Health-related quality of life after a diagnosis of bladder cancer: a longitudinal survey over the first year

OBJECTIVES

To describe the health-related quality of life (HRQoL) of patients in a prospective 12-month observational cohort study of new bladder cancer diagnoses and compare with national cancer and general population surveys.

PATIENTS AND METHODS

A prospective UK study in patients with new bladder cancer diagnoses at 13 NHS Trusts. The HRQoL data were collected at 3, 6, 9 and 12 months. Questionnaires used included: the EuroQoL five Dimensions (EQ-5D), European Organisation for Research and Treatment of Cancer quality of life questionnaire (EORTC QLQ)-30-item core, EORTC QLQ-24-item non-muscle-invasive bladder cancer, and EORTC QLQ-30-item muscle-invasive bladder cancer. Results were compared with the Cancer Quality of Life Survey and Health Survey for England.

RESULTS

A total of 349 patients were recruited, 296 (85%) completed the first (baseline) and 233 (67%) the final survey. The patients underwent transurethral resection of bladder tumour (TURBT) ± intravesical therapy (238 patients, 80%), radical cystectomy/radiotherapy (51, 17%) or palliation (seven, 2%). At baseline, patients needing radical treatment reported worse HRQoL including lower social function (74.2 vs 83.8, P = 0.002), increased fatigue (31.5 vs 26.1, P = 0.03) and more future worries (39.2 vs 29.4, P = 0.005) than patients who underwent TURBT. Post-treatment surveys showed no change/improvements for patients who underwent TURBT but deterioration for the radically treated cohort. At final survey, reports were similar to baseline, regardless of treatment. Radically treated patients continued to report poorer HRQoL including issues with body image (23.4 vs 12.5, P = 0.007) and male sexual function (75.8 vs 40.4, P < 0.001) compared to those who underwent TURBT. Radically treated patients reported lower EQ-5D utility scores and more problems with usual activities than the general population.

DISCUSSION

Patients undergoing TURBT can be reassured regarding HRQoL following treatment. However, those requiring radical treatment report greater changes in HRQoL with the need for appropriate clinical and supportive care to minimise the impact of treatments.

Families' experiences accessing care after genomic sequencing in the pediatric cancer context: "It's just been a big juggle"

Access to genomic sequencing (GS) and resulting recommendations have not been well described in pediatric oncology. GS results may provide a cancer predisposition syndrome (CPS) diagnosis that warrants screening and specialist visits beyond cancer treatment, including testing or surveillance for family members. The Texas KidsCanSeq (KCS) Study evaluated implementation of GS in a diverse pediatric oncology population. We conducted semi-structured interviews (n = 20) to explore experiences of KCS patients' families around learning about a CPS diagnosis and following up on recommended care. We used qualitative content analysis to develop themes and subthemes across families' descriptions of their experiences accessing care and to understand which factors presented barriers and/or facilitators. We found participants had difficulty differentiating which follow-up care recommendations were made for their child's current cancer treatment versus the CPS. In families' access to follow-up care for CPS, organizational factors were crucial: travel time and distance were common hardships, while coordination of care to streamline multiple appointments with different providers helped facilitate CPS care. Financial factors also impacted families' access to CPS-related follow-up care: having financial assistance and insurance were facilitators for families, while costs and lack of insurance posed as barriers for patients who lost coverage during transitions from pediatric to adult care, and for adult family members who had no coverage. Factors related to beliefs and perceptions, specifically perceiving the risk as less salient to them and feeling overwhelmed with the patient's cancer care, presented barriers to follow-up care primarily for family members. Regarding social factors, competing life priorities made it difficult for families to access follow-up care, though having community support alleviated these barriers. We suggest interventions to improve coordination of cancer treatment and CPS-related care and adherence to surveillance protocols for families as children age, such as care navigators and integrating longitudinal genetic counseling into hereditary cancer centers.

In-person and virtual adaptation of an interprofessional palliative care communications skills training course for pediatric oncology clinicians

Purpose

Effective, empathic communication is crucial for pediatric oncology clinicians when discussing palliative and end-of-life (PC/EOL) care with parents of children with cancer. Unfortunately, many parents report inadequate communication at these distressing times. This study evaluates the communication skills training (CST) clinicians received to deliver a PC/EOL communication intervention as part of a multi-site randomized-controlled trial (RCT).

Methods

Clinicians from eight sites formed dyads (one physician and one nurse [RN] or advanced practice provider [APP]) and were trained over 3 days (in-person or virtually). Training was adapted from VitalTalk™ and included didactic instruction, videos, visual aids, and dedicated time to practice with simulated patients. Study participants completed a confidential, post-training online evaluation survey. A self-reported quality assurance checklist was used to measure fidelity to the communication protocol when delivered to parents during the RCT.

Results

Thirty clinicians completed training; 26 completed post-training surveys including twelve (46.1%) physicians, 8 (30.8%) RNs and 6 (23.1%) APPs. Most were female (65.4%); white (80.8%), not Latinx (88.5%); 40-50 years old (53.9%); and in practice over 10 years (65.4%). Nine (34.6%) trained in-person; the rest trained virtually. Ninety-two percent reported the course was valuable or very valuable for developing their PC/EOL communication skills and 96% reported learning something new. Dyads trained virtually had similar fidelity to those trained in-person (95% and 90% respectively) when delivering the PC/EOL communication intervention to parents.

Conclusion

This PC/EOL CST was valuable for improving pediatric oncology clinicians' communication skills, successfully implemented in-person and virtually, and translated effectively into practice.

Circulating tumor DNA sequencing of pediatric solid and brain tumor patients: An institutional feasibility study

The potential of circulating tumor DNA (ctDNA) analysis to serve as a real-time "liquid biopsy" for children with central nervous system (CNS) and non-CNS solid tumors remains to be fully elucidated. We conducted a study to investigate the feasibility and potential clinical utility of ctDNA sequencing in pediatric patients enrolled on an institutional clinical genomics trial. A total of 240 patients had tumor DNA profiling performed during the study period. Plasma samples were collected at study enrollment from 217 patients and then longitudinally from a subset of patients. Successful cell-free DNA extraction and quantification occurred in 216 of 217 (99.5%) of these initial samples. Twenty-four patients were identified whose tumors harbored 30 unique variants that were potentially detectable on a commercially-available ctDNA panel. Twenty of these 30 mutations (67%) were successfully detected by next-generation sequencing in the ctDNA from at least one plasma sample. The rate of ctDNA mutation detection was higher in patients with non-CNS solid tumors (7/9, 78%) compared to those with CNS tumors (9/15, 60%). A higher ctDNA mutation detection rate was also observed in patients with metastatic disease (9/10, 90%) compared to non-metastatic disease (7/14, 50%), although tumor-specific variants were detected in a few patients in the absence of radiographic evidence of disease. This study illustrates the feasibility of incorporating longitudinal ctDNA analysis into the management of relapsed or refractory patients with childhood CNS or non-CNS solid tumors.

Abstract 5932: Clonal mapping phylogenetic and transcriptomic analysis of an M36 PDX amputation lung metastatic osteosarcoma model

Introduction: Osteosarcoma is a primary malignant bone tumor characterized by the production of spindle cells resulting in immature bone formation. It has been revealed that metastatic cancers including osteosarcoma have a subset of cells with different phenotypic and genetic signatures conferring advantage to drive progression and drug resistance within the intra-tumorally heterogeneous population. However, the lack of a defined in vivo model that can identify the rare genetic subpopulation and recapitulate clonal evolution has been a challenge. In this study, we used an established model to track and identify the clonal subpopulations and assess the genetic signatures that confer specific advantages selecting for uncontrolled growth, adaptation and colonization in the lungs.

Methods: We injected barcoded M36 PDX osteosarcoma cells intratibially in ten severe combined immunodeficiency disease (SCID) mice to track the clonal population/subpopulation of cells that metastasize the established primary tumors to the lungs. Limb amputation was performed on the tumor bearing leg upon detection of palpable tumor. Lung tissue was harvested post-amputation following death from metastasis or euthanasia. DNA and RNA from frozen tissues was extracted and analyzed by PCR, NGS, WES and RNA sequencing to map clonality, mutational and evolutionary profiles.

Results: Limb amputation was performed in 7 mice with all mice surviving the surgery. The mean mouse survival following amputation was 46.9 days and the longest survival was 167 days. Four (40%) of the primary tumor bearing mice had lung metastasis. A Shannon-Wiener and Jaccard similarity index show a diversity in clonal architecture between the primary tumors of all mice injected on the same day and a diversity in clonal population in both the primary tumors and their matched lung metastatic nodules. Clonal mapping further revealed 21 unique clones shared in all primary tumors examined. However, the clonal frequencies and distribution varied within each primary tumor and across the tumor samples. Interestingly, clonal frequencies increased in the lung metastatic nodules when compared to their matched primary tumors. Four distinct clones that were present in all the primary tumors were also found in all lung metastatic samples. These unique clones, here in called “seeding clones” may play an important role in the lung metastatic process.

