A maelstrom of migrating monocytes drives neurodegeneration.

Neurodegeneration is a devastating complication of Langerhans cell histiocytosis (LCH), but it is not clear how it develops. In this issue of Immunity, Wilk et al. demonstrate that circulating BRAFV600E+ myeloid cells damage the blood-brain barrier and infiltrate the brain. Dual inhibition of the MAPK and senescence pathways can block parenchymal injury, providing a potential therapeutic avenue for histiocytic neurodegeneration.

MRD at the end of induction and EFS in T-cell lymphoblastic lymphoma: Children's Oncology Group trial AALL1231.

ABSTRACT: Defining prognostic variables in T-lymphoblastic lymphoma (T-LL) remains a challenge. AALL1231 was a Children's Oncology Group phase 3 clinical trial for newly diagnosed patients with T acute lymphoblastic leukemia or T-LL, randomizing children and young adults to a modified augmented Berlin-Frankfurt-Münster backbone to receive standard therapy (arm A) or with addition of bortezomib (arm B). Optional bone marrow samples to assess minimal residual disease (MRD) at the end of induction (EOI) were collected in T-LL analyzed to assess the correlation of MRD at the EOI to event-free survival (EFS). Eighty-six (41%) of the 209 patients with T-LL accrued to this trial submitted samples for MRD assessment. Patients with MRD <0.1% (n = 75) at EOI had a superior 4-year EFS vs those with MRD ≥0.1% (n = 11) (89.0% ± 4.4% vs 63.6% ± 17.2%; P = .025). Overall survival did not significantly differ between the 2 groups. Cox regression for EFS using arm A as a reference demonstrated that MRD EOI ≥0.1% was associated with a greater risk of inferior outcome (hazard ratio, 3.73; 95% confidence interval, 1.12-12.40; P = .032), which was independent of treatment arm assignment. Consideration to incorporate MRD at EOI into future trials will help establish its value in defining risk groups. CT# NCT02112916.

How I treat newly diagnosed and refractory T-cell acute lymphoblastic lymphoma in children and young adults.

T-cell lymphoblastic lymphoma (T-LLy) and T-cell acute lymphoblastic leukemia (T-ALL) have historically been considered a spectrum of the same disease. However, recent evidence demonstrating differential responses to chemotherapy raise the possibility that T-LLy and T-ALL are distinct clinical and biologic entities. Here, we examine differences between the 2 diseases and use illustrative cases to highlight key recommendations on how to best treat patients with newly diagnosed and relapsed/refractory T-LLy. We discuss results of recent clinical trials incorporating use of nelarabine and bortezomib, choice of induction steroid, role of cranial radiotherapy, and risk stratification markers to identify patients at highest risk of relapse and to further refine current treatment strategies. Because prognosis for relapsed or refractory T-LLy patients is poor, we discuss ongoing investigations incorporating novel therapies, including immunotherapeutics, into upfront and salvage regimens and the role of hematopoietic stem cell transplantation.

Langerhans cell histiocytosis: NACHO update on progress, chaos, and opportunity on the path to rational cures.

Langerhans cell histiocytosis (LCH) is a myeloid neoplastic disorder characterized by lesions with CD1a-positive/Langerin (CD207)-positive histiocytes and inflammatory infiltrate that can cause local tissue damage and systemic inflammation. Clinical presentations range from single lesions with minimal impact to life-threatening disseminated disease. Therapy for systemic LCH has been established through serial trials empirically testing different chemotherapy agents and durations of therapy. However, fewer than 50% of patients who have disseminated disease are cured with the current standard-of-care vinblastine/prednisone/(mercaptopurine), and treatment failure is associated with long-term morbidity, including the risk of LCH-associated neurodegeneration. Historically, the nature of LCH-whether a reactive condition versus a neoplastic/malignant condition-was uncertain. Over the past 15 years, seminal discoveries have broadly defined LCH pathogenesis; specifically, activating mitogen-activated protein kinase pathway mutations (most frequently, BRAFV600E) in myeloid precursors drive lesion formation. LCH therefore is a clonal neoplastic disorder, although secondary inflammatory features contribute to the disease. These paradigm-changing insights offer a promise of rational cures for patients based on individual mutations, clonal reservoirs, and extent of disease. However, the pace of clinical trial development behind lags the kinetics of translational discovery. In this review, the authors discuss the current understanding of LCH biology, clinical characteristics, therapeutic strategies, and opportunities to improve outcomes for every patient through coordinated agent prioritization and clinical trial efforts.

