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Primary central nervous system lymphoma (PCNSL) is a rare extranodal lymphomatous malignancy that affects the brain, spinal cord, leptomeninges, or vitreoretinal space, without evidence of systemic involvement. The diagnosis of PCNSL requires a high level of suspicion because clinical presentation varies depending upon involved structures. Initiation of treatment is time sensitive for optimal neurologic recovery and disease control. In general, the prognosis of PCNSL has improved significantly over the past few decades, largely as a result of the introduction and widespread use of high-dose methotrexate (MTX) chemotherapy, which is considered the backbone of first-line polychemotherapy treatment. Upon completion of MTX-based treatment, a consolidation strategy is often required to prolong duration of response. Consolidation can consist of radiation, maintenance therapy, nonmyeloablative chemotherapy, or myeloablative treatment followed by autologous stem cell transplant. Unfortunately, even with consolidation, relapse is common, and 5-year survival rates stand at only 30% to 40%. Novel insights into the pathophysiology of PCNSL have identified key mechanisms in tumor pathogenesis, including activation of the B-cell receptor pathway, immune evasion, and a suppressed tumor immune microenvironment. These insights have led to the identification of novel small molecules targeting these aberrant pathways. The Bruton tyrosine kinase inhibitor ibrutinib and immunomodulatory drugs (lenalidomide or pomalidomide) have shown promising clinical response rates for relapsed/refractory PCNSL and are increasingly used for the treatment of recurrent disease. This review provides a discussion of the clinical presentation of PCNSL, the approach to work-up and staging, and an overview of recent advancements in the understanding of the pathophysiology and current treatment strategies for immunocompetent patients.

Supplementary Methods. Supplementary Table S1: Baseline characteristics of PCNSL Patients. Supplementary Table S2: Baseline characteristics of SCNSL patients. Supplementary Table S3: Corticosteroid use. Supplementary Table S4: Genes with Recurrent Mutations in PCNSL (non-aSHM). Supplementary Table S5: Genes that are targeted by aSHM in PCNSL. Supplementary Table S6: Comparison of mutation prevalence in current PCNSL genomic landscape analysis (red) with prior studies in PCNSL and DLBCL. Supplementary Table S7: Gene set enrichment analysis of CD79B-mutant PCNSLs compared to CD79B-wildtype PCNSLs. Supplementary Figure S1: Ibrutinib concentrations in Cerebrospinal Fluid (CSF). Supplementary Figure S2: Comparison of mutation frequencies in PCNSL and DLBCL outside the CNS. Supplementary Figure S3: Cell-of-origin (COO) Markers in PCNSL. Supplementary Figure S4: CD79B-mutant PCNSL xenograft models. Supplementary Figure S5: Comparison of PCNSL cells with non-CNS DLBCL cell lines. Supplementary Figure S6: Inhibition of individual PI3K isoforms does not induce cell death in CD79B-mutant PCNSL cells. Supplementary Figure S7: In-vitro effects of ibrutinib on CD79B-mutant PCNSL cells.

mp3 file (11 MB). In the May edition of the Cancer Discovery podcast, Science Writer Elizabeth McKenna talks with Ingo K. Mellinghoff about his paper, which suggests that the disappointing clinical activity of first-generation EGFR inhibitors in glioblastoma versus lung cancer may be attributed to the different conformational requirements of mutant EGFR in these two cancer types.

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Purpose:The genomic landscape of gliomas has been characterized and now contributes to disease classification, yet the relationship between molecular profile and disease progression and treatment response remain poorly understood.Experimental Design: We integrated prospective clinical sequencing of 1,004 primary and recurrent tumors from 923 glioma patients with clinical and treatment phenotypes.Results:Thirteen percent of glioma patients harbored a pathogenic germline variant, including a subset associated with heritable genetic syndromes and variants mediating DNA repair dysfunctions (29% of the total) that were associated with somatic biallelic inactivation and mechanism-specific somatic phenotypes. In astrocytomas, genomic alterations in effectors of cell-cycle progression correlated with aggressive disease independent of IDH mutation status, arose preferentially in enhancing tumors (44% vs. 8%, P < 0.001), were associated with rapid disease progression following tumor recurrence (HR = 2.6, P = 0.02), and likely preceded the acquisition of alkylating therapy-associated somatic hypermutation. Thirty-two percent of patients harbored a potentially therapeutically actionable lesion, of whom 11% received targeted therapies. In BRAF-mutant gliomas, response to agents targeting the RAF/MEK/ERK signaling axis was influenced by the type of mutation, its clonality, and its cellular and genomic context.Conclusions:These data reveal genomic correlates of disease progression and treatment response in diverse types of glioma and highlight the potential utility of incorporating genomic information into the clinical decision-making for patients with glioma.