Conclusions: We previously showed that the barcoded osteosarcoma PDX models are inter and intratumorally heterogenous both in vitro and in vivo. In the current model, we identify the multiple tumorigenic seeding clones that potentially act as drivers in the lung metastatic process. Furthermore, we show the dynamic evolutionary relationships between the clones by reconstructing a phylogenetic map of the M36 PDX tumor model.

Funding: Swim Across America, Foster Foundation and the Barbara Epstein Foundation.

Citation Format: Sylvester Jusu, Zhongting Zhang, Zhang Wendong, Zhaohui Xu, Michael Roth, Jonathan Gill, Richard Gorlick. Clonal mapping phylogenetic and transcriptomic analysis of an M36 PDX amputation lung metastatic osteosarcoma 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 5932.

Abstract 1202: Targeting cell adhesion molecule 1 (CADM1) with an antibody drug conjugate for the treatment of osteosarcoma

Introduction: Survival outcomes for patients with osteosarcoma have been stagnant for decades. There is an urgent need to identify new surface targets in osteosarcoma and develop novel therapies to increase cure rates. Antibody-drug conjugates, due to their targeted delivery of cytotoxic payloads to specific targets, are an attractive class of agents for potential use in osteosarcoma.

Methods: We used an integrated proteomic and transcriptomic surfaceome profiling approach to identify cell-surface proteins that are highly expressed in osteosarcoma but minimally expressed on normal tissues. Cell-surface expression of the identified target antigen was validated by IHC and flow cytometry in osteosarcoma cell lines, patient-derived xenograft (PDX) models, and a patient tumor tissue microarray. As a proof of concept, humanized CADM1 antibody (clone PTA021-A1) was conjugated with tesirine (SG3249), a pyrrolobenzodiazepine (PBD) dimer payload. The antitumor activity of this antibody-drug conjugate was tested in vitro and in vivo in osteosarcoma cell lines and PDX models.

Results: Cell Adhesion Molecule 1 (CADM1) was found to be enriched in osteosarcoma at both protein and mRNA levels, while minimally expressed in normal tissues. Flow cytometry validated the cell-surface localization and expression levels of CADM1 in 7 osteosarcoma cell lines. We performed immunohistochemistry (IHC) staining using an osteosarcoma tissue microarray from 37 patients and 19 PDX models. CADM1 was expressed in 100% of the patient samples and PDXs. The newly developed ADC induced cytotoxic effects in 100% (5/5) of osteosarcoma cell lines, with IC 50 at 120h ranging from 0.009 to 0.1 ug/ml. In vivo testing is ongoing. Preliminary data shows objective response and prolonged survival in selected osteosarcoma PDX models. The mice tolerated the ADC well with minimal toxicity.

Conclusions: CADM1 is highly expressed in most osteosarcoma samples and minimally expressed in normal human tissue, which makes it an attractive target for respective antigen-targeting ADC therapies. The CADM1 targeting ADC showed antitumor activities in osteosarcoma preclinical models which may warrant further investigation of CADM1 targeted therapies for osteosarcoma.

Acknowledgments: This work was funded by Swim Across America, the Foster Foundation, the Osteosarcoma Institute Translational and Preclinical Grant, and the Barbara Epstein Foundation.

Citation Format: Yifei Wang, Zhongting Zhang, Wendong Zhang, Xiangjun Tian, Rossana Lazcano, Michael Roth, Jonathan Gill, Douglas Harrison, Zhaohui Xu, Yizheng Tu, Sylvester Jusu, Giuseppe Longo, Xin Zhou, Jing Wang, Richard Gorlick. Targeting cell adhesion molecule 1 (CADM1) with an antibody drug conjugate for the treatment of osteosarcoma [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 1202.

Impact of allogeneic stem cell transplantation on thyroid function

PURPOSE

Primary hypothyroidism is a main endocrine complication after allogeneic stem cells transplantation (allo-SCT) in children, but in adults data on post-SCT hypothyroidism are limited. The aims of this observational, cross-sectional study were to assess the prevalence of hypothyroidism in adult allo-SCT recipients according to time from transplantation, and to identify risk factors.

METHODS

One hundred and eighty-six patients (M 104; F 82; median age 53.4 years) who underwent allo-SCT between January 2010 and December 2017 were enrolled and divided into three groups, according to time from allo-SCT (1-3 years; 3-5 years; > 5 years). Pre-transplant TSH and fT4 levels were available for all patients. After transplantation, TSH, fT4 and anti-thyroperoxidase antibodies (TPO-Ab) were evaluated.

RESULTS

After a follow-up of 3.7 years, 34 (18.3%) patients developed hypothyroidism, with higher prevalence in females (p < 0.001) and in patients who received matched unrelated donor grafts (p < 0.05). No difference in prevalence was found at different time points. Patients who developed hypothyroidism showed higher rate of TPO-Ab positivity (p < 0.05) and higher pre-transplant TSH levels (median 2.34 µU/ml) compared to those with preserved thyroid function (median 1.53 µU/ml; p < 0.001). Multivariable analysis identified higher pre-transplant TSH levels as a positive predictor of hypothyroidism (p < 0.005). The ROC curve analysis identified a pre-SCT TSH cutoff of 1.84 µU/ml, which can predict hypothyroidism with sensitivity 74.1% and specificity 67.2%.

CONCLUSIONS

About one out of four patients developed hypothyroidism after allo-SCT, with a greater incidence in females. Pre-transplant TSH levels seem to predict the onset of post-SCT hypothyroidism.

Disparities in Deceased Donor Kidney Offer Acceptance: A Survey of Canadian Transplant Nephrologists, General Surgeons and Urologists

Background

Significant variability in organ acceptance thresholds have been demonstrated across the United States, but data regarding the rate and rationale for kidney donor organ decline in Canada are lacking.

Objective

To examine decision making regarding deceased kidney donor acceptance and non-acceptance in a population of Canadian transplant professionals.

Design

A survey study of theoretical deceased donor kidney cases of increasing complexity.

Setting

Canadian transplant nephrologists, urologists, and surgeons making donor call decisions responding to an electronic survey between July 22 and October 4, 2022.

Participants

Invitations to participate were distributed to 179 Canadian transplant nephrologists, surgeons, and urologists through e-mail. Participants were identified by contacting each transplant program and requesting a list of physicians who take donor call.

Measurements

Survey respondents were asked whether they would accept or decline a given donor, assuming there was a suitable recipient. They were also asked to cite reasons for donor non-acceptance.

Methods

Donor scenario-specific acceptance rates (total acceptance divided by total number of respondents for a given scenario and overall) and reasons for decline were determined and presented as a percentage of the total cases declined.

Results

In all, 72 respondents from 7 provinces completed at least one question of the survey, with considerable variability between acceptance rates for centers; the most conservative center declined 60.9% of donor cases, whereas the most aggressive center declined only 28.1%, P-value < .001. There was an increased risk of non-acceptance with advancing age, donation after cardiac death, acute kidney injury, chronic kidney disease, and comorbidities.

Limitations

As with any survey, there is the potential for participation bias. In addition, this study examines donor characteristics in isolation, however, asks respondent to assume there is a suitable candidate available. In reality, whenever donor quality is considered, it should be considered in the context of the intended recipient.

Conclusion

In a survey of increasingly medically complex deceased kidney donor cases, there was significant variability in donor decline among Canadian transplant specialists. Given relatively high rates of donor decline and apparent heterogeneity in acceptance decisions, Canadian transplant specialists may benefit from additional education regarding the benefits achieved from even medically complex kidney donors for appropriate candidates relative to remaining on dialysis on the transplant waitlist.

A phase I trial of metformin in combination with vincristine, irinotecan, and temozolomide in children with relapsed or refractory solid and central nervous system tumors: A report from the national pediatric cancer foundation

BACKGROUND

Patients with relapsed and refractory solid and central nervous system (CNS) tumors have poor outcomes and need novel therapeutic options. Vincristine, irinotecan, and temozolomide (VIT) is a common chemotherapy regimen in relapsed pediatric tumors with an established toxicity profile. Metformin shows preclinical anti-cancer activity through multiple pathways.

METHODS

The objective of this Phase I trial was to establish the maximum tolerated dose (MTD) and recommended Phase II dose (RP2D) of metformin in combination with VIT in children with relapsed and refractory solid and CNS tumors. A 3 + 3 design was used to test the addition of metformin at five dose levels (666, 999, 1333, 1666, and 2000 mg/m² /day). Therapy toxicity, pharmacokinetics, and radiologic response to treatment were evaluated.

