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Under-enrollment in clinical trials significantly limits valid analyses of clinical interventions and generalizability of findings. Often it results in premature study termination, with estimates of 22% to 50% of clinical trials terminated due to poor accrual. Currently, there are limited reports addressing the influence of race/ethnicity and socioeconomic status on clinical trial enrollment in adult glioma patients. The goal of this study was to test the hypothesis that race and socioeconomic status negatively impact therapeutic clinical trial enrollment. 988 adult patients were identified from the UCSF Tumor Board Registry and analyzed to determine the rate of therapeutic clinical trial screening and study enrollment. At initial diagnosis, 43.6% and 17.5% of glioma patients were screened and enrolled in a therapeutic clinical trial, respectively. At recurrence, 49.8% and 26.3% of patients were screened and enrolled in a clinical trial, respectively. Thirty-three percent of the study population belonged to a NIH-designated underrepresented minority group; Asian/Pacific-Islander comprised 19.6% of the overall cohort. On univariate analysis, only in-state location, distance to the hospital, and WHO grade were associated with enrollment at initial diagnosis and recurrence. Minority status, insurance type, median household income, and percent below poverty were not associated with clinical trial enrollment. Minority and socioeconomic status did not impact adult glioma clinical trial enrollment. Proximity to the tertiary care cancer center may be an important consideration for minority patients. Patient screening should be carefully considered in order to avoid bias based on minority and socioeconomic status.

BACKGROUND Gliomas are devastating primary tumors of the central nervous system that often present with difficult to manage symptoms in addition to the antineoplastic tumor itself. Due to recent increase in popularity and societal acceptance of cannabis products, their use by glioma patients has increased. METHODS We conducted a single center, prospective study: patients with glioma answered a locally validated survey to inquire about their cannabis use at baseline and every three months. Quality of Life was measured using the EORTC QLQ-C30, its complementary module BN-20 and the EQ-5D-5L instrument. Eligible participants were classified as cannabis users or non-users. We performed linear regression clustered by subjects to see differences by user group and trends overtime. RESULTS To date, 89 patients agreed to participate, enrolled, and answered the baseline questionnaires, and 64 have answered the 3 month follow up survey. The mean age was 49.7(SD 13.74), 55 were male, 55 were cannabis users at baseline (61.8%) and 34 at 3 months (53.13%). Patients who were cannabis users scored 11.73 lower points at baseline when compared to non-users (79.65 [SD 18.93] vs 67.92 [SD 19.22]) in the QLQ-C30 instrument. Similarly, cannabis users recorded 9.624 lower points at 3 months compared to non-users (70.1 [SD 21.33] vs 79.72 [SD13.95]). The difference-in-difference estimator was 2.108 (p< 0.7). CONCLUSION Although we observed cannabis users scoring lower QoL measurements (p< 0.05) at baseline and 3 months, we observed a slight improvement in QoL of cannabis users while observing no change or decline (in some measures) among non-users. Our findings provide insight to the impact that cannabis has in QoL over time. While not conclusive, these preliminary results need to be studied on a longer-term basis with a larger sample size in order to detect trends on quality of life among patients with different tumor types.

BACKGROUND Surgery is the mainstay of meningioma treatment, but improvements in meningioma risk stratification are needed and indications for postoperative radiotherapy are controversial. DNA methylation profiling, copy number variants (CNVs), exome sequencing, and RNA sequencing have improved understanding of meningioma biology, but have not superseded histologic grading, or revealed biomarkers for radiotherapy responses. To address these unmet needs, we optimized and validated a targeted gene expression biomarker predicting meningioma outcomes and responses to radiotherapy. METHODS Targeted gene expression profiling was performed on a discovery cohort of 173 meningiomas (median follow-up 8.1 years) and a validation cohort of 331 meningiomas (median follow-up 6.1 years) treated with surgery (n=504) and postoperative radiotherapy (n=73) at independent, international institutions (70% WHO grade 1, 24% WHO grade 2, 6% WHO grade 3). Optimized targeted gene expression models predicting clinical outcomes (34 genes) or radiotherapy responses (12 genes) were developed from the discovery cohort, and compared to histologic and molecular classification systems by performing DNA methylation profiling, CNV analysis, exome sequencing, and RNA sequencing on the same meningiomas. RESULTS Targeted gene expression profiling achieved a concordance-index of 0.75 ± 0.03 (SEM) for local freedom from recurrence (LFFR) and 0.72 ± 0.03 for overall survival (OS) in the validation cohort, outperforming WHO grade (5-year LFFR delta-AUC 0.15, 95% CI 0.076-0.229, p=0.001) and DNA methylation grouping (delta-AUC 0.075, 95% CI 0.006-0.130, p=0.01) for LFFR, disease-specific survival, and OS. The biomarker was independently prognostic after accounting for WHO grade, extent of resection, primary versus recurrent presentation, CNV status, DNA methylation group, and Ki67 labeling index, and identified meningiomas benefiting from radiotherapy (interaction p-value=0.0008), suggesting postoperative radiotherapy could be refined in 30.2% of cases. CONCLUSIONS Targeted gene expression profiling of 504 meningiomas improves discrimination of meningioma local recurrence, disease-specific survival, and overall survival, and predicts radiotherapy responses.

