Automated Capture and Analysis of Circulating Tumor Cells in Pediatric, Adolescent and Young Adult Patients with Central Nervous System Tumors.

Tumors of the central nervous system (CNS) are the most common and lethal childhood malignancy. Detection of residual disease and longitudinal monitoring of treatment response in patients are challenging and rely on serial imaging. This current standard of care fails to detect microscopic disease or provide molecular characteristics of residual tumors. As such, there is dire need for minimally invasive liquid biopsy techniques. We have previously shown the high specificity of using cell surface vimentin (CSV) to identify circulating tumor cells (CTCs) from patients bearing various types of cancers. Here, we describe the first report of CTCs captured from peripheral blood samples in 58 pediatric CNS tumor patients. In this study, we used a CSV-coated cell capture chip, the Abnova CytoQuest automated CTC isolation system, to boost the CTC capture from pediatric patients with CNS tumors. We successfully isolated CTCs in six glioma patients using immunostaining of histone H3 lysine27-to-methionine (H3K27M) mutations which are highly expressed by this tumor. We show that CSV is a viable marker for CNS CTC isolation and that this is a feasible method for detecting microscopic disease. Larger-scale studies focusing on CTCs in pediatric CNS tumors to explore their diagnostic and prognostic value are warranted.

Impact of Biomarker-Matched Therapies on Outcomes in Patients with Sarcoma Enrolled in Early-Phase Clinical Trials (SAMBA 101).

PURPOSE: Developing new therapeutics for any of the more than 100 sarcoma subtypes presents a challenge. After progression from standard therapies, patients with sarcoma may be referred for enrollment in early-phase trials. This study aimed to investigate whether enrollment in biomarker-matched early-phase clinical trials leads to better outcomes for patients with advanced sarcoma. EXPERIMENTAL DESIGN: In this retrospective analysis, investigational treatment characteristics and longitudinal survival outcomes were analyzed in patients with biopsy-confirmed sarcoma enrolled in early-phase trials at MD Anderson Cancer Center from May 2006 to July 2021. RESULTS: Five hundred eighty-seven patients were included [405 soft tissue, 122 bone, 60 gastrointestinal stromal tumor (GIST); median of three prior lines of therapy]. Most common subtypes were leiomyosarcoma (17.2%), liposarcoma (14.0%), and GIST (10.2%). Molecular testing was available for 511 patients (87.1%); 221 patients (37.6%) were treated in matched trials. Overall response rate was 13.1% matched compared with 4.9% in unmatched (P < 0.001); the clinical benefit rate at 6 months was 43.9% vs. 19.9% (P < 0.001). Progression-free survival was longer for patients in matched trials (median, 5.5 vs. 2.4 months; P < 0.001), and overall survival was also superior for patients in matched trials (median, 21.5 vs. 12.3 months; P < 0.001). The benefit of enrollment in matched trials was maintained when patients with GIST were excluded from the analysis. CONCLUSIONS: Enrollment in biomarker-matched early-phase trials is associated with improved outcomes in heavily pretreated patients with metastatic sarcoma. Molecular testing of tumors from patients with advanced sarcoma and enrollment in matched trials is a reasonable therapeutic strategy.

Trastuzumab Deruxtecan, Antibody-Drug Conjugate Targeting HER2, Is Effective in Pediatric Malignancies: A Report by the Pediatric Preclinical Testing Consortium.

HER2 is expressed in many pediatric solid tumors and is a target for innovative immune therapies including CAR-T cells and antibody-drug conjugates (ADC). We evaluated the preclinical efficacy of trastuzumab deruxtecan (T-DXd, DS-8201a), a humanized monoclonal HER2-targeting antibody conjugated to a topoisomerase 1 inhibitor, DXd, in patient- and cell line-derived xenograft (PDX/CDX) models. HER2 mRNA expression was determined using RNA-seq and protein expression via IHC across multiple pediatric tumor PDX models. Osteosarcoma (OS), malignant rhabdoid tumor (MRT), and Wilms tumor (WT) models with varying HER2 expression were tested using 10 mice per group. Additional histologies such as Ewing sarcoma (EWS), rhabdomyosarcoma (RMS), neuroblastoma (NB), and brain tumors were evaluated using single mouse testing (SMT) experiments. T-DXd or vehicle control was administered intravenously to mice harboring established flank tumors at a dose of 5 mg/kg on day 1. Event-free survival (EFS) and objective response were compared between treatment and control groups. HER2 mRNA expression was observed across histologies, with the highest expression in WT (median = 22 FPKM), followed by MRT, OS, and EWS. The relationship between HER2 protein and mRNA expression was inconsistent. T-DXd significantly prolonged EFS in 6/7 OS, 2/2 MRT, and 3/3 WT PDX models. Complete response (CR) or maintained CR (MCR) were observed for 4/5 WT and MRT models, whereas stable disease was the best response among OS models. SMT experiments also demonstrated activity across multiple solid tumors. Clinical trials assessing the efficacy of a HER2-directed ADC in pediatric patients with HER2-expressing tumors should be considered.

