Brastianos, Priscilla K.

Abstract Background Meningiomas lack effective therapies for recurrent or aggressive disease. NF2 inactivation, commonly in meningioma, may sensitize tumors to FAK inhibition and interact with MAPK signaling. This study investigated the therapeutic activity of defactinib (FAK inhibitor) and avutometinib (RAF/MEK inhibitor) alone and in combination in preclinical meningioma models. Methods MAPK-altered meningioma cell lines, IOMM-Lee (NF2 wild-type, BRAF p.V600E) and CH157-MN (NF2 mutant, NRAS p.Q61K), BenMen-1 (NF2 mutant, MAPK wild-type), and three patient-derived NF2 mutant cell lines were cultured in matrigel and treated with defactinib and avutometinib in 3D cell viability assays. In vivo, flank and intracranial xenograft models of IOMM-Lee and CH157-MN were treated with VS-4718 (FAK inhibitor, superior pharmokinetics in mice), avutometinib, or combination. Tumor growth, survival, and pharmacokinetic/pharmacodynamic properties were assessed. Results In vitro, combination therapy showed synergistic or additive effects in CH157-MN and IOMM-Lee cells, respectively. Defactinib alone demonstrated activity in NF2-mutant patient-derived and BenMen-1 cells, while avutometinib did not. In vivo, avutometinib monotherapy suppressed tumor growth and extended survival in both flank and intracranial xenograft models, with evidence of favorable pharmacokinetic properties and target pathway inhibition in intracranial tumors. Combination therapy provided enhanced and sustained control of flank CH157-MN meningioma compared to avutometinib alone but did not significantly improve survival over avutometinib alone in intracranial models. Conclusions Avutometinib demonstrated robust anti-tumor effects in flank and intracranial models of MAPK-altered meningioma. Combination benefits were context dependent. Defactinib activity in NF2-mutant patient-derived cells without targetable MAPK-kinase alterations highlights the importance of genomic biomarkers to guide personalized strategies.

Abstract Background DNA methylation profiling can be used to robustly predict postsurgical outcomes and response to radiotherapy (RT) for meningioma patients. To allow for seamless integration of these complementary models into clinical practice, a practical framework is needed. Methods We leveraged a cohort of nearly 2000 surgically-treated meningiomas with DNA methylation profiling and clinical outcomes data. Existing methylation-based prediction models were dichotomized to yield four risk groups: low and high recurrent risk, each with RT sensitive and resistant subgroups. Risk groups were correlated with progression-free survival in the context of existing biomarkers including extent of resection and WHO grade. Results We first demonstrated that all risk groups benefit from gross total resection. All “high-risk, RT sensitive” tumors (n = 306, 15.7%) also benefited from adjuvant RT: after GTR, median PFS increased from 4.68 (4.13-9.48) years to not reached (P = .003); after subtotal resection (STR), from 2.12 (1.59-3.02) to 4.09 (3.41-not reached) years (P = .004). “Low-risk, RT sensitive cases” (n = 1207, 61.8%) also benefited from RT after STR (median PFS 7.39 (6.66-12.8) vs. 16.53 (10.35-not reached) years, P = .03), suggesting that RT be considered in these patients. Neither “low-risk RT resistant” (n = 84, 4.3%) nor “high-risk RT resistant” (n = 356, 18.2%) cases benefited from RT, and the latter group was associated with universally poor outcomes. Conclusions We identify methylation-defined risk groups of meningioma for which additional benefit is gained from adjuvant RT, leading to a clinical decision-making framework for straightforward integration of molecular models into clinical practice.

