A formative cross-sectional study to assess caregiver's health-seeking behaviour and knowledge surrounding malaria, and understand the burden of malaria among children under-five in conflict-affected communities of Cameroon

BACKGROUND

Malaria remains a major global health problem often worsened by political instability and armed conflict. The purpose of the study was to explore community knowledge, attitudes and practices on malaria prevention, and to understand the burden of malaria and health-seeking behaviours of caregivers of children under-five in conflict-affected communities of the South West and Littoral Regions of Cameroon.

METHODS

A cross-sectional survey involving internally displaced persons (IDPS), host population, and their children under-five was conducted across 80 communities. The survey was conducted from May to June 2021. Participants were interviewed using a structured questionnaire. Malaria prevalence for children under-five was determined using rapid diagnostic tests (RDT) on blood samples. Association between variables and displacement status was measured using chi square test and multivariate logistic regression model was fitted to identify factors associated with adequate knowledge on malaria prevention.

RESULTS

A total of 2386 adults participated in the study and 1543 RDTs were conducted for children under-five. Adequate levels of knowledge and attitudes on malaria prevention was recorded among 1258 (52.9%) of the participants, with very strong evidence to suggest the level to be higher among the host (59.5%) compared to the IDPs (49.5%) and returnees (39.7%) (p < 0.001). Good practices towards malaria prevention was 43.3%, with very strong evidence indicating lower levels among IDPs (42.8%) and returnees (28.5%) compared to the host (49.4%) (p < 0.001). Malaria prevalence for children under-five was 54.0% and adequate health-seeking for suspected episodes of malaria was 53.0%, without any difference among IDPs (51.78%) and returnees (48.7%) compared to host populations (55.4%) (p = 0.154). Multivariate logistic regression model showed that there was quite strong evidence to suggest primary and secondary levels of education have higher odds of having correct knowledge of malaria prevention (adjusted odds ratio (AOR) 1.71, 95% confidence interval (CI): 1.11-2.64, p = 0.015 and AOR 1.80, 95% CI 1.15-2.82, p = 0.010 respectively). There was very strong evidence to suggest that owning a radio or a television was associated with greater odds of having a higher knowledge on malaria prevention (AOR 1.49, 95% CI 1.233-1.81, p = 0.000 and AOR 1.47, 95% CI 1.18-1.84, p = 0.001).

CONCLUSION

Over half of the population have correct knowledge and attitudes towards malaria prevention but gaps in complete knowledge remained. Some of the caregivers know the correct malaria preventive practices coupled with largely unsatisfactory treatment approaches and reflected by the high prevalence of malaria among their children. In order to effectively treat malaria, innovative strategies should target community participation.

Familial rare EGFR-mutant lung cancer syndrome: Review of literature and description of R776H family

BACKGROUND

Interest in hereditary lung cancer is increasing, in particular germline mutations in the Epidermal Growth Factor Receptor (EGFR) gene. We review the current literature on this topic, discuss risk of developing lung cancer, treatment and screening options and describe a family of 3 sisters with lung cancer and their unaffected mother all with a rare EGFR germline mutation (EGFR p.R776H).

METHODS

We searched PubMed, Medline, Embase, the Cochrane Library, Google Scholar and scanned reference lists of articles. Search terms included "EGFR germline" and "familial lung cancer" or "EGFR familial lung cancer". We also describe our experience of managing a family with rare germline EGFR mutant lung cancer.

RESULTS

Although the numbers are small, the described cases in the literature show several similarities. The patients are younger and usually have no or light smoking history. 50% of the patients were treated with a tyrosine kinase inhibitor (TKIs) with OS over six months.

CONCLUSION

Although rare, germline p.R776H EGFR lung cancer mutations are over-represented in light or never smoking female patients who often also possess an additional somatic EGFR mutation. Treatment with TKIs appears suitable but further research is needed into the appropriate screening regime for unaffected carriers or light/never smokers.

A174 A NOVEL MECHANISM OF CROHN’S DISEASE SEVERITY IN WOMEN: EVALUATING THE IMPACT OF AN ESTROGEN-FARNESOID X RECEPTOR INTERACTION ON INTESTINAL BARRIER FUNCTION

Background

Crohn’s disease (CD) is associated with deficits in intestinal barrier function. Activation of bile acid-sensing nuclear receptor Farnesoid X receptor (NR1H4, FXR) is associated with protective effects against reduced intestinal barrier function; namely through promoting tight junction complex genes (TJCGs) and reducing expression of inflammatory cytokines. The FXR -1G>T variant is associated with decreased FXR activation and increased risk of, and early progression to, CD-related surgery in females only. It is hypothesized an estrogen-FXR interaction is mediating this effect.

Purpose

We aimed to assess the combined effect of estrogen and FXR genetic variation on intestinal barrier function using a cell-based model and its impact in a clinical cohort.

Method

Caco-2 cells were characterized for expression of TJCGs (zonula occludens-1, occludin, junctional adhesion molecule A, and claudin-1 and claudin-2), FXR, and nuclear estrogen receptors (ERα, ERβ) by qPCR. The influence of FXR activation on TJCGs was characterized by incubation of Caco-2 cells with chenodeoxycholic acid (CDCA). FXR-knockout stable Caco-2 line was developed using CRISPR-Cas9 methods and verified by qPCR and genotyping. The effect of estradiol on expression of TJCGs in FXR-knockout and wildtype Caco-2 cell monolayers was compared by qPCR. Future experiments include comparison of FXR-knockout and wildtype monolayer permeability with estrogen exposure by transwell permeability assay.

The effect of FXR genotype and exogenous estrogen CD severity (surgery, hospitalization, fistulizing disease) was evaluated in our female cohort by multivariate analysis.

Result(s)

Increased expression of TJCGs was seen in native Caco-2 monolayers incubated with CDCA. FXR-knockout cell line was then successfully created and confirmed. FXR-knockout cells showed decreased expression of TJCGs with the exception of zonula occludens-1. Estradiol exposure resulted in a dose-dependent decline in TJCGs expression in the wildtype Caco-2 cell line, however this effect was lost in the FXR-knockout cell line.

Preliminary analysis of patient cohort data (n=359) showed exogenous estrogen was associated with lower surgery risk (OR = 0.603, 95% CI= 0.373–0.964, p < 0.05; Fischer’s exact test) and trended towards decreasing fistulizing disease risk in a multiple logistic regression model which included FXR genotype. The association of FXR genotype with increased surgery risk was also confirmed in this logistic regression model.

Conclusion(s)

Herein, we show that FXR activity affects expression of TJCGs, and this effect is attenuated by estrogen interactions. Our patient cohort preliminary analysis confirmed an increased CD severity risk associated with FXR genotype and demonstrated a trend of decreasing CD severity with exogenous estrogen exposure. Further studies will assess the mechanisms by which FXR and estrogen interact to influence intestinal permeability.

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Department of Medicine, Western University

Disclosure of Interest

D. Taylor: None Declared, L. Donovan: None Declared, J. Choi: None Declared, R. Kim: None Declared, U. Schwarz: None Declared, A. Wilson Consultant of: Consulting fees from Fresenius Kabi, Speakers bureau of: Speaking fees from Takeda and Pfizer

Optimizing the role of 'lead mothers' in seasonal malaria chemoprevention (SMC) campaigns: formative research in Kano State, northern Nigeria

BACKGROUND

Seasonal malaria chemoprevention (SMC) is a safe and effective intervention for preventing malaria in children under 5 years of age. Lead mothers are community health volunteers that help caregivers comply with monthly administration of anti-malarial drugs during SMC campaigns. The lead mother approach is used in several SMC implementing states across Nigeria, but there is lack of evidence about their roles and how effective they are. This study sought to better understand the current role of lead mothers, identify areas for improvement and ways to optimize the role of lead mothers during SMC campaigns.

