Stupp, Roger

Abstract BACKGROUND: Glioblastoma (GBM) is the most aggressive primary brain tumor that virtually always recurs with no established standard therapy at recurrence. Median survival after recurrence is 7-12 months. Selective internal radiation therapy (SIRT) with Yttrium-90 (Y90) glass microspheres (TheraSphere™, Boston Scientific, Marlborough, MA) is an FDA approved standard treatment for hepatocellular carcinoma, and represents a novel strategy to treat regionally localized brain tumors. We are conducting a first-in-human clinical trial (under IDE) using Y90 microspheres modified to treat tumors in the brain. The goal of selectively delivering Y90 intra-arterially is to achieve higher tumoral absorbed doses while limiting non-target exposure. DESIGN: The primary objective is to evaluate the safety of Y90 microspheres treatment. Target enrollment is 12 patients at 5 participating medical centers. Key inclusion criteria include: 1st or 2nd recurrence of GBM , size 1-5cm, located in the non-dominant hemisphere in a non-eloquent region, accessible neurovascular anatomy for single intra-arterial treatment based on a diagnostic cerebral angiogram. After consent, patients will undergo screening angiography and imaging that be reviewed by the trial steering committee to determine treatment suitability. Treatment consists of Y90 microspheres administered intra-arterially to deliver 40Gy ± 10% to the treatment volume. Post-administration Y90 PET and MRI images allow assessment of dose distribution and acute safety. Following overnight admission, patients will be followed as outpatients weekly x 4, and then monthly up to month 6. Primary endpoints include treatment-related limiting toxicities, dose limiting toxicity defined as non-hematological toxicities ≥ grade 3, CNS toxicity ≥ grade 3 (eg. symptomatic ischemia or edema) related to non-target embolization, occurring through 30 days post procedure. Secondary endpoints include: treatment-related serious adverse events, change in post-treatment neurological function, technical success, objective response rate, progression-free survival, and overall survival. The study is registered with clinicaltrials.gov, number: NCT05303467.

Abstract The Response Assessment in Neuro-Oncology (RANO) criteria for high-grade gliomas (RANO-HGG) and low-grade gliomas (RANO-LGG) were developed to improve the reliability of response assessment in glioma trials. Over time some limitations of these criteria were identified, and uncertainty emerged regarding integrating features of the modified RANO (mRANO) or the immunotherapy RANO (iRANO) criteria. Informed by data from a cohort of glioblastoma patients and other evaluations of RANO criteria that allowed evaluation of features of the different criteria, we propose updates to the RANO criteria (RANO 2.0). Based on the 2021 WHO classification of gliomas, we recommend a standard set of criteria for both high and low-grade gliomas, to be used for all trials regardless of the treatment modalities being evaluated. In the newly diagnosed setting, the post-radiotherapy MRI, rather than the post-surgical MRI, will be used as the baseline for future comparison. Since the incidence of pseudoprogression is high in the 12 weeks following radiotherapy, continuation of treatment and confirmation of progression during this period with a repeat MRI, or histopathologic evidence of unequivocal recurrent tumor, is required to define tumor progression. However, confirmation scans are not mandatory after this period nor for recurrent tumors. For treatments with a high likelihood of pseudoprogression, mandatory confirmation of progression with a repeat MRI is an option. The primary measurement remains the maximum cross-sectional area of tumor (2-dimensional) but volumetric measurements are an option. For IDH-wildtype glioblastoma, the non-enhancing disease will no longer be evaluated. In IDH-mutated tumors with a significant non-enhancing component, clinical trials may require evaluating both the enhancing and non-enhancing tumor components for response assessment.

Adult-type diffusely infiltrating gliomas, of which glioblastoma is the most common and aggressive, almost always recur after treatment and are fatal. Improved understanding of therapy-driven tumor evolution and acquired therapy resistance in gliomas is essential for improving patient outcomes, yet the majority of the models currently used in preclinical research are of therapy-naïve tumors. Here, we describe the development of therapy-resistant IDH-wildtype glioblastoma patient-derived xenografts (PDX) through orthotopic engraftment of therapy naïve PDX in athymic nude mice, and repeated in vivo exposure to the therapeutic modalities most often used in treating glioblastoma patients: radiotherapy and temozolomide chemotherapy. Post-temozolomide PDX became enriched for C>T transition mutations, acquired inactivating mutations in DNA mismatch repair genes (especially MSH6), and developed hypermutation. Such post-temozolomide PDX were resistant to additional temozolomide (median survival decrease from 80 days in parental PDX to 42 days in a temozolomide-resistant derivative). However, temozolomide-resistant PDX were sensitive to lomustine (also known as CCNU), a nitrosourea which induces tumor cell apoptosis by a different mechanism than temozolomide. These PDX models mimic changes observed in recurrent GBM in patients, including critical features of therapy-driven tumor evolution. These models can therefore serve as valuable tools for improving our understanding and treatment of recurrent glioma.

