Giannini, Caterina

Abstract Methylation profiling has revealed unexpected relationships between traditional histopathology-based versus biologically-based classifications of brain tumors. Methylation class pleomorphic xanthoastrocytoma (mcPXA) comprises tumors with the same methylation signature as classical PXA but with additional morphologic patterns, including overlap with glioblastoma (GBM). To characterize mcPXA, we examined epidemiologic, histologic, and molecular features as well as clinical behavior of a cohort (n=313) of tumors matching to mcPXA by the DKFZ classifier (v12 score >= 0.85). Patient median age was 19 (range 1-73) with a female predominance (178 female/135 male). CDKN2A/B homozygous deletion was observed in 273 (87%) cases. In the subset of cases tested for BRAF p.V600E (n=120), 111 (93%) harbored the mutation. Concomitant chr7+/chr10- was observed in 66 (21%) cases. In the subset of cases tested for TERT promoter mutations (n=50), 11 (22%) harbored the mutation, always with co-occurrence of BRAF p.V600E (11/11) and infrequently with chr7+/chr10- (3/11). MGMT promoter methylation was observed in 40 (13%) cases. Overall and progression-free survival (OS, PFS) in mcPXA were similar to grade 2-3 IDH-mutant astrocytoma (A-IDH). Prognostic factors in mcPXA included GBM-like histopathology (defined as cases diagnosed as GBM prior to methylation profiling), concomitant chr7+/chr10-, and MGMT promoter methylation. GBM-like histopathology was associated with shorter OS (p=0.02) and PFS (p< 0.01) compared to cases without GBM-like histopathology. Concomitant chr7+/chr10- was associated with shorter PFS (p=0.02), and MGMT promoter methylation was associated with shorter OS (p=0.03). Our findings demonstrate that mcPXA tumors affect adolescents and young adults, share molecular features of classical PXA, and manifest clinical behavior similar to classical PXA, but subsets of tumors with atypical features (chr7+/chr10-, MGMT promoter methylation, and/or GBM-like histopathology) are more aggressive. The use of a molecular definition of PXA reveals that this tumor type is more common than previously appreciated and warrants in-depth study for therapeutic options.

Abstract WSD0922-Fu is an oral, CNS-penetrant, small molecule EGFR inhibitor which potently inhibits EGFR aberrations specific to non-small cell lung cancer (NSCLC) and high-grade astrocytoma (HGA). MC1914 (NCT04197934) is a first-in-human phase 1 trial in patients with EGFR aberrant recurrent HGA and NSCLC. Adult patients with either recurrent EGFR mutant NSCLC with CNS metastases or recurrent EGFR aberrant HGA were enrolled and treated across six cohorts (40 mg once daily to 320 mg twice daily, 28-day cycles) to determine the maximum tolerated dose (MTD). 25 patients (17 HGA, 8 NSCLC) were enrolled (median age = 57 years; 24% female; 36% ECOG 0). All patients with HGA received prior radiation and temozolomide. All patients with NSCLC had previous disease progression on EGFR inhibitor therapy (prior osimertinib 88%). The median duration of WSD0922-Fu exposure among all patients was 55 days (range 3 to >279 days) [NSCLC median = 131 days; HGA median = 51 days]. Common treatment-related adverse events are comparable to other EGFR inhibitors (fatigue, acneiform rash, diarrhea, nausea, pruritis). At Cycle 1 Day 15 for patients treated at MTD (160 mg twice daily), the mean terminal elimination half-life (%CV) in the plasma was 31.6 h (102%) (median 14.5 h). The mean Cmax, Tmax, oral clearance at steady state, and AUC (0-12 h) (%CV) were 4513 ng/mL (50%), 2.0 hr (69%), 6.9 L/hr/m2 (42%), and 28084 h*ng/mL (52%), respectively. Among patients with NSCLC treated at MTD or higher dose levels and with available response data, 100% (5/5) of patients demonstrated clinical benefit (SD + PR) while 60% of patients had partial responses. Intracranial and extracranial efficacy was concordant. Furthermore, prolonged stable disease (9 cycles) was observed in a patient with EGFRvIII mutant GBM. Expansion cohorts are in progress to optimize WSD0922-Fu dose and schedule for future phase 2 development.