METHODS

This paper reports the formative phase of a three-phased intervention development study. The formative phase involved semi-structured interviews with stakeholders from national, state, local government and community levels (n = 20). Thematic analysis was used to identify key themes, forming the basis of a subsequent co-design workshop with stakeholders routinely involved in SMC campaigns.

RESULTS

The findings of the formative phase converged around four overarching themes: skills and attributes required of lead mothers; factors that affect lead mother's roles; how lead mothers interact with Community Health Influencers Promoters Services (CHIPS) agents and re-imagining the role of lead mothers during SMC campaigns.

CONCLUSION

This formative work in Kano state indicates that through their strong connection to communities and unique relationship with caregivers, lead mothers can and do influence caregivers to adopt healthy behaviours during SMC campaigns. However, there is room for improvement in how they are recruited, trained and supervised. There is need to improve lead mothers' knowledge and skills through adequate training and supporting materials, so they can deliver targeted health messages to caregivers. Sustainability of the lead mother approach is at risk if policymakers do not find a way of transitioning their role into the existing community health worker infrastructure, for example by using CHIPs agents, and ensuring less reliance on external donor support.

Targeting of low ALK antigen density neuroblastoma using AND logic-gate engineered CAR-T cells

BACKGROUND AIMS

The targeting of solid cancers with chimeric antigen receptor (CAR) T cells faces many technological hurdles, including selection of optimal target antigens. Promising pre-clinical and clinical data of CAR T-cell activity have emerged from targeting surface antigens such as GD2 and B7H3 in childhood cancer neuroblastoma. Anaplastic lymphoma kinase (ALK) is expressed in a majority of neuroblastomas at low antigen density but is largely absent from healthy tissues.

METHODS

To explore an alternate target antigen for neuroblastoma CAR T-cell therapy, the authors generated and screened a single-chain variable fragment library targeting ALK extracellular domain to make a panel of new anti-ALK CAR T-cell constructs.

RESULTS

A lead novel CAR T-cell construct was capable of specific cytotoxicity against neuroblastoma cells expressing low levels of ALK, but with only weak cytokine and proliferative T-cell responses. To explore strategies for amplifying ALK CAR T cells, the authors generated a co-CAR approach in which T cells received signal 1 from a first-generation ALK construct and signal 2 from anti-B7H3 or GD2 chimeric co-stimulatory receptors. The co-CAR approach successfully demonstrated the ability to avoid targeting single-antigen-positive targets as a strategy for mitigating on-target off-tumor toxicity.

CONCLUSIONS

These data provide further proof of concept for ALK as a neuroblastoma CAR T-cell target.

NCOG-24. TIME TO FIRST RECURRENCE AND SURVIVAL IN IDH-WILDTYPE GLIOBLASTOMA

INTRODUCTION

Time to recurrence is a source of considerable anxiety in glioblastoma. Assuming survival to a certain timepoint without tumor progression, how do odds/outcomes change relative to initial starting conditions? Is there a single timepoint with highest risk of tumor progression, after which "the longer you go, the longer you go"?

METHODS

Newly-diagnosed glioblastomas were retrospectively reviewed (n=209). Pre-2012 diagnoses (n=2) & IDH-mutants excluded (n=8). Median PFS/OS and remaining time to mPFS were calculated for sub-populations without disease progression (POD) at 0, 3, 6, 8, 12, and 24 months post-surgery.

RESULTS

199 IDH-wildtype glioblastomas identified -- 40% women, median age 63 years (range 26-91), 43% gross-total resection, 65% MGMT unmethylated, 65% upfront RT 60Gy (23% 40Gy) -- mPFS 8 months / mOS 19 months. Patients without POD within 3 months had mOS 20 months. Outcomes progressively improve at later timepoints-- mPFS 10/13/20/39 months and mOS 23/27/39/65 months, for patients without POD at 6/8/12/24 months post-surgery respectively. Patients without POD at 24 months comprised 10% of original cohort (n=20; 8 deaths). As a surrogate for risk of tumor progression, remaining time to mPFS was calculated (taken as difference between timepoint in question, and mPFS for the population of patients without POD up to that timepoint) and followed a J-shape curve -- 8 months (at 0 months post-surgery), 4 months (for patients without POD at 6 months post-surgery), 7-8 months (for patients without POD at 10-14 months post-surgery), to 13 and 15 months (for patients without POD at 18 and 24 months post-surgery, respectively).

DISCUSSION

Sub-populations without early progression appear to have improved survival relative to baseline, which has implications for clinical trials without internal controls. Nevertheless, highest risk for tumor progression seems to be at 6 months post-surgery, after which it appears "the longer you go, the longer you go."

QOL-01. RISK FACTORS FOR AND CONSEQUENCES OF PROLONGED DEXAMETHASONE USE IN PATIENTS WITH GLIOBLASTOMA (GBM)

BACKGROUND

Dexamethasone is the primary treatment for tumor-associated edema. Prolonged use can have significant side effects and may negatively impact survival in GBM. Factors associated with steroid dependence and steroid associated side effects (SASEs) are not well established.

METHODS

We performed a retrospective study of patients with newly diagnosed, IDH-wildtype GBM at our center. Demographics, clinical and tumor characteristics, dexamethasone usage, and SASEs (infections, myopathy, hypertension, fractures, mood symptoms, weight gain, and hyperglycemia) were extracted through chart review. We compared survival outcomes (OS) between patients with and without steroid dependence. Risk factors for steroid dependence were identified through logistic regression analysis.

RESULTS

39/92 (35.9%) patients developed steroid dependence. Of these, 26/39 (66.7%) were on steroids at the start of initial treatment. Patients who developed steroid dependence were older, more likely to have STR/biopsy, bilateral disease, KPS &lt; 90, baseline neurological deficits, and to be obese (BMI ≥ 30). 94.9% of patients with steroid dependence experienced ≥ 1 SASE (vs. 34%) and 46.2% experienced ≥ 3 SASEs (vs. 3.8%). Mood symptoms (69.2% vs. 26.4%), hyperglycemia (53.8% vs. 7.5%) and infections (51.3% vs. 7.5%) were the most common SASEs. Median OS was inferior in steroid-dependent patients (18 vs 25 mo). Baseline obesity was identified as a risk factor for developing steroid dependence (OR 5.9).

DISCUSSION

SASEs are common in patients on prolonged steroids. Obesity may increase the risk of developing steroid dependence. Identifying patients at highest risk for steroid dependence may help guide future interventions to mitigate the negative effects of prolonged dexamethasone use.

Delivery of seasonal malaria chemoprevention with enhanced infection prevention and control measures during the COVID-19 pandemic in Nigeria, Burkina Faso and Chad: a cross-sectional study

Background

Seasonal malaria chemoprevention (SMC) is a WHO-recommended intervention for children aged 3–59 months living in areas of high malaria transmission to provide protection against malaria during the rainy season. Operational guidelines were developed, based on WHO guidance, to support countries to mitigate the risk of coronavirus disease 2019 (COVID-19) transmission within communities and among community distributors when delivering SMC.

