PLAT-02) were categorized according to the durability of their response to CD19 CAR T therapy. Bone marrow aspirates from patients with leukemias resistant to therapy (4 pre-treatment with 2 paired post-treatment) were analyzed and compared to patients with therapy sensitive leukemias (5 pre-treatment). We performed bulk whole-exome sequencing and RNA-seq, single cell (sc) RNA-seq, scB cell receptor (BCR)-seq, methylation array, H3K27ac ChIP-seq, and ATAC-seq.

Results

Initial genomic analysis revealed a total of 5 previously reported recurrent hotspot mutations in ABL1, 2 x KRAS (Q61H), IKZF1, and EP300. RNA-seq analyses identified actionable fusions in 2 x ABL1, 2 x ETV6, 2 x ETV5, and 1x KMT2A with variable partners. Interestingly, a therapy-sensitive leukemia harbored a KMT2A-AFF1fusion that was previously shown to predispose patients treated with blinatumomab to leukemic plasticity and lineage switching. Additionally, we identified in-frame CREBBP-fusions in all leukemias that failed to achieve CD19 CAR T cell induced B cell aplasia. CREBBP perturbations have previously been associated with relapsed and refractory ALL. Integrated gene expression and epigenetic analyses identified several pathways associated with resistant disease. ATAC-seq and methylation data are being analyzed for lineage specification. Similarly, scRNA- and scBCR-seq data are being analyzed for the existence of mixed lineage and gene expression-based heterogeneity that may predict clonal selection under CAR T pressure.

Conclusions

This study establishes one of the most comprehensive approaches to genomic profiling for leukemia patient samples. Although our analysis is preliminary and sample number is small, in-depth analyses are highlighting crucial differences in leukemia that will allow improved prediction of responsiveness to CAR T therapy.

Citation Format: Katherine E. Masih, Rebecca Gardner, Berkley E. Gryder, Justin Lack, Benjamin Z. Stanton, Ashley Wilson, Olivia Finney, Sivasish Sindiri, Young Song, Zachary Rae, Michael Kelly, Chaoyu Wang, Xinyu Wen, Adam Cheuk, Jun S. Wei, Michael Jensen, Rimas Orentas, Javed Khan. An integrated genomic, epigenetic, proteomic, and single cell analysis of pediatric B cell acute lymphoblastic leukemia to elucidate resistance mechanisms to CD19 CAR T cell therapy [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr LB-056.

CD19 CAR T cell product and disease attributes predict leukemia remission durability

BACKGROUND

Chimeric antigen receptor (CAR) T cells can induce remission in highly refractory leukemia and lymphoma subjects, yet the parameters for achieving sustained relapse-free survival are not fully delineated.

METHODS

We analyzed 43 pediatric and young adult subjects participating in a Phase I trial of defined composition CD19CAR T cells (NCT02028455). CAR T cell phenotype, function and expansion, as well as starting material T cell repertoire, were analyzed in relation to therapeutic outcome (defined as achieving complete remission within 63 days) and duration of leukemia free survival and B cell aplasia.

RESULTS

These analyses reveal that initial therapeutic failures (n = 5) were associated with attenuated CAR T cell expansion and/or rapid attrition of functional CAR effector cells following adoptive transfer. The CAR T products were similar in phenotype and function when compared to products resulting in sustained remissions. However, the initial apheresed peripheral blood T cells could be distinguished by an increased frequency of LAG-3+/TNF-αlow CD8 T cells and, following adoptive transfer, the rapid expression of exhaustion markers. For the 38 subjects who achieved an initial sustained MRD-neg remission, remission durability correlated with therapeutic products having increased frequencies of TNF-α-secreting CAR CD8+ T cells, and was dependent on a sufficiently high CD19+ antigen load at time of infusion to trigger CAR T cell proliferation.

CONCLUSION

These parameters have the potential to prospectively identify patients at risk for therapeutic failure and support the development of approaches to boost CAR T cell activation and proliferation in patients with low levels of CD19 antigen.

TRIAL REGISTRATION

ClinicalTrials.gov NCT02028455.