Table S1: Patient-level clinical annotation. Table S2: Sample-level clinical annotation. Table S3: Patient-level treatment lines. Table S4: Gene panels for targeted sequencing. Table S5: Somatic mutations. Table S6: Gene-level copy number alterations. Table S7: Hotspot mutations in 3,130 sequenced glioma patients. Table S8: Pathogenic and likely pathogenic germline variants identified. Table S9: Pathways and gene content for cohort-wide pathway-level analyses.

Supp. Fig.1. CONSORT Flow Diagram Supp. Fig.2. MRI Perfusion Parameters Supp. Fig. 3. Immunohistochemistry Supp. Fig. 4. Gene Expression Profile Supp. Table 1. Adverse Events Supp. Table 2. Pharmacokinetic Data Supp. Table 3. Molar Drug Levels Supplemental Methods

Figure S1: Distribution of systemic therapies received. Figure S2: Number of sequenced samples per patient. Figure S3: Subgroup-defining genomic lesions in IDH-wildtype and -mutant gliomas. Figure S4: Frequency of mutations in primary tumors. Figure S5: Frequency of glioma type-defining genes. Figure S6: Outcome by enhancement and cell-cycle alteration status. Figure S7: Alteration of key functional groups in IDH-WT astrocytic tumors. Figure S8: Cell-cycle alterations and outcome in 1p19q-intact IDH WT tumors. Figure S9: Rate of alkylating therapy-induced hypermutation by WHO class. Figure S10: Frequency of actionable alterations. Figure S11: BRAF hotspot mutations in glioma. Figure S12: MR brain images for three patients receiving MAPK-directed therapy.

Purpose: Bevacizumab is associated with decreased vascular permeability that allows for more aggressive radiotherapy schedules. We conducted a phase II trial in newly diagnosed glioblastoma utilizing a novel hypofractionated stereotactic radiotherapy (HFSRT) schedule combined with temozolomide and bevacizumab.Experimental Design: Patients with tumor volume ≤60 cc were treated with HFSRT (6 × 6 Gy to contrast enhancement and 6 × 4 Gy to FLAIR hyperintensity with dose painting) combined with concomitant/adjuvant temozolomide and bevacizumab at standard doses. Primary endpoint was 1-year overall survival (OS): promising = 70%; nonpromising = 50%; α = 0.1; β = 0.1.Results: Forty patients were enrolled (median age: 55 years; methylated MGMT promoter: 23%; unmethylated: 70%). The 1-year OS was 93% [95% confidence interval (CI), 84–100] and median OS was 19 months. The median PFS was 10 months, with no pseudo-progression observed. The objective response rate (ORR) was 57%. Analysis of The Cancer Genome Atlas glioblastoma transcriptional subclasses (Nanostring assay) suggested patients with a proneural phenotype (26%) fared worse (ORR = 14%, vs. 77% for other subclasses; P = 0.009). Dynamic susceptibility-contrast perfusion MRI showed marked decreases in relative cerebral blood volume over time (P < 0.0001) but had no prognostic value, whereas higher baseline apparent diffusion coefficient (ADC) ratios and persistent hypermetabolism at the 6-month FDG-PET predicted poor OS (P = 0.05 and 0.0001, respectively). Quality-of-life (FACT-BR-4) and neuropsychological test scores were stable over time, although some domains displayed transient decreases following HFSRT.Conclusions: This aggressive radiotherapy schedule was safe and more convenient for patients, achieving an OS that is comparable with historical controls. Analysis of advanced neuroimaging parameters suggests ADC and FDG-PET as potentially useful biomarkers, whereas tissue correlatives uncovered the poor prognosis associated with the proneural signature in non–IDH-1–mutated glioblastoma. Clin Cancer Res; 20(19); 5023–31. ©2014 AACR.

Purpose: High-grade gliomas are associated with a dismal prognosis. Notch inhibition via the gamma-secretase inhibitor RO4929097 has emerged as a potential therapeutic option based on modulation of the cancer-initiating cell (CIS) population and a presumed antiangiogenic role.Experimental Design: In this phase 0/I trial, 21 patients with newly diagnosed glioblastoma or anaplastic astrocytoma received RO4929097 combined with temozolomide and radiotherapy. In addition to establishing the MTD, the study design enabled exploratory studies evaluating tumor and brain drug penetration and neuroimaging parameters. We also determined functional effects on the Notch pathway and targeting of CISs through analysis of tumor tissue sampled from areas with and without blood–brain barrier disruption. Finally, recurrent tumors were also sampled and assessed for Notch pathway responses while on treatment.Results: Treatment was well tolerated and no dose-limiting toxicities were observed. IHC of treated tumors showed a significant decrease in proliferation and in the expression of the Notch intracellular domain (NICD) by tumor cells and blood vessels. Patient-specific organotypic tumor explants cultures revealed a specific decrease in the CD133+ CIS population upon treatment. Perfusion MRI demonstrated a significant decrease in relative plasma volume after drug exposure. Gene expression data in recurrent tumors suggested low Notch signaling activity, the upregulation of key mesenchymal genes, and an increase in VEGF-dependent angiogenic factors.Conclusions: The addition of RO4929097 to temozolomide and radiotherapy was well tolerated; the drug has a variable blood–brain barrier penetration. Evidence of target modulation was observed, but recurrence occurred, associated with alterations in angiogenesis signaling pathways. Clin Cancer Res; 22(19); 4786–96. ©2016 AACR.