Methods

A cross-sectional study to determine adherence to infection prevention and control (IPC) measures during two distribution cycles of SMC in Nigeria, Chad and Burkina Faso. Community distributors were observed receiving equipment and delivering SMC. Adherence across six domains was calculated as the proportion of indications in which the community distributor performed the correct action. Focus group discussions were conducted with community distributors to understand their perceptions of the IPC measures and barriers and facilitators to adherence.

Results

Data collectors observed community distributors in Nigeria (n = 259), Burkina Faso (n = 252) and Chad (n = 266) receiving IPC equipment and delivering SMC. Adherence to IPC indications varied. In all three countries, adherence to mask use was the highest (ranging from 73.3% in Nigeria to 86.9% in Burkina Faso). Adherence to hand hygiene for at least 30 s was low (ranging from 3.6% in Nigeria to 10.3% in Burkina Faso) but increased substantially when excluding the length of time spent hand washing (ranging from 36.7% in Nigeria to 61.4% in Burkina Faso). Adherence to safe distancing in the compound ranged from 5.4% in Chad to 16.4% in Nigeria. In Burkina Faso and Chad, where disinfection wipes widely available compliance with disinfection of blister packs for SMC was low (17.4% in Burkina Faso and 16.9% in Chad). Community distributors generally found the IPC measures acceptable, however there were barriers to optimal hand hygiene practices, cultural norms made social distancing difficult to adhere to and caregivers needed assistance to administer the first dose of SMC.

Conclusion

Adherence to IPC measures for SMC delivery during the COVID-19 pandemic varied across domains of IPC, but was largely insufficient, particularly for hand hygiene and safe distancing. Improvements in provision of protective equipment, early community engagement and adaptations to make IPC measures more feasible to implement could increase adherence.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12936-022-04091-z.

Extending seasonal malaria chemoprevention to five cycles: a pilot study of feasibility and acceptability in Mangodara district, Burkina Faso

Background

Seasonal malaria chemoprevention (SMC) involves administering antimalarial drugs at monthly intervals during the high malaria transmission period to children aged 3 to 59 months as recommended by the World Health Organization. Typically, a full SMC course is administered over four monthly cycles from July to October, coinciding with the rainy season. However, an analysis of rainfall patterns suggest that the malaria transmission season is longer and starting as early as June in the south of Burkina Faso, leading to a rise in cases prior to the first cycle. This study assessed the acceptability and feasibility of extending SMC from four to five cycles to coincide with the earlier rainy season in Mangodara health district.

Methods

The mixed-methods study was conducted between July and November 2019. Quantitative data were collected through end-of-cycle and end-of-round household surveys to determine the effect of the additional cycle on the coverage of SMC in Mangodara. The data were then compared with 22 other districts where SMC was implemented by Malaria Consortium. Eight focus group discussions were conducted with caregivers and community distributors and 11 key informant interviews with community, programme and national-level stakeholders. These aimed to determine perceptions of the acceptability and feasibility of extending SMC to five cycles.

Results

The extension was perceived as acceptable by caregivers, community distributors and stakeholders due to the positive impact on the health of children under five. However, many community distributors expressed concern over the feasibility, mainly due to the clash with farming activities in June. Stakeholders highlighted the need for more evidence on the impact of the additional cycle on parasite resistance prior to scale-up. End-of-cycle survey data showed no difference in coverage between five SMC cycles in Mangodara and four cycles in the 22 comparison districts.

Conclusions

The additional cycle should begin early in the day in order to not coincide with the agricultural activities of community distributors. Continuous sensitisation at community level is critical for the sustainability of SMC and acceptance of an additional cycle, which should actively engage male caregivers. Providing additional support in proportion to the increased workload from a fifth cycle, including timely remuneration, is critical to avoid the demotivation of community distributors. Further studies are required to understand the effectiveness, including cost-effectiveness, of tailoring SMC according to the rainy season. Understanding the impact of an additional cycle on parasite resistance to SPAQ is critical to address key informants’ concerns around the deviation from the current four-cycle policy recommendation.

Extending Delivery of Seasonal Malaria Chemoprevention to Children Aged 5-10 Years in Chad: A Mixed-Methods Study

BACKGROUND

To prevent malaria among children aged 3-59 months in areas with high seasonal transmission, seasonal malaria chemoprevention (SMC) is recommended. In Chad, there is evidence of SMC administration to children aged older than 5 years (referred to as "leakage"). This study aimed to understand the reasons for leakage and explore the feasibility and acceptability of extending the delivery of SMC to children aged 5-10 years in Chad.

METHODS

We conducted a mixed-methods study in Massaguet health district with a cross-sectional survey to determine SMC coverage for children aged up to 10 years after SMC cycles 1 and 3 (n=90 and n=100 caregivers surveyed, respectively) and at the end of cycle 4 (n=101 caregivers surveyed). We conducted 14 key informant interviews at the national and district level and 8 focus group discussions with community distributors and caregivers.

RESULTS

In the compounds surveyed, there were no children aged 5-10 years in cycle 1. In cycles 3 (n=1 children) and 4 (n=16 children), there was 100% (95% confidence interval [CI]=2.5, 100.0) and 62.5% (95% CI=35.4, 84.8) coverage of SMC in children aged 5-10 years, respectively. Extension of SMC to older children was considered acceptable, but there were concerns about feasibility and ensuring the sustainability of the current program in children aged 3-59 months. Key informants acknowledged the need to secure additional funding to pilot SMC in older age groups and were uncertain about the impact of the current SMC program at scale.

CONCLUSION

Key informants considered extending SMC to children aged 5-10 years acceptable but did not deem it a current priority. They expressed an urgent need to address leakage and reinforce both the sustainability and quality of the current SMC program.

Relapsed Medulloblastoma in Pre-Irradiated Patients: Current Practice for Diagnostics and Treatment

Relapsed medulloblastoma (rMB) accounts for a considerable, and disproportionate amount of childhood cancer deaths. Recent advances have gone someway to characterising disease biology at relapse including second malignancies that often cannot be distinguished from relapse on imaging alone. Furthermore, there are now multiple international early-phase trials exploring drug-target matches across a range of high-risk/relapsed paediatric tumours. Despite these advances, treatment at relapse in pre-irradiated patients is typically non-curative and focuses on providing life-prolonging and symptom-modifying care that is tailored to the needs and wishes of the individual and their family. Here, we describe the current understanding of prognostic factors at disease relapse such as principal molecular group, adverse molecular biology, and timing of relapse. We provide an overview of the clinical diagnostic process including signs and symptoms, staging investigations, and molecular pathology, followed by a summary of treatment modalities and considerations. Finally, we summarise future directions to progress understanding of treatment resistance and the biological mechanisms underpinning early therapy-refractory and relapsed disease. These initiatives include development of comprehensive and collaborative molecular profiling approaches at relapse, liquid biopsies such as cerebrospinal fluid (CSF) as a biomarker of minimal residual disease (MRD), modelling strategies, and the use of primary tumour material for real-time drug screening approaches.

Health management information system (HMIS) data quality and associated factors in Massaguet district, Chad

Background

Quality data from Health Management Information Systems (HMIS) are important for tracking the effectiveness of malaria control interventions. However, HMIS data in many resource-limited settings do not currently meet standards set by the World Health Organization (WHO). We aimed to assess HMIS data quality and associated factors in Chad.

