Citations

Abstract Therapeutic advances for glioblastoma have been minimal over the past 2 decades. In light of the multitude of recent phase III trials that have failed to meet their primary endpoints following promising preclinical and early-phase programs, a Society for Neuro-Oncology Think Tank was held in November 2020 to prioritize areas for improvement in the conduct of glioblastoma clinical trials. Here, we review the literature, identify challenges related to clinical trial eligibility criteria and trial design in glioblastoma, and provide recommendations from the Think Tank. In addition, we provide a data-driven context with which to frame this discussion by analyzing key study design features of adult glioblastoma clinical trials listed on ClinicalTrials.gov as “recruiting” or “not yet recruiting” as of February 2021.

Abstract Immunotherapy has revolutionized treatment for many hard-to-treat cancers but has yet to produce significant improvement in outcomes for patients with glioblastoma. This reflects the multiple and unique mechanisms of immune evasion and escape in this highly heterogeneous tumor. Glioblastoma engenders profound local and systemic immunosuppression and is remarkably effective at inducing T-cell dysfunction, posing a challenge to any immunotherapy-based approach. To overcome these mechanisms, multiple disparate modes of immune-oriented therapy will be required. However, designing trials that can evaluate these combinatorial approaches requires careful consideration. In this review, we explore the immunotherapy resistance mechanisms that have been encountered to date and how combinatorial approaches may address these. We also describe the unique aspects of trial design in both preclinical and clinical settings and consider endpoints and markers of response best suited for an intervention involving multiple agents.

Neutral lipids are a critical source for cellular energy and are stored within specialized organelles known as lipid droplets (LD). Degradation of LDs for energy utilization is accomplished by two principal pathways: lipolysis that is activated by cAMP to recruit adipose triglyceride lipase (ATGL) to the LD surface, and lipophagy that utilizes the autophagic machinery to target and traffic LDs for degradation by lysosomal acid lipase (LAL). However, the mechanisms underlying synergy between these seemingly distinct pathways are not well understood. Previous studies show that autpohagic membrane cannot effectively engulf large organelles, but is size‐restricted to small cargo. Based on this, we HYPOTHESIZE that lipolysis and lipophagy are sequential pathways whereby lipolysis first reduces the size of large LDs to allow for subsequent autophagic engulfment of small LDs for lipophagy. Methods Using light and electron microscopy combined with biochemical approaches, we explored LD size and the sequential nature of lipolysis and lipophagy in primary rat and AML12 hepatocytes. Live‐cell microscopy was used for the first time to monitor LDs transitioning from lipolysis in the cytoplasm to lipophagy within endolysosomal vesicles. Results Confocal microscopy of endogenous ATGL revealed a preferential association with large LDs with an average size of 4.0 μm 2 , seven‐fold larger than LDs not associated with ATGL. In striking comparison, LDs associated with components of the autophagic machinery (LC3, Lamp3) were 50% smaller in size (0.39 μm 2 ). Consistent with this observation, siRNA knockdown of ATGL resulted in the persistence of large LDs (2.8 μm 2 ), whereas knockdown of LAL left cells filled with numerous small LDs (1.5 μm 2 ). These observations were mimicked by inhibitors of ATGL (atglistatin) and LAL (lalistat). In support of these findings, differential centrifugation of AML12 homogenates allowed for separation of two distinct populations of LDs: a buoyant fraction of large LDs enriched in the cytosolic lipase ATGL, and a second collection of smaller, less buoyant LDs enriched in lysosomal enzymes such as Lamp2A, the autophagosome marker LC3‐II, and the endosomal marker Tsg101. Most interesting are time lapse movies of live cells showing engulfment of small LDs by a Lamp3‐positive late endosomal compartment, suggesting that these organelles play an important role in the direct targeting and engulfment of LDs for lipophagy. Conclusion Hepatocytes appear to catabolize LDs in a tandem stepwise process that first utilizes cytosolic lipases to substantially reduce LD size, thereby allowing for subsequent engulfment of small LDs by autophagosomes as well as late endosomes and lysosomes. Support or Funding Information Supported by NIAAA RO1AA020735 to MAM; NIDDK award T32DK007352 to MBS and RJS, and the Mayo Clinic Kogod Aging Fellowship to MBS. This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal .

Fatty liver disease affects 80–100 million Americans and is a precursor to irreversible and sometimes fatal liver damage. The initial stages of fatty liver disease are marked by the hepatocellular accumulation of fat‐storage organelles known as lipid droplets (LDs) that are degraded by two pathways: lipolysis that involves the recruitment of cytosolic lipases (ATGL, HSL) to the LD surface, and lipophagy that relies on autophagic membranes to target and traffic LDs for lysosomal degradation. Importantly, the mechanisms underlying a cooperation between these seemingly distinct pathways are not well understood. Previous studies have shown that the autophagic engulfment of cytosolic cargo is size‐restricted. Because of this, we HYPOTHESIZE that lipolysis and lipophagy occur as sequential processes initiated by cytosolic lipases to reduce LD size and allow for subsequent engulfment by autophagic membranes. Methods In AML12 hepatocytes, immunofluorescence microscopy and biochemical approaches were used to determine the enrichment of lipolysis vs lipophagy machinery on large vs. small LDs. Live‐cell microscopy was used for the first time to monitor LDs transitioning from lipolysis to lipophagic engulfment. Results Confocal microscopy of AML12 cells immunolabeled for adipose triglyceride lipase (ATGL) revealed a preferential association with large LDs with an average area of 4.0 μm 2 , seven‐fold larger than LDs not associated with ATGL. In striking comparison, LDs associated with components of the autophagic machinery (LC3) were two‐fold smaller in area (0.39 μm 2 ). Consistent with this observation was the finding that siRNA knockdown of ATGL resulted in the persistence of large LDs (2.8 μm 2 ), whereas knockdown of lysosomal acid lipase (LAL) left cells filled with many LDs of a smaller size (1.5 μm 2 ). These observations were mimicked by inhibitors of ATGL (atglistatin) and lysosomal acidification (chloroquine). In support of these findings, differential centrifugation of AML12 homogenates allowed for separation of two distinct populations of LDs: a buoyant fraction of large LDs enriched in the cytosolic lipase ATGL, and a second collection of smaller, less buoyant LDs enriched in lysosomal enzymes such as Lamp2A and the autophagosome marker LC3‐II. Most interesting are time lapse movies of live cells showing engulfment of small LDs by a LAMP3‐positive late endosomal/lysosomal compartment, suggesting that these organelles play an important role in the direct targeting and engulfment of LDs for lipophagy. Conclusion Hepatocytes appear to catabolize LDs in a tandem stepwise process that first utilizes cytosolic lipases to substantially reduce LD size, thereby allowing for subsequent engulfment by autophagosomes as well as late endosomes and lysosomes. Support or Funding Information This study was generously supported by funding from NIAAA R01AA020735, NIDDK T32DK007352, and the Mayo Clinic Robert and Arlene Kogod Center on Aging. This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal .

2016 Background: Among the primary aims of new therapies for glioblastoma (GBM) are the reduction of morbidity and restoration or preservation of quality of life (QoL). Selinexor (SEL) is a first-in class, oral, selective inhibitor of nuclear export which blocks exportin 1 (XPO1), forcing the nuclear retention and reactivation of tumor suppressor proteins, ultimately causing cell death in cancer cells. SEL is approved for the treatment of previously treated multiple myeloma and DLBCL. XPORT-GBM-029 (NCT04421378) is a phase 1 dose finding study followed by an open-label randomized phase 2, 3-arm trial to evaluate SEL in combination with standard therapies for newly diagnosed and recurrent GBM: Arm A (ndGBM, uMGMT) – radiation +/- SEL; Arm B (ndGBM, mMGMT) – radiation and temozolomide +/- SEL; Arm C (rGBM) – lomustine +/- SEL at first relapse. We look to identify sensitive, reliable, and clinically meaningful digital assessments of the functional status of ndGBM and rGBM patients via a patient-centric approach. Methods: XPORT-GBM-029 incorporates standard clinical and imaging evaluations of GBM progression with novel digital tools that objectively measure motor and cognitive function. The study is conducted at 50 sites globally with the aim of enrolling 350 patients with newly diagnosed and recurrent GBM. Following discussions with KOLs and patient advocacy partners at EndbrainCancer, we surveyed GBM patients and their caregivers to identify disease manifestations critical to patients’ QoL. The survey revealed four key areas impacting patients’ QoL that can be affected by GBM therapies and can be objectively monitored: cognitive function, lateralization, fatigue, and sleep. In this trial we use objective measurements to evaluate SEL’s effects on GBM patients’ QoL. Patients wear inertial sensors to measure their activity and sleep and complete a cognitive battery at baseline and before each MRI. Results: Associations between objective digital measures of activity, gait, fatigue, sleep, and cognition will be examined with respect to clinical assessments including physical examinations, modified Response Assessment in Neuro-Oncology (mRANO), Neurologic Assessment in Neuro-Oncology (NANO), Karnofsky Performance Score (KPS) and Patient Reported Outcome (PRO) QoL questionnaires. Descriptive summary statistics and plots are employed in exploratory data analysis, and other advanced data mining methods may also be considered. Conclusions: XPORT-GBM-029 trial is probably the first large, prospective, longitudinal study in GBM patients employing digital markers and may provide useful information regarding the utility of wearable and mobile devices for measuring functional outcomes in clinical trials. Clinical trial information: NCT04421378.