FUNDING

Partial funding for this study was provided by Stand Up to Cancer & St. Baldrick's Pediatric Dream Team Translational Research Grant (SU2C-AACR-DT1113), RO1 CA136551-05, Alex Lemonade Stand Phase I/II Infrastructure Grant, Conquer Cancer Foundation Career Development Award, Washington State Life Sciences Discovery Fund, Ben Towne Foundation, William Lawrence & Blanche Hughes Foundation, and Juno Therapeutics, Inc., a Celgene Company.

New Agents, Emerging Late Effects, and the Development of Precision Survivorship

Incremental improvements in the treatment of children and adolescents with cancer have led to 5-year survival rates reaching nearly 85%. In the past decade, impressive progress has been made in understanding the biology of many pediatric cancers. With that understanding, multiple new agents have become available that offer the promise of more-effective and less-toxic treatment. These include agents that target various cell surface antigens and engage the adaptive immune system, as well as those that interfere with key signaling pathways involved in tumor development and growth. For local control, surgery and radiation techniques also have evolved, becoming less invasive or featuring new techniques and particles that more precisely target the tumor and limit the dose to normal tissue. Nevertheless, targeted agents, like conventional chemotherapy, radiotherapy, and surgery, may have off-target effects and deserve long-term follow-up of their safety and efficacy. These include injury to the endocrine, cardiovascular, and immunologic systems. New radiation and surgical techniques that theoretically reduce morbidity and improve long-term quality of life must also be validated with actual patient outcomes. Finally, with advances in genomics, information on host susceptibility to late effects is beginning to emerge. Such knowledge, coupled with improved metrics that better describe the spectrum of potential late effects across the entire lifespan, can lead to the development of decision models that project the potential long-term health outcomes associated with various treatment and follow-up strategies. These developments will help extend the current focus on precision medicine to precision survivorship, where clinicians, patients, and families will have a better grasp of the potential risks, benefits, and tradeoffs associated with the growing number of cancer treatment options.

Chimeric Antigen Receptor T Cell-Mediated Neurotoxicity in Nonhuman Primates

Chimeric antigen receptor (CAR) T-cell immunotherapy has revolutionized the treatment of refractory leukemias and lymphomas, but is associated with significant toxicities, namely cytokine release syndrome (CRS) and neurotoxicity. A major barrier to developing therapeutics to prevent CAR T cell-mediated neurotoxicity is the lack of clinically relevant models. Accordingly, we developed a rhesus macaque (RM) model of neurotoxicity via adoptive transfer of autologous CD20-specific CAR T cells. Following cyclophosphamide lymphodepletion, CD20 CAR T cells expand to 272 to 4,450 cells/μL after 7 to 8 days and elicit CRS and neurotoxicity. Toxicities are associated with elevated serum IL6, IL8, IL1RA, MIG, and I-TAC levels, and disproportionately high cerebrospinal fluid (CSF) IL6, IL2, GM-CSF, and VEGF levels. During neurotoxicity, both CD20 CAR and non-CAR T cells accumulate in the CSF and in the brain parenchyma. This RM model demonstrates that CAR T cell-mediated neurotoxicity is associated with proinflammatory CSF cytokines and a pan-T cell encephalitis.Significance: We provide the first immunologically relevant, nonhuman primate model of B cell-directed CAR T-cell therapy-mediated CRS and neurotoxicity. We demonstrate CAR and non-CAR T-cell infiltration in the CSF and in the brain during neurotoxicity resulting in pan-encephalitis, accompanied by increased levels of proinflammatory cytokines in the CSF. Cancer Discov; 8(6); 750-63. ©2018 AACR.This article is highlighted in the In This Issue feature, p. 663.

Anti-LINGO-1 has no detectable immunomodulatory effects in preclinical and phase 1 studies

Objective:

To evaluate whether the anti-LINGO-1 antibody has immunomodulatory effects.

Methods:

Human peripheral blood mononuclear cells (hPBMCs), rat splenocytes, and rat CD4⁺ T cells were assessed to determine whether LINGO-1 was expressed and was inducible. Anti-LINGO-1 Li81 (0.1–30 μg/mL) effect on proliferation/cytokine production was assessed in purified rat CD4⁺ T cells and hPBMCs stimulated with antibodies to CD3 +/– CD28. In humans, the effect of 2 opicinumab (anti-LINGO-1/BIIB033; 30, 60, and 100 mg/kg) or placebo IV administrations was evaluated in RNA from blood and CSF samples taken before and after administration in phase 1 clinical trials; paired samples were assessed for differentially expressed genes by microarray. RNA from human CSF cell pellets was analyzed by quantitative real-time PCR for changes in transcripts representative of cell types, activation markers, and soluble proteins of the adaptive/innate immune systems. ELISA quantitated the levels of CXCL13 protein in human CSF supernatants.