RESULTS

Twenty-six patients (median age 13 years, range 2-18 years) were enrolled with 22 evaluable for toxicity. The most common diagnoses were Ewing sarcoma (n = 8), rhabdomyosarcoma (n = 3) and atypical teratoid/rhabdoid tumor (n = 3). The MTD was exceeded at Dose Level 5 due to two dose-limiting toxicities; both were Grade 3 diarrhea requiring prolonged hospitalization and intravenous fluids. The MTD was not determined due to study closure with less than six patients enrolled at Dose Level 4. Frequently observed toxicities were gastrointestinal (most notably diarrhea) and hematologic. Amongst 16 patients evaluable for best overall response, there was one complete response (Ewing sarcoma), three partial responses (Ewing sarcoma, glioblastoma multiforme, and alveolar rhabdomyosarcoma), and five patients with stable disease.

CONCLUSIONS

The MTD of VIT with metformin was not determined due to premature study closure. We recommend an RP2D of Dose Level 4, 1666 mg/m² /day. Radiographic responses were seen in multiple tumor types. Further evaluation for efficacy could be investigated in a Phase II trial.

Evaluation of the pan-class I phosphoinositide 3-kinase (PI3K) inhibitor copanlisib in the Pediatric Preclinical Testing Consortium in vivo models of osteosarcoma

Copanlisib is a pan-class I phosphoinositide 3-kinase (PI3K) inhibitor, with activity against all four PI3K class I isoforms (PI3Kα, PI3Kβ, PI3Kγ, and PI3Kδ). Whole-genome and RNA sequencing data have revealed several PI3K aberrations in osteosarcoma tumor samples. The in vivo anticancer effects of copanlisib were assessed in a panel of six osteosarcoma models. Copanlisib induced prolonged event-free survival in five of six osteosarcoma models; however, all models demonstrated progressive disease suggesting minimal activity. While copanlisib did not result in tumor regression, more data are needed to fully explore the role of the PI3K pathway in the pathogenesis of osteosarcoma.

Osteosarcoma

Osteosarcoma is the most common primary malignant tumour of the bone. Osteosarcoma incidence is bimodal, peaking at 18 and 60 years of age, and is slightly more common in males. The key pathophysiological mechanism involves several possible genetic drivers of disease linked to bone formation, causing malignant progression and metastasis. While there have been significant improvements in the outcome of patients with localized disease, with event-free survival outcomes exceeding 60%, in patients with metastatic disease, event-free survival outcomes remain poor at less than 30%. The suspicion of osteosarcoma based on radiographs still requires pathological evaluation of a bone biopsy specimen for definitive diagnosis and CT imaging of the chest should be performed to identify lung nodules. So far, population-based screening and surveillance strategies have not been implemented due to the rarity of osteosarcoma and the lack of reliable markers. Current screening focuses only on groups at high risk such as patients with genetic cancer predisposition syndromes. Management of osteosarcoma requires a multidisciplinary team of paediatric and medical oncologists, orthopaedic and general surgeons, pathologists, radiologists and specialist nurses. Survivors of osteosarcoma require specialized medical follow-up, as curative treatment consisting of chemotherapy and surgery has long-term adverse effects, which also affect the quality of life of patients. The development of osteosarcoma model systems and related research as well as the evaluation of new treatment approaches are ongoing to improve disease outcomes, especially for patients with metastases.

The utilization and mortality benefits of pulmonary artery catheterization in patients with cardiogenic shock

Introduction

Pulmonary artery catheterization (PAC) can provide essential hemodynamic data to assist in managing critical patients with cardiogenic shock. The use of PAC has been controversial as clinical studies have shown a lack of benefit. However, with the recent widespread availability of mechanical circulatory assists devices, the application and benefits of PAC are expected to rise.

Purpose

To determine the impact of PAC on inpatient outcomes and the utilization of advanced heart failure devices in these patients.

Methods

The National Inpatient Sample from 2016 to 2018 was queried to identify patients with cardiogenic shock. Of these patients, we compared those who received invasive hemodynamic monitoring (IHM) with PAC to those who did not receive PAC. Patients under age 18 and those undergoing surgical or transcatheter cardiac procedures during the same admission were excluded. Multivariate logistic regression was used to select matched samples between groups accounting for patient/hospital demographics and medical comorbidities. The primary endpoint was a comparison of in-hospital mortality, length of hospitalization, and medical costs. The secondary endpoints compared the utilization of mechanical circulatory assists devices: percutaneous ventricular assist devices (pVAD), extracorporeal membrane oxygenation (ECMO), and left ventricular assist device (LVAD), and the incidence of post-PAC complications: pneumothorax, sepsis, and hemorrhage/hematoma.

Results

We identified a total of 279,619 patients admitted with cardiogenic shock, of these patients 25,166 (9%) received IHM with PAC. Patients who had PAC had decreased in-hospital mortality (22.3% vs 29.7%; p&lt;0.001), increased length of hospitalization (12 days vs 9 days; p&lt;0.001), and increased medical costs ($65,884 vs $47,983; p&lt;0.001). Furthermore, in patients with PAC there was increased utilization of pVAD (4.5% vs 1.9%; p&lt;0.001), ECMO (0.07% vs 0.01%; p&lt;0.001), and LVAD (2.2% vs 0.3%; p&lt;0.001). There was no difference in the prevalence of post-PAC complications between both groups.

Conclusions

The use of IHM with PAC was associated with improved mortality and utilization of mechanical circulatory assist devices in patients with cardiogenic shock without increasing risk for post-procedural complications. Therefore, the increased average duration and medical costs of hospitalization with PAC patients likely resulted from improved patient survival. Therefore, the present study indicated that IHM with PAC is safe and beneficial for patients with cardiogenic shock.

Funding Acknowledgement

Type of funding sources: None.

IL12 immune therapy clinical trial review: Novel strategies for avoiding CRS-associated cytokines

Interleukin 12 (IL-12) is a naturally occurring cytokine that plays a key role in inducing antitumor immune responses, including induction of antitumor immune memory. Currently, no IL-12-based therapeutic products have been approved for clinical application because of its toxicities. On the basis of this review of clinical trials using primarily wild-type IL-12 and different delivery methods, we conclude that the safe utilization of IL-12 is highly dependent on the tumor-specific localization of IL-12 post administration. In this regard, we have developed a cell membrane-anchored and tumor-targeted IL-12-T (attIL12-T) cell product for avoiding toxicity from both IL-12 and T cells-induced cytokine release syndrome in peripheral tissues. A phase I trial using this product which seeks to avoid systemic toxicity and boost antitumor efficacy is on the horizon. Of note, this product also boosts the impact of CAR-T or TCR-T cell efficacy against solid tumors, providing an alternative approach to utilize CAR-T to overcome tumor resistance.

Abstract 3975: Clonal emergence of resistance to methotrexate in osteosarcoma barcoded PDX cells

Introduction: Osteosarcoma is known to have significant intratumoral heterogeneity. In order to elucidate the clonal emergence of resistance to targeted and cytotoxic chemotherapy in osteosarcoma we have worked on barcoding our cell lines derived from patient derived xenograft (PDX) models.

Methods: The cell lines were derived from the PDX models by disaggregation and serial culture using STR to confirm the identity of each of the derived cell lines. The cell lines were barcoded using a lentiviral vector to transduce cells with a unique DNA transcript that was incorporated into the tumor cell genome. Two different cytoxicity assays, the Alamar Blu Cytotoxicity test in combination with the Incucyte® Cytotxicity Assay protocol, were used to evaluate the resistance of the PDX cells to the drug Methotrexate (MTX) that is largely used in the treatment of this disease. Further evaluation of the clonality of the resistant cells will be performed by sequencing the barcodes which will be complemented by functional assays of MTX transport, metabolism and target inhibition.

Results: The PDX derived cell lines (n=10) were exposed to serial concentrations of MTX with different exposure durations obtaining the IC50 (range 0.23-376 uM) and IC95 (range 0.8- 4500 uM) for each PDX cell line. Subsequently every PDX cell line previously tested was exposed to the IC95 of MTX, in the same conditions used before, in order to obtain clones resistant to MTX. Numerous clones (72 clones from 10 cell lines) have been obtained. For each clone DNA and RNA has been extracted in order to perform sequencing of the DNA barcoded to determine if the genomic signature of the resistant clones is present in a subpopulation at the onset of treatment and if resistance arises from Darwinian selection or from stochastic alterations during and potentially related to treatment lead to emergence of a new resistant phenotype. RNA sequencing (RNA-Seq) will suggest the pathway alterations that may be associated with the emergence of resistance. Functional assays of MTX resistance will further define the basis of the resistance that emerged.

Conclusion: Barcoded PDX derived osteosarcoma cell lines have been created with resistant clones obtained after MTX treatment. Sequencing of barcodes, RNA-Seq profiling and functional assays will yield critical information on the clonality and mechanisms of resistance which will be presented. This work was supported by SAA, Inc., The Foster Foundation and the Barbara Epstein Foundation. Richard Gorlick receives support as the H. Grant Taylor, M.D., W.W. Sutow, M.D. and Margaret P. Sullivan, M.D. Distinguished Chair.