Abstract Background Survival in patients with IDH1/2-mutant (mt) anaplastic astrocytomas is highly variable. We have used the prospective phase 3 CATNON trial to identify molecular factors related to outcome in IDH1/2mt anaplastic astrocytoma patients. Methods The CATNON trial randomized 751 adult patients with newly diagnosed 1p/19q non-codeleted anaplastic glioma to 59.4 Gy radiotherapy +/− concurrent and/or adjuvant temozolomide. The presence of necrosis and/or microvascular proliferation was scored at central pathology review. Infinium MethylationEPIC BeadChip arrays were used for genome-wide DNA methylation analysis and the determination of copy number variations (CNV). Two DNA methylation-based tumor classifiers were used for risk stratification. Next-generation sequencing (NGS) was performed using 1 of the 2 glioma-tailored NGS panels. The primary endpoint was overall survival measured from the date of randomization. Results Full analysis (genome-wide DNA methylation and NGS) was successfully performed on 654 tumors. Of these, 432 tumors were IDH1/2mt anaplastic astrocytomas. Both epigenetic classifiers identified poor prognosis patients that partially overlapped. A predictive prognostic Cox proportional hazard model identified that independent prognostic factors for IDH1/2mt anaplastic astrocytoma patients included; age, mini-mental state examination score, treatment with concurrent and/or adjuvant temozolomide, the epigenetic classifiers, PDGFRA amplification, CDKN2A/B homozygous deletion, PI3K mutations, and total CNV load. Independent recursive partitioning analysis highlights the importance of these factors for patient prognostication. Conclusion Both clinical and molecular factors identify IDH1/2mt anaplastic astrocytoma patients with worse outcome. These results will further refine the current WHO criteria for glioma classification.

Abstract Background The Response Assessment in Neuro-Oncology Patient-Reported Outcome (RANO-PRO) working group aims to provide guidance on the use of PROs in brain tumor patients. PRO measures should be of high quality, both in terms of relevance and other measurement properties. This systematic review aimed to identify PRO measures that have been used in brain tumor studies to date. Methods A systematic literature search for articles published up to June 25, 2020 was conducted in several electronic databases. Pre-specified inclusion criteria were used to identify studies using PRO measures assessing symptoms, (instrumental) activities of daily living [(I)ADL] or health-related quality of life (HRQoL) in adult patients with glioma, meningioma, primary central nervous system lymphoma, or brain metastasis. Results A total of 215 different PRO measures were identified in 571 published and 194 unpublished studies. The identified PRO measures include brain tumor-specific, cancer-specific, and generic instruments, as well as instruments designed for other indications or multi- or single-item study-specific questionnaires. The most frequently used instruments were the EORTC QLQ-C30 and QLQ-BN20 (n = 286 and n = 247), and the FACT-Br (n = 167), however, the majority of the instruments were used only once or twice (150/215). Conclusion Many different PRO measures assessing symptoms, (I)ADL or HRQoL have been used in brain tumor studies to date. Future research should clarify whether these instruments or their scales/items exhibit good content validity and other measurement properties for use in brain tumor patients.

