Final report of the phase II NEXT/CNS-GCT-4 trial: GemPOx followed by marrow-ablative chemotherapy for recurrent intracranial germ cell tumors

Background

Patients with relapsed intracranial germinoma can achieve durable remission with standard chemotherapy regimens and/or reirradiation; however, innovative therapies are required for patients with relapsed and/or refractory intracranial nongerminomatous germ cell tumors (NGGCTs) due to their poor prognosis. Improved outcomes have been reported using reinduction chemotherapy to achieve minimal residual disease, followed by marrow-ablative chemotherapy (HDCx) with autologous hematopoietic progenitor cell rescue (AuHPCR). We conducted a phase II trial evaluating the response and toxicity of a 3-drug combination developed for recurrent intracranial germ cell tumors consisting of gemcitabine, paclitaxel, and oxaliplatin (GemPOx).

Methods

A total of 9 patients with confirmed relapsed or refractory intracranial GCT were enrolled after signing informed consent, and received at least 2 cycles of GemPOx, of which all but 1 had relapsed or refractory NGGCTs. One patient with progressive disease was found to have pathologically confirmed malignant transformation to pure embryonal rhabdomyosarcoma (without GCT elements), hence was ineligible and not included in the analysis. Patients who experienced sufficient responses proceeded to receive HDCx with AuHPCR. Treatment response was determined based on radiographic tumor assessments and tumor markers.

Results

A total of 7 patients achieved sufficient response and proceeded with HDCx and AuHPCR, and 5 subsequently received additional radiotherapy. A total of 2 patients developed progressive disease while receiving GemPOx. Myelosuppression and transaminitis were the most common treatment-related adverse events. With a mean follow-up of 44 months, 4 patients (3 NGGCTs, 1 germinoma) are alive without evidence of disease.

Conclusions

GemPOx demonstrates efficacy in facilitating stem cell mobilization, thus facilitating the feasibility of both HDCx and radiotherapy.

Unsupervised machine learning models reveal predictive clinical markers of glioblastoma patient survival using white blood cell counts prior to initiating chemoradiation

Background

Glioblastoma is a malignant brain tumor requiring careful clinical monitoring even after primary management. Personalized medicine has suggested the use of various molecular biomarkers as predictors of patient prognosis or factors utilized for clinical decision-making. However, the accessibility of such molecular testing poses a constraint for various institutes requiring identification of low-cost predictive biomarkers to ensure equitable care.

Methods

We collected retrospective data from patients seen at Ohio State University, University of Mississippi, Barretos Cancer Hospital (Brazil), and FLENI (Argentina) who were managed for glioblastoma-amounting to 581 patient records documented using REDCap. Patients were evaluated using an unsupervised machine learning approach comprised of dimensionality reduction and eigenvector analysis to visualize the inter-relationship of collected clinical features.

Results

We discovered that the serum white blood cell (WBC) count of a patient during baseline planning for treatment was predictive of overall survival with an over 6-month median survival difference between the upper and lower quartiles of WBC count. By utilizing an objective PD-L1 immunohistochemistry quantification algorithm, we were further able to identify an increase in PD-L1 expression in glioblastoma patients with high serum WBC counts.

Conclusions

These findings suggest that in a subset of glioblastoma patients the incorporation of WBC count and PD-L1 expression in the brain tumor biopsy as simple biomarkers predicting glioblastoma patient survival. Moreover, machine learning models allow the distillation of complex clinical data sets to uncover novel and meaningful clinical relationships.

Glioblastoma pseudoprogression and true progression reveal spatially variable transcriptional differences

Post-resection radiologic monitoring to identify areas of new or progressive enhancement concerning for cancer recurrence is critical during patients with glioblastoma follow-up. However, treatment-related pseudoprogression presents with similar imaging features but requires different clinical management. While pathologic diagnosis is the gold standard to differentiate true progression and pseudoprogression, the lack of objective clinical standards and admixed histologic presentation creates the needs to (1) validate the accuracy of current approaches and (2) characterize differences between these entities to objectively differentiate true disease. We demonstrated using an online RNAseq repository of recurrent glioblastoma samples that cancer-immune cell activity levels correlate with heterogenous clinical outcomes in patients. Furthermore, nCounter RNA expression analysis of 48 clinical samples taken from second neurosurgical resection supports that pseudoprogression gene expression pathways are dominated with immune activation, whereas progression is predominated with cell cycle activity. Automated image processing and spatial expression analysis however highlight a failure to apply these broad expressional differences in a subset of cases with clinically challenging admixed histology. Encouragingly, applying unsupervised clustering approaches over our segmented histologic images provides novel understanding of morphologically derived differences between progression and pseudoprogression. Spatially derived data further highlighted polarization of myeloid populations that may underscore the tumorgenicity of novel lesions. These findings not only help provide further clarity of potential targets for pathologists to better assist stratification of progression and pseudoprogression, but also highlight the evolution of tumor-immune microenvironment changes which promote tumor recurrence.

Vorasidenib in IDH1- or IDH2-Mutant Low-Grade Glioma

BACKGROUND

Isocitrate dehydrogenase (IDH)-mutant grade 2 gliomas are malignant brain tumors that cause considerable disability and premature death. Vorasidenib, an oral brain-penetrant inhibitor of mutant IDH1 and IDH2 enzymes, showed preliminary activity in IDH-mutant gliomas.

METHODS

In a double-blind, phase 3 trial, we randomly assigned patients with residual or recurrent grade 2 IDH-mutant glioma who had undergone no previous treatment other than surgery to receive either oral vorasidenib (40 mg once daily) or matched placebo in 28-day cycles. The primary end point was imaging-based progression-free survival according to blinded assessment by an independent review committee. The key secondary end point was the time to the next anticancer intervention. Crossover to vorasidenib from placebo was permitted on confirmation of imaging-based disease progression. Safety was also assessed.

RESULTS

A total of 331 patients were assigned to receive vorasidenib (168 patients) or placebo (163 patients). At a median follow-up of 14.2 months, 226 patients (68.3%) were continuing to receive vorasidenib or placebo. Progression-free survival was significantly improved in the vorasidenib group as compared with the placebo group (median progression-free survival, 27.7 months vs. 11.1 months; hazard ratio for disease progression or death, 0.39; 95% confidence interval [CI], 0.27 to 0.56; P<0.001). The time to the next intervention was significantly improved in the vorasidenib group as compared with the placebo group (hazard ratio, 0.26; 95% CI, 0.15 to 0.43; P<0.001). Adverse events of grade 3 or higher occurred in 22.8% of the patients who received vorasidenib and in 13.5% of those who received placebo. An increased alanine aminotransferase level of grade 3 or higher occurred in 9.6% of the patients who received vorasidenib and in no patients who received placebo.

CONCLUSIONS

In patients with grade 2 IDH-mutant glioma, vorasidenib significantly improved progression-free survival and delayed the time to the next intervention. (Funded by Servier; INDIGO ClinicalTrials.gov number, NCT04164901.).

Pretreatment findings on magnetic resonance imaging in primary central nervous system lymphoma may predict overall survival duration

BACKGROUND

and purpose: Primary central nervous system lymphoma (PCNSL) lesions often show avid contrast enhancement on T1-weighted contrast-enhanced MRI sequences. However, several case reports and a clinical study have described PCNSL in patients with no contrast enhancement on MRI. We assessed whether overall survival (OS) time was related to any tumor characteristics (lesion location, volume, and number; contrast enhancement; necrosis; proximity to the subarachnoid space; and edema) on MRI in patients with PCNSL.

MATERIALS AND METHODS

We retrospectively reviewed records (MRI features, pathology, and survival data) of all patients at our institution with PCNSL who had been seen from, 2007 through 2017, and had undergone pretreatment MRI.

RESULTS

We identified 79 patients (42 men, 37 women) with a mean age at diagnosis of 61.7 ± 10.4 years. The mean OS duration was 44.6 ± 41.7 months. The most common pathological diagnosis (74 patients) was diffuse large B-cell lymphoma. No associations were found between OS time and lesion location, volume, and number; contrast enhancement; necrosis; proximity to the subarachnoid space; or edema. However, a sole patient with non-enhancing PCNSL on MRI was found to have low-grade disease, with prolonged survival (>83 months). Several other patients with leptomeningeal disease had a mean OS time of 80 months. Patients with hemorrhagic lesions had a mean OS of 25.5 months.

CONCLUSIONS

The survival time for patients with PCNSL may be longer than previously thought, especially for patients with leptomeningeal seeding and lesions with hemorrhagic components Also, non-enhancing tumors may be less aggressive than enhancing tumors.

Unsupervised machine learning models reveal predictive markers of glioblastoma patient survival using white blood cell counts prior to initiating chemoradiation

Purpose

Glioblastoma is a malignant brain tumor requiring careful clinical monitoring even after primary management. Personalized medicine has suggested use of various molecular biomarkers as predictors of patient prognosis or factors utilized for clinical decision making. However, the accessibility of such molecular testing poses a constraint for various institutes requiring identification of low-cost predictive biomarkers to ensure equitable care.

Methods

We collected retrospective data from patients seen at Ohio State University, University of Mississippi, Barretos Cancer Hospital (Brazil), and FLENI (Argentina) who were managed for glioblastoma-amounting to nearly 600 patient records documented using REDCap. Patients were evaluated using an unsupervised machine learning approach comprised of dimensionality reduction and eigenvector analysis to visualize the inter-relationship of collected clinical features.

Results

We discovered that white blood cell count of a patient during baseline planning for treatment was predictive of overall survival with an over 6-month median survival difference between the upper and lower quartiles of white blood cell count. By utilizing an objective PDL-1 immunohistochemistry quantification algorithm, we were further able to identify an increase in PDL-1 expression in glioblastoma patients with high white blood cell counts.

Conclusion

These findings suggest that in a subset of glioblastoma patients the incorporation of white blood cell count and PDL-1 expression in the brain tumor biopsy as simple biomarkers predicting glioblastoma patient survival. Moreover, use of machine learning models allows us to visualize complex clinical datasets to uncover novel clinical relationships.

Multicenter Phase II Trial of the PARP Inhibitor Olaparib in Recurrent IDH1- and IDH2-mutant Glioma

Purpose

Isocitrate dehydrogenase (IDH) 1 and IDH2 mutations (IDH1/2mt) are frequent in glioma. Preclinical studies suggest IDH1/2mts confer "BRCAness" phenotype, a vulnerability that can be targeted through PARP inhibition. To test this hypothesis, we conducted a multicenter study of olaparib monotherapy in patients with IDH1/2mt gliomas.