Abstract BACKGROUND Craniopharyngiomas are a rare tumor along the pituitary-hypothalamic axis. Genetic analysis revealed that 95% of papillary craniopharyngiomas (PCP) have BRAF V600E mutations (Brastianos et al. Nature Genetics 2014). We previously reported that BRAF/MEK inhibition was associated with significant anti-tumor activity in newly-diagnosed PCP patients (Brastianos et al. NEJM 2023). We have now evaluated the efficacy of vemurafenib/cobimetinib in a separate cohort of patients with recurrent PCP whose tumors progressed after prior radiation. METHODS In this multicenter, NCI-sponsored cooperative group trial, patients with histologically confirmed BRAF-positive PCP who progressed after radiation were treated with vemurafenib/cobimetinib. The primary endpoint of response rate (RR) based on centrally determined imaging data was to be evaluated in 16 patients, where a partial response was defined as ≥20% decrease in volume. This single arm, Simon two-stage phase 2 trial had 89% power to detect a true RR ≥ 30% (vs. null 5%; α=0.04). In this design, 3 or more observed responses in 16 evaluable patients would be considered evidence of promising activity. RESULTS Of the planned 16 patients, a total of 5 patients enrolled before the study was closed due to slow accrual. Median follow-up was 50 months (95% CI: 32 to not yet reached). Based on volumetric response criteria, all 5 patients had a response to treatment (100%; 95% CI: 47.8% to 100%). To date, 2 patients progressed, one of whom died 22 months after study entry. This cohort met the criteria for efficacy under the original design with >3 responders. No grade 4 or 5 toxicities were observed. CONCLUSIONS Vemurafenib/cobimetinib resulted in an objective response in all patients with previously treated PCP. The study met primary endpoint, similar to that reported for previously untreated PCP. Thus, BRAF/MEK inhibitors could be an effective tool for previously treated PCP and warrants further evaluation. SUPPORT U10CA180821; U10CA180882; Genentech, https://acknowledgments.alliancefound.org;ClinicalTrials.gov: NCT03224767

Abstract BACKGROUND High-grade and recurrent meningiomas frequently demonstrate aggressive behavior and therapeutic resistance, with limited treatment options. Dysregulation of the MAPK and FAK pathways drive meningioma progression, but compensatory activation between these pathways could limit single agent efficacy. Recently, a clinical trial (Alliance A071401) showed encouraging efficacy of single-agent FAK inhibition in recurrent/progressive meningioma (Brastianos et al, JCO 2023). This preclinical study aimed to evaluate the therapeutic potential of dual RAF/MEK (avutometinib) and FAK (VS-4718) inhibition in suppressing tumor growth and improving survival in intracranial meningioma models. METHODS Orthotopic intracranial models were established by injecting IOMM-Lee (Fluc-mCherry) or CH157-MN (eGFP-LUC2) cells into nu/nu mice. Mice were randomized into four groups: vehicle, VS-4718 (murine formulation of defactinib, 50 mg/kg, BID), avutometinib (0.3 mg/kg, QD), or combination therapy. Treatments were administered for a 4-week period. Tumor growth was monitored via bioluminescent imaging (BLI) at baseline, midpoint, and study endpoint. Pharmacokinetic (PK) and pharmacodynamic (PD) effects were assessed by intratumoral drug concentrations and Western blotting for p-ERK and p-AKT, respectively. RESULTS In the NF2-mutant CH157-MN model, avutometinib increased median survival from 12.5 to 20.5 days (p=0.001), while combination therapy extended survival further to 22 days (p<0.0001 vs vehicle). Similarly, in the NF2-wildtype IOMM-Lee model, avutometinib raised survival from 27.5 to 33 days (p=0.0237), with combination therapy reaching 34.5 days (p=0.0057 vs vehicle). VS-4718 monotherapy did not extend survival in both models. BLI demonstrated significant inhibition of tumor growth in both avutometinib and combination groups in both tumor models. PK analysis revealed Kp values of 0.26–0.37 for avutometinib and 0.46–0.50 for VS-4718 in orthotopic tumor tissue. Furthermore, combination therapy lowered p-ERK in tumors (p=0.001) compared to vehicle. CONCLUSION Dual RAF/MEK and FAK inhibitor therapy blocks MAPK activation and enhances survival in orthotopic meningioma models, supporting further clinical evaluation for aggressive meningiomas.