Supplementary Data 1 ELIGIBILITY CRITERIA. Supplementary Data 2 HYPOFRACTIONATED STEREOTACTIC RADIOTHERAPY PLANNING. Supplementary Data 3 MRI ACQUISITION PARAMETERS AND PROCESSING. Supplementary Data 4 Nanostring-based Tissue Correlates Methods. Supplementary Data 5 Number of patients experiencing Grades 3-5 treatment-related toxicities. Supplementary Data 6 Univariate analysis of DSC MR perfusion and diffusion MRI. Supplementary Data 7 NEUROPSYCHOLOGICAL TEST Z-SCORES, QUALITY OF LIFE, DEPRESSION AND FATIGUE SCORES OVER TIME.

List of Supplementary Data

Relapsed/refractory Primary Central Nervous System Lymphoma (R/R PCNSL) has a poor prognosis with no established preferred treatment. We report the efficacy and toxicity of a combination chemotherapy regimen: methotrexate, carmustine, etoposide, and prednisone with or without rituximab (RMBVP). This retrospective study included thirty patients who received a median of two 28-day cycles (0.5-5). The median age was 66 years (23-81); median KPS was 70 (30-90); 14 (46.7%) were women. Patients received a median of 2 prior lines of therapy and all received prior methotrexate. Of 29 evaluable patients, the overall response rate was 73.3% (n = 22). Median progression-free survival (PFS) was 15.6 months. Patients who recurred or progressed

A woman in her 70s experienced painless vision loss in the right eye for 1 month. Acute retinal necrosis-induced panuveitis was the referral diagnosis. With dense vitreous haze, a vitrectomy was performed for vitreous biopsy followed by multimodal imaging. Vitreous biopsy yielded negative PCR results for herpes viruses and only inflammatory cells. Post-vitrectomy imaging showed involuted but pervasive pigmentary foci in the outer retina and the retinal pigment epithelium. Concurrently, peripheral blood showed pancytosis with giant platelets and a Janus kinase 2 (

Objectives:To report on the tolerability and efficacy of olaparib with temozolomide (TMZ) for gliomaMethods:Single-center retrospective series of glioma patients treated with olaparib/TMZ September 2018-December 2021Results:Twenty patients (median age: 42, median Karnofsky Performance Status: 90) received olaparib/TMZ for diagnoses of IDH-mutant oligodendroglioma (n=5), IDH-mutant astrocytoma grade 2-3 (n=4), IDH-mutant astrocytoma grade 4 (n=7), or IDH-wildtype glioma (n=4). One patient was treated upfront and 19 at recurrence (median=3). Olaparib 150mg was administered three times/week concurrent with TMZ 50-75mg/m2 daily. Fatigue, gastrointestinal symptoms, and hematologic toxicity were common. 6/20 patients required dose reduction (n=4) or discontinuation (n=2) due to toxicity. Radiographic response was evaluable in 16 and observed (complete + partial) in 4/8 with IDH-mutant grade 2-3 glioma. No responses were seen in patients with grade 4 IDH-mutant astrocytomas (0/5) or IDH-wildtype gliomas (0/3). Progression-free survival was 7.8, 1.3, and 2.0 months, respectively.Discussion:Olaparib/TMZ resulted in objective radiographic response in 50% of evaluable patients with recurrent IDH-mutant grade 2-3 gliomas with encouraging PFS and manageable toxicity. This supports a prospective trial of olaparib/TMZ for this population.Classification of Evidence:This case series provides Class IV evidence that treatment with olaparib/TMZ may result in radiographic response in patients with glioma.

Current clinical and imaging tools remain suboptimal for predicting treatment response and prognosis in CNS lymphomas. We investigated the prognostic value of baseline [18F]FDG PET in patients with CNS lymphoma receiving ibrutinib-based treatments. Fifty-three patients enrolled in a prospective clinical trial and underwent brain PET before receiving single-agent ibrutinib or ibrutinib in combination with methotrexate with or without rituximab. [18F]FDG uptake in these lesions was quantified by drawing PET volumes of interest around up to five [18F]FDG-avid lesions per patient (with uptake greater than surrounding brain). We measured standardized uptake values (SUVmax), metabolic tumor volumes, total lesion glycolysis (TLG), and the sum thereof in these lesions. We analyzed the relationship between PET parameters and mutation status, overall response rates, and progression-free survival (PFS). Thirty-eight patients underwent single-agent therapy and 15 received combination therapy. On PET, 15/53 patients had no measurable disease. In the other 38 patients, a total of 71 lesions were identified on PET. High-intensity [18F]FDG uptake and a larger volume of [18F]FDG-avid disease were inversely related to treatment outcome (p ≤ 0.005). In univariable analysis, PFS was linearly correlated with all PET parameters, with stronger association when sum-values were used. A multivariable model showed that risk of progression increased by 9% for every 5-unit increase in sumSUVmax (hazard ratio = 1.09 [95% CI: 1.04 to 1.14]). Higher lesional metabolic parameters are inversely related to outcome in patients undergoing ibrutinib-based therapies, and sumSUVmax emerged as a strong independent prognostic factor. NCT02315326; https://clinicaltrials.gov/ct2/show/NCT02315326?term=NCT02315326&draw=2&rank=1