Methods

Patients with recurrent, contrast-enhancing IDH1/2mt gliomas were enrolled in a two-step phase II trial; the primary endpoint was overall response rate per Response Assessment in Neuro-Oncology (RANO) criteria. Olaparib 300 mg orally twice daily was given.

Results

A total of 15 evaluable patients were enrolled. Histology was astrocytoma (N = 12) and oligodendroglioma (N = 3). Most toxicities were grade 1 or 2. Best response was stable disease (SD) in 9 (60%) patients. Median progression-free survival (PFS) was 3.63 months and median overall survival was 20.7 months. For patients with SD, median PFS was 5.53 months; 4 patients had SD for >6 months. Among patients with best response progressive disease (N = 6), 5 had grade 4 tumor and 4 had known CDKN2A alteration. PFS was 5.23 months for grades 2 or 3 tumors (N = 10) versus 1.8 months for grade 4 (N = 5; P = 0.0013).

Conclusion

The study did not meet the prespecified response-based activity threshold for moving to step 2. However, prolonged SD was observed in patients with grades 2 and 3 histologies, suggesting olaparib monotherapy could be of clinical benefit in select populations. Grade 4 tumors per 2021 World Health Organization classification defined by histology or CDKN2A alteration derived no benefit from this drug, highlighting the usefulness of this classification for future patient stratification and trial design.

Significance

A single-arm phase II trial of olaparib in IDH-mutant glioma demonstrated clinically significant prolonged SD for select patients with grade 2/3 disease, suggesting potential benefit of olaparib in IDH-mutant gliomas.

Association of Autologous Tumor Lysate-Loaded Dendritic Cell Vaccination With Extension of Survival Among Patients With Newly Diagnosed and Recurrent Glioblastoma: A Phase 3 Prospective Externally Controlled Cohort Trial

Importance

Glioblastoma is the most lethal primary brain cancer. Clinical outcomes for glioblastoma remain poor, and new treatments are needed.

Objective

To investigate whether adding autologous tumor lysate-loaded dendritic cell vaccine (DCVax-L) to standard of care (SOC) extends survival among patients with glioblastoma.

Design, Setting, and Participants

This phase 3, prospective, externally controlled nonrandomized trial compared overall survival (OS) in patients with newly diagnosed glioblastoma (nGBM) and recurrent glioblastoma (rGBM) treated with DCVax-L plus SOC vs contemporaneous matched external control patients treated with SOC. This international, multicenter trial was conducted at 94 sites in 4 countries from August 2007 to November 2015. Data analysis was conducted from October 2020 to September 2021.

Interventions

The active treatment was DCVax-L plus SOC temozolomide. The nGBM external control patients received SOC temozolomide and placebo; the rGBM external controls received approved rGBM therapies.

Main Outcomes and Measures

The primary and secondary end points compared overall survival (OS) in nGBM and rGBM, respectively, with contemporaneous matched external control populations from the control groups of other formal randomized clinical trials.

Results

A total of 331 patients were enrolled in the trial, with 232 randomized to the DCVax-L group and 99 to the placebo group. Median OS (mOS) for the 232 patients with nGBM receiving DCVax-L was 19.3 (95% CI, 17.5-21.3) months from randomization (22.4 months from surgery) vs 16.5 (95% CI, 16.0-17.5) months from randomization in control patients (HR = 0.80; 98% CI, 0.00-0.94; P = .002). Survival at 48 months from randomization was 15.7% vs 9.9%, and at 60 months, it was 13.0% vs 5.7%. For 64 patients with rGBM receiving DCVax-L, mOS was 13.2 (95% CI, 9.7-16.8) months from relapse vs 7.8 (95% CI, 7.2-8.2) months among control patients (HR, 0.58; 98% CI, 0.00-0.76; P < .001). Survival at 24 and 30 months after recurrence was 20.7% vs 9.6% and 11.1% vs 5.1%, respectively. Survival was improved in patients with nGBM with methylated MGMT receiving DCVax-L compared with external control patients (HR, 0.74; 98% CI, 0.55-1.00; P = .03).

Conclusions and Relevance

In this study, adding DCVax-L to SOC resulted in clinically meaningful and statistically significant extension of survival for patients with both nGBM and rGBM compared with contemporaneous, matched external controls who received SOC alone.

Trial Registration

ClinicalTrials.gov Identifier: NCT00045968.

NIMG-78. DEVELOPMENT OF A PRECLINICAL GLIOBLASTOMA MURINE MODEL FOR THE ASSESSMENT OF RADIATION NECROSIS USING DIFFUSION KURTOSIS IMAGING

Glioblastoma (GB) patients often present with either radiation-induced necrosis (RN) or develop tumor recurrence (TR). Radiologically, differentiating between these two disease states is particularly difficult, especially utilizing traditional MRI techniques. Accurately distinguishing these separate states is important, as failure to do so can ultimately lead to unnecessary surgical intervention or early cessation of appropriate radiation therapy. Currently, distinction between these pathologies is made using best clinical judgement by the neuro-oncology team. Therefore, there is a need for developing novel non-invasive techniques that can reliably distinguish between radiation necrosis and tumor recurrence. Primary data was collected utilizing orthotopically transplanted GL261 mouse GB cells in a C57BL/6 mouse. Tumor induction was verified by MRI after two weeks. RN and TR were initiated using an aggressive radiation dose fractionation (12 Gy or 60 Gy). This was completed using a 4 mm radiation cone such that one portion of the tumor received 100% dose of 12 Gy or 60 Gy fraction which is sufficient to cause RN, whereas the tumor edge received only 50% of the dose, allowing for tumor recurrence. Our data demonstrated mice tumor recurrence and radiation necrosis on MRI imaging. Axial T2-weighted MRI and DKI sequence at 2 weeks following implantation demonstrated edema compatible with tumor recurrence. One week later, the T2-weighted MRI and DKI sequences demonstrated continued tumor progression. In a separate mouse with orthotopic glioblastoma implantation with high dose (60 Gy) radiation treatment, T2 imaging and DKI demonstrated areas of tumor and suspected central radiation necrosis. DKI imaging biomarkers was compared by liquid biopsy, H&E staining, and Immunohistochemistry (IHC) analysis of sacrificed mice. Our H&E staining results showed typical pathological features of GB and RN, and TR in each case. This result demonstrated that our proposed model for radiation induction was effective at achieving its goal.

QLTI-02. AUTOMATED INTRAOPERATIVE RESECTION TECHNOLOGY GENERATES INCREASED TISSUE YIELD AND IMPROVED BIOLOGICAL PRESERVATION OF BRAIN TUMOR SPECIMENS FOR NEURO-ONCOLOGY RESEARCH

Glioblastoma (GB) is an aggressive tumor showing extensive intertumoral and intratumoral heterogeneity. While preserving as much surrounding normal brain tissue as possible, neurosurgeons must aim to harvest maximal tumor tissue from a variety of tumor locations in an effort to capture heterogenic samples in high volume for molecular and pathologic diagnosis and translational research. A key challenge is the ability to consistently procure high-quality biologically active specimens. In this investigation, we implemented an automated intraoperative system to eliminate inconsistencies in the methodology of tissue collection, handling, and biological preservation immediately in the OR suite to establish a repeatable, standardized practice for obtaining high-quality tissue samples without the need for additional staff. Through this process, we were able to characterize matched specimens from GB patients or GB tumors from corresponding GB-allograft mice and compare the quality of traditional handling and collection processes of intraoperative tissue used in most neurosurgical operating rooms versus an automated resection, collection, and biological preservation system (APS) that captures, preserves, and biologically maintains tissue in a prescribed and controlled microenvironment. Matched specimens/or tissues were then processed in parallel at various time points and temperatures, evaluating viability, RNA and protein concentrations, and isolation of GB cell lines. We found that APS-derived GB slices stored in an APS modified medium remained viable and maintained high-quality RNA and protein concentration for up to 24 hours. Our results showed that primary GB cell cultures derived in this manner had improved growth over the widely used collection and preservation methods. Currently, we are continuing the investigation of collected samples in brain tumor animal models to further understand potential differences within the tumor region harvested and the cellular changes that occur over time. Our hope is this research will lead to new discoveries in the diagnosis and treatment of brain tumors.

CTIM-27. AUTOLOGOUS TUMOR LYSATE-LOADED DENDRITIC CELL VACCINATION IMPROVES SURVIVAL IN PATIENTS WITH NEWLY DIAGNOSED AND RECURRENT GLIOBLASTOMA: SURVIVAL RESULTS FROM A PHASE 3 TRIAL

BACKGROUND

Standard of care (SOC) and patient survival in glioblastoma have changed little in the past 17 years. We evaluated in a phase 3 trial whether adding an autologous tumor lysate-loaded dendritic cell vaccine (murcidencel) to SOC extends survival. Patients and

METHODS

Newly diagnosed glioblastoma patients were randomized 2:1 to either murcidencel or placebo. Under a crossover design, all patients could receive murcidencel following tumor recurrence. All parties remained blinded regarding treatments before recurrence. Patients thus received murcidencel at new diagnosis (nGBM) or at recurrence (rGBM) following crossover from placebo. The primary and secondary endpoints compare overall survival (OS) with contemporaneous, matched external controls. Four sets of analyses were conducted to ensure rigorous matching of the controls, reduce biases, and confirm the robustness of the results.

RESULTS

331 patients were enrolled. With the crossover, 89% received murcidencel. Median OS (mOS) for nGBM patients (n = 232) was 19.3 months from randomization (22.4 months from surgery) with murcidencel vs. 16.5 months from randomization in the controls (HR = 0.80, p = 0.002). Survival at 48 months from randomization was 15.7% vs. 9.9%, and at 60 months was 13% vs. 5.7%. For rGBM (n = 64), mOS was 13.2 months from relapse vs. 7.8 months in the controls (HR = 0.58, p &lt; 0.001). Survival at 24 months post-recurrence was 20.7% vs. 9.6%, and at 30 months post-recurrence was 11.1% vs 5.1%. In nGBM patients with methylated MGMT (n = 90), mOS was 30.2 months from randomization (33 months from surgery) with murcidencel vs. 21.3 months from randomization in the controls (HR = 0.74, p = 0.027). The treatment was well tolerated, with only 5 serious adverse events deemed at least possibly related to the vaccine.

CONCLUSION

Clinically meaningful and statistically significant survival extension was seen in both nGBM and rGBM patients treated with murcidencel and SOC compared with contemporaneous, matched external controls who received SOC alone.