Citation Format: Giuseppe Longo, Sylvester Jusu, Zhongting Zhang, Zhaohui Xu, Wendong Zhang, Michael Roth, Rui Yang, Douglas Harrison, Jonathan Gill, Richard Gorlick. Clonal emergence of resistance to methotrexate in osteosarcoma barcoded PDX cells [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 3975.

Abstract 2016: Preclinical evaluation of uPARAP (MRC2) antibody-drug conjugates (ADCE-003,010,011) in osteosarcoma pdx models

Introduction: Antibody-drug Conjugates (ADCs) targeting differentially expressed tumor cell-surface antigens show robust clinical activity in several solid tumor cancers, but none is yet available for osteosarcoma. Due to the high unmet medical need in this indication, there is an urgent requirement to identify respective osteosarcoma cell-surface antigens and evaluate the antitumor activity of an ADC that can deliver tailored cytotoxic payloads to osteosarcoma tumors expressing these targets.

Methods: We used an integrated proteomic and transcriptomic surfaceome profiling approach to identify cell-surface proteins that are highly expressed in osteosarcoma but minimally expressed on normal tissues. uPARAP (MRC2) was found to be enriched in osteosarcoma at both protein and mRNA levels. The cell-surface expression of uPARAP (MRC2) was further validated by IHC and flow cytometry with osteosarcoma cell lines, PDX models, and patient tumor tissue microarray. As a proof of concept, three MRC2 targeted ADCs with different Microtubulin- and alkylating agent types of payloads were tested in 8 osteosarcoma PDX models. uPARAP (MRC2) ADC, control ADC, or vehicle control was administered IV to mice harboring flank tumors at a dose of 3mg/kg, weekly X 3 (ADCE-003), 2mg/kg on Day 1 (ADCE-010), and 10mg/kg weekly X 2 (ADCE-011). EFS for treatment (T) and control (C) groups, minimum relative tumor volume (minRTV), and objective response measures were analyzed.

Results: Western blotting confirmed the expression of uPARAP (MRC2) in 8 osteosarcoma cell lines and 8 PDX models. Flow cytometry further validated cell-surface localization and expression levels of uPARAP (MRC2) in 7 osteosarcoma cell lines. We then performed immunohistochemistry (IHC) staining using an osteosarcoma tissue microarray from 37 patients and 19 PDX models. uPARAP (MRC2) was expressed in 97% of the patient samples and 95% of the PDXs. 51% of the patient samples and 39% of the PDXs had an overall H-score of 100 or higher. Mice tolerated ADCs well with minimal toxicity. All 3 ADCs significantly prolonged EFS in 6/8 osteosarcoma models. Complete response (CR) or maintained CR were observed in 2 models in ADCE-010 and ADCE-011 groups, respectively.

Conclusions: uPARAP (MRC2) is highly expressed in most osteosarcoma samples, which makes it a viable target for respective antigen targeting ADC therapies. Three uPARAP (MRC2) targeting ADCs showed antitumor activities in osteosarcoma preclinical models which warrant further investigation of uPARAP targeting ADC therapies for osteosarcoma.

Citation Format: Yifei Wang, Wendong Zhang, Zhongting Zhang, Xiangjun Tian, Rossana Lazcano, Pooja Hingorani, Michael Roth, Jonathan Gill, Douglas Harrison, Zhaohui Xu, Jing Wang, Niels Behrendt, Christoffer F. Nielsen, Lars H. Engelholm, Richard Gorlick. Preclinical evaluation of uPARAP (MRC2) antibody-drug conjugates (ADCE-003,010,011) in osteosarcoma pdx models [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 2016.

RONC-06. Stereotactic radiosurgery and stereotactic radiotherapy for pediatric brain metastases or recurrences

BACKGROUND/PURPOSE: Stereotactic radiosurgery (SRS) and stereotactic radiotherapy (SRT) deliver highly conformal, ablative doses of radiation over 1–5 treatments, while minimizing dose to surrounding normal tissues. To document toxicities and outcomes of these treatments in children, our updated institutional experience with SRS or SRT for intracranial targets in pediatric patients was reviewed. METHODS: On an IRB approved study, institutional databases were reviewed to identify pediatric patients with intracranial lesions treated with SRS or SRT from October 2009 to July 2021. Medical records were retrospectively reviewed for patient and treatment characteristics. Outcomes were analyzed for symptomatic radionecrosis and CNS progression. RESULTS: Thirty SRS or SRT treatment courses in 26 patients age 3.2 to 17.8y (median, 15.6y) at the time of SRS or SRT were identified. Twenty-two patients had one treatment and four had two treatments. Sixteen patients had brain metastases from extracranial primary disease; 10 had recurrence of a primary CNS tumor. Fifteen patients had prior fractionated radiation to the brain. Nineteen treatments used Gamma Knife (GK) with Leksell frame, three used GK ICON with mask, and eight used linear accelerator with volumetric modulated arc therapy with thermoplastic mask. All patients (10 treatments in nine patients) treated since July 2016 received mask-based radiation. Twelve of 26 (46%) patients were treated with anesthesia. With 9.6-month median follow up (range, 0.1-96.2m), five patients had progression of treated lesions, eight had distant CNS failure, and one had both local and distant failure, for a crude local failure rate of 6/26 (23%) and a crude distant failure rate of 9/26 (35%). There were no skull fractures or other complications from Leksell frame placement. One patient developed symptomatic radionecrosis requiring surgery. CONCLUSION: SRS and SRT can be safely performed in pediatric patients with intracranial lesions. Mask-based immobilization provides an alternative to frame-based treatments.

Diffusely abnormal white matter in clinically isolated syndrome is associated with parenchymal loss and elevated neurofilament levels

We characterized the frequency of diffusely abnormal white matter (DAWM) across a broad spectrum of multiple sclerosis (MS) participants. 35% of clinically isolated syndrome (CIS), 57% of relapsing remitting and 64% of secondary progressive MS participants demonstrated DAWM. CIS with DAWM had decreased cortical thickness, higher lesion load and a higher concentration of serum neurofilament light chain compared to CIS without DAWM. DAWM may be useful in identifying CIS patients with greater injury to their brains. Larger and longitudinal studies are warranted.

Comparing outcomes of transcatheter versus surgical aortic valve replacement in patients with atrial arrythmias

Introduction

In patients with severe aortic valve stenosis, clinical trials have demonstrated a similar mortality risk with transcatheter aortic valve replacement (TAVR) compared to surgical aortic valve replacement (SAVR) in low to intermediate-risk patients. However, data comparing these procedures in patients with atrial arrhythmias is lacking.

Purpose

This study aimed to evaluate and compare the in-hospital mortality and outcomes of TAVR and SAVR for severe aortic stenosis in patients with atrial fibrillation or atrial flutter.

Methods

We performed a retrospective cross-sectional analysis using the 2018 National Inpatient Sample. Patients aged 50 years and older with TAVR or SAVR related hospitalizations were identified. Patients with endocarditis and those undergoing coronary artery bypass grafting or other valvular procedures were excluded. Propensity score matching was utilized to mitigate selection bias. The scoring was based on a multivariate logistic regression model accounting for age, gender, race, hospital type, hospital region, hospital teaching status, median household income, and medical comorbidities. Using 8-to-1-digit match, we paired each admission in TAVR group with one admission in SAVR group.

Results

In 2018, a total of 3487 TAVRs and 1466 SAVRs were performed in patients who had atrial fibrillation or atrial flutter. TAVR and SAVR had no statistically significant difference in inpatient mortality (0.9% vs 0.8%, p=0.79). However, SAVR was associated with higher odds of cardiogenic shock (OR 1.82; 95% CI 1.41–2.35, p&lt;0.0001), acute kidney injury (OR 2.29; 95% CI 1.77–2.97, p&lt;0.0001), mechanical ventilation (OR 2.06; 95% CI 1.75–2.43, p&lt;0.0001), pneumonia (OR 1.76; 95% CI 1.37–2.28, p&lt;0.0001), pneumothorax (OR 6.38; 95% CI 4.17–9.76, p&lt;0.0001) and postoperative hemorrhage (OR 3.21; 95% CI 2.13–4.85, p&lt;0.0001). On the contrary, SAVR was associated with decreased likelihood of subsequent cardiac conduction disorders (OR 0.63; 95% CI 0.51–0.79, p&lt;0.0001) and pacemaker implantation (OR 0.69; 95% CI 0.49–0.98, p=0.037). SAVR was associated with an increased length of hospitalization (3.9 vs. 8.4 days, p&lt;0.0001), with no difference in medical costs.

Conclusion

Inpatient mortality for TAVR and SAVR was similar in patients with atrial fibrillation and atrial flutter. TAVR was associated with a lower risk of inpatient complications, indicating greater suitability for high-risk patients. However, clinicians should be cognizant of the increased risk for cardiac conduction disorders after TAVR, necessitating pacemaker implantation.