Methods

A cross-sectional study was conducted in 14 health facilities in Massaguet district. Data on children under 15 years were obtained from the HMIS and from the external patient register covering the period January–December 2018. An additional questionnaire was administered to 16 health centre managers to collect data on contextual variables. Patient registry data were aggregated and compared with the HMIS database at district and health centre level. Completeness and accuracy indicators were calculated as per WHO guidelines. Multivariate logistic regressions were performed on the Verification Factor for attendance, suspected and confirmed malaria cases for three age groups (1 to < 12 months, 1 to < 5 years and 5 to < 15 years) to identify associations between health centre characteristics and data accuracy.

Results

Health centres achieved a high level of data completeness in HMIS. Malaria data were over-reported in HMIS for children aged under 15 years. There was an association between workload and higher odds of inaccuracy in reporting of attendance among children aged 1 to < 5 years (Odds ratio [OR]: 10.57, 95% CI 2.32–48.19) and 5– < 15 years (OR: 6.64, 95% CI 1.38–32.04). Similar association was found between workload and stock-outs in register books, and inaccuracy in reporting of malaria confirmed cases. Meanwhile, we found that presence of a health technician, and of dedicated staff for data management, were associated with lower inaccuracy in reporting of clinic attendance in children aged under five years.

Conclusion

Data completeness was high while the accuracy was low. Factors associated with data inaccuracy included high workload and the unavailability of required data collection tools. The results suggest that improvement in working conditions for clinic personnel may improve HMIS data quality. Upgrading from paper-based forms to a web-based HMIS may provide a solution for improving data accuracy and its utility for future evaluations of health interventions. Results from this study can inform the Ministry of Health and it partners on the precautions to be taken in the use of HMIS data and inform initiatives for improving its quality.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12911-021-01684-7.

NCOG-12. COGNITIVE FUNCTION (CF) & QUALITY OF LIFE (QOL) IN PATIENTS TREATED WITH PROCARBAZINE, CCNU, & VINCRISTINE (PCV) + RADIOTHERAPY (RT) VS. RT FOR ANAPLASTIC OLIGODENDROGLIOMA (AO) ON NRG RTOG TRIAL 9402

BACKGROUND

PCV+RT substantially prolongs survival in AO patients, but long-term CF and QOL implications are unclear. We compared CF and QOL by treatment arm in RTOG 9402 participants and evaluated the impact that baseline characteristics had on CF, QOL, and survival.

METHODS

CF and QOL were evaluated using the Mini Mental State Exam (MMSE) and Brain-Quality of Life (B-QOL) scale at baseline and annually. Scores were analyzed between treatment arms at each time point for patients with ≥ 10 years of follow-up data. Shared parameter models evaluated MMSE and B-QOL scores and survival for all patients.

RESULTS

42/148 (28.4%) participants in PCV+RT and 20/143 (14%) in RT alone arms survived ≥ 10 years. 35/42 and 39/42 (PCV+RT) and 18/20 and 17/20 (RT) participants completed baseline B-QOL and MMSE assessments, respectively. B-QOL scores did not differ between treatment groups at any time-point. Among 16 patients (10 PCV+RT, 6 RT) who completed year 10 MMSE evaluations, mean MMSE score at 10 years was higher in the RT arm (29.83 [95% CI 22.1, 30.0] vs. 26.50 [95% CI 29.4, 30.0], P= 0.04). Change in MMSE and B-QOL scores from baseline did not differ significantly between treatment groups at any time. In shared parameter models including all patients with baseline assessments, MMSE and B-QOL scores decreased over time (MMSE P= 0.0189, B-QOL P= 0.0005), but this did not differ by treatment group (MMSE P= 0.5727, B-QOL P= 0.3592). Younger age and higher KPS predicted better scores (MMSE P &lt; 0.0001, P = 0.0002; B-QOL P = 0.0043, P = 0.0007). PCV+RT predicted better survival in both models.

CONCLUSIONS

PCV+RT improves survival in AO. Shared parameter models show decrease in MMSE and B-QOL over time. However, relative to RT alone, the addition of PCV did not impact change in CF and QOL over time.

NCOG-27. STATUS AS A CLINICAL TRIAL PARTICIPANT AND OUTCOME IN IDH-WILDTYPE GLIOBLASTOMA

INTRODUCTION

Standard of care for glioblastoma consists of surgery, followed by combined chemoradiation and adjuvant chemotherapy, as per the seminal EORTC study from 2005. Clinical trial patients, being a population selected for functional status, hepatic function, renal function, and lack of other malignancies, may have improved outcome over the general treated population.

METHOD

Single center retrospective analysis of status as a clinical trial patient in the upfront setting and other clinical factors/biomarkers, analyzed for correlation with outcomes (PFS/OS) in IDH-wildtype glioblastomas.

RESULTS

82 patients with IDH-wildtype glioblastoma were identified between 2014 and 2020, treated with standard of care or with an upfront clinical study (43% women; median age 66 years, range 35-91 years of age). 22 patients (27%) were treated with upfront clinical study. Status as a patient treated in an upfront clinical study did not correlate with outcome (hazard ratio HR PFS 0.99, CI 0.57-1.7, p=0.97; HR OS 1.09, CI 0.56-2.1, p=0.81). Frontal lobe was most frequently involved (n=36, 44%), followed by parietal lobe (n=33, 40%). Age was not a strong predictor of survival (R2 0.01). No statistically significant correlation was observed between outcome and laterality or location. MGMT promoter methylation was associated with improved PFS (HR 0.56, CI 0.33-0.94, p=0.03) and OS (HR 0.40, CI 0.19-0.85, p=0.02), with mPFS 6 months vs 9 months and mOS 16 months vs 20 months (unmethylated vs methylated respectively).

CONCLUSION

In this retrospective cohort of IDH-wildtype glioblastomas, age, tumor laterality, and tumor location were not significant predictors of outcome. MGMT promoter methylation predicted for superior PFS/OS. Patient selection for clinical studies are influenced by entry criteria, however at least in this retrospective review, status as a clinical study patient in the upfront setting did not correlate with outcome compared to patients treated with upfront standard of care.

STEM-26. BLOOD-TUMOR BARRIER IS COMPOSED OF MECHANOSENSING TUMOR CELLS THAT MASK THERAPEUTIC VULNERABILITY

Two major obstacles in brain cancer treatment are the blood-tumor barrier (BTB), which restricts delivery of most therapeutic agents, and the quiescent brain tumor-initiating cells (BTICs), which evade cell cycle-targeting chemotherapy. Mechanosensation, the transduction of mechanical cues into cellular signaling, underlies physiological processes such as touch, pain, proprioception, hearing, respiration, epithelial homeostasis, and vascular and lymphatic development. We report that medulloblastoma (MB) BTICs are mechanosensing, a property conferred by force-activated ion channel Piezo2. In contrast to the prevailing view that astrocytes function as a physical barrier in BTB, BTICs project endfeet to ensheathe capillaries. MB develops a tissue stiffness gradient as a function of distance to capillaries. Piezo2 senses substrate stiffness to sustain local intracellular calcium, actomyosin tension, and adhesion at BTIC growth cones, which allow BTICs to mechanically interact with their substrate and sequester β-Catenin to prevent WNT/β-Catenin signaling in BTICs. Our single cell analysis uncovers a two-branched BTIC trajectory that progresses from a deep quiescent state to two cycling states. Tumor cell-specific Piezo2 knockout reverses the off-on WNT/β-Catenin signaling states in BTICs and endothelial cells, collapses the BTB, reduces quiescence depth of BTICs, and markedly enhances MB response to chemotherapy. Our study reveals that BTICs co-opt astrocytic mechanism to contribute to the BTB and provides the first evidence that BTB depends on mechanochemical signaling to mask tumor chemosensitivity. Targeting Piezo2 addresses BTB and BTIC properties that underlie therapy failures in brain cancer.