Advanced molecular and pathophysiologic characterization of primary central nervous system lymphoma (PCNSL) has revealed insights into promising targeted therapeutic approaches. Medical imaging plays a fundamental role in PCNSL diagnosis, staging, and response assessment. Institutional imaging variation and inconsistent clinical trial reporting diminishes the reliability and reproducibility of clinical response assessment. In this context, we aimed to: (1) critically review the use of advanced positron emission tomography (PET) and magnetic resonance imaging (MRI) in the setting of PCNSL; (2) provide results from an international survey of clinical sites describing the current practices for routine and advanced imaging, and (3) provide biologically based recommendations from the International PCNSL Collaborative Group (IPCG) on adaptation of standardized imaging practices. The IPCG provides PET and MRI consensus recommendations built upon previous recommendations for standardized brain tumor imaging protocols (BTIP) in primary and metastatic disease. A biologically integrated approach is provided to addresses the unique challenges associated with the imaging assessment of PCNSL. Detailed imaging parameters facilitate the adoption of these recommendations by researchers and clinicians. To enhance clinical feasibility, we have developed both “ideal” and “minimum standard” protocols at 3T and 1.5T MR systems that will facilitate widespread adoption.

INTRODUCTION Treatment of primary CNS lymphoma (PCNSL) has rapidly evolved, emphasizing improved efficacy while reducing neurotoxicity. PCNSL has historically been considered a multifocal disease and many patients relapse after first-line therapy. We evaluated relapse patterns in a large cohort of contemporarily treated patients. METHODS Consecutive PCNSL patients treated at MSKCC between 1983-2020 were analyzed. T1 post-contrast-enhancing disease on baseline MRI was characterized. Site of initial relapse was characterized as purely local (involving/adjacent to initial site) vs distant intraparenchymal, or other (e.g., both local and distant, systemic, ocular). Progression-free survival (PFS) was evaluated using Kaplan Meier methods. RESULTS Of 645 patients, 564 were eligible for analysis (diffuse large B-cell histology, sufficient data, ≥ 1 MRI response assessment). Median follow-up was 2.7 years (IQR 1.2-5.6). Median age was 63 years (range 19-90). Baseline disease was often supratentorial (420, 74%), multifocal (274, 49%), and bilateral (224, 40%). Fewer had leptomeningeal disease (94/430 CSF+, 22%; 117/559 radiographically positive, 21%). Most received methotrexate (MTX)-based induction (534, 96%), most commonly rituximab, MTX, procarbazine, vincristine (R-MVP; 257, 46%) or MVP (144, 26%). Overall, 286 (51%) patients relapsed with a median PFS of 2.1 years (95% CI 1.8-2.5). Of 275 characterizable relapses, 75 (27%) were exclusively local intraparenchymal, 91 (33%) were distant intraparenchymal, and 109 (40%) were other. Baseline unifocal disease often relapsed unifocally (66/118 baseline unifocal; 56%). Of 126 unifocal relapses, 45 (36%) were local. Of 202 patients with baseline supratentorial disease, 152 (75%) relapsed supratentorially. Unilateral relapses often remain ipsilateral (49% left- and 54% right-hemispheric lesions at baseline and relapse). CONCLUSIONS In a large PCNSL cohort, relapses often maintained baseline characteristics. For a disease historically considered multifocal, a substantial proportion of relapses were local. Future analyses will evaluate predictors of relapse, which can further efforts in informing personalization of treatment in the era of cellular therapies.