Purpose/Objective(s) Indications for postoperative radiotherapy after meningioma resection are controversial. DNA methylation profiling identifies meningiomas at risk for recurrence, but logistic and technical barriers have encumbered clinical translation of this approach. The aim of this study was to optimize and validate a clinically-tractable targeted gene expression biomarker to predict meningioma outcomes and responses to postoperative radiotherapy. Materials/Methods Targeted gene expression and Illumina 850k DNA methylation profiling were performed on a discovery cohort of 173 meningiomas (median follow-up 7.8 years) and an external validation cohort of 331 meningiomas (median follow-up 5.8 years) from patients treated with surgery (n = 504) and postoperative radiotherapy (n = 73) at independent, international institutions (70% WHO grade 1, 24% WHO grade 2, 6% WHO grade 3). RNA sequencing was performed on the discovery cohort, and 125 genes were selected for targeted gene expression profiling based on associations with meningioma recurrence. Regularized Cox regression was used to develop continuous gene expression risk score for local freedom from recurrence (LFFR). The model (34 meningioma genes and 7 housekeeping genes) and risk quartiles (low, low-intermediate, high-intermediate, and high) were locked and validated on the external cohort. Multivariate regressions (MVR) incorporating WHO grade, DNA methylation grouping, extent of resection, primary versus recurrent presentation, and postoperative radiotherapy were used to assess the risk score across clinical contexts. Results The gene expression risk score (concordance-index 0.78 ± 0.03) outperformed DNA methylation grouping (0.71 ± 0.03) and WHO grade (0.65 ± 0.03) in stratifying meningioma LFFR in the validation cohort (n = 331). The risk score classified 43% of WHO grade 1 meningiomas as high-intermediate (n = 82) or high risk (n = 34), with 5-year LFFR and overall survival (OS) of 83% and 89% for high-intermediate risk WHO grade 1 meningiomas, and 41% and 73% for high risk WHO grade 1 meningiomas, respectively. Low risk WHO grade 1 meningiomas (n = 50) had 5-year LFFR and OS of 92% and 88%, respectively. High and high-intermediate risk scores were independently prognostic for LFFR (HR 2.9, 95% CI 1.2-4.4) and OS (HR 2.7, 95% CI 1.3-5.6) on MVR. An interaction term between postoperative radiotherapy and risk score was predictive for LFFR (P = 0.046) and OS (P = 0.001) on MVR in the validation cohort, suggesting meningiomas with higher risk scores derived greater benefit from postoperative radiotherapy. Conclusion Here we use targeted gene expression profiling to develop a risk score predicting meningioma outcomes and responses to postoperative radiotherapy. This cost-effective assay outperforms DNA methylation grouping and WHO grade in discriminating meningioma outcomes, and may be useful for guiding clinical trial design.

Purpose of Review This review seeks to inform oncology clinicians and researchers about the development of novel immunotherapies for the treatment of glioblastoma. An enumeration of ongoing and recently completed clinical trials will be discussed with special attention given to current technologies implemented to overcome central nervous system–specific challenges including barriers to the peripheral immune system, impaired antigen presentation, and T cell dysfunction. Recent Findings The success of immunotherapy in other solid cancers has served as a catalyst to explore its application in glioblastoma, which has limited response to other treatments. Recent developments include multi-antigen vaccines that seek to overcome the heterogeneity of glioblastoma, as well as immune checkpoint inhibitors, which could amplify the adaptive immune response and may have promise in combinatorial approaches. Additionally, oncolytic and retroviruses have opened the door to a plethora of combinatorial approaches aiming to leverage their immunogenicity and/or ability to carry therapeutic transgenes. Summary Treatment of glioblastoma remains a serious challenge both with regard to immune-based as well as other therapeutic strategies. The disease has proven to be highly resistant to treatment due to a combination of tumor heterogeneity, adaptive expansion of resistant cellular subclones, evasion of immune surveillance, and manipulation of various signaling pathways involved in tumor progression and immune response. Immunotherapeutics that are efficacious in other cancer types have unfortunately not enjoyed the same success in glioblastoma, illustrating the challenging and complex nature of this disease and demonstrating the need for development of multimodal treatment regimens utilizing the synergistic qualities of immune-mediated therapies.