CTNI-50. A RANDOMIZED PHASE 2 TRIAL OF CEDIRANIB/OLAPARIB VERSUS BEVACIZUMAB IN PATIENTS WITH RECURRENT GLIOBLASTOMA: UPDATED RESULTS

PURPOSE

Hypoxia from inhibition of angiogenesis reduces DNA repair capacity. Targeting homologous recombination pathway also has anti-angiogenic effects. To examine the synergistic effects of disrupting DNA repair pathways and angiogenesis in glioblastoma, we combine cediranib (ced), a pan vascular endothelial growth factor (VEGF) receptor inhibitor with olaparib (ola), a poly-ADP ribose polymerase (PARP) inhibitor compared with bevacizumab (bev), a VEGF-A inhibitor alone. To identify potential biomarkers predicting response to treatments, we also perform whole exome sequencing on archival tissues.

METHODS

Bevacizumab-naïve adult patients with first or second recurrence of glioblastoma after radiation and temozolomide were randomly assigned to cediranib (30mg PO daily)/olaparib (200mg PO twice daily) or bevacizumab (10mg/kg IV every 2 weeks). The primary end point was progression-free survival (PFS) at 6 months. The secondary end points included safety and overall survival (OS). Whole exome sequencing of formalin-fixed paraffin embedded archival tissue from 23 patients was performed.

RESULTS

We are presenting the final data from this trial. Between December 2017 and November 2018, a total 70 adult patients with recurrent glioblastoma were randomly assigned to receive ced/ola (n = 35) or bev (n = 35). With a data cut off on 5/30/2022, median PFS was 118 days and 92 days in ced/ola and bev groups, respectively (hazard ratio, 1.099, 95% CI 0.6-2, p = 0.76). Median overall survival was 269.5 days and 192 days in ced/ola and bev groups, respectively (hazard ratio, 0.6892, 95% CI 0.39-1.2, p = 0.2). Whole exome sequencing was performed in total 23 patients (24 samples), 14 patients in the ced/ola group and 9 patients in the bev group.

CONCLUSION

No significant survival benefit was observed in patients with recurrent glioblastoma treated with ced/ola compared to patients treated with bev monotherapy. Potential biomarkers predicting response to treatment identified from the whole exome sequencing on archival tissues will be presented.

EXTH-91. GALECTIN-3 INHIBITOR PAIRED WITH FOCAL LOW-INTENSITY NONINVASIVE TDCS CAN ACHIEVE MAXIMAL THERAPEUTIC BENEFIT IN CLINICALLY RELEVANT MENINGIOMA MOUSE MODELS

Atypical and anaplastic meningiomas (WHO Grade 2 and WHO Grade 3 respectively) represent a subgroup of meningiomas that tend to have higher rates of recurrence with associated’s higher morbidity and mortality than the more common WHO Grade 1 meningiomas. Our laboratory data demonstrated that galectin-3 (Gal-3), a multifunctional β-galactoside-binding protein, is highly expressed in these meningioma subtypes as compared to normal brain tissue. However, the root of the profoundly immunosuppressive tumor microenvironment in meningioma cells is not fully understood. To address this, we used a Gal-3 inhibitor TD 139 paired with low-intensity non-invasive transcranial direct current stimulation (tDCS) to suppress tumor growth and enhance the immune response in the preclinical model. Treatment of tDCS (50 mV/mm for 30 min) followed by 1 mM of TD139 induced cell death in anaplastic meningioma in vitro human triple co-culture model but has no effect on mouse cortical neurons. Furthermore, we demonstrated that inhibiting of Gal-3 expression significantly decreased the protein levels of urokinase-type plasminogen activator receptor as well as phosphorylation of Akt and upregulates Bax expression. Treatment with TD139 (1mg/kg per day for 14 days) with tDCS [350 μA (1 x 30 min/day) for 7 times (within 14 Days) showed a significantly (∼60%) decrease in MGS2 atypical meningioma tumor growth in orthotopic allograft model (at Day 41). The percent survival of tumor-bearing mice treated with TD139 and tDCS was significantly higher than an untreated tumor or single treatment. Following TD139 plus tDCS treatment, our results demonstrated significant meningioma cell death via a decrease in NDRG4 (Meningioma marker) and were associated with downregulation of Ki-67 in treated tumors. Based on our substantial preliminary data, we believe that this proposed translational work has the potential to be an effective combinational modality form of treatment for atypical and malignant meningiomas.

Small Molecules and Immunotherapy Agents for Enhancing Radiotherapy in Glioblastoma

Glioblastoma (GBM) is an aggressive primary brain tumor that is associated with a poor prognosis and quality of life. The standard of care has changed minimally over the past two decades and currently consists of surgery followed by radiotherapy (RT), concomitant and adjuvant temozolomide, and tumor treating fields (TTF). Factors such as tumor hypoxia and the presence of glioma stem cells contribute to the radioresistant nature of GBM. In this review, we discuss the current treatment modalities, mechanisms of radioresistance, and studies that have evaluated promising radiosensitizers. Specifically, we highlight small molecules and immunotherapy agents that have been studied in conjunction with RT in clinical trials. Recent preclinical studies involving GBM radiosensitizers are also discussed.

Infigratinib in Patients with Recurrent Gliomas and FGFR Alterations: A Multicenter Phase II Study

PURPOSE

FGFR genomic alterations (amplification, mutations, and/or fusions) occur in ∼8% of gliomas, particularly FGFR1 and FGFR3. We conducted a multicenter open-label, single-arm, phase II study of a selective FGFR1-3 inhibitor, infigratinib (BGJ398), in patients with FGFR-altered recurrent gliomas.

PATIENTS AND METHODS

Adults with recurrent/progressive gliomas harboring FGFR alterations received oral infigratinib 125 mg on days 1 to 21 of 28-day cycles. The primary endpoint was investigator-assessed 6-month progression-free survival (PFS) rate by Response Assessment in Neuro-Oncology criteria. Comprehensive genomic profiling was performed on available pretreatment archival tissue to explore additional molecular correlations with efficacy.

RESULTS

Among 26 patients, the 6-month PFS rate was 16.0% [95% confidence interval (CI), 5.0-32.5], median PFS was 1.7 months (95% CI, 1.1-2.8), and objective response rate was 3.8%. However, 4 patients had durable disease control lasting longer than 1 year. Among these, 3 had tumors harboring activating point mutations at analogous positions of FGFR1 (K656E; n = 2) or FGFR3 (K650E; n = 1) in pretreatment tissue; an FGFR3-TACC3 fusion was detected in the other. Hyperphosphatemia was the most frequently reported treatment-related adverse event (all-grade, 76.9%; grade 3, 3.8%) and is a known on-target toxicity of FGFR inhibitors.

CONCLUSIONS

FGFR inhibitor monotherapy with infigratinib had limited efficacy in a population of patients with recurrent gliomas and different FGFR genetic alterations, but durable disease control lasting more than 1 year was observed in patients with tumors harboring FGFR1 or FGFR3 point mutations or FGFR3-TACC3 fusions. A follow-up study with refined biomarker inclusion criteria and centralized FGFR testing is warranted.

Multicenter phase 2 trial of the PARP inhibitor (PARPi) olaparib in recurrent IDH1 and IDH2-mutant contrast-enhancing glioma

2035

Background: Isocitrate dehydrogenase ( IDH) 1 and IDH2 mutations ( IDH1/2mt) are the most common mutations in gliomas, occurring in over 70% of low grade and 20% of higher grade gliomas. IDH1/2mts are associated with improved prognosis, although tumors typically recur and progress to a higher grade despite first lines of treatment. Recent preclinical studies have suggested IDHmt and accumulation of 2-HG confer a “BRCAness” phenotype, a vulnerability that can be targeted through PARPi. To test this hypothesis, we conducted a multicenter study of olaparib monotherapy in patients (pts) with IDH1/2mt gliomas that had progressed despite standard therapy. Methods: Eligible pts had contrast enhancing and biopsy confirmed IDH1/2mt glioma that progressed despite standard therapy. Pts with prior treatment with PARPi or IDHmt inhibitors were excluded. The primary endpoint was overall response rate (ORR). Secondary objectives were progression free survival (PFS), overall survival (OS) and duration of response (DR). Olaparib 300 mg orally twice daily was given. A standard Simon 2 stage design was used. Stage 1 included 15 pts. If 2/15 pts responded stage 2 would expand by 30 pts. Responses were assessed with RANO criteria and reviewed centrally. Results: 15 evaluable pts were enrolled. Most recent histology as per 2021 WHO classification was 12 astrocytoma (4 grade 2, 3 grade 3, 5 grade 4) and 3 oligodendroglioma (2 grade 2, 1 grade 3). A total of 13 pts’ tumors had IDH1 R132H mutations; 2 pts had IDH2mt (R172G, R172K). All pts had >1 and 10 pts had >2 prior lines of systemic therapy (median 2, range 1-4). Most toxicities were grade 1 or 2. Nausea (67%) and fatigue (47%) were most frequent. Grade 3 lymphopenia, thrombocytopenia, and hypertension were seen in 1 patient each. Best response was stable disease (SD) in 9 pts and 6 pts had disease progression (PD). The median PFS was 3.6 months, 6-month PFS rate 26.7%, median OS 13.2 months. For pts with SD, median PFS was 5.5 months; 4 pts had SD for > 6 months. 2/6 pts with PD had confirmed WHO grade 4 by histology; 4 had CDKN2A deletion. CDKN2A deletion was unknown for 2 pts. Conclusions: Olaparib was well tolerated in this pt population. The study did not meet the pre-specified response-based threshold for moving to step 2, but prolonged SD was observed in pts with grades 2 and 3 histologies, suggesting olaparib monotherapy could be of clinical benefit in select pts. Grade 4 tumors per the 2021 WHO classification defined by histology or CDKN2A mutation derived minimal to no benefit from this drug highlighting the usefulness of this new classification for future patient stratification and trial design and suggesting investigation of this treatment earlier in the disease course might be of interest. Further studies are needed to identify other molecular or clinical predictive markers of benefit from PARPi as well as novel drug combinations for improved efficacy in this population. Clinical trial information: NCT03212274.

Melanoma secretion of transforming growth factor-β2 leads to loss of epidermal AMBRA1 threatening epidermal integrity and facilitating tumour ulceration

BACKGROUND

For patients with early American Joint Committee on Cancer (AJCC)-stage melanoma the combined loss of the autophagy regulatory protein AMBRA1 and the terminal differentiation marker loricrin in the peritumoral epidermis is associated with a significantly increased risk of metastasis.

OBJECTIVES

The aim of the present study was to evaluate the potential contribution of melanoma paracrine transforming growth factor (TGF)-β signalling to the loss of AMBRA1 in the epidermis overlying the primary tumour and disruption of epidermal integrity.