Importance Molecular techniques, including next-generation sequencing, genomic copy number profiling, fusion transcript detection, and genomic DNA methylation arrays, are now indispensable tools for the workup of central nervous system (CNS) tumors. Yet there remains a great deal of heterogeneity in using such biomarker testing across institutions and hospital systems. This is in large part because there is a persistent reluctance among third-party payers to cover molecular testing. The objective of this Review is to describe why comprehensive molecular biomarker testing is now required for the accurate diagnosis and grading and prognostication of CNS tumors and, in so doing, to justify more widespread use by clinicians and coverage by third-party payers. Observations The 5th edition of the World Health Organization (WHO) classification system for CNS tumors incorporates specific molecular signatures into the essential diagnostic criteria for most tumor entities. Many CNS tumor types cannot be reliably diagnosed according to current WHO guidelines without molecular testing. The National Comprehensive Cancer Network also incorporates molecular testing into their guidelines for CNS tumors. Both sets of guidelines are maximally effective if they are implemented routinely for all patients with CNS tumors. Moreover, the cost of these tests is less than 5% of the overall average cost of caring for patients with CNS tumors and consistently improves management. This includes more accurate diagnosis and prognostication, clinical trial eligibility, and prediction of response to specific treatments. Each major group of CNS tumors in the WHO classification is evaluated and how molecular diagnostics enhances patient care is described. Conclusions and Relevance Routine advanced multidimensional molecular profiling is now required to provide optimal standard of care for patients with CNS tumors.

Abstract BACKGROUND Patients with meningiomas that have progressed after surgery and/or radiation have limited treatments. Loss of NF2 and CDKN2A/B are common in higher-grade meningiomas and promote meningioma progression. We evaluated the efficacy of abemaciclib, a cyclin-dependent kinase (CDK) 4/6 inhibitor, as part of Alliance A071401, a genomically-driven phase II trial in recurrent or progressive meningiomas. METHODS Eligible patients (pts) with grade 2/3 tumors and NF2 mutations or CDK pathway alterations were treated with abemaciclib 200 mg orally twice daily. Two co-primary endpoints were used: progression-free survival at 6 months (PFS6) and response rate (RR); the trial would be declared positive if either endpoint was met. Twenty-four evaluable pts provided ≥85% power to detect a PFS6 ≥41.5% (vs. null 15%; alpha=0.02), and ≥89% power to detect RR ≥20% (vs. null 2.5%; alpha=0.021). RESULTS Of 83 pts screened while the abemaciclib arm was open between September 15, 2021 and October 3, 2022, 36 eligible pts received abemaciclib. The observed PFS6 rate in the first 24 evaluable pts was 54% (95% CI 33-75%), thus the study met PFS6 endpoint. Of all 35 evaluable pts, median PFS was 7.6 months (95% CI 3.6-17.1 months), estimated 6-month PFS was 55% (95% CI 40-75%) and estimated 6-month OS was 88% (95% CI 77-100%). No objective responses were observed. Of the 36 pts who started treatment, two had a grade 4 adverse event at least possibly related to treatment which included ALT elevation(1), AST elevation(1) and vomiting(1). Patients with NF2 alterations (n=24) had favorable PFS6 outcomes (58%, 95% CI 37-78%) compared to those with CDK (n=4, 25%, 95% CI 1-81%) and CDK+NF2 alterations (n=7, 29% 95% CI 4-71%), (Fisher’s Exact p=0.036). CONCLUSIONS Abemaciclib was well-tolerated and resulted in improved PFS6, meeting the trial’s co-primary endpoint. Abemaciclib warrants further investigation for the treatment of patients with progressive meningiomas.