Meningiomas arising from the meningothelial central nervous system lining are the most common primary intracranial tumors, and a significant cause of neurologic morbidity and mortality1. There are no effective medical therapies for meningioma patients2,3, and new treatments have been encumbered by limited understanding of meningioma biology. DNA methylation profiling provides robust classification of central nervous system tumors4, and can elucidate targets for molecular therapy5. Here we use DNA methylation profiling on 565 meningiomas integrated with genetic, transcriptomic, biochemical, and single-cell approaches to show meningiomas are comprised of 3 epigenetic groups with distinct clinical outcomes and biological features informing new treatments for meningioma patients. Merlin-intact meningiomas (group A, 34%) have the best outcomes and are distinguished by a novel apoptotic tumor suppressor function of NF2/Merlin. Immune-enriched meningiomas (group B, 38%) have intermediate outcomes and are distinguished by immune cell infiltration, HLA expression, and lymphatic vessels. Hypermitotic meningiomas (group C, 28%) have the worst outcomes and are distinguished by convergent genetic mechanisms misactivating the cell cycle. Consistently, we find cell cycle inhibitors block meningioma growth in cell culture, organoids, xenografts, and patients. Our results establish a framework for understanding meningioma biology, and provide preclinical rationale for new therapies to treat meningioma patients.

Background “Diffuse midline glioma (DMG), H3 K27M-mutant” is a new tumor entity established in the 2016 WHO classification of Tumors of the Central Nervous System that comprises a set of diffuse gliomas arising in midline structures and is molecularly defined by a K27M mutation in genes encoding the histone 3 variants H3.3 or H3.1. While this tumor entity is associated with poor prognosis in children, clinical experience in adults remains limited. Methods Patient demographics, radiologic and pathologic characteristics, treatment course, progression, and patient survival were collected for 60 adult patients with DMG, H3 K27M-mutant. A subset of tumors also underwent next-generation sequencing. Analysis of progression-free survival and overall survival was conducted using Kaplan–Meier modeling, and univariate and multivariate analysis. Results Median patient age was 32 years (range 18–71 years). Tumors were centered in the thalamus (n = 34), spinal cord (10), brainstem (5), cerebellum (4), or other midline sites (4), or were multifocal (3). Genomic profiling revealed p.K27M mutations exclusively in the H3F3A gene and an absence of mutations in HIST1H3B or HIST1H3C, which are present in approximately one-third of pediatric DMGs. Accompanying mutations in TP53, PPM1D, FGFR1, NF1, and ATRX were frequently found. The overall survival of this adult cohort was 27.6 months, longer than historical averages for both H3 K27M-mutant DMG in children and IDH-wildtype glioblastoma in adults. Conclusions Together, these findings indicate that H3 K27M-mutant DMG represents a heterogeneous disease with regard to outcomes, sites of origin, and molecular pathogenesis in adults versus children.

Angiogenesis is a central feature of glioblastoma (GBM), with contribution from several mechanisms and signaling pathways to produce an irregular, poorly constructed, and poorly connected tumor vasculature. Targeting angiogenesis has been efficacious for disease control in other cancers, and given the (I) highly vascularized environment in GBM and (II) correlation between glioma grade and prognosis, angiogenesis became a prime target of therapy in GBM as well. Here, we discuss the therapies developed to target these pathways including vascular endothelial growth factor (VEGF) signaling, mechanisms of tumor resistance to these drugs in the context of disease progression, and the evolving role of anti-angiogenic therapy in GBM.

2045 Background: Recurrence of GBM after initial treatment with surgery, radiation, and chemotherapy is nearly universal. Salvage therapies have limited efficacy with median overall survival (OS) of approximately 9 months and 6-month-progression-free survival (PFS-6) of 10-25% for both targeted and traditional therapies. Given GBM’s molecular heterogeneity, targeting a single molecular abnormality in isolation has consistently failed as a strategy, and precision combination approaches are needed. Methods: The primary objective was to demonstrate the feasibility of implementing a personalized drug regimen for patients (pts) with surgically resectable recurrent GBM within 35 days of surgery. Secondary objectives included safety and efficacy. Eligible pts signed consent before surgery, and tumor tissue was analyzed using the CLIA-approved “UCSF500” next-generation sequencing panel with paired tumor/germline sequencing. A specialized genomic tumor board made individualized treatment recommendations incorporating sequencing results of the recurrent tumor and clinical history for each pt, using up to 4 FDA-approved drugs in combination (all drugs provided by study). Correlative studies will be reported separately. Results: 19 pts signed consent and 16 pts had surgery on trial, 1 with pathology showing treatment effect only. The remaining 15 pts were all genetically profiled and successfully started their individualized treatment within 35 days of surgery, meeting the primary feasibility endpoint. Conclusions: Implementation of an individualized treatment regimen was feasible in a timely fashion in surgically resectable recurrent GBM pts, with encouraging preliminary efficacy results. Further investigation is warranted, both to validate efficacy and to streamline this approach in larger pt populations. Clinical trial information: NCT03681028. [Table: see text]

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.