Prognostic Value of Cell-Surface Vimentin-Positive CTCs in Pediatric Sarcomas.

BACKGROUND: Despite advances in care, the 5 year overall survival for patients with relapsed and or metastatic sarcoma remains as low as < 35%. Currently, there are no biomarkers available to assess disease status in patients with sarcomas and as such, disease surveillance remains reliant on serial imaging which increases the risk of secondary malignancies and heightens patient anxiety. METHODS: Here, for the first time reported in the literature, we have enumerated the cell surface vimentin (CSV+) CTCs in the blood of 92 sarcoma pediatric and adolescent and young adult (AYA) patients as a possible marker of disease. RESULTS: We constructed a ROC with an AUC of 0.831 resulting in a sensitivity of 85.3% and a specificity of 75%. Additionally, patients who were deemed to be CSV+ CTC positive were found to have a worse overall survival compared to those who were CSV+ CTC negative. We additionally found the use of available molecular testing increased the accuracy of our diagnostic and prognostic tests. CONCLUSIONS: Our findings indicate that CSV+ CTCs have prognostic value and can possibly serve as a measure of disease burden.

Case Discussion and Literature Review: Cancer Immunotherapy, Severe Immune-Related Adverse Events, Multi-Inflammatory Syndrome, and Severe Acute Respiratory Syndrome Coronavirus 2.

Pediatric, adolescent and young adult (AYA) patients receiving novel cancer immunotherapies may develop associated toxicities with overlapping signs and symptoms that are not always easily distinguished from severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection/clinical sequelae. We describe 2 diagnostically challenging cases of SARS-CoV-2 and Multi-Inflammatory Syndrome-Adult (MIS-A), in patients with a history of acute lymphoblastic leukemia following cellular therapy administration and review evolving characterization of both the natural course of SARS-CoV-2 infection and toxicities experienced in younger cancer immunotherapy patients. Vigilant monitoring for unique presentations and epidemiologic surveillance to promptly detect changes in incidence of either condition may be warranted.

Diagnosis, grading and management of toxicities from immunotherapies in children, adolescents and young adults with cancer.

Cancer immunotherapies are associated with remarkable therapeutic response rates but also with unique and severe toxicities, which potentially result in rapid deterioration in health. The number of clinical applications for novel immune effector-cell therapies, including chimeric antigen receptor (CAR)-expressing cells, and other immunotherapies, such as immune-checkpoint inhibitors, is increasing. In this Consensus Statement, members of the Pediatric Acute Lung Injury and Sepsis Investigators (PALISI) Network Hematopoietic Cell Transplantation-Cancer Immunotherapy (HCT-CI) Subgroup, Paediatric Diseases Working Party (PDWP) of the European Society of Blood and Marrow Transplantation (EBMT), Supportive Care Committee of the Pediatric Transplantation and Cellular Therapy Consortium (PTCTC) and MD Anderson Cancer Center CAR T Cell Therapy-Associated Toxicity (CARTOX) Program collaborated to provide updated comprehensive recommendations for the care of children, adolescents and young adults receiving cancer immunotherapies. With these recommendations, we address emerging toxicity mitigation strategies, we advocate for the characterization of baseline organ function according to age and discipline-specific criteria, we recommend early critical care assessment when indicated, with consideration of reversibility of underlying pathology (instead of organ failure scores) to guide critical care interventions, and we call for researchers, regulatory agencies and sponsors to support and facilitate early inclusion of young patients with cancer in well-designed clinical trials.

ABBV-085, Antibody-Drug Conjugate Targeting LRRC15, Is Effective in Osteosarcoma: A Report by the Pediatric Preclinical Testing Consortium.