Significance Lipid droplets (LDs) are specialized fat-storage organelles that can be used as a fuel source by many types of cells when nutrients are scarce. One mechanism used by hepatocytes (the functional cells of the liver) for the catabolism of these energy reserves is the lysosome-directed process of autophagy. Traditionally, autophagy necessitates the enclosure of cargo within a double-membrane autophagosome before delivery to the lysosome for degradation. Here, we use live-cell and electron microscopy to demonstrate that stable contacts between LDs and lysosomes in hepatocytes can result in the transfer of both proteins and lipids from LDs directly into the lysosome in the absence of an autophagosomal intermediate. These findings reveal a mechanism used for lipid homeostasis in the liver.

Abstract BACKGROUND The original 3-arm CODEL design included a radiotherapy (RT)-alone control arm, an RT plus temozolomide (TMZ) arm, and an exploratory TMZ-alone arm. We report the analysis involving patients treated per the initial design. METHODS Adults (18+ years) with newly-diagnosed 1p/19q codeleted WHO grade III oligodendroglioma were randomized to RT (5940 cGy) alone (Arm A); RT with concomitant and adjuvant TMZ (Arm B); or TMZ alone (Arm C). Primary endpoint was OS, Arm A vs. B. Secondary comparisons were performed for OS and PFS, comparing pooled RT arms with the TMZ-alone arm. RESULTS 36 patients were randomized equally to the three arms. At median follow-up of 7.5 years, 83.3% (10/12) TMZ-alone patients had progressed, versus 37.5% (9/24) patients on the RT arms. PFS was shorter in TMZ-alone patients compared to RT-treated patients (HR=3.12; 95% CI: 1.26, 7.69; p=0.014). Death from disease progression occurred in 3/12 (25%) of TMZ-alone patients and 4/24 (16.7%) of RT-treated patients. OS did not statistically differ between arms, although this comparison was underpowered. After adjustment for IDH status (mutated vs. wildtype) in a Cox regression model, with IDH status and RT treatment status as co-variables (Arm C vs pooled A and B), PFS remained shorter for patients not receiving RT (HR= 3.33; 95% CI: 1.31, 8.45; p=0.011), and OS differences remained non-significant ((HR = 2.78; 95% CI 0.58, 13.22, p=0.20). Grade 3+ adverse events occurred in 25%, 42% and 33% patients (Arms A, B and C, respectively). Neurocognitive assessments, comparing baseline and 3 month timepoints, showed no significant differences between arms. CONCLUSIONS TMZ-alone treated patients experienced significantly shorter PFS than patients treated on the pooled RT arms, which remained significant when adjusting for IDH status. CODEL has been redesigned to compare the efficacy and toxicity of RT+PCV versus RT+TMZ. Clinicaltrials.gov Identifier: NCT00887146. Support: U10CA180821, U10CA180882, https://acknowledgments.alliancefound.org.

Abstract Background Two methods combining survival and health-related quality of life (HRQoL) data in glioma trials to calculate the “net clinical benefit” were evaluated: Quality-adjusted effect sizes (QASES) and joint modeling (JM). Methods The net clinical benefit in two trials was calculated as proof of concept for other trials. With the QASES method, effect sizes for differences in progression-free survival (PFS) or overall survival (OS) and HRQoL between the experimental arm and standard treatment arm were calculated, while the relative emphasis placed on survival/HRQoL varied. JM allows simultaneous modeling of HRQoL and OS/PFS. Results In the EORTC 26951 trial, combined radiochemotherapy significantly prolonged OS (difference 11.7 months), but also resulted in more patients experiencing clinically relevant worsening (≥10 points) in appetite loss and nausea/vomiting shortly after treatment. Using QASES, the survival benefit of additional procarbazine, lomustine, and vincristine (PCV) decreased from 42.3 months to 29.5 and 28.2 months when accounting for appetite loss and nausea/vomiting, respectively. JM analyses resulted in a loss of the beneficial effect of additional PCV between 13% and 24% when adjusting for different HRQoL parameters. The EORTC 22033 trial showed no significant PFS difference between radiotherapy or temozolomide alone (46 vs 39 months), nor clinically relevant differences in HRQoL. JM analyses also showed no significant association between PFS and HRQoL scales/items, whereas QASES showed that temozolomide alone was more favorable when considering symptom burden (47–49 instead of 39 months). Conclusions Both methods resulted in different outcomes, but adjusting for the impact of treatment on HRQoL resulted in theoretically reduced survival benefits.