924 The spatial hierarchy of primary and recurrent medulloblastoma tumor ecosystems

Background

Medulloblastoma recurrence occurs in approximately 30% of patients and is universally fatal, presenting one of the most significant unmet clinical challenges in pediatric oncology. It is now clear that medulloblastomas are complex ecosystems, evolving under selective pressure from their microenvironment and cell of origin. Different tumor-immune cell interactions, including, but not limited to, tumor-infiltrating lymphocytes and various tumor suppressive myeloid cell populations, significantly hamper effective treatment strategies for primary, metastatic, and recurrent tumors. Recurrent medulloblastomas are rarely biopsied making biological material for interrogation scarce. Research has assumed that recurrent and primary medulloblastoma tumors have similar biological composition and therefore will respond to the same therapeutic regimens, however, therapies designed using primary biopsies, but tested in Phase I/II trials on children with recurrent disease, have been largely unsuccessful. We hypothesize that there are select immunosuppressive population differences within primary vs. recurrent tumor microenvironments (TME) that need to be elucidated in order to improve treatment modalities and outcomes in pediatric patients.

Methods

Using Akoya’s MOTiFTM PD-1/PD-L1 Panel: Auto Melanoma Kit, the staining protocol was adapted for optimal staining performance on human brain tissue. Following this, 24-formalin-fixed, paraffin embedded pediatric medulloblastoma samples (primary and recurrent biopsies from 12 patients) were stained for the following markers on the Leica BOND RX. Multispectral images were acquired using the Vectra Polaris, and five regions of interest selected on each image. An analysis algorithm was developed using inForm tissue analysis software, and samples were batch processed and data exported. Cell counts, densities, and spatial parameters were generated using the R-script package phenoptrReports to produce outputs of the image analysis data.

Results

Following spectral unmixing and autofluorescence isolation, no signal crosstalk was observed. The average signal intensity counts for all markers was found to be within the recommended ranges of 10–30, with a coefficient of variation of ≤15%, indicating successful and consistent staining of the medulloblastoma samples. Comparison between primary vs. recurrent tissues revealed distinctive spatial differences between immune-tumor cell interactions.

Conclusions

We have demonstrated successful adaptation of the MOTiF PD-1/PD-L1 Melanoma panel kit in conjunction with the Phenoptics workflow to support examination of the TME in patient-matched primary and recurrent pediatric medulloblastoma tumor biopsies. Our study provides the first insight into distinctive spatial interactions between primary vs. recurrent tissues, which may improve strategies to comprehend cancer progression, immune surveillance, and ultimately the development of rational, targeted therapeutics based on the differences between the tumor compartments and their immune-microenvironment.

Ethics Approval

Ethical approval obtained by Brain UK, ref: 20/008. All participants gave consent to use of their material.

Hospitalization burden and end-of-life (EOL) care in elderly patients with glioblastoma (GBM)

31

Background: GBM is associated with a poor prognosis and early death in elderly patients. Prior studies have demonstrated a high burden of hospitalization in this population. We sought to evaluate and examine trends in hospitalizations and EOL care in GBM survivors. Methods: Using SEER-Medicare linked data, we performed a retrospective observational cohort study of patients aged ≥ 65 years diagnosed with GBM from 2005-2017 who lived at least 6 months from the time of diagnosis. Aggressive EOL care was defined as: chemotherapy or radiotherapy within 14 days of death (DOD), surgery within 30 DOD, > 1 emergency department visit, ≥ 1 hospitalization or intensive care unit admission within 30 DOD; in-hospital death; or hospice enrollment ≤ 3 DOD. We evaluated age, race, ethnicity, marital status, gender, socioeconomic status, comorbidities, prior treatment and percentage of time hospitalized. Multivariable logistic regression was performed to determine factors associated with aggressive end of life care. Results: Of 5827 patients, 2269 (38.9%) survived at least 6 months. Among these, 1106 (48.7%) survived 6-12 months, 558 (24.6%) survived 12-18 months, and 605 (26.7%) survived > 18 months. Patients who survived 6-12 months had the highest burden of hospitalization and spent a median of 10.6% of their remaining life in the hospital compared to those surviving 12-18 months (5.4%) and > 18 months (3%) (P < 0.001). 10.1% of the cohort had claims for palliative care services; 49.8% of initial palliative care consults occurred in the last 30 days of life. Hospice claims existed in 83% with a median length of stay 33 days (IQR 12, 79 days). 30.1% of subjects received aggressive EOL care. Receiving chemo at any time (OR 1.510, 95% CI 1.221-1.867) and spending ≥ 20% of life in the hospital after diagnosis (OR 3.331, 95% CI 2.567-4.324) were associated with aggressive EOL care. Women (OR 0.759, 95% CI 0.624-0.922), patients with higher socioeconomic status (OR 0.533, 95% CI 0.342-0.829), and those diagnosed ≥ age 80 (OR 0.723, 95% CI 0.528-0.991) were less likely to receive aggressive EOL care. Race, ethnicity, marital status, and extent of initial resection were not associated with aggressive EOL care. Conclusions: A minority of elderly patients with GBM in the SEER-Medicare database survived ≥ 6 months; hospitalizations were common and patients spent a significant proportion of their remaining life hospitalized. Although hospice utilization was high in this cohort, 30% of patients received aggressive EOL care. Despite the aggressive nature of GBM, few patients had palliative care consults during their illness. Increased utilization of palliative care services may help reduce hospitalization burden and aggressive EOL care in this population.

Community health worker knowledge, attitudes and practices towards COVID-19: Learnings from an online cross-sectional survey using a digital health platform, UpSCALE, in Mozambique

Healthcare workers (HCWs) are at the frontline of the Coronavirus Disease 2019 (COVID-19) pandemic response, yet there is a paucity of literature on their knowledge, attitudes and practices (KAP) in relation to the pandemic. Community Health Workers (CHWs) in Mozambique are known locally as agentes polivalentes elementares (APEs). While technical guidance surrounding COVID-19 is available to support APEs, communicating this information has been challenging due to restrictions on travel, face-to-face group meetings and training, imposed from May to August 2020. A digital health platform, upSCALE, that already supports 1,213 APEs and 299 supervisors across three provinces, is being used to support APEs on effective COVID-19 management by delivering COVID-19 sensitive SMS messages, training modules and a COVID-19 KAP survey. The KAP survey, conducted from June 2020 to August 2020, consisted of 10 questions. Of 1,065 active upSCALE APEs, 28% completed the survey. Results indicate that only a small proportion of APEs listed the correct COVID-19 symptoms, transmission routes and appropriate prevention measures (n = (25%), n = (16%) and n = (39%), respectively) specifically included in national health education materials. Misconceptions were mainly related to transmission routes, high risk individuals and asymptomatic patients. 84% said they followed all government prevention guidelines. The results from the KAP survey were used to support the rapid development and deployment of targeted COVID-19 awareness and education materials for the APEs. A follow-up KAP survey is planned for November 2020. Adapting the existing upSCALE platform enabled a better understanding, in real time, of the KAP of APEs around COVID-19 management. Subsequently, supporting delivery of tailored messages and education, vital for ensuring a successful COVID-19 response.