Membrane protein leucine-rich repeat containing 15 (LRRC15) is known to be expressed in several solid tumors including osteosarcoma. ABBV-085, an antibody-drug conjugate against LRRC15, conjugated to monomethyl auristatin E (MMAE), was studied in osteosarcoma patient-derived xenografts (PDXs) by the Pediatric Preclinical Testing Consortium (PPTC). LRRC15 expression data were obtained from PPTC RNA-sequencing data for the PDX models. The TARGET database was mined for LRRC15 expression in human osteosarcoma. Protein expression was confirmed via IHC in three PDX models. Seven osteosarcoma PDX models (OS1, OS9, OS33, OS34, OS42, OS55, and OS60) with varying LRRC15 gene expression were studied. ABBV-085 was administered at 3 mg/kg (OS33), 6 mg/kg (all seven PDXs), and 12 mg/kg (OS60) weekly for 4 consecutive weeks via intraperitoneal injection. Control cohorts included vehicle and an isotype MMAE-linked antibody. Tumor volumes and responses were reported using PPTC statistical analysis. OS1, OS33, OS42, OS55, and OS60 had high LRRC15 expression while OS9 and OS34 had low LRRC15 expression. ABBV-085 inhibited tumor growth in six of seven PDX models as compared with vehicle control and significantly improved event-free survival in five of seven models as compared with isotype controls. Two models showed maintained complete responses while all others showed progressive disease. Response correlated with LRRC15 expression. ABBV-085's antitumor activity against osteosarcoma PDX suggests LRRC15 may be a rational target for pursuing clinical trials in patients with this disease.

Association of T and N Categories of the American Joint Commission on Cancer, 8th Edition, With Metastasis and Survival in Patients With Orbital Sarcoma.

Importance: No previous studies to date have validated the American Joint Committee on Cancer (AJCC) 8th edition of the TNM classification for orbital sarcoma. Objectives: To determine the prognostic performance of the most recent TNM classification for orbital sarcoma and to identify other prognostic factors for local recurrence, lymph node metastasis, distant metastasis, and death due to disease. Design, Setting, and Participants: This single-center retrospective cohort study included 73 consecutive patients treated for orbital sarcoma from March 1, 2003, through June 30, 2018. Data were analyzed from November 1 to December 31, 2018. Main Outcomes and Measures: T and N categories at presentation and disease-related outcomes, including local recurrence, lymph node metastasis, distant metastasis (DM), and death due to disease (DD). Results: The 73 participants included 43 men (59%), and the median age was 21 (range, 0-77) years. The common histologic types were rhabdomyosarcoma (RMS) (35 [48%]), solitary fibrous tumor/hemangiopericytoma (10 [14%]), and Ewing sarcoma (8 [11%]). The most common TNM designations were T2 N0 M0 (26 [36%]) and T4 N0 M0 (24 [33%]). T category was associated with the risk of all disease-related outcomes, including local recurrence (hazard ratio [HR] for T2 vs T4, 0.22 [95% CI, 0.06-0.81]; HR for T3 vs T4, 0.59 [95% CI, 0.13-2.65]; P = .03), lymph node metastasis by the last follow-up (T1, 1 [14%]; T2, 0; T3, 0; T4, 12 [35%]; P = .001), DM (HR for T2 vs T4, 0.29 [95% CI, 0.08-1.07]; P = .04), and DD (HR of T2 vs T4, 0.16 [95% CI, 0.04-0.73]; HR of T3 vs T4, 0.30 [95% CI, 0.04-2.34]; P = .02). Higher risk of DM and higher risk of DD were associated with disease category of at least T3 (HR for DM, 3.24 [95% CI, 0.89-11.72; P = .06]; HR for DD, 6.32 [95% CI, 1.43-27.95; P = .005]), N1 disease (HR for DM, 13.33 [95% CI, 4.07-43.65; P < .001]; HR for DD, 7.07 [95% CI, 2.45-20.44; P < .001]), tumor size larger than 3 cm (HR for DM, 2.72 [95% CI, 0.92-8.05; P = .06]; HR for DD, 5.79 [95% CI, 1.85-18.14; P < .001]), and age of patient with RMS younger than 1 year or 10 years or older (HR for DM, 6.85 [95% CI, 0.83-56.53; P = .04]; HR for DD, 7.03 [95% CI, 0.85-57.83; P = .04]). Higher risk of local recurrence was associated with disease category of at least T3 (HR for3 cm, 0.27 [95% CI, 0.09-0.77]; P = .009). Higher risk of lymph node metastasis was associated with disease category of at least T3 (odds ratio [OR], 13.33 [95% CI, 1.77-602.30]; P = .004), alveolar RMS (OR, 9.98 [95% CI, 2.13-51.55]; P = .001), and age of patient with RMS younger than 1 year or 10 years or older (OR, 9.20 [95% CI, 1.01-458.29] P = .03). Conclusions and Relevance: In patients with orbital sarcoma, T and N categories at presentation (defined by the AJCC 8th edition classification) correlate with metastasis and survival. These findings appear to support consideration of strict surveillance testing for regional nodal and systemic metastases in patients with orbital sarcoma with disease category of at least T3 and/or N1 disease.

LigaSure Use Decreases Intraoperative Blood Loss Volume and Blood Transfusion Volume in Sarcoma Surgery.