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 PURPOSE Post-therapy recurrent glioblastoma (GBM) patient-derived xenografts (PDX), developed from corresponding treatment-naïve PDX, could serve as useful resources for identifying therapeutics with activity against recurrent GBM. The goal of this study was to determine whether treatment-naïve intracranial GBM PDX, in mice receiving radiotherapy (RT) and/or temozolomide (TMZ), acquire the same mutations that occur in post-RT+TMZ GBMs from patients. METHODS Luciferase-modified, treatment-naïve GBM PDX were engrafted in the brains of athymic nude mice, followed by treatment with RT only (2 Gy/day x 5), TMZ only (10 mg/kg/day x 5), or RT+TMZ. Bioluminescence imaging was used to monitor intracranial tumor growth, response to treatment, and recurrence from treatment. Some mice with recurrent tumors received additional TMZ treatment. When mice became symptomatic, intracranial tumors were resected and engrafted subcutaneously in a new mouse host, then sequentially propagated subcutaneously into additional host mice. After the third passage, whole-exome sequencing (WES) was done, comparing post-therapy with treatment-naïve PDX sequence variants. RESULTS Analysis of PDX WES showed the following: 1) TMZ consistently caused more genes to incur coding sequence mutations than RT, as much as 13x more; 2) TMZ-treated tumor mutations were mostly G-C to A-T transitions (71-92%), consistent with the known mutagenic effect of TMZ; and 3) post-therapy PDX acquire similar mutations as do recurrent GBMs in patients, for example involving DNA mismatch repair gene MSH6. One of the derivative PDX with MSH6 mutation has been retested for response to RT and TMZ, with results showing its having become TMZ, but not RT resistant. CONCLUSIONS The mutation profiles of RT+TMZ-treated PDX are similar to those reported for GBMs that recur after RT+TMZ in patients. The new PDX resources described here may prove useful for identifying effective treatments against recurrent GBM.

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.

Abstract INTRODUCTION The impact of treatment on both the quality and the quantity of life, i.e. the ‘net clinical benefit’, should be considered to facilitate shared decision making. Two methods that combine survival and health-related quality of life (HRQoL) data: Quality Adjusted Effect Sizes (QASES) and Joint Modelling (JM) were applied to gain insight in the net clinical benefit. METHODS The net clinical benefit in one RCT (EORTC 26951 comparing radiotherapy (RT) + PCV chemotherapy versus RT alone) was calculated as a proof of concept for other trials. With the QASES method, effect sizes for differences in survival and HRQoL between treatment arms were calculated. JM allows simultaneous modeling of a longitudinal outcome (HRQoL), and a time-to event outcome (survival). HRQoL scales/items that were selected for primary analysis in the main study were also selected for this analysis: fatigue, global health, social functioning, communication deficit, seizures, physical functioning, and nausea/vomiting. RESULTS 288/386 patients completed baseline HRQoL forms and were included in the analysis. Overall survival (OS) was significantly longer with combined treatment (42.3 vs. 30.6 months). The percentage of patients who experienced a clinically relevant deterioration (≥10 points) in nausea/vomiting, fatigue, social functioning and global health up to one year after treatment compared to baseline was larger in the RT+PCV arm. QASES corresponded to a reduction in the median OS difference from 9.7 months up till 5.5 months, given equal weights to OS and HRQoL. JM analyses resulted in a theoretical loss of treatment effect in OS of 2–6% when adjusting for HRQoL. CONCLUSION Both methods showed that adjusting for the impact of treatment on a relevant HRQoL parameter reduced the survival benefit in the experimental treatment arm compared to standard treatment arm. Applying these methods may facilitate communicating the impact of treatment to patients in clinical practice.

Abstract BACKGROUND The impact of treatment on both the quality and the quantity of life, i.e. the ‘net clinical benefit’, should be considered to inform glioma patients and facilitate shared decision making. We applied two methods (i.e. Quality Adjusted Effect Sizes (QASES) and Joint Modelling (JM)) that combine survival and health-related quality of life (HRQoL) data into one outcome, to gain insight in the net clinical benefit of a treatment strategy. In addition, we assessed if both methods result in similar interpretations. MATERIAL AND METHODS We calculated the net clinical benefit in one randomized controlled trial, EORTC 26951 comparing radiotherapy (RT) + PCV chemotherapy versus RT alone, as a proof of concept for other trials. With the QASES method, effect sizes for differences in survival and HRQoL between treatment arms were calculated. Next, the combined effect size can be determined by weighing the emphasis put on survival or HRQoL (e.g. survival more important). JM allows simultaneous modeling of a longitudinal outcome (HRQoL), and a time-to event outcome (survival). HRQoL scales/items that were selected for primary analysis in the main study were also selected for this analysis: fatigue, global health, social functioning, communication deficit, seizures, physical functioning, and nausea/vomiting. RESULTS 288/386 patients completed baseline HRQoL forms and were included in the analysis. Overall survival (OS) was significantly longer with combined treatment (difference of 10.8 months). In contrast, the percentage of patients who experienced a clinically relevant deterioration (≥10 points) in nausea/vomiting, fatigue, social functioning and global health up to one year after treatment compared to baseline was larger in the RT+PCV arm. The QASES corresponded to a reduction in the median OS difference from 10.8 months to 6.8 months when adjusted for the HRQoL scales/items, when given equal weights to OS and HRQoL. JM analyses resulted in a theoretical loss of treatment effect in OS of 2–6% when adjusting for HRQoL. CONCLUSION Both methods showed that adjusting for the impact of treatment on a relevant HRQoL parameter reduced the survival benefit in the experimental treatment arm compared to standard treatment arm. Applying these methods may facilitate communicating the impact of treatment to patients in clinical practice.