INTRODUCTION Treatment of brainstem tumors is often initiated without a tissue diagnosis due to the risk of biopsy. A subset of brainstem gliomas harbor an isocitrate dehydrogenase 1/2 (IDH) mutation, which predicts response to alkylator chemotherapy and IDH inhibitors; non-invasive diagnostic tests are needed to identify these mutations. METHODS We identified a cohort of patients with IDH-mutant brainstem gliomas through chart review of patients who underwent magnetic resonance spectroscopy (MRS) and/or brain biopsy. IDH mutation was established by biopsy, presence of a 2-hydroxyglutarate (2HG) peak on MRS, or identification on cerebrospinal fluid (CSF) sequencing of cell-free DNA (cfDNA). RESULTS We identified 15 patients with IDH-mutant brainstem gliomas, age range 5-48, 47% women. 15/15 were involving/abutting the brachium pontis, and 10/15 were non-enhancing at diagnosis. 13/15 patients were identified by biopsy, 1/15 by MRS and CSF, and 1/15 by MRS only. 10/13 patients with available data had a non-IDH1 R132H mutation in IDH1/2. 7/7 patients with MRS prior to radiation had a 2HG peak (MRS was concordant with tissue in all cases in which biopsy was obtained). 4/6 patients with MRS post-radiation retained a 2HG peak. 4 IDH-mutant tumors had sequencing of cfDNA and an IDH mutation was found in 2/4. Response data was available in 13/15 patients; all received radiation, 10 with concurrent temozolomide: best response was partial response in 8 and stable disease in 5. 4 patients received an IDH inhibitor: 2 patients after progression, and 2 as maintenance after radiation/temozolomide, achieving tumor control in all. For this cohort, median PFS was 71.4 months and median OS has not been reached. CONCLUSION IDH-mutant brainstem gliomas have a characteristic appearance, a high response rate to treatment, and a better overall prognosis than other brainstem tumors. MRS and CSF cfDNA sequencing allow for non-invasive diagnosis of IDH mutations in these patients.

BACKGROUND Emavusertib, an oral interleukin-1 receptor-associated kinase 4 (IRAK4) inhibitor, targets toll-like receptor (TLR) and interleukin-1 receptor (IL-1R) signaling pathway in B-cell proliferation. IRAK4 forms a Myddosome complex with MYD88 adaptor protein and drives overactivation of NF-κB, causing inflammation and tumor growth. Emavusertib has been reported to be well tolerated and active as monotherapy in heavily pretreated relapsed/refractory (R/R) non-Hodgkin lymphoma (NHL). In a murine PDX model of primary CNS lymphoma (PCNSL), emavusertib crossed the blood-brain barrier, resulting in tumor response and prolonged survival. In combination with Bruton tyrosine kinase (BTK) inhibitors, emavusertib showed in vivo anti-cancer synergy in B-cell NHL. METHODS This is an ongoing open-label trial (NCT03328078) in patients with R/R NHL. Currently, we are in the dose escalation portion of combination therapy to evaluate safety and efficacy following treatment of emavusertib at dose levels of 200 or 300mg BID with ibrutinib at full prescribed dose. As of May 6th, 2022, 13 patients have been treated with emavusertib+ibrutinib combination therapy. RESULTS Among the 13 patients, two were diagnosed with R/R PCNSL and had several prior lines of anti-cancer therapy. Emavusertib in combination with ibrutinib (560 mg daily) appeared to be well tolerated in these two subjects. One patient experienced Gr3 treatment-related adverse events (thrombocytopenia, muscle weakness, pain). The preliminary efficacy data demonstrated one CR and one SD. The patient who achieved CR after the combination therapy was originally intolerant to high-dose methotrexate based chemoimmunotherapy and did not achieve complete remission after switching to ibrutinib, providing early clinical evidence of CNS penetration and anti-tumor activity of emavusertib. CONCLUSION In R/R PCNSL, these preliminary data suggest that combination therapy has a tolerable safety profile with promising anti-cancer activity and may overcome ibrutinib resistance.

To optimise management of severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) infection identifying high-risk patients and maintaining treatment dose intensity is an important issue in patients with aggressive lymphomas. In the present study, we report on the presentation, management, and outcome of an international series of 91 patients with primary central nervous system lymphoma and SARS-CoV-2 infection. SARS-CoV-2 was diagnosed before/during first-line treatment in 64 patients, during follow-up in 21, and during salvage therapy in six. Among the 64 patients infected before/during first-line chemotherapy, 38 (59%) developed pneumonia and 26 (41%) did not clear the virus. Prolonged exposure to steroids before viral infection and/or treatment with high-dose cytarabine favoured pneumonia development and virus persistence and were associated with poorer survival; 81% of patients who did not clear virus died early from coronavirus disease 2019 (COVID-19). Vaccination was associated with lower pneumonia incidence and in-hospital mortality. Chemotherapy was initiated/resumed in 43 (67%) patients, more commonly among patients who did not develop pneumonia, cleared the virus, or did not receive steroids during infection. Chemotherapy resumption in patients with viral persistence should be indicated cautiously as it was associated with a poorer survival (6-month, 70% and 87%, p = 0.07). None of the 21 patients infected during follow-up died from COVID-19, requiring similar measures as infected subjects in the general population.