NIMG-67. DISAPPEARING DOTS – TRANSIENT LATE ENHANCING LESIONS YEARS AFTER BRAIN RADIOTHERAPY

BACKGROUND

Late-delayed radiation effects appear 6 months to years following radiotherapy. We characterize a species of small enhancing lesions in the late-delayed phase of post-radiotherapy that are distinct from the classic descriptions of radiation necrosis or pseudoprogression associated with mass effect and edema. These “disappearing dots” are small, do not exert mass effect nor edema, and spontaneously resolve.

METHOD

We retrospectively describe a series of cases with “disappearing dots” following brain radiotherapy.

RESULTS

There were 10 cases (4 men), median age 42 years (range 29-63). Diagnoses were glioblastoma (3); low grade astrocytoma, anaplastic astrocytoma, and anaplastic oligodendroglioma (2 each); and solitary fibrous tumor (1). All patients received 54-60 Gy (Gray) of external beam radiotherapy, except one (proton beam therapy to 60 cobalt Gray equivalent). Disappearing dots appeared at a median of 27 months (range 5-197) post-radiotherapy. Lesions were relatively small (~&lt; 1 cm3), peri-ventricular, and within the radiotherapy field. Most enlarged before resolving. Advanced MR imaging and fluorodeoxyglucose (FGD)-PET results were inconsistent. Lesions persisted a median of 8.5 months (range 1-49) before spontaneous resolution. All were asymptomatic. Biopsy in one case revealed treatment effects rather than recurrent tumor.

CONCLUSIONS

Asymptomatic small periventricular enhancing lesions can develop and remit spontaneously, years following brain radiotherapy. Such disappearing dots should be part of the differential diagnosis along with tumor recurrence. of new enhancing lesions in the late-delayed phase post-radiotherapy.

QOLP-08. UTILIZING STAKEHOLDER ENGAGEMENT TO DEVELOP A MINDFULNESS-BASED INTERVENTION FOR PATIENTS WITH GLIOBLASTOMA (GBM) AND THEIR CAREGIVERS

BACKGROUND

Patients with GBM and their caregivers report impaired quality of life (QOL). Distress, fatigue and anxiety are common. Mindfulness-based interventions (MBIs) can help reduce anxiety and depression and improve QOL in patients with chronic diseases and other types of cancer, but have not been well studied in patients with brain tumors and their caregivers. The feasibility and acceptability of an MBI in this population is unknown.

METHODS

Using the Consolidated Framework for Implementation Research (CFIR), we developed a 15-minute survey for patients with brain tumors and their caregivers to assess attitudes and beliefs toward a MBI. As this study is formative, we chose to assess select domains including intervention characteristics, characteristics of individuals (knowledge and beliefs), and the outer setting (patient needs and resources). Questions were adapted from the literature to reflect constructs from each domain or created by the authors. The survey was published using Qualtrics, an online survey platform. We partnered with OurBrainBank to distribute the survey to key stakeholders using social media platforms. OurBrainBank is a patient-led movement centered around a symptom-tracking app for patients and carers, participation in patient-driven research, improved access to clinical trials, and patient advocacy.

RESULTS

The survey was published on 5/29/20. In one week, we received 14 responses. 7/14 identified as having a brain tumor or being the primary caregiver for someone with a brain tumor. Of these, 5/7 indicated they would be possibly or definitely interested in participating in a research study testing a MBI. Over the next 5 months, we anticipate 200 people will complete the survey. We will analyze the results using descriptive statistics.

DISCUSSION

Technology can aid in stakeholder engagement which is critical to intervention development. Results from this survey will be used to develop a MBI tailored to patients with GBM and their caregivers.

QOLP-32. PATTERNS OF CARE AT END OF LIFE IN PATIENTS WITH GLIOMA

OBJECTIVE

To understand patterns of care at end of life in glioma patients.

BACKGROUND

Patients with gliomas often inquire about end-of-life issues. Understanding common clinical outcomes of tumor progression and end-of-life circumstances may reduce anxiety among patients and caregivers and inform care planning.

METHODS

Following IRB approval, we retrospectively analyzed circumstances surrounding death among patients with intracranial gliomas at Columbia University Irving Medical Center from 1/2014-2/2019, including immediate cause and location of death and implementation of palliative measures. Information unavailable from the medical record was supplemented by caregivers.

RESULTS

Data were available for 152 patients (95 men, 57 women; median age at death 61.5 years). Failure to thrive with transition to supportive care (n=117, 77%) was the most common immediate cause of death. Others included infection (19, 13%; with pulmonary (12, 8%), urinary tract (5, 3%), CNS (4, 3%), and GI (2, 1%) sources); seizures (8, 5%); intracerebral hemorrhage (5, 3%); cerebral edema (4, 3%); pulmonary embolism (4, 3%); autonomic failure (2, 1%); hemorrhagic shock (2, 1%); respiratory failure of unknown cause (2, 1%); pulmonary edema (1, 1%); and cardiac arrhythmia (1, 1%). Ten patients had multiple causes of death. Seventy-three patients (48%) died at home with hospice. Other locations were inpatient hospice (40, 26%); acute care hospital (34, 22%) including 27 (18%) with and 7 (5%) without comfort measures; skilled nursing facility (4, 3%) including 3 (2%) with and 1 (1%) without comfort measures; or religious facility (1, 1%) with comfort measures. Acute cardiac and/or pulmonary resuscitation was performed in 20 patients (13%); 8 (5%) died with no comfort measures.

CONCLUSIONS

Failure to thrive with transition to supportive care was the most common (77%) immediate cause of death followed by infection (13%). Hospice and/or palliative measures were implemented in 95% of patients, though resuscitative efforts were performed in 13%.

PATH-17. HYPERPROGRESSIVE DISEASE IN PATIENTS WITH RECURRENT HIGH GRADE GLIOMAS TREATED WITH IMMUNE CHECKPOINT INHIBITORS OR CYTOTOXIC THERAPIES

BACKGROUND

Hyperprogressive disease (HPD), defined as a ≥ 2-fold increase in tumor growth rate (TGR) compared to baseline following initiation of immune checkpoint inhibitors (ICI), has been described in solid tumors but is not well explored high grade gliomas (HGG). We investigated the rate of HPD in HGG patients receiving ICIs for first or second recurrence compared to those treated with non-immunotherapy agents.

METHODS

Patients with HGG receiving ICIs for 1st or 2nd recurrence compared to a controls receiving other therapies at first progression. Prior or concurrent bevacizumab or anti-VEGFR were exclusionary due to pseudoresponse and decreased enhancement with these drugs. HPD was calculated by comparing TGR immediately before and after treatment.

RESULTS

49 patients met inclusion criteria (27 ICI, 25 control). 25/27 patients receiving ICIs and 20/22 patients in the control group were evaluable in the analysis. The ICI group included 60% men (15/25) and 80% (20/25) had a diagnosis of primary GBM. 68% were treated at first progression (17/25). Controls were 80% male (16/20) and all had a diagnosis of primary GBM. 28% (7/25) of patients met criteria for HPD in the ICI group compared to 4/20 controls (20%). Median OS in patients with primary GBM was 26mo in the ICI group vs. 15.9mo in controls. Median survival past progression in patients with primary GBM receiving ICI for 1st recurrence (13/25) was 12mo vs. 10.6mo in controls. 40% of patients in both groups had next generation sequencing (5/7 with HPD in ICI and 2/4 in control). EGFR alterations and MDM2/4 amplifications were not associated with HPD whereas PTEN mutations were more common in HPD (71% vs. 33.3%).

CONCLUSION

HPD is observed in patients with HGG treated with ICI at comparable rates to those with other cancers, but was also observed in 20% of patients receiving other therapies.