METHODS

Immunohistochemistry was used to analyse AMBRA1 and TGF-β2 in a cohort of 109 AJCC all-stage melanomas, and TGF-β2 and claudin-1 in a cohort of 30 or 42 AJCC stage I melanomas, respectively, with known AMBRA1 and loricrin (AMLo) expression. Evidence of pre-ulceration was analysed in a cohort of 42 melanomas, with TGF-β2 signalling evaluated in primary keratinocytes.

RESULTS

Increased tumoral TGF-β2 was significantly associated with loss of peritumoral AMBRA1 (P < 0·05), ulceration (P < 0·001), AMLo high-risk status (P < 0·05) and metastasis (P < 0·01). TGF-β2 treatment of keratinocytes resulted in downregulation of AMBRA1, loricrin and claudin-1, while knockdown of AMBRA1 was associated with decreased expression of claudin-1 and increased proliferation of keratinocytes (P < 0·05). Importantly, we show loss of AMBRA1 in the peritumoral epidermis was associated with decreased claudin-1 expression (P < 0·05), parakeratosis (P < 0·01) and cleft formation in the dermoepidermal junction (P < 0·05).

CONCLUSIONS

Collectively, these data suggest a paracrine mechanism whereby TGF-β2 causes loss of AMBRA1 overlying high-risk AJCC early-stage melanomas and reduced epidermal integrity, thereby facilitating erosion of the epidermis and tumour ulceration.

Dose-escalated accelerated hypofractionation for elderly or frail patients with a newly diagnosed glioblastoma

BACKGROUND

The standard of care for elderly glioblastoma patients is 40 Gy in 15 fraction radiotherapy with temozolomide (TMZ). However, this regimen has a lower biologic equivalent dose (BED) compared to the Stupp regimen of 60 Gy in 30 fractions. We hypothesize that accelerated hypofractionated radiation of 52.5 Gy in 15 fractions (BED equivalent to Stupp) will have superior survival compared to 40 Gy in 15 fractions.

METHODS

Elderly patients (≥ 65 years old) who received hypofractionated radiation with TMZ from 2010 to 2020 were included in this analysis. Overall survival (OS) and progression free survival were defined as the time elapsed between surgery/biopsy and death from any cause or progression. Baseline characteristics were compared between patients who received 40 and 52.5 Gy. Univariable and multivariable analyses were performed.

RESULTS

Sixty-six newly diagnosed patients were eligible for analysis. Thirty-nine patients were treated with 40 Gy in 15 fractions while twenty-seven were treated with 52.5 Gy in 15 fractions. Patients had no significant differences in age, sex, methylation status, or performance status. OS was superior in the 52.5 Gy group (14.1 months) when compared to the 40 Gy group (7.9 months, p = 0.011). Isoeffective dosing to 52.5 Gy was shown to be an independent prognostic factor for improved OS on multivariable analysis.

CONCLUSIONS

Isoeffective dosing to 52.5 Gy in 15 fractions was associated with superior OS compared to standard of care 40 Gy in 15 fractions. These hypothesis generating data support accelerated hypofractionation in future prospective trials.

Abstract P044: A phase 1 dose escalation study of protein arginine methyltransferase 5 (PRMT5) brain penetrant inhibitor PRT811 in patients with advanced solid tumors, including recurrent high-grade gliomas

Background: PRMT5 catalyzes symmetric arginine dimethylation of protein substrates with important roles in cancer cell growth/survival, including glioblastoma (GBM) cells. PRT811 is a brain penetrant, potent, selective, oral PRMT5 inhibitor with preclinical efficacy in a GBM orthotopic model (Zhang AACR 2020). An open-label Phase I study of PRT811 in patients (pts) with advanced solid tumors and recurrent high-grade glioma (NCT04089449) is ongoing. Dose escalation results are presented herein. Materials and Methods: This study assesses the safety, pharmacokinetics (PK), pharmacodynamics (PD), and preliminary anti-tumor activity (RECIST v1.1, Lugano, & RANO) of PRT811 administered at varying doses/schedules (15-600 mg daily [QD]; 300 mg twice daily [BID]). Serum symmetric dimethylarginine (sDMA) and intron retention, a marker of PRMT5-mediated mRNA splicing fidelity, were assessed as measures of PRMT5 target engagement and function, respectively. Results: As of 18 June 2021, 38 unselected pts with recurrent or refractory disease had enrolled (22 solid tumor, 16 GBM). Median number of prior lines of systemic therapies was 2. No dose-limiting toxicities have been identified. Most frequent treatment-related adverse events (TRAEs), any grade, were nausea (n=10, 26%), vomiting (n=7, 18%), diarrhea (n=4, 11%), fatigue (n=4, 11%), constipation (n=3, 8%), and pruritis (n=3, 8%). Decreased lymphocyte count (n=1, 3%) and vomiting (n=1, 3%) were the only Grade ≥3 TRAEs. 28 pts discontinued treatment, mainly due to disease progression. No pts discontinued due to treatment-emergent AEs (TEAEs). PRT811 exhibited linear PK characteristics. At the highest evaluated dose (600 mg QD), Cmax,of 3777 nM, AUC of 12,487 nM.hr, and T½ of 5.8 hrs were observed. Comparison of PK parameters of 300 mg administered either QD or BID demonstrated similar PK with no accumulation with the BID schedule. Serum sDMA levels decreased by 80% with 600 mg QD. PRMT5-mediated mRNA splicing fidelity in peripheral blood mononuclear cells showed increased intron retention in specific transcripts at the higher PRT811 doses, indicating PRMT5 functional activity was decreased. A partial response was observed in 1 pt with GBM (&gt;9 months duration) who remains on study. In addition, a pt with uveal melanoma (spliceosome SF3B1 mutation) achieved a 25% decrease in tumor burden per RECIST v1.1. An additional 3 pts with solid tumors had stable disease ≥6 mo. Conclusions: PRT811 was well tolerated with a favorable safety profile when administered at either QD or BID schedules. Target engagement and inhibition of PRMT5 functional activity were observed across multiple dose levels. Preliminary evidence of antitumor activity was observed in GBM and uveal melanoma. The expansion phase of the study will be initiated in select tumor types upon establishing the recommended expansion dose.

Citation Format: Gerald S. Falchook, Jon Glass, Varun Monga, Pierre Giglio, David Mauro, John Viscusi, Peggy Scherle, Neha Bhagwat, William Sun, Rachel Chiaverelli, Eric Mintah, Lydia Clements, Tanner M. Johanns, Meredith McKean. A phase 1 dose escalation study of protein arginine methyltransferase 5 (PRMT5) brain penetrant inhibitor PRT811 in patients with advanced solid tumors, including recurrent high-grade gliomas [abstract]. In: Proceedings of the AACR-NCI-EORTC Virtual International Conference on Molecular Targets and Cancer Therapeutics; 2021 Oct 7-10. Philadelphia (PA): AACR; Mol Cancer Ther 2021;20(12 Suppl):Abstract nr P044.

Prognostic implications of epidermal and platelet-derived growth factor receptor alterations in 2 cohorts of IDHwt glioblastoma

Background

Glioblastoma remains a deadly brain cancer with dismal prognosis. Genetic alterations, including IDH mutations, 1p19q co-deletion status and MGMT promoter methylation have been proven to be prognostic and predictive to response to treatment in gliomas. In this manuscript, we aimed to correlate other mutations and genetic alterations with various clinical endpoints in patients with IDH-wild-type (IDHwt) glioblastoma.

Methods

We compiled a comprehensive clinically annotated database of IDHwt GBM patients treated at the Ohio State University Wexner Medical Center for whom we had mutational data through a CLIA-certified genomic laboratory. We then added data that is publicly available from Memorial Sloan Kettering Cancer Center through cBioPortal. Each of the genetic alterations (mutations, deletions, and amplifications) served as a variable in univariate and multivariate Cox proportional hazard models.

Results

A total of 175 IDHwt GBM patients with available MGMT promoter methylation data from both cohorts were included in the analysis. As expected, MGMT promoter methylation was significantly associated with improved overall survival (OS). Median OS for MGMT promoter methylated and unmethylated GBM was 26.5 and 18 months, respectively (HR 0.45; P = .003). Moreover, EGFR/ERBB alterations were associated with favorable outcome (HR of 0.37 (P = .003), but only in MGMT promoter unmethylated GBM. We further found that patients with EGFR/ERBB alterations who also harbored PDGFRA amplification had a significantly worse outcome (HR 7.89; P = .025).

Conclusions

Our data provide further insight into the impact of genetic alterations on various clinical outcomes in IDHwt GBM in 2 cohorts of patients with detailed clinical information and inspire new therapeutic strategies for IDHwt GBM.

Assessment of Leptomeningeal Carcinomatosis Diagnosis, Management and Outcomes in Patients with Solid Tumors Over a Decade of Experience

Objective

Leptomeningeal carcinomatosis (LMC), a common complication of advanced malignancies, is associated with high morbidity and mortality, yet diagnosis and treatment decisions remain challenging. This study describes the diagnostic and treatment modalities for LMC and identifies factors associated with overall survival (OS).

Materials and Methods

We performed a single-institution retrospective study (registration #: OSU2016C0053) of 153 patients diagnosed with LMC treated at The Ohio State University, Comprehensive Cancer Center, (OSUCCC)-James between January 1, 2010 and December 31, 2015.

Results

Median age at diagnosis was 55.7 years, and 61% had Eastern Cooperative Oncology Group baseline performance status ≤1. Most common primary tumors were breast (43%), lung (26%), and cutaneous melanoma (10%). At presentation, most patients were stage III-IV (71%) with higher grade tumors (grade III: 46%). Metastases to bone (36%), brain (33%), and lung (12%) were the most common sites with a median of 0.5 years (range, 0-14.9 years) between the diagnosis of first metastasis and of LMC. 153 (100%) patients had MRI evidence of LMC. Of the 67 (44%) who underwent lumbar puncture (LP), 33 (22%) had positive cerebrospinal fluid (CSF) cytology. Most patients received radiotherapy for LMC (60%) and chemotherapy (93%) for either the primary disease or LMC. 28 patients received intrathecal chemotherapy, 22 of whom had a primary diagnosis of breast cancer. 98% died with median OS of all patients was 1.9 months (95% CI: 1.3-2.5 months).

Conclusion

Despite improved treatments and targeted therapies, outcomes of LMC remain extremely poor. Positive CSF cytology was associated with lower OS in patients who had cytology assessed and specifically in patients with breast cancer. CSF cytology serves as an important indicator for prognosis and helps aid in developing individualized therapeutic strategies for patients with LMC.