Evaluation of Culture Conducive to Academic Success by Gender at a Comprehensive Cancer Center.

INTRODUCTION: The primary objective of this study was to determine whether workplace culture in academic oncology differed by gender, during the COVID-19 pandemic. MATERIALS AND METHODS: We used the Culture Conducive to Women's Academic Success (CCWAS), a validated survey tool, to investigate the academic climate at an NCI-designated Cancer Center. We adapted the CCWAS to be applicable to people of all genders. The full membership of the Cancer Center was surveyed (total faculty = 429). The questions in each of 4 CCWAS domains (equal access to opportunities, work-life balance, freedom from gender bias, and leadership support) were scored using a 5-point Likert scale. Median score and interquartile ranges for each domain were calculated. RESULTS: A total of 168 respondents (men = 58, women = 106, n = 4 not disclosed) submitted survey responses. The response rate was 39% overall and 70% among women faculty. We found significant differences in perceptions of workplace culture by gender, both in responses to individual questions and in the overall score in the following domains: equal access to opportunities, work-life balance, and leader support, and in the total score for the CCWAS. CONCLUSIONS: Our survey is the first of its kind completed during the COVID-19 pandemic at an NCI-designated Cancer Center, in which myriad factors contributed to burnout and workplace challenges. These results point to specific issues that detract from the success of women pursuing careers in academic oncology. Identifying these issues can be used to design and implement solutions to improve workforce culture, mitigate gender bias, and retain faculty.

International expert consensus recommendations for the diagnosis and treatment of Langerhans cell histiocytosis in adults.

Langerhans cell histiocytosis (LCH) can affect children and adults with a wide variety of clinical manifestations, including unifocal, single-system multifocal, single-system pulmonary (smoking-associated), or multisystem disease. The existing paradigms in the management of LCH in adults are mostly derived from the pediatric literature. Over the last decade, the discovery of clonality and MAPK-ERK pathway mutations in most cases led to the recognition of LCH as a hematopoietic neoplasm, opening the doors for treatment with targeted therapies. These advances have necessitated an update of the existing recommendations for the diagnosis and treatment of LCH in adults. This document presents consensus recommendations that resulted from the discussions at the annual Histiocyte Society meeting in 2019, encompassing clinical features, classification, diagnostic criteria, treatment algorithm, and response assessment for adults with LCH. The recommendations favor the use of 18F-Fluorodeoxyglucose positron emission tomography-based imaging for staging and response assessment in the majority of cases. Most adults with unifocal disease may be cured by local therapies, while the first-line treatment for single-system pulmonary LCH remains smoking cessation. Among patients not amenable or unresponsive to these treatments and/or have multifocal and multisystem disease, systemic treatments are recommended. Preferred systemic treatments in adults with LCH include cladribine or cytarabine, with the emerging role of targeted (BRAF and MEK inhibitor) therapies. Despite documented responses to treatments, many patients struggle with a high symptom burden from pain, fatigue, and mood disorders that should be acknowledged and managed appropriately.

T-cell activation profiles distinguish hemophagocytic lymphohistiocytosis and early sepsis.