Funding Acknowledgement

Type of funding sources: None. Characteristics of the matched cohortForest plot comparing outcomes

Comparing the adverse outcomes of left atrial appendage occlusion in patients with diabetes

Introduction

In patients with atrial fibrillation, it is estimated that greater than 90 percent of left atrial thrombi are located in the left atrial appendage. Multiple percutaneously implanted devices have been approved worldwide for left atrial appendage occlusion (LAAO) to reduce stroke risk in patients not suitable for long-term oral anticoagulation. Device implantation has been associated with a high success rate and low risk for peri-procedural complications. However, as the prevalence of diabetes continues to rise, there is a considerable need to establish peri-procedural risk in these patients.

Purpose

This study aimed to evaluate and compare the in-hospital outcomes of LAAO in patients with and without diabetes.

Methods

We performed a retrospective cross-sectional analysis using the 2018 National Inpatient Sample. All patients aged 18 years and older with atrial fibrillation and LAAO-related hospitalizations were included in this study. To mitigate selection bias and control for patient and institutional imbalances, propensity scoring method was used to select matched sample between patients with diabetes and patients without diabetes. The scoring was based on a multivariate logistic regression model accounting for age, gender, race, hospital type, hospital region, hospital teaching status, median household income, and medical comorbidities. Using an 8-to-1-digit match, we paired each admission in the diabetes group with one admission without diabetes.

Results

We identified a total of 3572 patients admitted for LAAO; 1298 of these patients had comorbid diabetes. Diabetics did not have a higher risk of in-hospital mortality with LAAO (0.2% vs 0.3%, p=0.620). The risk for 17 out of the 18 identified peri-procedural complications was similar in patients with and without diabetes. However, diabetes was associated with an increased risk of acute kidney injury (Adjusted OR 1.75; 95% CI 1.05–2.93, p=0.03). Interestingly, 0 endocarditis events were captured in both groups, indicating that this complication is only seen in long-term follow-up and had a peri-procedural risk of 0%.

Conclusion

As the use of implantable LAAO devices increases worldwide, clinicians should be cognizant of the increased risk for peri-procedural acute kidney injury in diabetics. Patients with diabetes often have diabetes-induced chronic kidney disease with susceptibility to acute injury. Therefore, volume status should be closely monitored in the peri-procedural period to mitigate further damage to the kidneys in these patients.

Funding Acknowledgement

Type of funding sources: None. Characteristics of the matched cohortOutcomes in the matched cohort

1543 Response to Neoadjuvant Chemotherapy as An Indication for Breast-Conserving Surgery

Aim

Pathological response to neoadjuvant chemotherapy (NAC) seeks to induce tumour regression pre-operatively. The present study aimed to assess tumour response to NAC and to evaluate the appropriateness of subsequent breast-conserving surgery (BCS) to avoid disfiguration of healthy breast tissue.

Method

Analysis of all patients undergoing NAC and wide local excision (WLE) surgery for primary breast cancer between April 2012 and December 2020 at a tertiary breast unit was conducted. Statistical analysis was performed using IBM® SPSS Statistics Software v27.0.

Results

A database of 1490 female patients undergoing WLE was retrieved, of whom 88 received NAC. Average patient age was 56 (SD = 11). Tumours were either invasive ductal (n = 86, 97.7%) or lobular (n = 2, 2.27%) carcinomas and grade 2 (n = 31, 35.2%) or grade 3 (n = 57, 64.8%). Chemotherapy regimens included: 30 FEC-T (34.1%), 22 FEC (25%), 19 TC (21.6%) and 17 other (19.3%). On average, tumour diameter (mm) decreased by 45.9%(34.5) with NAC and a further 2.29%(57.7) from NAC cessation to excision. Tumour diameter varied significantly across time points χ2 (3) = 29.057, p &lt; 0.001. Post-hoc tests revealed a significant reduction in tumour diameter from pre- to post-NAC [Mean(SD):

Conclusions

Tumour diameter significantly reduced with the addition of NAC. There was no statistical difference between post-NAC and post-operative diameter, suggesting no growth between NAC cessation and surgery. Our findings support the use of NAC, where possible, to avoid the need for large resection margins.

Abstract LB252: Evaluation of the pan-class I phosphoinositide 3-kinase (PI3K) inhibitor copanlisib in the Pediatric Preclinical Testing Consortium osteosarcoma in vivo models

Background. Copanlisib is a pan-class I phosphoinositide 3-kinase (PI3K) inhibitor with activity against all four PI3K class I isoforms (PI3Kα, PI3Kβ, PI3Kγ, and PI3Kδ). Copanlisib was approved for use by the FDA in the treatment of refractory follicular lymphoma in 2017. Preclinical data have suggested that deregulation of the PI3K pathway is a key driver of multiple malignancies. The relevance of this pathway in osteosarcoma tumorigenesis remains a subject of debate, however, whole genome and RNA sequencing data have revealed several PI3K aberrations in osteosarcoma tumor samples. The in vivo effects of copanlisib were studied in the Pediatric Preclinical Testing Consortium osteosarcoma xenograft models. Methods. The in vivo anticancer effects of copanlisib were assessed in a panel of 6 osteosarcoma models (OS-2, OS-9, OS-31, OS-33, OS-36, and OS-60). Copanlisib was administered by oral gavage at a dose of 10 mg/kg/day, two days on and five days off, repeated weekly for 4 weeks. Time to event and tumor volume responses were defined and analyzed utilizing standard PPTC statistical methods. Results. Copanlisib was well tolerated in the models with minimal weight loss and no treatment related mortality as compared to controls. Copanlisib induced prolonged event-free survival (EFS) in 5/6 osteosarcoma models (p&lt;0.05, Gehan-Wilcoxon). Tumor regression (mean minimum attained relative tumor volume (minRTV) &lt; 1.0) was not observed for any of the tested models. 3/6 models exhibited lower min RTV compared to untreated controls (p &lt; 0.05, Wilcoxon rank sum). All osteosarcoma models showed progressive disease as their objective response measure. Conclusions. While copanlisib induced prolonged EFS in 5/6 osteosarcoma models, no tumor regression was seen, with all models developing progressive disease suggesting minimal activity. While copanlisib did not result in tumor regression, further study is needed to fully explore the role of the PI3K pathway in the pathogenesis of osteosarcoma.

Citation Format: Douglas Harrison, Jonathan Gill, Pooja Hingorani, Michael Roth, Wendong Zhang, Beverly Teicher, Eric J. Earley, Stephen W. Erickson, Gregory Gatto, Raushan T. Kurmasheva, Peter J. Houghton, Malcolm A. Smith, Edward A. Kolb, Richard Gorlick. Evaluation of the pan-class I phosphoinositide 3-kinase (PI3K) inhibitor copanlisib in the Pediatric Preclinical Testing Consortium osteosarcoma in vivo models [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr LB252.

Advancing therapy for osteosarcoma

Improving the survival of patients with osteosarcoma has long proved challenging, although the treatment of this disease is on the precipice of advancement. The increasing feasibility of molecular profiling together with the creation of both robust model systems and large, well-annotated tissue banks has led to an increased understanding of osteosarcoma biology. The historical invariability of survival outcomes and the limited number of agents known to be active in the treatment of this disease facilitate clinical trials designed to identify efficacious novel therapies using small cohorts of patients. In addition, trial designs will increasingly consider the genetic background of the tumour through biomarker-based patient selection, thereby enriching for clinical activity. Indeed, osteosarcoma cells are known to express a number of surface proteins that might be of therapeutic relevance, including B7-H3, GD2 and HER2, which can be targeted using antibody-drug conjugates and/or adoptive cell therapies. In addition, immune-checkpoint inhibition might augment the latter approach by helping to overcome the immunosuppressive tumour microenvironment. In this Review, we provide a brief overview of current osteosarcoma therapy before focusing on the biological insights from the molecular profiling and preclinical modelling studies that have opened new therapeutic opportunities in this disease.

Initial in vivo testing of TPO-receptor agonist eltrombopag in osteosarcoma patient-derived xenograft models by the pediatric preclinical testing consortium

Eltrombopag is a small molecule, thrombopoietin receptor agonist approved for the treatment of patients with aplastic anemia and chronic immune thrombocytopenia. It is also a polyvalent cation chelator and inhibits leukemia cell proliferation via reduction of intracellular iron. The in vivo efficacy of eltrombopag was tested against a panel of six Pediatric Preclinical Testing Consortium osteosarcoma xenografts at doses of 5 mg/kg/day (moderate dose) and 50 mg/kg/day (high dose). Eltrombopag, at moderate doses, failed to significantly improve event-free survival (EFS) in 6/6 models. At high doses, eltrombopag significantly prolonged EFS in 2/2 models, though the effect size was small. All models tested demonstrated progressive disease. While eltrombopag did not meaningfully inhibit osteosarcoma growth, it also did not stimulate tumor growth, suggesting it may be safely investigated as a supportive care agent to enhance platelet recovery post chemotherapy.