AbstractAccurate pathologic diagnoses and molecularly informed treatment decisions for a wide variety of cancers depend on robust clinical molecular testing that uses genomic, epigenomic, and transcriptomic-based tools. Nowhere is this more essential than in the workup of brain tumors, as emphasized by the incorporation of molecular criteria into the 2016 World Health Organization classification of central nervous system tumors and the updated official guidelines of the National Comprehensive Cancer Network. Despite the medical necessity of molecular testing in brain tumors, access to and utilization of molecular diagnostics is still highly variable across institutions, and a lack of reimbursement for such testing remains a significant obstacle. The objectives of this review are (i) to identify barriers to adoption of molecular testing in brain tumors, (ii) to describe the current molecular tools recommended for the clinical evaluation of brain tumors, and (iii) to summarize how molecular data are interpreted to guide clinical care, so as to improve understanding and justification for their coverage in the routine workup of adult and pediatric brain tumor cases.

Abstract Background: Glioblastomas (GBMs) are aggressive primary brain tumors with high levels of genomic heterogeneity impacting prognosis and treatment response. A recurrent in-frame deletion within the extracellular domain of the epidermal growth factor receptor (EGFR variant III, or vIII) is found in a substantial fraction of GBMs. Methods: The Radiation Therapy Oncology Group (RTOG) 0525 trial of temozolomide dosing in newly-diagnosed GBM enrolled 1174 patients. Of these, 494 eligible GBMs were analyzed for EGFRvIII expression by RT-PCR. The Kaplan-Meier method was used to compare the progression free survival (PFS) and overall survival (OS) of GBMs expressing EGFRvIII with those not expressing EGFRvIII. Results: 142 of 494 tested GBMs (29%) had expressed EGFRvIII. There were no significant differences in PFS or OS between patients whose tumors did (494) or did not (631) undergo EGFRvIII expression analysis. EGFRvIII expression was significantly associated with age (p=0.005), Karnofsky performance status (p=0.02), and RTOG recursive partitioning analysis (RPA) class (p=0.005). EGFRvIII expression analyzed in the entire study population did not reveal an association with PFS or OS. In a univariate subgroup analysis of patients treated on the standard-of-care arm of RTOG-0525, EGFRvIII expression was was significantly associated with worse PFS (HR=1.43, 95% CI: [1.05, 1.96], p=0.025), and worse OS (HR 1.45, 95% CI:[1.03, 2.05], p=0.032). However, in multivariate models, when adjusted for RPA class and MGMT methylation status, EGFRvIII was not an independent predictor of either PFS or OS. Conclusion: For GBMs treated with standard-of-care therapy in RTOG-0525, EGFRvIII expression was associated with worse PFS and OS. However, well-established stratification metrics such as age, KPS, and RPA override this prognostic association, suggesting that trials of therapeutic modalities directed against EGFRvIII should utilize these standard prognostic variables when survival is being analyzed or compared. Project Support: This project was supported by RTOG grant U10 CA21661, and CCOP grant U10 CA37422 from the National Cancer Institute (NCI) and Schering-Plough Corporation. Citation Information: Mol Cancer Ther 2013;12(11 Suppl):A110. Citation Format: Daniel P. Cahill, Asha George, Mark R. Gilbert, Arnab Chakravarti, Roger Stupp, Monika Hegi, Paul Brown, Kurt A. Jaeckle, Benjamin Corn, Erik P. Sulman, Luis Souhami, Maria Werner-Wasik, Bethany M. Anderson, Minesh Mehta, Kenneth D. Aldape. EGFRvIII expression is associated with shorter progression-free and overall survival in glioblastoma patients treated with standard-of-care temozolomide and radiation: A report from the RTOG-0525 trial. [abstract]. In: Proceedings of the AACR-NCI-EORTC International Conference: Molecular Targets and Cancer Therapeutics; 2013 Oct 19-23; Boston, MA. Philadelphia (PA): AACR; Mol Cancer Ther 2013;12(11 Suppl):Abstract nr A110.