Abstract BACKGROUND Patients with meningiomas who have progressed after multimodal treatments face a significant shortage of viable therapeutic options. Recent advancements in the molecular understanding of meningiomas have identified the FAK and RAF/MEK signaling pathways as potential promising targets for progressive meningiomas. METHODS In vitro, we tested two human meningioma cell lines, IOMM-Lee (NF2 wild-type and CDKN2A loss) and CH157-MN (NF2 mutant). The cells were plated in Matrigel-coated wells, treated with defactinib (FAK inhibitor), VS-6766 (RAF/MEK inhibitor, avutometinib) and the combination over a 7-day period and assessed for cell viability using the CellTiter-Glo 3D assay. In vivo, we tested the efficacy of the FAK inhibitor VS-4718 (possessing favorable pharmacokinetic properties in mice) and RAF/MEK inhibitor VS-6766, both given daily via oral gavage, in athymic nude mice bearing IOMM-Lee or CH157-MN tumors. RESULTS In the matrigel assay, VS-6766 suppressed IOMM-Lee and CH157-MN cells in a dose dependent manner. The drug combination was mostly additive in IOMM-Lee cells. However, CH157-MN cells showed a strong synergistic response across all drug concentrations tested. In the IOMM-Lee flank tumor model, VS-4718 alone had no effect, while VS-6766 alone or in combination significantly reduced tumor growth and extended median survival from 25 days to 47 days (p < 0.05). In the CH157 flank tumor model, VS-4718 monotherapy did not affect tumor growth or survival, but VS-6766 monotherapy slowed tumor growth and increased median survival from 10 days to 31 days (p < 0.001). Combining both drugs further reduced tumor growth and extended median survival to 42 days (p < 0.001). CONCLUSION Treatment with FAK and RAF/MEK inhibitors showed synergistic or combination effects in the NF2 mutant CH157-MN model in vitro and in vivo. RAF/MEK inhibitor monotherapy was effective for the IOMM-Lee model (NF2 wild-type), without clear benefit of combining with the FAK inhibitor. Investigations in intracranial tumor models are underway.

Abstract Meningiomas are the most frequent primary intracranial tumors. Hence, they constitute a major share of diagnostic specimens in neuropathology practice. The 2021 WHO Classification of Central Nervous System Tumors (“CNS5”) has introduced the first molecular grading parameters for meningioma with oncogenic variants in the TERT promoter and homozygous deletion of CDKN2A/B as markers for CNS WHO grade 3. However, after the publication of the new classification volume, clarifications were requested, not only on novel but also on long-standing questions in meningioma grading that were beyond the scope of the WHO “blue book.” In addition, more recent research into possible new molecular grading parameters could not yet be implemented in the 2021 classification but constitutes a compelling body of literature. Hence, the consortium to inform molecular and practical approaches to CNS tumor taxonomy-not official WHO (cIMPACT-NOW) Steering Committee convened a working group to provide such clarification and assess the evidence of possible novel molecular criteria. As a result, this cIMPACT-NOW update provides guidance for more standardized morphological evaluation and interpretation, most prominently pertaining to brain invasion, identifies scenarios in which advanced molecular testing is recommended, proposes to assign CNS WHO grade 2 for cases with CNS WHO grade 1 morphology but chromosomal arm 1p deletion in combination with 22q deletion and/or NF2 oncogenic variants, and discusses areas in which the current evidence is not yet sufficient to result in new recommendations.