PATH-29. HIGH FREQUENCY OF CLINICALLY-RELEVANT TUMOR VARIANTS DETECTED BY MOLECULAR TESTING OF HIGH-RISK PEDIATRIC CNS TUMORS – PRELIMINARY FINDINGS FROM THE TEXAS KidsCanSeq STUDY

BACKGROUND

DNA and RNA-based tumor sequencing tests have the potential to guide the clinical management of children with CNS tumors. However, data describing the utility of these tests are limited.

METHODS

Children with high-risk or recurrent CNS tumors are included in the diverse cohort of patients enrolling in the KidsCanSeq study from six Texas sites. DNA and RNA from FFPE tumor is subjected to targeted sequencing using a 124-gene mutation panel and an 81-gene fusion panel. Tumor capture transcriptome sequencing, exome sequencing, and copy number array (as well as germline panel and exome testing) are also performed. Tumor variants are classified using AMP/ASCO/CAP consensus guidelines.

RESULTS

A total of 74 children with high-risk/recurrent CNS tumors enrolled as of 1/28/20. Targeted tumor DNA and RNA panel testing was completed for 57 patients with varied diagnoses. At least one tumor variant with strong or potential clinical significance was identified in 43 of 57 (75%) tumors, with therapeutic significance in 20 of 57 (35%) tumors. The 38 therapeutically-relevant variants most frequently affected MAPK signaling (BRAF x9, EGFR x3, FGFR2, FGFR3, KRAS, NF1, NTRK2) and the AKT/mTOR pathway (PIK3CA x3, PTEN x2, mTOR, TSC1, PIK3R1). Most had not been detected by prior targeted diagnostic testing (27/38, 71%).

CONCLUSION

Integrated DNA and RNA-based panel testing identified variants with potential to impact clinical decision-making in a majority of children with high-risk/recurrent CNS tumors. The comparative yield of panel testing vs. exome/transcriptome/array will be evaluated in the KidsCanSeq study cohort.

Dose-response effect of eribulin in preclinical models of osteosarcoma by the pediatric preclinical testing consortium

The pediatric preclinical testing program previously demonstrated activity of eribulin in osteosarcoma patient-derived xenograft (PDX) models. The phase 2 trial in patients with relapsed osteosarcoma failed to meet response endpoints. Eribulin was evaluated in the original and an expanded set of PDX models and tested at multiple dose levels and schedules to evaluate dose-response. Maximal response was observed at the highest dose, consistent with prior results. The alternative schedule generated similar responses. We demonstrate steep dose-response for eribulin in osteosarcoma PDX models, implying that any deviation from achievement of effective concentrations may have a significant impact on activity.

Abstract 5415: Profiling cancer testis antigens in osteosarcomas

Cancer testis antigens (CTA) are reported to have restricted expression in placenta and testis, but they are also known to be expressed in some malignant tumors. Immunotherapy targeting CTAs in melanomas and certain types of soft tissue sarcomas have shown potential therapeutic value. However, the expression pattern of CTAs in osteosarcoma (OS) has not been fully elucidated. To characterize the CTA landscape of OS, we compared RNA sequencing data from 40 high-risk OS patients treated at MD Anderson Cancer Center and 111 OS patients available through a public online database. All of these tumor data are subsequently compared with testis/placenta and other normal tissue RNA-sequencing data from the NIH Genotype-Tissue Expression (GTEx) database as well as an online dataset which includes normal bone tissue. 53 genes that are significantly highly expressed in OS and testis/placenta (log fold change tumor versus normal &gt;1.0 for each tissue, p &lt; 0.01) are selected. Of those, 11 genes have been annotated in the Cancer Testis Database (CTdatabase) such as MAGEA3/A6 and LY6K. We also identified 42 genes that are not annotated in the CTdatabase. The co-expression pattern of CTAs in OS was also investigated by unsupervised hierarchical cluster analysis. The expression of selected CTAs was validated by IHC staining with an OS tissue microarray from 100 patients, and western blot using PDX models and patient-derived cell lines. Interestingly, the results demonstrated that multiple CTAs such as MAGEA3, LY6K and PAGE5 are also highly expressed in normal bone tissue. The current results suggest further development of immunotherapy approaches targeting CTAs in OS.

Citation Format: Zhongting Zhang, Yifei Wang, Wendong Zhang, Zhaohui Xu, Xin Zhou, Michael Roth, Jonathan Gill, Douglas Harrison, Pooja Hingorani, Sylvester Jusu, Sankar Kannan, Xiangjun Tian, Jing Wang, Rossana N Segura Lazcano, Alexander Lazar, Richard Gorlick. Profiling cancer testis antigens in osteosarcomas [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 5415.

Abstract 5405: Integrative surfaceome profiling identifies MMP14, MRC2 and CD276 as candidate immunotherapeutic target in osteosarcomas

Osteosarcoma (OS) is the most common primary malignant bone tumor in pediatric patients. However, the survival rate of patients with osteosarcomas has not improved for the last several decades. Current developments in immunotherapeutic strategies may increase the efficacy of these treatments for solid tumors. However, these treatments, such as antibody-drug conjugates (ADCs) or CAR-T cell therapy have not been sufficiently studied in OS because of a lack of known tumor-specific target. In this study, we developed an integrative pipeline combining the transcriptomic data from OS patients and the cell-surface proteomics data generated from a panel of patient-derived OS cell lines and PDX models and relating these to normal tissue expression. RNA sequencing data from 40 high-risk OS patients treated at MD Anderson Cancer Center was pooled with 111 OS patients available through the public TARGET online database. All the tumor data was subsequently compared with normal tissue RNA-sequencing data from the NIH Genotype-Tissue Expression (GTEx) database. The significantly differentially expressed genes (log fold change tumor versus normal &gt;1.5 for each tissue, p &lt; 0.01) were selected. We further filtered this gene list by cell surface protein prediction based on the Compartments subcellular localization database. To determine protein expression levels, we prepared surface protein extracts from a panel of patient-derived OS cell lines and PDX models. Proteomic mass spectrometry was used to profile these OS surface proteins. We also included the proteomics data of OS tissue and 39 types of normal human organs via the public proteomic database. Integrative analysis of the transcriptomic and proteomic data demonstrated MMP14, MRC2, and CD276 are highly expressed in OS compared to normal tissues across all datasets. The expression of the three cell surface proteins was validated by IHC staining with an OS tissue microarray from 100 patients, and western blot with our PDX tissues and patient-derived cell lines. A previously reported preclinical study has shown the CD276 ADC (mCD276-PBD) has good antitumor activity against xenograft models of OS. Multiple preclinical tests including CD276 CAR-T cells, MRC2 ADC and MMP14 Bicycle Drug Conjugate (BT1718) are planned to further validate the therapeutic potential of these targets. Our current findings have not been previously reported in OS. The results might warrant further development of ADC and CAR-T cell therapy for osteosarcomas against these targets.

Citation Format: Yifei Wang, Zhongting Zhang, Wendong Zhang, Zhaohui Xu, Xin Zhou, Michael Roth, Jonathan Gill, Douglas Harrison, Pooja Hingorani, Sankar Kannan, Sylvester Jusu, Xiangjun Tian, Jing Wang, Rossana Lazcano, Alexander Lazar, Richard Gorlick. Integrative surfaceome profiling identifies MMP14, MRC2 and CD276 as candidate immunotherapeutic target in osteosarcomas [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 5405.

Abstract LB-217: Preclinical evaluation of trastuzumab deruxtecan (T-DXd; DS-8201a), a HER2 antibody-drug conjugate, in pediatric solid tumors by the Pediatric Preclinical Testing Consortium (PPTC)

Introduction: HER2 is expressed in a subset of pediatric solid tumors and is a target of interest for innovative immune therapies including CAR-T cells and antibody-drug conjugates (ADCs). We evaluated preclinical efficacy of T-DXd, a humanized monoclonal HER2 antibody conjugated to a topoisomerase 1 inhibitor payload, DXd, in solid tumor patient derived xenograft (PDX) models. Methods: 7 osteosarcoma (OS), 2 rhabdoid tumor (RT) and 3 Wilms tumor (WT) PDX models with varying HER2 expression were tested using 10 mice per group. ERBB2 mRNA expression was determined using RNA seq. T-DXd or vehicle control was administered IV to mice harboring flank tumors at a dose of 5mg/kg on Day 1. Standard PPTC statistical methods were employed for EFS for treatment (T) and control (C) groups, minimum relative tumor volume (minRTV) and objective response measure. Results: Among PPTC solid tumor models ERBB2 mRNA expression was observed across multiple histologies, with highest expression observed for WT (median = 22 FPKM), followed by RT, OS, and Ewing sarcoma. The relationship between HER2 expression by IHC and by RNAseq was inconsistent. Mice tolerated T-DXd with minimal toxicity. T-DXd significantly prolonged EFS in 5/7 OS, 2/2 RT and 3/3 WT PDX models (see table). Complete response (CR) or maintained CR were observed for 4 of 5 WT and RT models, while stable disease was the best response among OS models. Conclusions: T-DXd exhibits single agent anti-tumor activity in models of pediatric solid tumors. Single mouse testing experiments will be used to extend knowledge of the range of activity of T-DXd for pediatric solid tumors. Correlations between ERBB2 gene expression, HER2 expression by IHC, and genetic changes associated with camptothecin sensitivity are ongoing and will be presented. Clinical trials assessing efficacy of a HER2-directed ADC in pediatric patients with HER2-expressing tumors should be considered.