Targeted Therapy for BRAF Mutant Brain Tumors

OPINION STATEMENT

Molecular heterogeneity has confounded attempts to target individual pathways in brain tumors. However, gliomas with BRAF mutations have been identified as being uniquely vulnerable to targeted therapies. Such mutations are predominantly seen in brain tumors of the adolescent and young adult population. Given that accurate and timely identification of such mutations is essential for offering appropriate treatment, treatment centers should offer both immunohistochemical and sequencing methods for detection of these mutations to guide treatment. Additional studies of these tumors at recurrence would also allow identification of breakthrough resistance mechanisms that may also be targetable for treatment. Due to the relative rarity of these tumors, multicenter collaborative studies will be essential in achieving long term control of these tumors.

Intraoperative 3 T MRI is more correlative to residual disease extent than early postoperative MRI

PURPOSE

Extent of resection of low grade glioma (LGG) is an important prognostic variable, and may influence decisions regarding adjuvant therapy in certain patient populations. Immediate postoperative magnetic resonance image (MRI) is the mainstay for assessing residual tumor. However, previous studies have suggested that early postoperative MRI fluid-attenuated inversion recovery (FLAIR) (within 48 h) may overestimate residual tumor volume in LGG. Intraoperative magnetic resonance imaging (iMRI) without subsequent resection may more accurately assess residual tumor. Consistency in MRI techniques and utilization of higher magnet strengths may further improve both comparisons between MRI studies performed at different time points as well as the specificity of MRI findings to identify residual tumor. To evaluate the utility of 3 T iMRI in the imaging of LGG, we volumetrically analyzed intraoperative, early, and late (~ 3 months after surgery) postoperative MRIs after resection of LGG.

METHODS

A total of 32 patients with LGG were assessed retrospectively. Residual tumor was defined as hyperintense T2 signal on FLAIR. Volumetric assessment was performed with intraoperative, early, and late postoperative FLAIR via TeraRecon iNtuition.

RESULTS

Perilesional FLAIR parenchymal abnormality volumes were significantly different comparing intraoperative and early postoperative MRI (2.17 ± 0.45 cm³ vs. 5.47 ± 1.07 cm³, respectively (p = 0.0002)). A significant difference of perilesional FLAIR parenchymal abnormality volumes was also found comparing early and late postoperative MRI (5.47 ± 1.07 cm³ vs. 3.22 ± 0.64 cm³, respectively (p = 0.0001)). There was no significant difference between intraoperative and late postoperative Perilesional FLAIR parenchymal abnormality volumes.

CONCLUSIONS

Intraoperative 3 T MRI without further resection appears to better reflect the volume of residual tumor in LGG compared with early postoperative 3 T MRI. Early postoperative MRI may overestimate residual tumor. As such, intraoperative MRI performed after completion of tumor resection may be more useful for making decisions regarding adjuvant therapy.

Large Adult Spinal Diffuse Midline Histone H3 Lysine27-to-Methionine-Mutant Glioma With Intramedullary and Extramedullary Components Presenting With Progressive Hydrocephalus: A Case Report Highlighting Unique Imaging Findings and Treatment

Diffuse midline glioma with histone H3 lysine27-to-methionine mutation (H3 K27M mutation) is a rare, aggressive tumor that is designated as World Health Organization (WHO) grade IV regardless of histologic features. Preoperative diagnosis remains challenging due to limited evidence regarding distinctive clinical and imaging characteristics. We describe the case of a young woman who presented with progressively worsening headaches due to communicating hydrocephalus. MR imaging with contrast of the cervical and thoracic spine revealed diffuse leptomeningeal enhancement with focal areas of intramedullary and subarachnoid T2 hyperintensity and enhancement, suggestive of a potential infectious process. Intraoperatively, no epidural pathology was identified, and with the differential diagnosis remaining broad, a second procedure was conducted involving intradural exploration and biopsy of a lesion. This was then identified as a diffuse midline glioma with H3 K27M mutation. The nonfocal clinical presentation in the setting of communicating hydrocephalus as well as the significant exophytic tumor growth and imaging findings made the initial diagnosis unique and challenging. This case, therefore, emphasizes the rare presentation of this tumor, and the need for further understanding of the clinical and imaging characteristics of this disease as well as the need for effective therapeutics.

Phase 2 trial of newly diagnosed high-grade glioma treated with concurrent radiation therapy, temozolomide, and BMX-001

TPS2069

Background: High-grade gliomas (WHO grade III-IV) patients experience marked morbidity and mortality. While the standard of care for newly diagnosed high-grade glioma patients is surgery followed by concurrent chemotherapy and radiation therapy (RT), the outcomes remain poor. BMX-001 (MnTnBuOE-2-PyP5+) is a metalloporphyrin with differential action in response to radiation therapy and chemotherapy-induced oxidative stress. As shown in preclinical evaluations, BMX-001, when used with radiation, can protect normal, healthy tissues and augment cell kill in malignant cancer cells, notably, human glioblastoma xenografts. We evaluated the safety of BMX-001 in combination with concurrent RT and temozolomide (TMZ) in a phase 1 study of newly diagnosed high-grade glioma patients and we found that BMX-001 is safe and well-tolerated in this population. The maximum tolerated dose of BMX-001 during concurrent RT and TMZ was determined to be 28 mg delivered subcutaneously (SC) followed by 16 biweekly SC doses at 14 mg (Peters et al., Neuro-Oncology 2018). Methods: For this multi-site, open-label, phase 2 study (NCT02655601), we will randomize approximately 160 patients 1:1 to concurrent RT and TMZ with BMX-001 versus concurrent RT and TMZ alone. Key eligibility criteria include newly diagnosed histologically confirmed high-grade glioma (WHO III-IV), 18 ≥ years, and Karnofsky performance status ≥ 70%. The primary endpoint is overall survival. Secondary endpoints are objective cognitive performance, bone marrow protection, safety and tolerability, progression-free survival, overall tumor response rate, and plasma pharmacokinetics. Exploratory endpoints are patient-reported outcomes of health-related quality of life (as assessed by Functional Assessment of Cancer Therapy–Brain, Functional Assessment of Cancer Therapy-Cognition, and Functional Assessment of Chronic Illness Therapy-Fatigue), qualitative hair loss, and white matter integrity (as measured by MRI diffusion tensor/susceptibility imaging). Since November 2018, this phase 2 study has enrolled 147 of 160 high-grade glioma patients at nine sites in US. Clinical trial information: NCT02655601.

Trial in progress: Phase I/II study of radiation therapy followed by intrathecal trastuzumab/pertuzumab in the management of HER2+ breast leptomeningeal disease

TPS1099

Background: HER2+ breast cancer patients with leptomeningeal disease (LMD) represent a poor prognosis population with a high unmet clinical need. Although a multitude of treatment options are available for the management of systemic disease, once metastases travel to the leptomeninges, patients have a lack of treatment options aside from traditional local approaches. Data from a phase I/II study reveals intrathecal (IT) trastuzumab to be well tolerated with improved overall survival (OS) compared to historical controls in HER2+ breast LMD. Radiotherapy can improve the flow of IT therapy through the cerebrospinal fluid (CSF) and provide symptomatic relief. The monoclonal antibody pertuzumab is used in conjunction with trastuzumab in the management of metastatic and localized HER2+ breast cancer. Given the role of radiotherapy in the management of LMD along with the role of pertuzumab in the management of HER2+ breast cancer, there is a strong clinical rationale to combine radiotherapy with IT trastuzumab/pertuzumab in the management of HER2+ breast LMD. Methods: The study is designed as a prospective, single-arm, nonrandomized, open-label, phase I/II trial of radiation therapy followed by IT trastuzumab/pertuzumab in the management of HER2+ breast LMD. HER2+ LMD patients identified by magnetic resonance imaging (MRI) and/or CSF cytology, ≥ 18, with a life expectancy > 8 weeks are eligible. Treatment is initiated with radiotherapy, whole brain radiotherapy and/or focal brain/spine radiation followed by IT trastuzumab/pertuzumab. Safety and feasibility will be monitored by a modified toxicity probability interval-2 (mTPI-2) design. Dose reductions of IT trastuzumab will not be allowed. Once the maximum tolerated dose of IT pertuzumab is determined, the phase II portion of the study will commence to determine OS. Secondary objectives involve defining the CSF pharmacokinetics of IT trastuzumab/pertuzumab, evaluating the response rate (leptomeningeal and parenchymal), and progression free survival (leptomeningeal and parenchymal) following IT trastuzumab/pertuzumab. In the phase 2 portion, a single-arm two-stage trial is designed using the Restricted-Kwak-and-Jung’s Method. The primary endpoint is one-year OS. An interim analysis will be performed after 20 patients are enrolled. This study is open with 1 patient enrolled at the time of submission. Clinical trial information: NCT04588545 .

A Bayesian adaptive randomized phase II multicenter trial of bevacizumab with or without vorinostat in adults with recurrent glioblastoma

BACKGROUND

Bevacizumab has promising activity against recurrent glioblastoma (GBM). However, acquired resistance to this agent results in tumor recurrence. We hypothesized that vorinostat, a histone deacetylase (HDAC) inhibitor with anti-angiogenic effects, would prevent acquired resistance to bevacizumab.

METHODS

This multicenter phase II trial used a Bayesian adaptive design to randomize patients with recurrent GBM to bevacizumab alone or bevacizumab plus vorinostat with the primary endpoint of progression-free survival (PFS) and secondary endpoints of overall survival (OS) and clinical outcomes assessment (MD Anderson Symptom Inventory Brain Tumor module [MDASI-BT]). Eligible patients were adults (≥18 y) with histologically confirmed GBM recurrent after prior radiation therapy, with adequate organ function, KPS ≥60, and no prior bevacizumab or HDAC inhibitors.

RESULTS

Ninety patients (bevacizumab + vorinostat: 49, bevacizumab: 41) were enrolled, of whom 74 were evaluable for PFS (bevacizumab + vorinostat: 44, bevacizumab: 30). Median PFS (3.7 vs 3.9 mo, P = 0.94, hazard ratio [HR] 0.63 [95% CI: 0.38, 1.06, P = 0.08]), median OS (7.8 vs 9.3 mo, P = 0.64, HR 0.93 [95% CI: 0.5, 1.6, P = 0.79]) and clinical benefit were similar between the 2 arms. Toxicity (grade ≥3) in 85 evaluable patients included hypertension (n = 37), neurological changes (n = 2), anorexia (n = 2), infections (n = 9), wound dehiscence (n = 2), deep vein thrombosis/pulmonary embolism (n = 2), and colonic perforation (n = 1).