Purpose of review Primary central nervous system (CNS) lymphoma is a rare, aggressive extranodal non-Hodgkin lymphoma confined to the brain, eyes, CSF, or spinal cord without systemic, non-CNS involvement. This article reviews the clinical presentation, imaging characteristics, diagnostic workup, novel pathophysiologic insights, and treatment of immunocompetent patients with primary CNS lymphoma. Recent findings The prognosis of primary CNS lymphoma has significantly improved over the past few decades because of the introduction of and widespread use of high-dose methotrexate, which is now the backbone of all first-line combination chemotherapy treatments. Despite this progress, durable remission is still observed in only approximately 50% of patients. Novel insights into the pathophysiology of primary CNS lymphoma have identified the B-cell receptor pathway as well as the suppressed tumor immune microenvironment and immune evasion as key mechanisms in the pathogenesis of primary CNS lymphoma. Novel, small molecules and agents targeting these aberrant pathways have been introduced into clinical trials of recurrent/refractory primary CNS lymphomas. Agents such as the Bruton tyrosine kinase (BTK) inhibitor ibrutinib or immunomodulatory drugs such as lenalidomide and pomalidomide have shown promising response rates in the relapsed setting. Summary Diagnosis of primary CNS lymphoma requires a high level of suspicion because clinical signs and deficits can vary and depend on the involved CNS compartments. Rapid initiation of therapy is essential for recovery and prognosis. The optimal treatment regimen has not been defined, but methotrexate-based chemotherapy regimens are considered the standard treatment approach for induction treatment. Novel, targeted agents have recently been introduced into the therapeutic arsenal.

Primary central nervous system lymphomas (PCNSLs) are rare cancers of the central nervous system (CNS) and are predominantly diffuse large B-cell lymphomas of the activated B-cell (ABC) subtype. They typically present in the sixth and seventh decade of life, with the highest incidence among patients aged >75 years. Although many different regimens have demonstrated efficacy in newly diagnosed and relapsed or refractory PCNSL, there have been few randomized prospective trials, and most recommendations and treatment decisions are based on single-arm phase II trials or even retrospective studies. High-dose methotrexate (HD-MTX; 3–8 g/m2) is the backbone of preferred standard induction regimens. Various effective regimens with different toxicity profiles can be considered that combine other chemotherapies and/or rituximab with HD-MTX, but there is currently no consensus for a single preferred regimen. There is controversy about the role of various consolidation therapies for patients who respond to HD-MTX–based induction therapy. For patients with relapsed or refractory PCNSL who previously experienced response to HD-MTX, repeat treatment with HD-MTX–based therapy can be considered depending on the timing of recurrence. Other more novel and less toxic regimens have been developed that show efficacy in recurrent disease, including ibrutinib, or lenalidomide ± rituximab. There is uniform agreement to delay or avoid whole-brain radiation therapy due to concerns for significant neurotoxicity if a reasonable systemic treatment option exists. This article aims to provide a clinically practical approach to PCNSL, including special considerations for older patients and those with impaired renal function. The benefits and risks of HD-MTX or high-dose chemotherapy with autologous stem cell transplantation versus other, better tolerated strategies are also discussed. In all settings, the preferred treatment is always enrollment in a clinical trial if one is available.

Background Leptomeningeal metastases (LM) are associated with limited survival and treatment options. While involved-field radiotherapy is effective for local palliation, it lacks durability. We evaluated the toxicities of proton craniospinal irradiation (CSI), a treatment encompassing the entire central nervous system (CNS) compartment, for patients with LM from solid tumors. Methods We enrolled patients with LM to receive hypofractionated proton CSI in this phase I prospective trial. The primary endpoint was to describe treatment-related toxicity, with dose-limiting toxicity (DLT) defined as any radiation-related grade 3 non-hematologic toxicity or grade 4 hematologic toxicity according to the Common Terminology Criteria for Adverse Events that occurred during or within 4 weeks of completion of proton CSI. Secondary endpoints included CNS progression-free survival (PFS) and overall survival (OS). Results We enrolled 24 patients between June 2018 and April 2019. Their median follow-up was 11 months. Twenty patients were evaluable for protocol treatment–related toxicities and 21 for CNS PFS and OS. Two patients in the dose expansion cohort experienced DLTs consisted of grade 4 lymphopenia, grade 4 thrombocytopenia, and/or grade 3 fatigue. All DLTs resolved without medical intervention. The median CNS PFS was 7 months (95% CI: 5–13) and the median OS was 8 months (95% CI: 6 to not reached). Four patients (19%) were progression-free in the CNS for more than 12 months. Conclusion Hypofractionated proton CSI using proton therapy is a safe treatment for patients with LM from solid tumors. We saw durable disease control in some patients.

Primary central nervous system lymphoma is a rare and aggressive extranodal non-Hodgkin lymphoma restricted to the brain, spinal cord, cerebrospinal fluid, and eyes. Optimization of treatment including high-dose methotrexate-based chemotherapy followed by consolidation therapy in the form of autologous stem cell transplant or whole-brain radiation leads to improved survival. However, several patients do not respond to upfront therapy and the relapse risk is high. Additionally, there is a risk of delayed neurotoxicity, particularly in older patients. Recent molecular insights underlying the pathophysiology of PCNSL have led to the development of clinical trials involving targeted therapies and immunotherapies for salvage.