Tumor-treating fields (TTF) increase patient survival in glioblastoma, and are approved for recurrent (2011) and de novotumors (2016). Since 2012, 52 patients with gliomas at Columbia University were treated with TTF. Given preclinical data suggesting synergy between TTF and PD1-targeted therapy, the rates and outcomes of combination TTF and immunotherapy were analyzed. Of 52 patients, 40% were women. Median age at diagnosis was 58 (23-84) years. WHO glioma grade was II (6%), III (10%), or IV (84% of patients). TTF was used at recurrence in 42 (81%), with 0-4 prior recurrences. Prior therapy included bevacizumab (20%), resection (gross-total in 54%), radiation (60Gy in 85%), and temozolomide (100%). 11 (75%) patients met a compliance goal of 75%. Only 2 (4%) experienced skin toxicity requiring interruption. Concurrent systemic therapy included temozolomide (31%), nitrosourea (8%), bevacizumab (37%), or immunotherapy (54% of patients). At interim follow-up, progression free (PFS) and overall (OS) survival were 3.6 and 21.5 months, respectively. Objective response rate (ORR) based on RANO was increased in patients treated with concurrent immunotherapy (26% vs. 13%). Among GBM patients treated with concurrent immunotherapy, median PFS was significantly increased (4.6 vs. 3.5 mo, p=0.04), and survival trended upward (8.3 vs. 6.5 mo, p=0.32). After long-term follow-up, PFS, OS, and impact of compliance rates will be re-analysed. TTF improves survival for glioblastoma patients and immunotherapy shows promise in other cancers. The possible synergy between these modalities in preclinical studies and this retrospective series warrants further study in a randomized controlled trial. We propose a single-arm phase II trial of concurrent PD1 inhibitor and TTF for patients with bevacizumab-naïve glioblastoma, at diagnosis or recurrence. OS is the primary endpoint; secondary endpoints include PFS, ORR, and predictive value of PDL1 expression, and impact of compliance. Results from the EF-14 trial will serve as a historical control.

Tumor-treating fields (TTF) are approved for use in patients with glioblastomas at recurrence (2011) or adjuvant setting (2016) due to survival benefit in various trials. Since 12/2012, 46 patients were treated with TTF for de novo or recurrent gliomas at Columbia University. Rates and outcomes of combination with immunotherapy were analyzed, given the recent preclinical data of synergism between TTF and PD1 targeted therapy. The impact of compliance was also analyzed in multivariable analyses in this retrospective cohort. Of 44 treated patients, 18 (41%) were women and 2 (5%), 4 (9%) and 36 (86%) had WHO grade II, III and IV gliomas. Median age at diagnosis was 56 (23-84) years. TTF was used at recurrence in 38 (86%), with a median of 2 (0-4) prior recurrences. Prior therapies included bevacizumab (22, 50%), surgery [25/44 (57%) gross total], radiation and temozolomide. Median TTF therapy duration was 1.8 (0.1-20.3) months. Only 2 (5%) experienced skin toxicity requiring interruptions. Compliance goal of 75% was met by 11/44 (25%) glioma patients. Concurrent systemic therapy was used in 35 (80%), including temozolomide (12, 27%), nitrosourea (2, 5%), bevacizumab (17, 39%), immunotherapy (26, 59%) or other (5, 11%). Objective response rate (ORR) based on RANO was noted in 25/42 (60%) of all gliomas and 21/38 (55%) of glioblastomas, At interim follow-up, progression free (PFS) and overall (OS) survival were 2.7 and 6.9 months, respectively. PFS was significantly increased among glioblastoma patients treated with concurrent immunotherapy (PFS: 3.3 vs. 1.95, p=0.0364). Long-term follow-up PFS and OS will be re-analyzed, along with the potential confounding impact of compliance rates. TTF improves survival for patients with glioblastomas. Immunotherapy shows promise for various tumor histologies. The possible synergism between these modalities in preclinical studies and this retrospective glioma series warrants further study in randomized controlled gliomas trials. We propose a single-arm phase II trial of concurrent PD1 inhibitor and TTF for patients with bevacizumab-naïve glioblastoma at second or third recurrence. OS is the primary endpoint; secondary endpoints include PFS, ORR, predictive value of PDL1 expression, and impact of compliance. Results from the EF-14 trial will serve as a historical control. Citation Format: Yazmin Odia, Jessica Schulte, Fabio Iwamoto. Rates and impact of combination immunotherapy with tumor treating fields in a glioma cohort [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 CT102. doi:10.1158/1538-7445.AM2017-CT102