CONCLUSIONS

Bevacizumab combined with vorinostat did not yield improvement in PFS or OS or clinical benefit compared with bevacizumab alone or a clinical benefit in adults with recurrent GBM. This trial is the first to test a Bayesian adaptive design with adaptive randomization and Bayesian continuous monitoring in patients with primary brain tumor and demonstrates the feasibility of using complex Bayesian adaptive design in a multicenter setting.

Impact of cerebrospinal fluid flow study in patients undergoing intrathecal chemotherapy via ventricular catheter reservoir

PURPOSE

Leptomeningeal carcinomatosis (LMC) is a form of CNS cancer metastasis with severe morbidity. Intrathecal chemotherapy (ITC) administration through an implanted ventricular catheter reservoir (IVCR) is often utilized. Additionally, a nuclear imaging flow study can be performed prior to ITC administration to assess cerebrospinal fluid (CSF) flow. The clinical impact of a CSF flow study is unclear.

METHODS

A retrospective chart review identified 31 patients with LMC that underwent IVCR placement between 2011 and 2019. Data extracted included patient demographics, nuclear imaging flow study, surgical complications, ITC toxicities and outcomes.

RESULTS

Potential drug-induced neurologic toxicities (headache, nausea/vomiting, altered mental status, etc.) were noted in (n = 4/16) 25% of patients who underwent a flow study prior to initiation of ITC, compared to (n = 1/15) 6.6% of patients who did not undergo a flow study. Median overall survival (OS) was 4.0 and 32.8 months for the patients that underwent a flow study versus patients who did not, respectively (p < 0.01). The mean interval from IVCR implantation to initiation of ITC was 15.2 ± 8.5 days and 3.3 ± 3.0 days in patients who underwent CSF flow study and patients that did not, respectively (p < 0.0001).

CONCLUSIONS

A flow study can provide information regarding CSF flow dynamics prior to initiation of ITC; however this might delay initiation of ITC which may negatively impact OS. Additionally, in our study patients that underwent a flow study had more ITC induced drug toxicity events compared to those that did not. Further studies are needed to clarify the role of CSF flow study in these patients.

The role of VEGF receptor inhibitors in preventing cerebral radiation necrosis: a retrospective cohort study

Background

Radiation necrosis (RN) is a potential complication after radiation therapy for brain tumors. It is hypothesized that VEGF plays an important role in the pathophysiology of RN. Bevacizumab, a monoclonal antibody against VEGF-A, is often successful in the management of RN. The objective of this study is to assess whether VEGF receptor (VEGFR) inhibitors, a group of oral tyrosine kinase inhibitors (TKIs), can prevent or reverse RN.

Methods

We retrospectively studied a cohort of 102 patients with renal cell carcinoma and brain metastases seen at The Ohio State University James Cancer Center between January 1, 2011 and April 30, 2019. We identified those who developed RN and analyzed the temporal relationship between the use of VEGFR TKIs and the development of RN.

Results

The cumulative incidence of RN is 13.7% after radiation treatments that included LINAC-based stereotactic radiosurgery, fractionated stereotactic radiotherapy, or Gamma Knife radiosurgery. There was no statistically significant difference in the cumulative incidence of RN between patients taking TKIs and patients who were off TKIs (9.9% and 11.5% respectively, P = .741). The median time to development of RN was only numerically shorter in patients taking TKIs (151 vs 315 days, P = .315). One patient developed RN after stopping cabozantinib. Eight patients developed RN while on cabozantinib, pazopanib, or sunitinib. One patient was started on axitinib during active RN without significant improvement subsequently.

Conclusions

VEGFR TKIs do not consistently prevent RN. The therapeutic effects of VEGFR TKIs against RN warrant further research.

Phase I trial of intracerebral convection-enhanced delivery of carboplatin for treatment of recurrent high-grade gliomas

Background

Carboplatin is a potent cytoreductive agent for a variety of solid tumors. However, when delivered systemically, clinical efficacy for the treatment of high grade gliomas is poor due to limited penetration across the blood-brain barrier (BBB). Direct intracerebral (IC) convection-enhanced delivery (CED) of carboplatin has been used to bypass the BBB and successfully treat the F98 rat glioma. Based on these studies, we initiated a Phase I clinical trial.

Objective

This Phase I clinical trial was conducted to establish the maximum tolerated dose and define the toxicity profile of carboplatin delivered intracerebrally via convection enhanced delivery (CED) for patients with high grade glial neoplasms.

Methods

Cohorts of 3 patients with recurrent WHO grade III or IV gliomas were treated with escalating doses of CED carboplatin (1–4 μg in 54mL over 72 hours) delivered via catheters placed at the time of recurrent tumor resection. The primary outcome measure was determination of the maximum tolerated dose (MTD). Secondary outcome measures included overall survival (OS), progression-free survival (PFS), and radiographic correlation.

Results

A total of 10 patients have completed treatment with infusion doses of carboplatin of 1μg, 2μg, and 4μg. The total planned volume of infusion was 54mL for each patient. All patients had previously received surgery and chemoradiation. Histology at treatment include GBM (n = 9) and anaplastic oligodendroglioma (n = 1). Median KPS was 90 (range, 70 to 100) at time of treatment. Median PFS and OS were 2.1 and 9.6 months after completion of CED, respectively. A single adverse event possibly related to treatment was noted (generalized seizure).

Conclusions

IC CED of carboplatin as a potential therapy for recurrent malignant glioma is feasible and safe at doses up to 4μg in 54mL over 72 hours. Further studies are needed to determine the maximum tolerated dose and potential efficacy.

GCT-66. FINAL REPORT OF THE PROSPECTIVE NEXT/CNS-GCT-4 CONSORTIUM TRIAL (GemPOx FOLLOWED BY MARROW-ABLATIVE CHEMOTHERAPY) IN PATIENTS WITH REFRACTORY/RECURRENT CNS GERM CELL TUMORS

BACKGROUND

We report the responses, toxicities and long-term outcomes of gemcitabine, paclitaxel and oxaliplatin (GemPOx) regimen administered, in responsive patients, prior to single cycle marrow-ablative chemotherapy (thiotepa, etoposide and carboplatin) with autologous hematopoietic progenitor cell rescue (HDCx+AuHPCR).

METHODS

Since December 2009, 11 recurrent/refractory patients (10 MMGCT, 1 germinoma; 10 males; mean age 16.5 years, range 7–46 years) have been treated with up to four cycles of gemcitabine (800mg/M2), paclitaxel (170mg/M2) and oxaliplatin (100mg/M2) administered on one day at 14 days intervals.

RESULTS

All 11 patients were enrolled on a prospective multi-center trial, which was closed in October 2019. Three patients achieved complete remissions (tumor marker and/or imaging studies), five achieved partial remissions, two developed disease progression (PD), and one was withdrawn after one cycle for severe paclitaxel neurotoxicity followed by rapid tumor progression and death. One patient with PD after one cycle had pathologically-confirmed metastatic transformation to pure embryonal rhabdomyosarcoma, and rapidly expired. A second patient, with pure pineal choriocarcinoma, progressed after the second GemPOx cycle, ultimately died of tumor progression. Eight of the 11 responsive patients subsequently underwent HDCx+AuHPCR; five of these received some form of radiotherapy. Seven patients (six MMGCT, one germinoma) are alive and disease-free without recurrence for a mean of 94 months (range 74–118 months) since completion of therapy.

CONCLUSION

GemPOx is an effective re-induction regimen for patient with recurrent CNS germ cell tumors, with acceptable toxicities; when followed by marrow-ablative chemotherapy and subsequent irradiation/re-irradiation, the regimen produces encouraging long-term disease-free survival.

RARE-30. A RARE CASE OF PRIMARY EWING’S SARCOMA OF THE CERVICAL SPINE

Ewing sarcoma family of tumors predominantly affect the pediatric population in the long bones of the extremities or the pelvis, and only 8% of cases arise within the spine. Primary Ewing’s sarcoma of the cervical spine is extremely rare and less than 30 cases have been reported in the literature thus far. Here we present a case of primary Ewing’s sarcoma of the cervical spine in a 28-year-old female who presented with a three-month history of neck pain and right arm radiculopathy. MRI revealed a homogeneously contrast enhancing, eccentric mass with dural tail at C2-C7. After undergoing a hemilaminectomy, histopathology confirmed extraosseous Ewing’s sarcoma with CD99 positivity. A comprehensive systemic and neuraxis work-up ruled out overt metastasis. We extrapolated data from children’s cooperative group studies and IESS-II clinical trial to formulate a three phase treatment protocol as described below. To date, patient is in remission with no evidence of any residual disease in the cervical spine. In conclusion, although Primary Ewing’s sarcoma of the cervical spine is extremely rare it should be considered a differential diagnosis in patients with neck pain and a spinal mass under the age of thirty. Less than 25% of EFT’s present with overt metastasis and almost all have subclinical metastatic disease at the time of diagnosis, therefore, a comprehensive evaluation and systemic chemotherapy is recommended. We recommend a multidisciplinary approach of surgical decompression to preserve neurological functions, followed by compressed chemotherapy regimens, reevaluation for local treatment, and adjuvant chemotherapy.

NCOG-42. INITIAL PRESENTATION AND OUTPATIENT VISIT COMPLIANCE OF INMATES WITH BRAIN TUMORS

INTRODUCTION

While advocacy for inmates with cancer has recently gained momentum, little is known about management of brain tumors in inmates. Delays in acknowledging or recognizing nonspecific initial symptoms can lead to delayed diagnosis and treatment. Inmates with cancer are reported to either be ignored or receive substandard care due in part to cost or logistics (American Civil Liberties Union; ASCO Post 2018).

METHODS

In this retrospective study, we identified inmates with gliomas seen in the Ohio State University Neuro-oncology Center between 1/1/2010-4/20/2019.

RESULTS

Twelve patients were identified. Median age at presentation was 39.5 years (range 28-62). Eleven patients were Caucasian and one was African American. Diagnoses included glioblastoma (GBM) (n=6), anaplastic astrocytoma (n=1), anaplastic oligodendroglioma (n=1), low-grade astrocytoma (n=3) and anaplastic pleomorphic xanthroastrocytoma (n=1). Patients were more likely to present early after seizures or focal neurologic deficits (9/12) than after headaches alone. Patients with GBM started RT 12-71 days after surgery (median 34.5). One patient’s post-RT MRI was delayed by a month and another with GBM had treatment held after 4 cycles of adjuvant temozolomide (TMZ) due to “incarceration issues”. For one patient who received adjuvant TMZ, the facility failed to communicate with the primary team throughout treatment. Two patients suffered significant nausea while on chemotherapy due to inability to obtain ondansetron in prison, or due to wrong timing. 7/12 (58%) patients were lost to follow-up for periods of 3-15 months during treatment. Three patients refused adjuvant treatment.