EFS T - C(days)EFS T/C Ratiop-value Gehan-WilcoxonminRTVmean±SDminRTVp-valueObjective Response MeasureOS-120.31.85p &lt; 0.0011.152±0.090p = 0.023PD1OS-230.12.76p &lt; 0.0010.815±0.183p &lt; 0.001PD2OS-94.11.14p = 0.1031.334±0.203p = 1.000PD1OS-1734.01.97p = 0.0091.172±0.179p = 0.017PD1OS-3111.91.84p &lt; 0.0011.676±0.395p = 0.015PD1OS-3361.34.87p &lt; 0.0010.486±0.220p &lt; 0.001SDOS-603.81.11p = 0.0161.084±0.103p = 0.007PD1BT29 (RT)&gt; 58.4&gt; 3.28p &lt; 0.0010.019±0.041p &lt; 0.001MCRRBD2 (RT)&gt; 97.3&gt; 13.57p &lt; 0.0010.021±0.066p &lt; 0.001CRKT-10 (WT)&gt; 85.1&gt; 7.57p &lt; 0.0010.000±0.000p &lt; 0.001MCRKT-11 (WT)18.32.62p &lt; 0.0010.954±0.486p &lt; 0.001PD2KT-13 (WT)&gt; 71.5&gt; 3.69p &lt; 0.0010.019±0.060p &lt; 0.001MCR

Citation Format: Pooja Hingorani, Wendong Zhang, Raushan Kurmasheva, Zhongting Zhang, Yifei Wang, Zhaohui Xu, Michael Roth, Jonathan Gill, Douglas Harrison, Stephen Erickson, Edward A. Kolb, Malcolm Smith, Peter Houghton, Richard Gorlick. Preclinical evaluation of trastuzumab deruxtecan (T-DXd; DS-8201a), a HER2 antibody-drug conjugate, in pediatric solid tumors by the Pediatric Preclinical Testing Consortium (PPTC) [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 LB-217.

Urethral catheter trapped in the ureter removed using holmium laser: An unusual case and review of the literature

Inadvertent placement of a urethral catheter into the ureter is a rare but documented complication of catheterisation. Management becomes more challenging when the catheter cannot be removed using conservative techniques. We present the case of an 85-year-old male with a history of bladder cancer treated with intravesical Bacillus Calmette–Guérin (BCG) therapy who was found to have a urethral catheter stuck in his left ureter on computerized tomography scan after a routine catheter change. The catheter balloon was punctured using ureteroscopy and Holmium laser. Our literature review identified five other cases where a misguided urethral catheter required surgical intervention for removal from the ureter and the different techniques used are discussed. Risk factors appear to be pregnancy and structural changes to the bladder resulting in widened ureteric orifices including BCG therapy. We suggest that laser puncture of an inflated catheter balloon is a safe and effective method for facilitating removal.

Level of evidence:

4

Impact of Lagtime, Health Insurance Type, and Income Status at Diagnosis on the Long-Term Survival of Adolescent and Young Adult Cancer Patients

Purpose: Delays in diagnosis can affect the short-term survival outcomes of adolescent and young adult (AYA) cancer patients. We sought to determine the extent to which delayed diagnosis, health insurance type, and income status are associated with the long-term survival of AYA cancer patients. Methods: We reviewed an institutional cohort of 268 patients age 15-29 years who were diagnosed with the most common neoplasms of the AYA population between 2001 and 2003. We grouped patients by the time of onset of cancer symptomatology to verified diagnosis (lagtime to diagnosis; short or long), health insurance type at diagnosis (public or private), zip-code-based median household income (≤U.S. $50,000 or >U.S. $50,000), and demographic variables. Overall survival (OS) and late OS (LOS; the time from the 5-year anniversary of cancer diagnosis to death from any cause) were the outcomes of interest. Results: OS and LOS did not differ between those with short or long lagtimes to diagnosis for all cancer and for specific cancer types. Among patients with long lagtimes, those with private insurance had significantly better LOS than those with public insurance (p = 0.03). Compared with those who had public insurance, patients who had private insurance at diagnosis had significantly better LOS (p = 0.008). Patients with household incomes >U.S. $50,000 had better LOS than those with household incomes ≤U.S. $50,000 (p = 0.02). Patients with public insurance and household incomes ≤U.S. $50,000 had the poorest LOS. Conclusions: AYA cancer patients with either public health insurance or a low household income at diagnosis are at risk of an inferior LOS.

Cell surface vimentin-positive circulating tumor cell-based relapse prediction in a long-term longitudinal study of postremission neuroblastoma patients

Neuroblastoma (NB) is a deadly childhood disease that carries a 50% chance of relapse for anyone in remission and similar level of 5-year survival. We investigated the value of our proprietary approach-cell surface vimentin (CSV) positive circulating tumor cells (CTC) to monitor treatment response and predict relapse in NB patients under remission in a Phase II long-term preventative clinical trial. We longitudinally analyzed peripheral blood samples from 93 patients for 27 cycles (~25 months) and discovered that the presence of CSV⁺ CTCs in the first two sequential samples (baseline, cycle 4 [month 3-4]) was a significant indicator of earlier relapse. We observed strong correlation between relapse-free survival (RFS) and lack of CSV⁺ CTCs in first 4 cycles of therapy (95%). There was sensitivity reaching 100% in predicting RFS in patients who had neither CSV⁺ CTCs nor MycN amplification. Of note, the low number of CSV⁺ CTCs seems equivalent to low tumor load because the prevention therapy difluoromethylornithine yields faster reduction of relapse risk when none or only 1-2 CSV⁺ CTCs (every 6 mL) are present in the blood samples compared to >3 CSV⁺ CTCs. To the best of our knowledge, this is the first study that directly observes CTCs in under remission NB patients for relapse prediction and the first to gather sequential CSV⁺ CTC data in any study in a long-term longitudinal manner.

221Evaluating the ability of different substrate mapping techniques to identify scar-related ventricular tachycardia circuits using computational modelling

Funding Acknowledgements

National Institute for Health Research; British Heart Foundation; and The Wellcome Trust and Engineering and Physical Sciences Research Council.

Background

Accurate identification of targets for catheter ablation therapy of ventricular tachycardias (VTs) in the postinfarction heart remains a significant challenge. Identification of such targets often requires VT-induction to delineate the entry/exit points of the reentrant circuit sustaining the VT. However, inducibility may not be possible due to hemodynamic instability. In this scenario, substrate ablation strategies can still be performed to uncover the arrhythmogenic substrate during sinus or paced rhythm. However, substrate mapping may fail to accurately delineate the reentrant circuit resulting in VT recurrence after the procedure.

Purpose

To use computer simulations to compare the ability of different electroanatomical maps constructed following typical substrate ablation strategies to identify the VT exit site.

Methods

An image-based computational model of the porcine post-infarction left ventricle was constructed to simulate VT and paced rhythm. Electroanatomical maps were constructed based on the following features extracted from electrograms computed on the endocardial surface: activation time (AT), bipolar electrogram amplitude, signal fractionation and the reentry vulnerability index (RVI - a metric combining activation and repolarization timings to identify tissue susceptibility to reentry). Potential ablation targets during substrate mapping were compared for: highest 5% AT gradient; lowest 5% bipolar signal amplitudes; areas with fragmented signals (more than one peak); and lowest 5% RVI. The minimum distance, d, between the manually identified VT exit site and the targets was measured.

Results

The RVI performed better than the other metrics at detecting the VT exit site (see Figure). The minimum distance between sites of lowest RVI and the exit site was 3.2mm compared to 13.1mm and 15.9mm in traditional AT and voltage maps, respectively. As the scar was not transmural, parameters derived from all electrograms (including those located on dense scar regions) were used to construct the electroanatomical maps. This improved the performance of the RVI significantly, making it more specific than the other metrics as can be seen in the Figure.

Conclusions

Among all metrics investigated here, the RVI identified the vulnerable region closest to VT exit site. This finding suggests that activation-repolarization metrics may improve the detection of pro-arrhythmic regions without having to induce VT. Moreover, the RVI may be particularly well suited for detecting vulnerable regions within non-transmural scars.