Hyperprogressive disease in patients with recurrent high grade gliomas treated with immune checkpoint inhibitors or other therapies

e13575

Background: Hyperprogressive disease (HPD) has been described in solid tumor patients treated with immune checkpoint inhibitors (ICI). HPD is defined as a ≥2-fold increase in tumor growth rate (TGR) following initiation of ICI. HPD has not been explored in patients with high grade gliomas (HGG) on ICI or standard cytotoxic regimens. In advanced cancer patients receiving ICI, MDM2/4 amplification or EGFR alterations, both found in HGG, correlated with HPD. We compared the rate of HPD in recurrent HGG patients receiving ICIs to those treated with non-immunotherapy agents. Methods: Patients with HGG on ICIs for 1st or 2nd recurrence were compared to a control group receiving other therapies at 1st recurrence. Patients with prior or concurrent bevacizumab or anti-VEGFR were excluded due to pseudoresponse and decreased enhancement with these drugs. HPD was calculated by comparing TGR immediately before and after treatment. Results: 49 patients met inclusion criteria (27 ICI, 25 control). 25/27 patients treated with ICIs and 20/22 patients in the control group had complete imaging and were eligible for analysis. In the ICI group, 60% were men (15/25) and 88% (22/25) had a diagnosis of GBM. 68% were treated at first progression (17/25). Controls were 80% male (16/20) and all had a diagnosis of GBM. 30% (6/20) were 65 years or older at diagnosis in the control group compared to 28% (7/25) in the ICI group. In total, 7/25 patients met criteria for HPD in the ICI group (28%) compared to 4/20 patients in the control group (20%). 10/25 patients (5/7 with HPD) in the ICI group and 8/20 patients (2/4 with HPD) in the control group had next generation sequencing of their tumors. EGFR alterations and MDM2/4 amplifications were not associated with HPD whereas PTEN mutations were more common in the HPD group (71% HPD vs. 33.3% no HPD). Conclusions: HPD is observed in patients with HGG treated with ICI at comparable rates to those with other cancers, but was also observed in 20% of patients receiving other therapies. While the numbers are small, PTEN mutations may be associated with HPD in patients with HGG. In contrast to other solid tumors, EGFR alterations and MDM2/4 amplifications were not associated with HPD in HGG.

Therapeutic targeting of ependymoma as informed by oncogenic enhancer profiling

Genomic sequencing has driven precision-based oncology therapy; however, genetic drivers remain unknown or non-targetable for many malignancies, demanding alternative approaches to identify therapeutic leads. Ependymomas are chemotherapy-resistant brain tumours, which, despite genomic sequencing, lack effective molecular targets. Intracranial ependymomas are segregated based on anatomical location – supratentorial region (ST) or posterior fossa (PF) – and further divided into distinct molecular subgroups that reflect differences in age of onset, gender predominance, and response to therapy^1–3. The most common and aggressive subgroup, Posterior Fossa Ependymoma Group A (PF-EPN-A), occurs in young children and appears to lack recurrent somatic mutations². Conversely, Posterior Fossa Ependymoma Group B (PF-EPN-B) tumours display frequent large-scale copy number gains and losses yet favourable clinical outcomes^1,3. Greater than 70% of supratentorial ependymomas are defined by highly recurrent gene fusions in the NFκB subunit RELA (ST-EPN-RELA), and less frequently involve fusion of the gene encoding the transcriptional activator YAP1 (ST-EPN-YAP1).^1,3,4 Subependymomas, a distinct histologic variant, can also be found within the ST and PF compartments accounting for the majority of tumours in the molecular subgroups ST-EPN-SE and PF-EPN-SE, respectively¹. Here, we mapped active chromatin landscapes in 42 primary ependymomas in two non-overlapping primary ependymoma cohorts with the goal of identifying essential super enhancer associated genes on which tumour cells were dependent. Enhancer regions revealed putative oncogenes, molecular targets, and pathways, which when subjected to small molecule inhibitor or shRNA treatment, diminished proliferation of patient-derived neurospheres and increased survival in mouse models of ependymomas. Through profiling of transcriptional enhancers, our study provides a framework for target and drug discovery in other cancers recalcitrant to therapeutic development because of their lack of known genetic drivers.

Translating Healthy Living Messages to Postpartum Women and Their Partners After Gestational Diabetes (GDM): Body Habitus, A1C, Lifestyle Habits, and Program Engagement Results From the Families Defeating Diabetes (FDD) Randomized Trial

PURPOSE

The Families Defeating Diabetes intervention evaluated a postpartum healthy living program for women with recent gestational diabetes mellitus (GDM).

DESIGN

Randomized controlled trial.

SETTING

Tertiary centers in London, Calgary, and Victoria, Canada.

PARTICIPANTS

Women with GDM and partners; 46% of eligible maternal participants agreed to participate.

INTERVENTION

Interventional (INT) participants received a healthy living seminar at 3 months; access to a walking group/Website; biweekly e-mails. Control (CON) participants received a contemporary postpartum diabetes prevention handout.

MEASURES

Maternal, partner, and offspring demographics at baseline, 3, and 12 months.

ANALYSIS

Percentages of women losing ≥7% of postpartum weight were compared by χ² testing; body habitus comparisons by analysis of covariance (ANCOVA); maternal A1C comparisons by unpaired t tests; participant outcome associations by Pearson correlation coefficients.

RESULTS

Maternal participants were 170 (89 INT and 81 CON) with 63 partners (30 INT and 33 CON); 103 (73 maternal; 30 partners) were lost to follow-up; 57% of maternal participants completed 12 months; 33% INT women (n = 50) lost ≥7% weight versus 25% CON women (n = 47), P = .43. Interventional participant results did not correlate with accession of study elements. Maternal completion was significantly associated with partner involvement, breastfeeding, higher income, and education. Paternal weights correlated significantly with maternal and offspring weights.

CONCLUSION

Families Defeating Diabetes outcomes were not significantly different for INT maternal or paternal participants versus CON participants. Secondary outcomes of future value included statistically significant positive associations between paternal participation, socioeconomic indicators, and maternal study completion, significant correlations between maternal, paternal, and offspring weights as well as insights into study component engagement.

Identification of GPC2 as an Oncoprotein and Candidate Immunotherapeutic Target in High-Risk Neuroblastoma

We developed an RNA-sequencing-based pipeline to discover differentially expressed cell-surface molecules in neuroblastoma that meet criteria for optimal immunotherapeutic target safety and efficacy. Here, we show that GPC2 is a strong candidate immunotherapeutic target in this childhood cancer. We demonstrate high GPC2 expression in neuroblastoma due to MYCN transcriptional activation and/or somatic gain of the GPC2 locus. We confirm GPC2 to be highly expressed on most neuroblastomas, but not detectable at appreciable levels in normal childhood tissues. In addition, we demonstrate that GPC2 is required for neuroblastoma proliferation. Finally, we develop a GPC2-directed antibody-drug conjugate that is potently cytotoxic to GPC2-expressing neuroblastoma cells. Collectively, these findings validate GPC2 as a non-mutated neuroblastoma oncoprotein and candidate immunotherapeutic target.

Abstract 685: GPC2 is an oncogene and immunotherapeutic target in high-risk neuroblastoma

Background: GD2-directed immunotherapeutic strategies have improved outcomes in neuroblastoma; however, the majority of patients treated suffer relapse and GD2 expression on pain fibers causes dose-limiting toxicities.