CONCLUSIONS

Although this is a small series, our results highlight the inequities and challenges faced by inmates with gliomas who are more likely to forego treatments or whose incarceration prevents them from keeping appropriate treatment and follow-up schedules. Additional studies are needed to define and address these deficiencies in the care of inmates with brain tumors and other cancers.

NCMP-01. THE ROLE OF VASCULAR ENDOTHELIAL GROWTH FACTOR RECEPTOR INHIBITORS IN PREVENTING CEREBRAL RADIATION NECROSIS: A RETROSPECTIVE COHORT STUDY

INTRODUCTION

Radiation necrosis (RN) is a potential complication after radiation therapy to primary brain tumors and brain metastases. The pathophysiology of RN is not well understood but it is hypothesized that vascular endothelial growth factor (VEGF) plays an important role. Bevacizumab, a monoclonal antibody against VEGF-A, is often successful in the management of RN. The objective of this study is to assess whether VEGF receptor (VEGFR) inhibitors, a group of oral tyrosine kinase inhibitors (TKIs), can prevent or reverse cerebral radiation necrosis

METHODS

We retrospectively studied a cohort of 102 patients with renal cell carcinoma (RCC) and brain metastases seen at The Ohio State University James Cancer Center between 01/01/2011 and 04/30/2019. We identified those who developed RN and analyzed the temporal relationship between the use of VEGFR TKIs and the development of RN.

RESULTS

The cumulative incidence of RN in our cohort is 13.7% after radiation treatments that included LINAC-based stereotactic radiosurgery, fractionated stereotactic radiotherapy, or Gamma Knife radiosurgery. There was no statistically significant difference in the cumulative incidence of RN between patients taking TKIs and patients who were off TKIs (9.9% and 11.5% respectively, p= 0.741). The median time to development of RN was only numerically shorter in patients taking TKIs (151 versus 315 days, p=0.315). One patient developed RN after stopping cabozantinib. Three other patients developed RN while on cabozantinib. Two patients developed RN while on pazopanib, and 3 patients developed RN while on sunitinib. One patient was started on axitinib during active RN without significant improvement subsequently.

CONCLUSIONS

VEGFR TKIs do not consistently prevent or reverse cerebral radiation necrosis and do not seem to have the efficacy that bevacizumab has against RN.

NCMP-12. RAPIDLY PROGRESSIVE NEUROPATHIES AS THE SOLE PRESENTATION OF NEUROLYMPHOMATOSIS

Neurolymphomatosis (NL) is a rare and challenging entity characterized by hematological neoplastic infiltration of the peripheral nervous system. Only 40% of the cases have malignant cells on CSF sampling. We present a 52-year-old Caucasian male with primary refractory diffuse large B-cell lymphoma (DLBCL) who relapsed within 3 months of achieving complete remission to R-CHOP. First, he experienced right tongue numbness and lumbar pain. Initial MRI of the face, brain and entire spine, and CSF analysis were unremarkable. Three weeks later, he noticed left facial numbness, dysphonia, and left leg weakness. Neuraxis MRI revealed enhancement of left CN V3 and several cervical, thoracic, and lumbar nerve roots. PET/CT showed increased uptake at L4 nerve root. EMG/NGS showed left L5 denervation. After one week, he further developed new right CN VI palsy, left-sided ptosis, anisocoria, and right arm weakness. Repeat MRI showed worsening enhancement and thickening of multiple cranial nerves, cervical and lumbosacral plexus. Extensive testing for infectious, inflammatory, and paraneoplastic processes was negative. Patient underwent plasmapheresis with no response. Biopsy of nerve root was deferred due to potential permanent deficits that would impair his quality of life. Repeat CSF testing was negative for malignancy and PET/CT showed SUV of 23.8 at L4-5 with multiple new hypermetabolic foci in muscle and ribs. He received R-HD-methotrexate with clinical and radiographic (PET/CT) improvement following 2 cycles. He completed 4 cycles of R-HD methotrexate-based chemotherapy followed by autologous hematopoietic stem cell transplantation. Most of his symptoms resolved and he remained stable for about a year when PET/CT showed disease progression. He subsequently received CAR-T cell therapy with adequate tolerance and remains clinically stable. Even with negative initial imaging and CSF studies, a careful exam and attention to uncommon presentations along with serial advanced imaging (MRI, PET/CT) surveillance are key to early detection and timely treatment.

NCMP-07. TREATMENT-INDUCED CEREBRAL NECROSIS IN GLIOMAS: THE OHIO STATE UNIVERSITY COMPREHENSIVE CANCER CENTER (OSUCCC) EXPERIENCE

INTRODUCTION

Treatment-induced cerebral necrosis (TN) is a challenging complication encountered in neuro-oncology. Diagnosis and treatment of TN remains poorly defined.

METHODS

In this single institution, retrospective study, consecutive patients with gliomas and TN between 01/01/2012 and 04/20/2020 at the OSUCCC were identified. Details of the tumor treatment, molecular markers, radiological and pathological findings of TN, as well as treatment, recurrence rate and management upon recurrence were collected.

RESULTS

Of the 53 patients analyzed, 37 had glioblastoma, 7 had anaplastic oligodendroglioma and 9 had grade II or III astrocytoma. MGMT promoter hypermethylation was present in 31/50 (59%) and IDH mutation in 17/53 (32%). Diagnosis of TN was based on histology in 43/53 (81%) or clinical/radiographic features in 10/53 (19%). Worsening of focal weakness (36%), seizures (9%) or being (30%) were common presentations at TN diagnosis. Patient with right compared to left hemisphere involvement were more symptomatic at TN diagnosis. (p=0.049). Bevacizumab (BEV) (51%), resection (28%), steroids only (9%) or Laser Interstitial Thermal Therapy (6%) were used to treat TN. Steroids were weaned off in 20/27 (74%) after receiving BEV. Among all treatments, BEV was significantly associated with a better outcome (resolution or partial improvement of enhancement in 84.6%) (p=0.0006, Bonferroni corrected p&lt; 0.005). TN Recurrence occurred in 36%, 70% and 100% of the patients treated with BEV, resection and LITT respectively. The median duration to TN recurrence was 10 weeks (range: 3–70 weeks). Initial treatment used for TN, MGMT methylation and IDH mutation status did not predict TN recurrence. (p=0.074; p=0.819; p=0.607 respectively).

CONCLUSIONS

BEV appears to be a superior treatment to control TN overall. Recurrence of TN in patients previously treated with BEV was 36%. There was no difference in the risk of developing recurrent TN based on MGMT or IDH status.

Characterizing benefit from temozolomide in MGMT promoter unmethylated and methylated glioblastoma: a systematic review and meta-analysis

Background

The current standard of care for the management of patients with newly diagnosed glioblastoma (GBM) includes maximal safe resection followed by radiotherapy (RT) with concurrent and adjuvant temozolomide (TMZ). While it is well established that TMZ has better efficacy in patients with MGMT promoter methylation, it remains an area of debate whether TMZ should be omitted when treating GBM patients with unmethylated MGMT.

Methods

We conducted a systematic review and meta-analysis to provide separate estimates of median overall survival (OS) and progression-free survival (PFS) for patients with methylated and unmethylated GBM treated with RT with or without TMZ. We searched multiple databases from inception to January 13, 2020.

Results

The median OS for patients with unmethylated GBM treated with RT/TMZ pooled from 5 phase III studies (N = 655) was 14.11 months (95% confidence interval [CI], 13.18–15.04) with a median PFS of 4.99 months (95% CI, 4.25–5.72). In contrast, the median OS for patients with methylated GBM pooled from 6 studies (N = 753) was 24.59 months (95% CI, 22.19–26.99) with a median PFS pooled from 7 studies (N = 805) of 9.51 months (95% CI, 7.41–11.61). There is a paucity of prospective data pertaining to OS/PFS in unmethylated patients treated with RT only and therefore a direct comparison was not possible.

Conclusions

This meta-analysis provides estimates of survival for patients with MGMT methylated or unmethylated GBM treated with RT/TMZ. Further research is needed to delineate whether TMZ should be withheld for patients with unmethylated GBM outside of the setting of clinical trials.

High-dose methotrexate-based regimens with or without vincristine for the treatment of primary central nervous system lymphoma

Background

Primary central nervous system lymphoma (PCNSL) is a rare malignancy with few treatment options. One regimen used for induction is rituximab, high-dose methotrexate (HD-MTX), procarbazine, and vincristine (R-MPV). A common institutional practice is removing vincristine (VCR) from this regimen due to its poor CNS penetration and associated toxicities. The aim of this study was to evaluate how the omission of VCR from HD-MTX-based induction impacted clinical outcomes.

Methods

In a retrospective review, patients with PCNSL who received HD-MTX-based induction therapy between January 1, 2010 and May 31, 2018 were evaluated. Patients were stratified according to treatment into 2 groups, VCR-containing therapy versus no VCR. The primary endpoint was complete response (CR) rate following the completion of induction chemotherapy. Secondary endpoints included progression-free survival (PFS), overall survival (OS), and adverse event rate.

Results

Twenty-nine patients were included: 16 patients in the VCR group and 13 in the non-VCR group. A CR was achieved in 7 (44%) and 5 (38%) (odds ratio [OR] = 1.24; 95% confidence interval [CI]: 0.28-5.53) patients, respectively. Median OS was 85.3 (95% CI: 20.2-85.3) versus 67.1 months (95% CI: 10.5-NR) and median PFS was 60.7 (95% CI: 9.4-NR) versus 23.7 months (95% CI: 4.7-NR) in the VCR group versus non-VCR group, respectively. The incidence of any grade peripheral neuropathy was higher in the VCR group.

Conclusions

CR rate, OS, and PFS were similar between groups regardless of VCR inclusion. Adverse events were higher in the VCR group. Larger studies are required to further evaluate the efficacy of VCR in PCNSL induction regimens.

Meningioangiomatosis: Clinical, Imaging, and Histopathologic Characteristics

Meningioangiomatosis is a rare benign lesion involving the central nervous system. Radiographic appearance can be highly variable which makes pre-operative diagnosis difficult. In this report, we describe meningioangiomatosis in a previously healthy 17-year-old woman who presented with seizures and continued headache and dizziness. This patient presented with a predominately calcified lesion on imaging and eventually underwent near total resection. Meningioangiomatosis is difficult to preoperatively identify, but is an important consideration as prognosis with surgical resection is typically good.