Results:

LINGO-1 is not expressed in hPBMCs, rat splenocytes, or rat CD4⁺ T cells; LINGO-1 blockade with Li81 did not affect T-cell proliferation or cytokine production from purified rat CD4⁺ T cells or hPBMCs. LINGO-1 blockade with opicinumab resulted in neither significant changes in immune system gene expression in blood and CSF, nor changes in CXCL13 CSF protein levels (clinical studies).

Conclusions:

These data support the hypothesis that LINGO-1 blockade does not affect immune function.

Classification of evidence:

This study provides Class II evidence that in patients with MS, opicinumab does not have immunomodulatory effects detected by changes in immune gene transcript expression.

First Dark Matter Search Results from the XENON1T Experiment

We report the first dark matter search results from XENON1T, a ∼2000-kg-target-mass dual-phase (liquid-gas) xenon time projection chamber in operation at the Laboratori Nazionali del Gran Sasso in Italy and the first ton-scale detector of this kind. The blinded search used 34.2 live days of data acquired between November 2016 and January 2017. Inside the (1042±12)-kg fiducial mass and in the [5,40]  keV_{nr} energy range of interest for weakly interacting massive particle (WIMP) dark matter searches, the electronic recoil background was (1.93±0.25)×10^{-4}  events/(kg×day×keV_{ee}), the lowest ever achieved in such a dark matter detector. A profile likelihood analysis shows that the data are consistent with the background-only hypothesis. We derive the most stringent exclusion limits on the spin-independent WIMP-nucleon interaction cross section for WIMP masses above 10  GeV/c^{2}, with a minimum of 7.7×10^{-47}  cm^{2} for 35-GeV/c^{2} WIMPs at 90% C.L.

Outcomes of adults and children with primary mediastinal B-cell lymphoma treated with dose-adjusted EPOCH-R

Treatment with dose-adjusted EPOCH (etoposide, doxorubicin, cyclophosphamide, vincristine, prednisone) chemotherapy and rituximab (DA-EPOCH-R) has become the standard of care for primary mediastinal B-cell lymphoma (PMBCL) at many institutions despite limited data in the multi-centre setting. We report a large, multi-centre retrospective analysis of children and adults with PMBCL treated with DA-EPOCH-R to characterize outcomes and evaluate prognostic factors. We assessed 156 patients with PMBCL treated with DA-EPOCH-R across 24 academic centres, including 38 children and 118 adults. All patients received at least one cycle of DA-EPOCH-R. Radiation therapy was administered in 14·9% of patients. With median follow-up of 22·6 months, the estimated 3-year event-free survival (EFS) was 85·9% [95% confidence interval (CI) 80·3-91·5] and overall survival was 95·4% (95% CI 91·8-99·0). Outcomes were not statistically different between paediatric and adult patients. Thrombotic complications were reported in 28·2% of patients and were more common in paediatric patients (45·9% vs. 22·9%, P = 0·011). Seventy-five per cent of patients had a negative fluorodeoxyglucose positron emission tomography (FDG-PET) scan at the completion of DA-EPOCH-R, defined as Deauville score 1-3. Negative FDG-PET at end-of-therapy was associated with improved EFS (95·4% vs. 54·9%, P < 0·001). Our data support the use of DA-EPOCH-R for the treatment of PMBCL in children and adults. Patients with a positive end-of-therapy FDG-PET scan have an inferior outcome.

Voluntary premarital screening to prevent sickle cell disease in Jamaica: does it work?