A woman in her 70s experienced painless vision loss in the right eye for 1 month. Acute retinal necrosis-induced panuveitis was the referral diagnosis. With dense vitreous haze, a vitrectomy was performed for vitreous biopsy followed by multimodal imaging. Vitreous biopsy yielded negative PCR results for herpes viruses and only inflammatory cells. Post-vitrectomy imaging showed involuted but pervasive pigmentary foci in the outer retina and the retinal pigment epithelium. Concurrently, peripheral blood showed pancytosis with giant platelets and a Janus kinase 2 (JAK2) mutation, which prompted a haematological evaluation. CT and MRI revealed a right frontal lobe intra-axial mass, diagnosed as diffuse large B cell lymphoma (DLBCL). Subsequently, bone marrow aspirate confirmed the pathogenic V617FJAK2mutation. Following chemotherapy, the patient achieved lymphoma regression and uveitic quiescence. This is the first case report of acute unilateral panuveitis in a patient withJAK2mutation and DLBCL but without evidence of intraocular involvement.

Purpose of review Primary central nervous system lymphoma (PCNSL) is a rare but aggressive variant of non-Hodgkin lymphoma. The diagnostic gold standard remains the pathologic review of tumor tissue mainly collected though biopsies. The majority of PCNSL are diffuse large B cell lymphoma (DLBCL). Biopsies are invasive procedures, and there have been efforts to develop minimally invasive diagnostic testing using serum and cerebral spinal fluid. This article reviews multiple markers that could potentially serve as future diagnostic tools and predictors of treatment response. Recent findings Many studies have attempted to classify DLBCL into different subtypes for prognostic purposes using methods such as immunohistochemistry. PCNSL often falls under the activated B-cell-like subgroup, and further genomic sequencing has identified alterations in genes within the B-cell receptor signaling axis at increased frequencies. Two such genes, MYD88 and CD79B, implicate the involvement of the NF-kB (nuclear factor kappa-light-chain enhancer of activated B cells) pathway, and targeted agents to this pathway are currently being used in the treatment of relapsed/refractory PCNSL. Summary Although recent genomic profiling of PCNSL has increased the understanding of drivers in this disease and has also led to the introduction of targeted inhibitors, these markers have not yet been used for diagnostic and/or prognostic purposes. Further studies will need to evaluate if they hold great diagnostic potential.

BTK plays an important role in B cell receptor and Toll-like receptor signaling pathways, which are constitutively active in primary CNS lymphomas, and hence represents an excellent therapeutic target. Ibrutinib, a first-generation BTKi, was evaluated in phase 1/2 trials for R/R PCNSL, SCNSL, and PVRL, showing limited survival benefit. GB5121 is a novel, orally available, covalent BTKi with superior specificity, CNS penetration, and CNS target occupancy in preclinical testing versus other BTKis including ibrutinib. GB5121 is well-suited for evaluation in CNS lymphoma. This is a phase 1b/2 open-label study of GB5121 in adults with R/R PCNSL, isolated SCNSL or PVRL and will be conducted in three parts: phase 1b dose-escalation, expansion, and phase 2. Eligibility criteria for phase 1b dose-escalation and expansion (N≈30 for each) include age ≥18 years, ECOG≤2, R/R PCNSL, R/R SCNSL with CNS-only relapse, or R/R PVRL. Patients with newly diagnosed PCNSL who cannot tolerate standard high-dose methotrexate-based therapies are also eligible. Patients with prior allogeneic stem cell transplant are excluded. A Bayesian optimal interval design will be employed to perform dose escalation to determine the recommended phase 2 dose (RP2D). In the absence of dose-limiting toxicity (DLT), dose levels will increase sequentially according to a modified Fibonacci approach. Safety, tolerability, PK/PD, DLT, maximum tolerated dose, and preliminary therapeutic activity will be assessed to determine the optimal biological dose informing the RP2D. Phase 1b expansion will further explore therapeutic activity and characterize safety and tolerability of GB5121 at the RP2D. Phase 2 will initiate following RP2D determination. This is a single-arm, open-label study to investigate GB5121 safety and efficacy in patients with R/R PCNSL. Adverse events will be graded per CTCAE v5.0. Clinical response will be determined using International Primary CNS Lymphoma Collaborative Group criteria. Progression-free and overall survival will be evaluated. Enrollment begins May 2022 (NCT05242146).

Background High-dose methotrexate (HD-MTX) has broad use in the treatment of central nervous system (CNS) malignancies but confers significant toxicity without inpatient hydration and monitoring. Glucarpidase is a bacterial recombinant enzyme dosed at 50 units (u)/kg, resulting in rapid systemic MTX clearance. The aim of this study was to demonstrate feasibility of low-dose glucarpidase to facilitate MTX clearance in patients with CNS lymphoma (CNSL). Methods Eight CNSL patients received HD-MTX 3 or 6 g/m2 and glucarpidase 2000 or 1000u 24 h later. Treatments repeated every 2 weeks up to 8 cycles. Results Fifty-five treatments were administered. Glucarpidase 2000u yielded > 95% reduction in plasma MTX within 15 min following 33/34 doses (97.1%) and glucarpidase 1000u yielded > 95% reduction following 15/20 doses (75%). Anti-glucarpidase antibodies developed in 4 patients and were associated with MTX rebound. In CSF, glucarpidase was not detected and MTX levels remained cytotoxic after 1 (3299.5 nmol/L, n = 8) and 6 h (1254.7 nmol/L, n = 7). Treatment was safe and well-tolerated. Radiographic responses in 6 of 8 patients (75%) were as expected following MTX-based therapy. Conclusions This study demonstrates feasibility of planned-use low-dose glucarpidase for MTX clearance and supports the hypothesis that glucarpidase does not impact MTX efficacy in the CNS. Clinical trial registration NCT03684980 (Registration date 26/09/2018).