Methods: To identify alternative cell surface immunotherapeutic targets, we compared high-risk neuroblastoma (n=126 tumors) and normal tissue RNA sequencing data (GTEx; n=7859 samples from 31 normal tissues) and prioritized genes by differential and absolute expression and cell surface prediction. Genes were further surveyed for somatic copy number gain and correlative expression with MYCN amplification. Differential protein expression and localization were confirmed in neuroblastoma primary tumors (n=98), patient-derived xenografts (n=32; PDXs), cell lines (n=23), and normal pediatric tissues (n=36). Cell lines were subjected to candidate gene gain and loss of function studies (n=11). Additional pediatric tumor RNA sequencing data was surveyed followed by confirmatory immunohistochemistry (IHC). Finally, candidate specific antibodies were isolated from a human Fab phage library and utilized for antibody-drug conjugate (ADC) engineering followed by cytotoxicity studies.

Results: We identified 33 differentially expressed cell surface molecules from which we prioritized glypican-2 (GPC2) for validation given GPC2’s robust differential expression (log-fold change tumor vs. normal tissue = 1.71-9.22; p=1.99 x 10-9-1.88 x10-300), high-level absolute RNA expression (median FPKM=60), and frequent DNA copy number gain associated with higher GPC2 expression (35%, n=182 tumors; p&lt;0.005). GPC2 expression was also higher in MYCN amplified neuroblastomas (p&lt;0.05), MYCN binds the GPC2 promoter shown by chromatin immunoprecipitation (ChIP) sequencing and reporter assays, and MYCN depletion resulted in decreased GPC2 expression. Immunoblot, flow cytometry, immunofluorescence, and IHC analysis of primary tumors, PDXs, and cell lines confirmed dense cell surface GPC2 expression. Medulloblastomas (n=62) were also found to have high GPC2 expression that positively correlated with MYC, MYCN, and GPC2 loci gain (p&lt;0.0001). Pediatric normal tissues had very restricted cell surface GPC2 expression, with only low levels found in the esophagus and skin. GPC2 depletion in neuroblastoma cell lines resulted in apoptosis and growth inhibition and GPC2 forced over-expression increased neuroblastoma cell proliferation (p&lt;0.001 for all assays). Finally, a human GPC2 antibody, D3-GPC2-Fab, was developed and shown to bind GPC2 with high affinity and specificity. D3-GPC2-IgG1 induced internalization of GPC2 and was conjugated to pyrrolobenzodiazepine (PBD) dimers to form an ADC which induced potent and specific cytotoxicity to GPC2 expressing neuroblastoma cells (IC50 = 1.7-11 pM).

Conclusions: GPC2 is an oncogene and immunotherapeutic target in neuroblastoma and potentially other cancers.

Citation Format: Kristopher R. Bosse, Pichai Raman, Maria Lane, Robyn T. Sussman, Jo Lynne Harenza, Daniel Martinez, Sabine Heitzeneder, Zhongyu Zhu, Komal Rathi, Michael Randall, Laura Donovan, Sorana Morrissy, Doncho V. Zhelev, Yang Feng, Jennifer Hwang, Yanping Wang, Bruce Pawel, Tricia Bhatti, Mariarita Santi, Javed Khan, Michael Taylor, Dimiter S. Dimitrov, Crystal Mackall, John M. Maris. GPC2 is an oncogene and immunotherapeutic target in high-risk neuroblastoma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 685. doi:10.1158/1538-7445.AM2017-685

Synergistic effect of reirradiation and PD-1 inhibitors in recurrent high-grade gliomas

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Background: To date, studies of single agent PD-1 or PDL-1 inhibitors in recurrent high-grade gliomas (HGG) have shown infrequent responses ( < 10%) and limited efficacy. Reirradiation is considered one of the standard salvage regimens for selected patients with recurrent gliomas but tumor responses are also infrequent ( < 5%). Radiotherapy counteracts the immunosuppressive tumor microenvironment by increasing MHC class I expression and enhancing tumor neoantigen presentation and has a significant synergistic effect with PD-1 inhibition in preclinical models of glioma. Methods: From December 2014 to June 2016, 20 patients (14 men, 6 women) with recurrent HGG were treated with the combination of reirradiation and PD-1 inhibitors. 18 patients had a glioblastoma, 1 anaplastic astrocytoma and 1 anaplastic oligodendroglioma. The median KPS at the start of this regimen was 70 (50 to 80). The median number of prior treatments for recurrent tumor was 2 (1-4), 100% had prior radaition, 95% prior temozolomide and 55% prior bevacizumab. 8 patients received pembrolizumab (2 mg/Kg every 3 weeks) and 12 patients received nivolumab (3 mg/Kg or 240 mg flat dose every 2 weeks). Median reirradiation dose was 35 Gy (12 Gy to 35 Gy). Results: There were 7 confirmed partial responses (35% objective response rate, ORR), 5 stable disease and 8 progressive disease. The median duration of response was 5 months (2.2 to 10+ months). Median PFS was 4 months and median OS was 10 months. Most common side effects were increased ALT (3 patients) and fatigue (2 patients). There was no obvious case of cerebral edema related to treatment. 5 patients required a mild increase of dexamethasone (2-4 mg) and all other 15 patients had decreased or stable dexamethasone dosage after the reirradiation. Conclusions: PD-1 inhibitors in combination with re-irradiation can be administered safely to patients with recurrent HGG. The ORR of 35% is an early signal of the potential synergist effect of the combination of PD-1 inhibitors with re-irradiation in HGG. This retrospective analysis of a heavily pre-treated population of recurrent HGG showed significantly higher ORR than either PD-1 inhibitors or re-irradiation alone. A clinical trial under development to test this hypothesis.

Short- and long-term outcomes of metformin compared with insulin alone in pregnancy: a systematic review and meta-analysis

AIM

To assess the short- and long-term maternal and fetal impact of metformin in pregnancy compared with insulin.

METHODS

We performed a comprehensive literature search of MEDLINE, EMBASE, BIOSIS, Cochrane Database of Systematic Reviews and ClinicalTrials.gov. Eligible studies were randomized control trials (RCTs) or follow-up of an RCT that: (1) compared metformin with insulin in pregnancy in women with gestational diabetes mellitus or Type 2 diabetes; and (2) reported maternal or fetal outcomes of interest. Two reviewers extracted the data, evaluated study quality and calculated pooled estimates.

RESULTS

Sixteen studies (n = 2165 in quantitative analysis) were included. Metformin lowered the risk of neonatal hypoglycaemia [risk ratio (RR) = 0.63; 95% confidence interval (95% CI), 0.45 to 0.87], large for gestational age babies (RR = 0.80; 95% CI, 0.64 to 0.99), pregnancy-induced hypertension (RR = 0.56; 95% CI, 0.37 to 0.85) and total maternal pregnancy weight gain [mean difference (MD) -2.07; 95% CI -2.88 to -1.27]. Metformin did not increase preterm delivery (RR = 1.18; 95% CI 0.67 to 2.07), small for gestational age babies (RR = 1.20; 95% CI, 0.67 to 2.14), perinatal mortality (RR = 0.82; 95% CI, 0.17 to 3.92) or Caesarean section (RR = 0.97; 95% CI, 0.80 to 1.19). Long-term outcome information is limited.

CONCLUSIONS

Our review found that metformin had no short-term adverse effects on pregnancy, potential benefits in the neonatal period, but limited long-term follow-up information. Prior to routine use, we recommend further follow-up studies of offspring exposed to metformin in utero.