2001 Background: Systemic treatments are limited for patients with meningiomas that have progressed after surgery and/or radiation. Loss of NF2and CDKN2A/Bare common in higher grade meningiomas and promote meningioma progression in preclinical models. We evaluated the efficacy of abemaciclib, a cyclin-dependent kinase (CDK) 4/6 inhibitor, as part of Alliance umbrella trial A071401, a genomically driven phase II study in recurrent or progressive meningiomas. Methods: Eligible patients (pts) with grade 2/3 tumors and NF2 mutations or CDK pathway alterations were treated with abemaciclib 200 mg orally twice daily until progressive disease. Two co-primary endpoints were used: progression-free survival at 6 months (PFS6) and response rate (RR) by Macdonald criteria; the trial would be declared positive if either endpoint was met. Twenty-four evaluable pts provided >85% power to detect a PFS6 >41.5% (vs. null 15%; alpha =0.02). The threshold for promising results for PFS6 was 8+/24 pts. For RR, 24 evaluable pts provided >89% power to detect RR >20% (vs. null 2.5%; alpha = 0.021). The threshold for promising results for RR was 3+/24 pts. Results: Of 83 pts screened while the abemaciclib arm was open between September 15, 2021 and October 3, 2022, 36 eligible pts received treatment. The mean number of treatment cycles administered was 7 and median follow-up since start of treatment was 11 months. The first 24 pts that met eligibility criteria and began treatment were considered evaluable for the primary endpoint analysis. Of the 24 pts evaluated, 58% were female and the median age was 62 years. The observed PFS6 rate was 54% (13/24 pts, 95% confidence interval 33-75%), thus the study met PFS6 endpoint. No objective responses were observed. Of the 36 pts who started treatment, eight had a grade 3 and two had a grade 4 adverse event at least possibly related to treatment. Grade 3 toxicities included anemia (2), neutropenia (2), leukopenia (1), blurry vision (1), diarrhea (2), fatigue (2), ALT elevation (1), dehydration (1), hyperkalemia (1), hyponatremia (1), dizziness (1), acute kidney injury (1), and thromboembolic event (1). Grade 4 toxicities included ALT elevation (1), AST elevation (1) and vomiting (1). Conclusions: Abemaciclib was well tolerated and resulted in an improved PFS6. The overall trial endpoint was met. Abemaciclib warrants further investigation for the treatment of patients with progressive grade 2/3 meningiomas. Support: U10CA180821, U10CA180882; UG1CA189867 (NRG Oncology); Eli Lilly; https://acknowledgments.alliancefound.org . Clinical trial information: NCT02523014 .

AbstractMeningeal solitary fibrous tumors (SFT) are rare and have a high frequency of local recurrence and distant metastasis. In a cohort of 126 patients (57 female, 69 male; mean age at surgery 53.0 years) with pathologically confirmed meningeal SFTs with extended clinical follow‐up (median 9.9 years; range 15 days–43 years), we performed extensive molecular characterization including genome‐wide DNA methylation profiling (n = 80) and targeted TERT promoter mutation testing (n = 98). Associations were examined with NAB2::STAT6 fusion status (n = 101 cases; 51 = ex5‐7::ex16‐17, 26 = ex4::ex2‐3; 12 = ex2‐3::exANY/other and 12 = no fusion) and placed in the context of 2021 Central Nervous System (CNS) WHO grade. NAB2::STAT6 fusion breakpoints (fusion type) were significantly associated with metastasis‐free survival (MFS) (p = 0.03) and, on multivariate analysis, disease‐specific survival (DSS) when adjusting for CNS WHO grade (p = 0.03). DNA methylation profiling revealed three distinct clusters: Cluster 1 (n = 38), Cluster 2 (n = 22), and Cluster 3 (n = 20). Methylation clusters were significantly associated with fusion type (p < 0.001), with Cluster 2 harboring ex4::ex2‐3 fusion in 16 (of 20; 80.0%), nearly all TERT promoter mutations (7 of 8; 87.5%), and predominantly an “SFT” histologic phenotype (15 of 22; 68.2%). Clusters 1 and 3 were less distinct, both dominated by tumors having ex5‐7::ex16‐17 fusion (respectively, 25 of 33; 75.8%, and 12 of 18; 66.7%) and with variable histological phenotypes. Methylation clusters were significantly associated with MFS (p = 0.027), but not overall survival (OS). In summary, NAB2::STAT6 fusion type was significantly associated with MFS and DSS, suggesting that tumors with an ex5::ex16‐17 fusion may have inferior patient outcomes. Methylation clusters were significantly associated with fusion type, TERT promoter mutation status, histologic phenotype, and MFS.