To determine whether identifying haemoglobin genotype, and providing education and counselling to senior school students will influence their choice of partner and reduce the frequency of births with sickle cell disease. The Manchester Project provided free voluntary blood tests to determine haemoglobin genotype to the fifth and sixth forms (grades 11-13), median age of 16.7 years, of all 15 secondary schools in the parish of Manchester in south central Jamaica. A total of 16,636 students complied, and counselling was offered to carriers of abnormal genes over 6 years (2008-2013). The genotypes of their offspring were determined by newborn screening of 66,892 deliveries in 12 regional hospitals over 8 years (2008-2015). The study focused on the genotypes of live deliveries to female students with the four most common haemoglobin genotypes: 7905 with an AA genotype, 898 with the sickle cell trait, 326 with the HbC trait and 78 with the beta thalassaemia trait. A total of 2442 live deliveries were identified by the end of 2015 in mothers screened at school. Eleven babies had clinically significant genotypes, and the prevalence of SS and SC disease did not differ from that predicted by random mating. First pregnancy was not delayed in AS or AC mothers. There was no evidence that knowledge of maternal haemoglobin genotype influenced choice of partner. On an interview, mothers of affected babies correctly recalled their genotype, but either did not discuss this with their partners or the latter refused to be tested. Subjects delaying child bearing for tertiary education would be largely excluded from the present study of first pregnancies and may make greater use of this information. Future options are a greater role for prenatal diagnosis.

Treatment-related adverse events associated with a modified UK ALLR3 induction chemotherapy backbone for childhood relapsed/refractory acute lymphoblastic leukemia

BACKGROUND

The UK ALLR3 (R3) regimen has been adopted to treat pediatric relapsed acute lymphoblastic leukemia (ALL) by many centers in the United States and has become a preferred therapeutic backbone for testing novel agents in clinical trials. A detailed toxicity profile of this platform has not previously been reported. The toxicity and response rates for its use beyond first relapse are unknown.

PROCEDURES

We performed a multi-institutional, retrospective study including children with relapsed ALL treated with the R3 reinduction chemotherapy backbone block 1 across five pediatric centers. Data were extracted from medical records and analyzed.

RESULTS

Fifty-nine patients were included in the study, including 16 patients with ≥2nd relapse. Ninety-seven percent of patients experienced at least one Grade ≥3 nonhematologic adverse event (AE). Grade 3 or higher infection was reported in 90% of patients. Other nonhematologic Grade ≥3 AEs included electrolyte abnormalities, elevation in hepatic enzymes, and pain. Eighty-five percent of patients achieved a complete remission (CR). There were no significant differences in the incidence of AEs, CR rate, and rate of minimal residual disease negativity between patients with 1st or ≥2nd relapse.

CONCLUSION

Our study confirmed that R3 block 1 is a highly active reinduction regimen in childhood relapsed ALL. However, it was associated with a high incidence of severe toxicities, particularly infection. The toxicity profiled in our report should be used to inform optimal supportive care and future clinical trial design with the R3 backbone, particularly when new agents are combined with this regimen.

Newborn screening for sickle cell disease in Jamaica: logistics and experience with umbilical cord samples

The study aims to describe the logistics and results of a programme for newborn screening for sickle cell disease based on samples from the umbilical cord. Samples were dried on Guthrie cards and analysed by high pressure liquid chromatography. All suspected clinically significant abnormal genotypes were confirmed by age 4-6 weeks with family studies and then recruited to local sickle cell clinics. The programme has screened 66,833 samples with the sickle cell trait in 9.8 % and the HbC trait in 3.8 %. Sickle cell syndromes occurred in 407 babies (204 SS, 148 SC, 35 Sbeta⁺ thalassaemia, 6 Sbeta^o thalassaemia, 6 sickle cell-variants, 8 sickle cell-hereditary persistence of fetal haemoglobin) and HbC syndromes in 42 (22 CC, 14 Cbeta⁺ thalassaemia, 1 Cbeta^o thalassaemia, 5 HbC- hereditary persistence of fetal haemoglobin). Focusing on the year 2015, screening was performed in 15,408, compliance with sample collection was 98.1 %, and maternal contamination occurred in 335 (2.6 %) but in only 0.05 % did diagnostic confusion require patient recall and further tests. This model of newborn screening for sickle cell disease is accurate, robust and economic. It is hoped that it may be helpful for other societies with high prevalence of abnormal haemoglobins and limited resources, who are planning to embark on newborn screening for sickle cell disease.