Hemophagocytic lymphohistiocytosis (HLH) is a fatal disorder of immune hyperactivation that has been described as a cytokine storm. Sepsis due to known or suspected infection has also been viewed as a cytokine storm. Although clinical similarities between these syndromes suggest similar immunopathology and may create diagnostic uncertainty, distinguishing them is critical as treatments are widely divergent. We examined T-cell profiles from children with either HLH or sepsis and found that HLH is characterized by acute T-cell activation, in clear contrast to sepsis. Activated T cells in patients with HLH were characterized as CD38high/HLA-DR+ effector cells, with activation of CD8+ T cells being most pronounced. Activated T cells were type 1 polarized, proliferative, and displayed evidence of recent and persistent activation. Circulating activated T cells appeared to be broadly characteristic of HLH, as they were seen in children with and without genetic lesions or identifiable infections and resolved with conventional treatment of HLH. Furthermore, we observed even greater activation and type 1 polarization in tissue-infiltrating T cells, described here for the first time in a series of patients with HLH. Finally, we observed that a threshold of >7% CD38high/HLA-DR+ cells among CD8+ T cells had strong positive and negative predictive value for distinguishing HLH from early sepsis or healthy controls. We conclude that the cytokine storm of HLH is marked by distinctive T-cell activation whereas early sepsis is not, and that these 2 syndromes can be readily distinguished by T-cell phenotypes.

Three-year results from phase I of ZUMA-4: KTE-X19 in pediatric relapsed/refractory acute lymphoblastic leukemia.

Here we present the 3-year results of ZUMA-4, a phase I/II multicenter study evaluating the safety and efficacy of KTEX19, an autologous anti-CD19 chimeric antigen receptor (CAR) T-cell therapy, in pediatric/adolescent patients with relapsed/refractory B-cell acute lymphoblastic leukemia. Phase I explored two dose levels and formulations. The primary endpoint was the incidence of dose-limiting toxicities. Thirty-one patients were enrolled; KTE-X19 was administered to 24 patients (median age 13.5 years, range 3-20; median follow-up 36.1 months). No dose-limiting toxicities were observed. All treated patients had grade ≥3 adverse events, commonly hypotension (50%) and anemia (42%). Grade 3 cytokine release syndrome rates were 33% in all treated patients, 75% in patients given the dose of 2×106 CAR T cells/kg, 27% in patients given the dose of 1×106 cells/kg in the 68 mL formulation, and 22% in patients given the dose of 1×106 cells/kg in the 40 mL formulation; the percentages of patients experiencing grade ≥3 neurologic events were 21%, 25%, 27%, and 11% respectively. Overall complete remission rates (including complete remission with incomplete hematologic recovery) were 67% in all treated patients, 75% in patients given 2×106 CAR T cells/kg, 64% in patients given 1×106 cells/kg in the 68 mL formulation, and 67% in patients given 1×106 cells/kg in the 40 mL formulation. Overall minimal residual diseasenegativity rates were 100% among responders; 88% of responders underwent subsequent allogeneic stem-cell transplantation. In the 1×106 (40 mL) group (recommended phase II dose), the median duration of remission censored at allogeneic stem-cell transplantation and median overall survival were not reached. Pediatric/adolescent patients with relapsed/refractory B-cell acute lymphoblastic leukemia achieved high minimal residual disease-negative remission rates with a manageable safety profile after a single dose of KTE-X19. Phase II of the study is ongoing at the dose of 1×106 CAR T cells/kg in the 40 mL formulation. ClinicalTrials.gov: NCT02625480.

How I approach B-lymphoblastic lymphoma in children.

There are limited data pertaining to the prognostic features and optimal therapeutic approach for the 20%-25% of children with lymphoblastic lymphoma (LLy) who have the B-lymphoblastic subtype. Outcomes are favorable following treatment modeled after acute lymphoblastic leukemia (ALL) regimens, but prognosis is dismal after relapse, and there are no established features for predicting therapy response. Ongoing US and international trials will include the largest cohort of uniformly treated patients with B-LLy to date, providing an opportunity to define clinical and molecular predictors of relapse and to establish a standard of care for treatment to improve outcomes for this rare pediatric cancer.

Children's Oncology Group's 2023 blueprint for research: Non-Hodgkin lymphoma.