INTRODUCTION: The LigaSure system has been successfully used in thoracic and abdominal surgery. However, to date, its use in the resection of sarcomas has not been systematically studied. We aimed to determine whether the use of the LigaSure system reduces blood loss and blood transfusion volumes in sarcoma surgery. METHODS: One hundred forty-two consecutive patients who underwent sarcoma surgeries between July 2010 and October 2016 were included. Conventional electrocautery alone (n = 91) and with LigaSure (n = 51) were compared. Case-matched samples (n = 46) from each group were additionally compared. RESULTS: The use of the LigaSure system resulted in a significant decrease in mean intraoperative blood loss (P = 0.02) and blood transfusion volume (P = 0.04). Likewise, a significant decrease in both mean and median intraoperative blood loss (P = 0.003; P < 0.0001) was seen with LigaSure in the case-matched analysis. In the soft-tissue sarcoma subgroup, a significant decrease was observed in mean hemoglobin reduction (P = 0.03) and mean intraoperative blood loss with LigaSure (P = 0.04). No adverse perioperative complications attributed to the LigaSure system were identified. CONCLUSIONS: The LigaSure vessel sealing and dividing system is a safe and effective hemostatic tool for deep dissection in bone and soft-tissue sarcoma surgery. LEVEL OF EVIDENCE: Level III, therapeutic study.

A randomized trial of the effectiveness of the neutropenic diet versus food safety guidelines on infection rate in pediatric oncology patients.

BACKGROUND: The neutropenic diet (ND) is prescribed to avoid introduction of bacteria into a host's gastrointestinal tract and reduce infection. Due to a lack of evidence to support the ND, there continues to be debate among pediatric oncologists regarding its usefulness. This prospective randomized controlled trial evaluated the difference in neutropenic infection rates in pediatric oncology patients randomized to Food and Drug Administration approved food safety guidelines (FSGs) versus the ND plus FSGs during one cycle of chemotherapy. PROCEDURE: Pediatric patients receiving cancer treatment with myelosuppressive chemotherapy were eligible. Neutropenic infection was the primary outcome and defined as (i) fever with neutropenia or (ii) hospital admission and treatment for clinical infection and neutropenia. The rate of neutropenic infection was compared with Student's t-test for independent samples. Documented infections were identified by comprehensive chart review and compared between groups using a χ2 test. RESULTS: One hundred fifty patients were randomly assigned to FSGs (n = 73) or ND + FSGs (n = 77). The most common diagnoses were acute lymphoblastic leukemia (32%) and sarcoma (32%). There was no significant difference between the groups in the percentage of patients who developed neutropenic infection: FSGs 33% versus ND + FSGs 35% (P = 0.78). Patients randomized to ND + FSGs reported that following the diet required more effort than those on FSGs alone. CONCLUSION: The ND offers no benefit over FSGs in the prevention of infection in pediatric oncology patients undergoing myelosuppressive chemotherapy and adherence requires more effort for patients and families. Institutions caring for children with cancer should consider replacing ND guidelines with FSGs.

Management of chemotherapy-induced febrile neutropenia in pediatric oncology patients: A North American survey of pediatric hematology/oncology and pediatric infectious disease physicians.

BACKGROUND: Chemotherapy-induced febrile neutropenia (FN) is traditionally managed with hospital admission for parenteral antibiotics until neutropenia resolves. Recent studies have explored risk stratification and the safety of managing "low-risk" patients as outpatients. Few studies have directly assessed pediatric provider preferences for managing FN. PROCEDURE: We conducted a survey of practicing US and Canadian pediatric hematology/oncology (PHO) and pediatric infectious disease (PID) physicians to assess their FN management preferences using case scenarios with varying risk profiles. RESULTS: Twenty-one percent (n = 186) of PHO and 32% (n = 123) of PID physicians completed the survey. Overall, both groups of providers agreed regarding which patients with FN could be managed outpatient. For a child with acute lymphoblastic leukemia receiving maintenance chemotherapy with an absolute neutrophil count (ANC) of 400 cells/µl, 35% (n = 66) of PHO and 49% (n = 60) of PID physicians would consider outpatient management (P = 0.02). Of those physicians selecting inpatient management, 41% (n = 49) of PHO and 52% (n = 33) of PID physicians would be willing to discharge the patient without an increase in ANC, if afebrile with a negative blood culture (P = 0.16). For a similar patient with an ANC of 100 cells/µl, only 23% (n = 35) of PHO and 42% (n = 39) of PID physicians would consider discharge without an increase in ANC (P = 0.002). CONCLUSIONS: Despite the lack of established guidelines for low-risk pediatric FN, a significant proportion of North American physicians report willingness to modify traditional management. This reinforces the need for evidence-based low-risk criteria and outpatient management guidelines to optimize consistency of care for these patients.