Abstract Figure. VT and Substrate Mapping

0416 Poor Sleep Quality Predicts Serum Markers of Neurodegeneration and Cognitive Deficits in Warriors with Mild Traumatic Brain Injury

Introduction

Increasing evidence links neurodegeneration to traumatic brain injury (TBI), and a separate body of literature links neurodegeneration to sleep dysfunction, implicating increased toxin production and decreased glymphatic clearance. Sleep disorders affect 50% of TBI patients, yet the sleep-neurodegeneration connection in these patients remains unexplored. We hypothesized that warfighters with TBI and sleep dysfunction would have increased neuronal injury, revealing potential mechanistic underpinnings for TBI outcomes. We measured plasma biomarkers, cognitive function and sleep surveys for correlation analysis.

Methods

In a retrospective cross-sectional study of warfighters (n=113 chronic mild TBI patients), the Pittsburgh sleep quality index (PSQI) was compared with amyloid β42 (Aβ42), neurofilament light (NFL), tau, and phospho-tau (threonine 181) isolated from plasma and exosomes. Executive function was tested with the categorical fluency test. Exosomes were precipitated from plasma. Proteins were measured with the Single Molecule Array (Quanterix). Linear models were adjusted for age, ApoE, and number of TBIs.

Results

Poor sleepers with TBI (PSQI&gt;8) had elevated NFL compared to good sleepers in plasma (p=0.007) and exosomes (p=0.00017), and PSQI directly correlated with NFL (plasma: Beta=0.23, p=0.0079; exosomes: Beta=2.19, p=0.0013) stronger than any other marker of neurodegeneration. Poor sleepers also showed higher obstructive sleep apnea (OSA) risk compared to good sleepers by STOP-BANG scores (3.6, SD=1.6 vs 2.8, SD=1.74; p=0.0014) as well as decreased categorical fluency (20.7, SD=4.1) (18.3, SD=4.6, p=.0067). Plasma tau and Aβ42 also correlated with PSQI (Beta=0.64, p=0.028, and Beta=0.40, p=0.049 respectively).

Conclusion

This is the first reported data correlating markers of neuronal injury and cognitive deficits with sleep complaints and OSA risk in patients with TBI - possibly identifying treatable pathophysiological mediators of TBI neurodegeneration. Limitations include a small sample size, lack of objective sleep measures, and inability to establish directionality due to cross-sectional design. Prospective trials will be required to further explore our proposed hypothesis. If confirmed, these findings would call for targeting sleep disorders in the TBI population to mitigate risk of neurodegeneration.

Support

This work was supported by grant funding from: Department of Defense, Chronic Effects of Neurotrauma Consortium (CENC) Award W81XWH-13-2-0095 and Department of Veterans Affairs CENC Award I01 CX001135.

0021 RNA Sequencing Reveals Transcriptomic Changes in Individuals with Insomnia

Introduction

Insomnia affects 10–20% of the US population and is associated with negative health and psychosocial sequelae. Despite the public health impact of insomnia little is known about its underlying molecular mechanisms. The purpose of this study is to examine differentially expressed genes in 15 patients with chronic insomnia and age- and sex-matched good sleepers (n=15).

Methods

We performed total RNA-seq on 30 whole blood samples collected at 09:00 at 150 bp paired-ends on the Illumina NovaSeq-6000 platform. Alignment was performed using the STAR version 2.7.2a software on the human reference genome (GRCh38). Differential gene expression analysis was performed using DESeq2 version 1.24.0. Pathway analysis was performed using IPA, release 2019-08-30.

Results

An average of 86.7 million paired end reads per sample were sequenced. We found that 289 genes were differentially expressed in insomnia patients with a log fold change (LFC) ±0.50 and had a FDR p-value &lt; 0.05. Top dysregulated genes include CSMD1 (L2FC=-2.78; p=1.35E-06), DUX4L9 (L2FC=3.40; p=2.81E-06) and GRM4 (L2FC=2.45; p=4.50E-05). Among the functionally relevant genes, CSMD encodes a complement control protein that is known to participate in the complement activation and inflammation in the developing central nervous system. UTS2 (L2FC=1.778; p=8.94E-06) is involved in regulation of orexin A and B activity and rapid eye movement during sleep. Ingenuity Pathway Analysis revealed 3 associated networks: Hematological, Hereditary Disorder, Organismal Injury and Abnormalities (score: 46), Developmental, Hereditary Disorder, Metabolic Disease (score: 43), and Cell Cycle, Cell mediated Immune Response, Cellular Development (score: 43).

Conclusion

Overall, our study revealed dysregulated genes in individuals who suffer from insomnia. Notably, dysregulation of these functionally relevant genes could impair functional brain connectivity and synaptic function. Further investigation of these biological pathways will be useful to elucidate the pathogenesis of insomnia and identify novel biomarkers or drug targets for developing improved diagnostics and therapeutics.

Support

National Institutes of Nursing Research, Graduate Partnership Program

1118 Examining the Role of Serum and Exosomal Biomarkers in Symptoms of Fatigue and Daytime Sleepiness Following Traumatic Brain Injury

Introduction

Fatigue and daytime sleepiness are two of the most common chronic symptoms reported after traumatic brain injury (TBI). However, there is limited understanding of the pathophysiological mechanisms following TBI that result in these symptoms. Previous research has observed elevations in peripheral blood levels of proteins in TBI patients versus controls, including neurofilament light chain (NFL)—predominantly expressed in long myelinated subcortical axons—and glial fibrillary acidic protein (GFAP)—predominantly expressed in reactive astrocytes responding to central nervous system injuries. This study examines the relationship between serum and exosomal NFL and GFAP, and symptoms of fatigue and daytime sleepiness in TBI patients 1-year after injury.

Methods

Sixty-seven patients with TBIs ranging from mild to severe were included in this study. Blood samples were collected from all participants 1-year post TBI, with concentrations of GFAP and NFL measured in serum and exosomes using Single Molecule Array technology (Simoa), an ultrasensitive assay. Participants reported fatigue using the Fatigue Severity Scale (FSS), and daytime sleepiness using the Epworth Sleepiness Scale (ESS).

Results

A linear regression model of fatigue symptoms and exosomal NFL controlling for age revealed that fatigue was negatively associated with exosomal NFL concentrations (β = -.317, p = .041, ηp2 = -.343) and accounted for 20.2% of the change in NFL. Serum NFL concentrations were not associated with fatigue, nor were GFAP serum or exosomes. No significant associations were found between NFL, GFAP, and daytime sleepiness.

Conclusion

Our findings suggest that exosomal NFL may be related to mechanisms underlying TBI-related fatigue and the potential of NFL as a biomarker of fatigue. To our knowledge, this study is the first to examine the relationship between post-TBI NFL levels and fatigue symptoms. Further investigation into serum and exosome biomarkers of TBI-related fatigue and daytime sleepiness is warranted.

Support

National Institutes of Health and Center for Neuroscience and Regenerative Medicine

INNV-40. TARGETED NEXT GENERATION SEQUENCING OF PEDIATRIC HIGH-GRADE GLIOMA AND ITS THERAPEUTIC IMPLICATIONS, MD ANDERSON EXPERIENCE

INTRODUCTION

The new understanding of molecular pathways in cancer is paving the way towards personalized cancer medicine, especially in refractory disease. High-grade gliomas (HGG) are common pediatric brain tumors that tend to recur, with no available standard therapy upon recurrence. HGG are challenging tumors with illusive biology and poor outcome. We report here the molecular testing of 27 pediatric HGG patients.

MATERIALS AND METHODS

An analysis of pediatric patients with HGG treated at UT MD Anderson Cancer Center (MDACC) who underwent molecular genetic profiling using next generation sequencing with different genomic panels (AmpliSeq™Cancer Hotspot and Oncomine Panels – by Thermo Fisher Scientific).

RESULTS

27 patients with HGG (median age 14 years, range 3–18 years old) underwent genomic profiling. Primary diagnoses were glioblastoma multiforme (n=22), anaplastic astrocytoma (n = 2), gliosarcoma (n= 1), anaplastic pleomorphic xanthoastrocytoma (n= 1) and anaplastic oligoastrocytoma (n= 1). There are 46 genes common to the panels used. The most common mutation was in TP53 (73%). Other mutations included PIK3CA (19%), IDH1 (11.5%), 7.7% for ATM, EGFR and PTEN, and 3.8% for BRAF, FGFR1 and FGFR2. 24 out of 27 patients were tested at initial diagnosis and 3 upon relapse/progression. Patients at initial diagnosis received standard of care therapy of radiation and temozolomide. Only 5 patients received targeted therapy upon progression/recurrence. Some challenges of genomically-matched therapy included lack of clinical trials accepting pediatric patients, unavailability of a liquid form of a drug, and insurance disapproval for off-label use.

CONCLUSION

The next generation of therapy for childhood cancers will be based upon in-depth molecular phenotyping that may facilitate the development of rational risk-adapted and target-based therapies. This cohort, though limited by sample size, highlights the opportunity to perform molecular testing and identification of alterations in actionable genes.