Pediatric non-Hodgkin lymphoma (NHL) includes over 30 histologies (many with subtypes), with approximately 800 cases per year in the United States. Improvements in survival in NHL over the past 5 decades align with the overall success of the cooperative trial model with dramatic improvements in outcomes. As an example, survival for advanced Burkitt lymphoma is now >95%. Major remaining challenges include survival for relapsed and refractory disease and long-term morbidity in NHL survivors. Langerhans cell histiocytosis (LCH) was added to the NHL Committee portfolio in recognition of LCH as a neoplastic disorder and the tremendous unmet need for improved outcomes. The goal of the Children' Oncology Group NHL Committee is to identify optimal cures for every child and young adult with NHL (and LCH). Further advances will require creative solutions, including engineering study groups to combine rare populations, biology-based eligibility, alternative endpoints, facilitating international collaborations, and coordinated correlative biology.

Inhibition of the Sec61 translocon overcomes cytokine-induced glucocorticoid resistance in T-cell acute lymphoblastic leukaemia.

Glucocorticoid (GC) resistance is a poor prognostic factor in T-cell acute lymphoblastic leukaemia (T-ALL). Interleukin-7 (IL-7) mediates GC resistance via GC-induced upregulation of IL-7 receptor (IL-7R) expression, leading to increased pro-survival signalling. IL-7R reaches the cell surface via the secretory pathway, so we hypothesized that inhibiting the translocation of IL-7R into the secretory pathway would overcome GC resistance. Sec61 is an endoplasmic reticulum (ER) channel that is required for insertion of polypeptides into the ER. Here, we demonstrate that KZR-445, a novel inhibitor of Sec61, potently attenuates the dexamethasone (DEX)-induced increase in cell surface IL-7R and overcomes IL-7-induced DEX resistance.

JAK/STAT pathway inhibition sensitizes CD8 T cells to dexamethasone-induced apoptosis in hyperinflammation.

Cytokine storm syndromes (CSS) are severe hyperinflammatory conditions characterized by excessive immune system activation leading to organ damage and death. Hemophagocytic lymphohistiocytosis (HLH), a disease often associated with inherited defects in cell-mediated cytotoxicity, serves as a prototypical CSS for which the 5-year survival is only 60%. Frontline therapy for HLH consists of the glucocorticoid dexamethasone (DEX) and the chemotherapeutic agent etoposide. Many patients, however, are refractory to this treatment or relapse after an initial response. Notably, many cytokines that are elevated in HLH activate the JAK/STAT pathway, and the JAK1/2 inhibitor ruxolitinib (RUX) has shown efficacy in murine HLH models and humans with refractory disease. We recently reported that cytokine-induced JAK/STAT signaling mediates DEX resistance in T cell acute lymphoblastic leukemia (T-ALL) cells, and that this could be effectively reversed by RUX. On the basis of these findings, we hypothesized that cytokine-mediated JAK/STAT signaling might similarly contribute to DEX resistance in HLH, and that RUX treatment would overcome this phenomenon. Using ex vivo assays, a murine model of HLH, and primary patient samples, we demonstrate that the hypercytokinemia of HLH reduces the apoptotic potential of CD8 T cells leading to relative DEX resistance. Upon exposure to RUX, this apoptotic potential is restored, thereby sensitizing CD8 T cells to DEX-induced apoptosis in vitro and significantly reducing tissue immunopathology and HLH disease manifestations in vivo. Our findings provide rationale for combining DEX and RUX to enhance the lymphotoxic effects of DEX and thus improve the outcomes for patients with HLH and related CSS.

Decitabine and vorinostat with FLAG chemotherapy in pediatric relapsed/refractory AML: Report from the therapeutic advances in childhood leukemia and lymphoma (TACL) consortium.