BMX-HGG: Phase II trial of newly diagnosed high-grade glioma treated with concurrent radiation therapy, temozolomide, and BMX-001

TPS2577

Background: Patients diagnosed with malignant high-grade gliomas (WHO grade III-IV) experience significant morbidity and mortality associated with these cancers. While the mainstay of therapy for patients with newly diagnosed high-grade glioma is surgery followed by concurrent chemotherapy and radiation therapy (RT), the outcomes remain very poor. BMX-001 (MnTnBuOE-2-PyP5+) is a metalloporphyrin with differential action in response to radiation therapy and chemotherapy-induced oxidative stress. Early preclinical studies demonstrated BMX-001’s ability to act as a radioprotectant to healthy tissue such as a central nervous white matter and as a radiosensitizer to cancer cells, in particular, human glioblastoma xenografts. We evaluated the safety of BMX-001 in combination with concurrent RT and temozolomide (TMZ) in a phase I study of newly diagnosed high-grade glioma patients, and we found that BMX-001 is safe and well-tolerated in this population. The maximum tolerated dose of BMX-001 during concurrent RT and TMZ was determined to be 28 mg delivered subcutaneously (SC) followed by 16 biweekly SC doses at 14 mg (Peters et al., Neuro-Oncology 2018). Methods: For this multi-site, open-label, phase II study (NCT02655601), we will randomize approximately 160 patients 1:1 to concurrent RT and TMZ with BMX-001 versus concurrent RT and TMZ alone. Key eligibility criteria include newly diagnosed histologically confirmed high-grade glioma (WHO III-IV), 18 ≥ years, and Karnofsky performance status ≥ 70%. The primary endpoint is overall survival. Secondary endpoints include cognitive performance as assessed by standardized cognitive testing, bone marrow protection, safety and tolerability, progression-free survival, overall tumor response rate, and plasma pharmacokinetics. Exploratory endpoints are health-related quality of life (as assessed by Functional Assessment of Cancer Therapy–Brain, Functional Assessment of Cancer Therapy-Cognition, and Functional Assessment of Chronic Illness Therapy-Fatigue), qualitative hair loss, and white matter integrity (as measured by MRI diffusion tensor/susceptibility imaging). Since November 2018, this phase II study has enrolled 64 of 160 high-grade glioma patients at six sites with future sites planned to be implemented. Clinical trial information: NCT02655601 .

Abstract P2-20-07: Assessment of leptomeningeal carcinomatosis management and outcomes in patients with advanced breast cancer from 2005 to 2015: A single institution experience

Background Leptomeningeal carcinomatosis (LMC) is a complication of advanced malignancies wherein metastatic disease invades the meninges of the central nervous system via contiguous spread from bone or brain metastases or hematogenous spread from systemic disease. Breast cancer is the most common solid tumor etiology of LMC. Approximately 5% of patients (pts) with breast cancer develop LMC. LMC has a median survival of 4 weeks when untreated and 8-16 weeks with treatment. The diagnosis of LMC remains challenging with only 60% of pts having cerebrospinal fluid (CSF) positive for malignant cells. There is no generally accepted standard of care for treatment of LMC but it may involve intrathecal or systemic chemotherapy, whole brain or spinal radiotherapy, or a combination of modalities. We aimed to assess detection and treatment strategies of LMC in pts with breast cancer treated at the Ohio State University Comprehensive Cancer Center-James (OSUCCC-James) to better characterize the disease and guide clinical care. Methods An IRB-approved single-institution retrospective protocol was developed. Medical records of 469 pts who had undergone a procedure related to LMC diagnosis or treatment were identified and reviewed to determine study eligibility. Comprehensive data was obtained through information warehouse and chart review was performed for the eligible 69 pts with breast cancer diagnosed with LMC and treated at the OSUCCC-James between January 1, 2005 and December 31, 2015. Descriptive statistics were used to summarize demographic and clinical characteristics. Overall survival (OS) was defined as time from LMC diagnosis to death or last known follow-up, and was generated using Kaplan Meier methods. Comparisons in OS between groups were analyzed using Log-rank tests. Results Sixty-nine female pts were included in the analysis with the following characteristics: median age 55.7 years (range: 48-60.6 years), Eastern Cooperative Oncology Group (ECOG) performance status of 0-2 (86%; N=59), and Caucasian (78%; N=54). They had the following subtypes hormone receptor positive (HR +), and human epidermal growth factor receptor (HER2) negative (61%, N=42), triple negative (25%, N=17) and HER2 positive (10%, N=7). The most common sites of metastases included bone (42%), brain (28%), and lung (12%). The median time between the diagnosis of first metastasis and LMC was 0.9 years (range: 0-3.2 years). Of the 40 (58%) pts who underwent lumbar puncture, 21 (52%) pts had positive CSF cytology. Sixty-eight pts (99%) had MRI findings suggestive of LMC. The most common treatment modalities were systemic chemotherapy (N=14, 41%), radiotherapy (N=12, 35%), and intrathecal chemotherapy (N=14, 35%). Fifty-six pts (81%) had a change in systemic chemotherapy agent after diagnosis. The median OS of all pts was 2.4 months (95% confidence interval: 1.2-4.4). Pts with ER+/PR+/HER2- had a better OS (4.4 months, 95%CI 1.5, 6.1)) compared to those with HER2+ (1.3 months, 95%CI 0.2, 1.9) or ER-/PR-/HER2- (0.6 months, 95%CI 0.0, 15.8) subtypes (p-value=0.004). Pts with negative CSF cytology had a greater OS compared to those with positive CSF cytology (9.8 vs. 0.7 months, p=0.026) and pts who had a change in systemic treatment had a greater OS compared with patients who had no new treatment (2.5 months vs. 1.2 months, p =0.039). No significant difference was seen in OS between ECOG performance status groups. Conclusions LMC is a relatively rare yet devastating complication of breast cancer. Based on our institutional experience, LMC remains a clinical challenge and is associated with poor OS. Pts with triple negative and HER2 positive disease and those with high disease burden fare worse. Pts who had change in systemic therapy fare better. Dedicated clinical trials are urgently needed to improve outcomes.

Citation Format: Hannah Rinehardt, Nicole Williams, Evan Morgan, Mahmooud Kassem, Marilly Palettas, Abdul Miah, Iyad Alnahhas, Pilar Guillermo Prieto Eibl, Anupama Suresh, Vinay Puduvalli, Pierre Giglio, Maryam Lustberg, Robert Wesolowski, Sagar Sardesai, Daniel Stover, Jeffrey VanDeusen, Jose Bazan, Bhuvaneswari Ramswamy, Anne Noonan. Assessment of leptomeningeal carcinomatosis management and outcomes in patients with advanced breast cancer from 2005 to 2015: A single institution experience [abstract]. In: Proceedings of the 2019 San Antonio Breast Cancer Symposium; 2019 Dec 10-14; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2020;80(4 Suppl):Abstract nr P2-20-07.

PATH-12. IDENTIFYING MOLECULAR PROGNOSTIC MARKERS IN IDHwt GLIOBLASTOMA

BACKGROUND

Despite our deeper understanding of the genomic alterations associated with glioblastoma (GBM), only a few genetic and epigenetic modifications have been proven to be meaningful in clinical practice. We have identified molecular parameters of prognostic relevance in IDHwt GBM using patient data from the Ohio State University (OSU) and the publicly available MSK-IMPACT database.

METHODS

A clinically annotated database of glioma patients at OSU- whose tumors were analyzed through Foundation One genomic testing- was utilized to examine mutation and copy number variation (CNV) data. 73 patients with IDHwt GBM were included in this study cohort along with 200 similar patients from the MSK-IMPACT cohort. Data from the MSKCC group was extracted from the cBioPortal database. Altered genes were correlated with clinical outcomes using Cox proportional hazards models. Univariate and multivariate analyses were applied, and variables included: MDM/P53, CDKN2A/B, CDK/CCND, RB1, EGFR/ ERBB, FGFR, PDGFR/KIT, NF1, PI3K, PI3K class 2, MYC and TERT promoter mutations.

RESULTS

Using univariate and multivariate analyses, EGFR activating alterations (amplification, mutations) and RB1 alterations (deletion, mutations) showed significant correlation with favorable outcome in IDHwt GBM: HR 0.496 for EGFR (p< 0.0001) and 0.454 for RB1 (p=0.025). Furthermore, the presence of PDGFR alterations, in EGFR altered tumors only, carried a significantly worse survival in univariate and multivariate analyses: HR 5.094 (p=0.004). This suggests an interaction between EGFR and PDGFR that could be of therapeutic relevance.

CONCLUSIONS

We found that GBM tumors harboring EGFR and/or RB1 alterations have better survival compared to tumors that are EGFR/RB1 wild-type. Moreover, PDGFR alterations worsens survival in EGFR altered GBM. This data provides further insights that might guide targeted therapies in IDHwt GBM.

RARE-23. HIGH DOSE METHOTREXATE WITH OR WITHOUT VINCRISTINE FOR PRIMARY CNS LYMPHOMA, THE OHIO STATE UNIVERSITY EXPERIENCE

OBJECTIVES

1) Determine the response rate (RR) after chemotherapy with high-dose methotrexate with or without vincristine in patients with primary CNS lymphoma. 2) Determine the difference in adverse effects with the use of vincristine. 3) Determine the difference in progression-free survival (PFS) and overall survival (OS) between the 2 groups.

METHODS

Retrospective study in patients 18–89 years with primary CNS lymphoma that received chemotherapy with rituximab (R), methotrexate (M), procarbazine (P), and vincristine (V) R-MPV, R-MV, R-MP, or R-M between 2010 and 2018 at The Ohio State University. Response rate by cycle 7 was compared with odds ratio. Kaplan-Meier curves were used to compare OS and PFS.

RESULTS

29 patients were included: 16 (55%) received vincristine. 14/16 patients treated with vincristine and 4/13 in the other group also had procarbazine. 12/29 patients had a complete response after a maximum of 7 cycles. The odds of complete response were 24% higher in patients treated with vincristine but the difference did not reach statistical significance. Side effects were higher in the vincristine arm. The most common was peripheral neuropathy (75% vs 8% - all grades). Median PFS was 60.7 months for the vincristine group and 23.7 months for the non-vincristine group. Median OS was 85.3 months for the vincristine group and 67.1 months for the non-vincristine group. OS and PFS curves did not differ significantly.

CONCLUSIONS

The use of vincristine in high-dose methotrexate chemotherapy regimens for CNS lymphoma was not associated with a statistically significant difference in RR. Patients who received vincristine had more side effects and there were no significant differences in OS and PFS. The sample size and rate of procarbazine use may be confounding factors. Further studies are necessary to determine the effect of vincristine in RR and OS in these patients.