Abstract Methylation profiling of brain tumors has revealed novel clusters whose biological and clinical significance is unknown. These include three entities termed by the 12.5 version of the Heidelberg methylation classifier as adult-type diffuse high grade glioma, IDH-wildtype, subtype B (HGG_B), subtype E (HGG_E), and subtype F (HGG_F). We have identified 75 cases belonging to these groups: HGG_B (25 cases, 32% female), HGG_E (40 cases, 42% female), and HGG_F (18 cases, 33% female). Although originally characterized as “adult-type,” we find that 70% of HGG_E cases are pediatric, with a median age at diagnosis of 11 years. HGG_B cases are predominantly seen in young adults, and HGG_F in older adults. The histology varies among methylation classes, with HGG_B cases demonstrating high-grade, predominantly astrocytic, morphology, while HGG_E cases demonstrate high-grade glial histology with distinct nuclear features, and HGG_F cases show highly infiltrative but lower grade glial morphology. Patient outcome data obtained to date shows a collective median survival exceeding 5 years, suggesting re-consideration of the proposed grading for these tumors. MGMT promoter methylation differs across the HGG_B (0%), HGG_E (12%), and HGG_F (0%) subtypes. Mutational analyses show enrichment of TERT promoter mutations in the HGG_F group, while HGG_E samples are enriched for tumors with POLE mutations and elevated tumor mutation burden. HGG_E tumors show epigenetic similarity to pediatric high-grade diffuse gliomas (pedHGG_RTK1A); we therefore propose that HGG_E be considered a pediatric-type HGG. HGG_B tumors show demographic and genomic similarities to high-grade astrocytomas with piloid features, including a subset of cases with CDKN2A/2B loss and ATRX mutation. HGG_F separate into two groups dictated by brain location, and despite the presence of TERT promoter mutations, appear distinct from GBMs. Overall, our work represents an initial effort to understand the morphologic, genomic and clinical characteristics of these previously uncharacterized subtypes of gliomas.

The European Stroke Organisation (ESO) guideline on Primary Angiitis of the Central Nervous System (PACNS), developed according to ESO standard operating procedures (SOP) and Grading of Recommendations, Assessment, Development and Evaluation (GRADE) methodology, was elaborated to assist clinicians in the diagnostic and treatment pathway of patients with PACNS in their decision making. A working group involving vascular neurologists, neuroradiologists, rheumatologists, a neuropathologist and a methodologist identified 17 relevant clinical questions; these were addressed according to the patient/population, intervention, comparison and outcomes (PICO) framework and systematic literature reviews were performed. Notably, each PICO was addressed with respect to large vessel (LV)-PACNS and small vessel (SV)-PACNS. Data to answer many questions were scarce or lacking and the quality of evidence was very low overall, so, for some PICOs, the recommendations reflect the ongoing uncertainty. When the absence of sufficient evidence precluded recommendations, Expert Consensus Statements were formulated. In some cases, this applied to interventions in the diagnosis and treatment of PACNS which are embedded widely in clinical practice, for example patterns of cerebrospinal fluid (CSF) and Magnetic Resonance Imaging (MRI) abnormalities. CSF analysis for hyperproteinorrachia and pleocytosis does not have evidence supporting their use as diagnostic tools. The working group recommended that caution is employed in the interpretation of non-invasive vascular imaging due to lack of validation and the different sensitivities in comparison with digital subtraction angiography (DSA) and histopathological analyses. Moreover, there is not a neuroimaging pattern specific for PACNS and neurovascular issues are largely underreported in PACNS patients. The group’s recommendations on induction and maintenance of treatment and for primary or secondary prevention of vascular events also reflect uncertainty due to lack of evidence. Being uncertain the role and practical usefulness of current diagnostic criteria and being not comparable the main treatment strategies, it is suggested to have a multidisciplinary team approach in an expert center during both work up and management of patients with suspected PACNS. Highlighting the limitations of the currently accepted diagnostic criteria, we hope to facilitate the design of multicenter, prospective clinical studies and trials. A standardization of neuroimaging techniques and reporting to improve the level of evidence underpinning interventions employed in the diagnosis and management of PACNS. We anticipate that this guideline, the first comprehensive European guideline on PACNS management using GRADE methodology, will assist clinicians to choose the most effective management strategy for PACNS.