Survival outcomes for relapsed/refractory pediatric acute myeloid leukemia (R/R AML) remain dismal. Epigenetic changes can result in gene expression alterations which are thought to contribute to both leukemogenesis and chemotherapy resistance. We report results from a phase I trial with a dose expansion cohort investigating decitabine and vorinostat in combination with fludarabine, cytarabine, and G-CSF (FLAG) in pediatric patients with R/R AML [NCT02412475]. Thirty-seven patients enrolled with a median age at enrollment of 8.4 (range, 1-20) years. There were no dose limiting toxicities among the enrolled patients, including two patients with Down syndrome. The recommended phase 2 dose of decitabine in combination with vorinostat and FLAG was 10 mg/m2 . The expanded cohort design allowed for an efficacy evaluation and the overall response rate among 35 evaluable patients was 54% (16 complete response (CR) and 3 complete response with incomplete hematologic recovery (CRi)). Ninety percent of responders achieved minimal residual disease (MRD) negativity (<0.1%) by centralized flow cytometry and 84% (n = 16) successfully proceeded to hematopoietic stem cell transplant. Two-year overall survival was 75.6% [95%CI: 47.3%, 90.1%] for MRD-negative patients vs. 17.9% [95%CI: 4.4%, 38.8%] for those with residual disease (p < .001). Twelve subjects (34%) had known epigenetic alterations with 8 (67%) achieving a CR, 7 (88%) of whom were MRD negative. Correlative pharmacodynamics demonstrated the biologic activity of decitabine and vorinostat and identified specific gene enrichment signatures in nonresponding patients. Overall, this therapy was well-tolerated, biologically active, and effective in pediatric patients with R/R AML, particularly those with epigenetic alterations.

Perceptions of specialty palliative care and its role in pediatric stem cell transplant: A multidisciplinary qualitative study.

BACKGROUND: Consultation of specialty palliative care remains uncommon in pediatric stem cell transplant (SCT) despite growing evidence that early integration of palliative care improves outcomes in patients with advanced cancers or undergoing SCT. Little is known about how multidisciplinary pediatric SCT teams perceive palliative care and its role in SCT. PROCEDURE: We conducted semistructured interviews of members of a multi-disciplinary SCT team to understand their perceptions of palliative care, how specialty palliative care is integrated into SCT, and to identify barriers to increased integration. Eligible participants included physicians, nurses, inpatient nurse practitioners, social workers, and child life specialists. Data were analyzed using thematic analysis. RESULTS: Four major themes were identified. First, SCT team members held a favorable perception of the palliative care team. Second, participants desired increased palliative care integration in SCT. Third, participants believed that the palliative care team had insufficient resources to care for the large number of SCT patients, which led to the SCT team limiting palliative care consultation. And, finally, the lack of a standardized palliative care consultation process prevented greater integration of palliative care in SCT. CONCLUSIONS: SCT team members held a favorable perception of palliative care and saw a role for greater palliative care integration throughout the SCT course. We identified modifiable barriers to greater palliative care integration. SCT teams who desire greater palliative care integration may adapt and implement an existing model of palliative care integration in order to improve standardization and increase integration of specialty palliative care in SCT.

A pilot trial of prophylactic defibrotide to prevent serious thrombotic microangiopathy in high-risk pediatric patients.

BACKGROUND: Transplant-associated thrombotic microangiopathy (TA-TMA) is an endothelial injury complication of hematopoietic stem cell transplant (HSCT) leading to end-organ damage and high morbidity and mortality. Defibrotide is an anti-inflammatory and antithrombotic agent that may protect the endothelium during conditioning. PROCEDURE: We hypothesized that prophylactic use of defibrotide during HSCT conditioning and acute recovery could prevent TA-TMA. A pilot single-arm phase II trial (NCT#03384693) evaluated the safety and feasibility of administering prophylactic defibrotide to high-risk pediatric patients during HSCT and assessed if prophylactic defibrotide prevented TA-TMA compared to historic controls. Patients received defibrotide 6.25 mg/kg IV q6h the day prior to the start of conditioning through day +21. Patients were prospectively monitored for TA-TMA from admission through week 24 post transplant. Potential biomarkers of endothelial injury (suppression of tumorigenicity 2 [ST2], angiopoietin-2 [ANG-2], plasminogen activator inhibitor-1 [PAI-1], and free hemoglobin) were analyzed. RESULTS: Twenty-five patients were enrolled, 14 undergoing tandem autologous HSCT for neuroblastoma and 11 undergoing allogeneic HSCT. Defibrotide was discontinued early due to possibly related clinically significant bleeding in 12% (3/25) of patients; no other severe adverse events occurred due to the study intervention. The other 22 patients missed a median of 0.7% of doses (0%-5.2%). One patient developed nonsevere TA-TMA 12 days post HSCT. This observed TA-TMA incidence of 4% was below the historic rate of 18%-40% in a similar population of allogeneic and autologous patients. CONCLUSIONS: Our study provides evidence that defibrotide prophylaxis is feasible in pediatric patients undergoing HSCT at high risk for TA-TMA and preliminary data indicating that defibrotide may reduce the risk of TA-TMA.

Concurrent Subcutaneous Panniculitis-like T-Cell Lymphoma and B-Cell Acute Lymphoblastic Leukemia in 2 Pediatric Patients.

Subcutaneous panniculitis-like T-cell lymphoma is a cutaneous lymphoma characterized by CD8+ T-cell infiltrate in the subcutis that is rare in children. Acute lymphoblastic lymphoma is the most common pediatric malignancy and often presents with fevers and pancytopenia. Herein, we report 2 pediatric patients presenting with subcutaneous panniculitis-like T-cell lymphoma and B-cell acute lymphoblastic lymphoma, distinct hematologic malignancies arising from different lymphoid lineages, with no identifiable germline cancer predisposition.

Preclinical efficacy of daratumumab in T-cell acute lymphoblastic leukemia.

As a consequence of acquired or intrinsic disease resistance, the prognosis for patients with relapsed or refractory T-cell acute lymphoblastic leukemia (T-ALL) is dismal. Novel, less toxic drugs are clearly needed. One of the most promising emerging therapeutic strategies for cancer treatment is targeted immunotherapy. Immune therapies have improved outcomes for patients with other hematologic malignancies including B-cell ALL; however no immune therapy has been successfully developed for T-ALL. We hypothesize targeting CD38 will be effective against T-ALL. We demonstrate that blasts from patients with T-ALL have robust surface CD38 surface expression and that this expression remains stable after exposure to multiagent chemotherapy. CD38 is expressed at very low levels on normal lymphoid and myeloid cells and on a few tissues of nonhematopoietic origin, suggesting that CD38 may be an ideal target. Daratumumab is a human immunoglobulin G1κ monoclonal antibody that binds CD38, and has been demonstrated to be safe and effective in patients with refractory multiple myeloma. We tested daratumumab in a large panel of T-ALL patient-derived xenografts (PDX) and found striking efficacy in 14 of 15 different PDX. These data suggest that daratumumab is a promising novel therapy for pediatric T-ALL patients.

Manipulating DNA damage-response signaling for the treatment of immune-mediated diseases.

Antigen-activated lymphocytes undergo extraordinarily rapid cell division in the course of immune responses. We hypothesized that this unique aspect of lymphocyte biology leads to unusual genomic stress in recently antigen-activated lymphocytes and that targeted manipulation of DNA damage-response (DDR) signaling pathways would allow for selective therapeutic targeting of pathological T cells in disease contexts. Consistent with these hypotheses, we found that activated mouse and human T cells display a pronounced DDR in vitro and in vivo. Upon screening a variety of small-molecule compounds, we found that potentiation of p53 (via inhibition of MDM2) or impairment of cell cycle checkpoints (via inhibition of CHK1/2 or WEE1) led to the selective elimination of activated, pathological T cells in vivo. The combination of these strategies [which we termed "p53 potentiation with checkpoint abrogation" (PPCA)] displayed therapeutic benefits in preclinical disease models of hemophagocytic lymphohistiocytosis and multiple sclerosis, which are driven by foreign antigens or self-antigens, respectively. PPCA therapy targeted pathological T cells but did not compromise naive, regulatory, or quiescent memory T-cell pools, and had a modest nonimmune toxicity profile. Thus, PPCA is a therapeutic modality for selective, antigen-specific immune modulation with significant translational potential for diverse immune-mediated diseases.