This review addresses the challenges of primary central nervous system (CNS) lymphoma diagnosis, assessment of treatment response, and detection of recurrence. Primary CNS lymphoma is a rare form of extra-nodal non-Hodgkin lymphoma that can involve brain, spinal cord, leptomeninges, and eyes. Primary CNS lymphoma lesions are most commonly confined to the white matter or deep cerebral structures such as basal ganglia and deep periventricular regions. Contrast-enhanced magnetic resonance imaging (MRI) is the standard diagnostic modality employed by neuro-oncologists. MRI often shows common morphological features such as a single or multiple uniformly well-enhancing lesions without necrosis but with moderate surrounding edema. Other brain tumors or inflammatory processes can show similar radiological patterns, making differential diagnosis difficult. [18F]-fluorodeoxyglucose (FDG) positron emission tomography (PET) has selected utility in cerebral lymphoma, especially in diagnosis. Primary CNS lymphoma can sometimes present with atypical findings on MRI and FDG PET, such as disseminated disease, non-enhancing or ring-like enhancing lesions. The complementary strengths of PET and MRI have led to the development of combined PET-MR systems, which in some cases may improve lesion characterization and detection. By highlighting active developments in this field, including advanced MRI sequences, novel radiotracers, and potential imaging biomarkers, we aim to spur interest in sophisticated imaging approaches.

BACKGROUND Primary central nervous system lymphoma (PCNSL) is a rare central nervous system malignancy, and long-term follow up studies are uncommon. First line therapy is based on high-dose methotrexate and different consolidation therapy options. This is a long-term follow up study of PCNSL patients enrolled in a prospective trial using R-MPV chemotherapy regimen followed by high dose chemotherapy and autologous stem cell rescue to determine long-term survival and cognitive effects. METHODS From June 2005 to September 2011, 32 newly diagnosed immunocompentent PCNSL were enrolled. Patients received 5-7 doses of rituximab (500mg/m2), methotrexate (3.5 gm/m2), procarbazine (100mg/m2), and vincristine (1.4mg/m2) (R-MVP). Consolidation therapy consisted of high dose chemotherapy (HDC) with thiotepa (250 mg/m2), busulfan (3.2 mg/kg), and cyclophosphamide (60 mg/kg), followed by autologous stem cell rescue (ASCT) in those with partial or complete response to R-MVP. Long-term follow-up status including disease status, cognitive status (KPS, NANO score), and leukoencephalopathy (modified Fazkas Scale) were collected. RESULTS 26 of 36 underwent HDC and ACST. Of those, 3 died due to treatment related effects; 2 died of disease progression within two years after ASCT. After a median follow-up of 10.5 years, none of the remaining 21 patients progressed. At the time of last follow up, the median KPS was 90, compared to 80 at time of ASCT. The median NANO score and leukoencephalopathy score post ASCT and at follow-up did not change. Of note, 2 of 4 patients with a partial or complete response to R-MVP that elected not to proceed with HDC-ASCT consolidation, experienced progression at a mean of 52 months. CONCLUSION Long-term follow up demonstrates that treatment was tolerated well with stable leukoencephalopathy on MRI and good performance status. Disease recurrence 2 years after HDC with ASCT consolidation was not observed.

BACKGROUND Medical therapies for recurrent brain tumors are limited. Abemaciclib is a small molecule CDK4/6 inhibitor that has demonstrated antitumor activity in multiple cancer types and crosses the blood-brain barrier. METHODS We conducted a phase II trial of single-agent abemaciclib in patients with recurrent primary brain tumors utilizing a novel CNS basket trial design with multiple tumor types accrued to separate cohorts including patients with recurrent IDH-wildtype gliomas (Cohort A), any recurrent gliomas requiring cytoreductive surgery (Cohort B), and any other recurrent primary brain tumors (Cohort C) including IDH-mutant gliomas, meningiomas, and other tumor types. In all patients, abemaciclib was administered orally at 200mg twice daily for each 28-day cycle. In cohort B abemaciclib was administered 4-7 days prior to surgery then resumed after recovery. Neuroimaging disease assessments were performed every two cycles. Cohorts were individually assessed for efficacy, tumoral molecular characteristics, and exploratory biomarker analyses. Next generation sequencing was performed on patients who had prior surgery. RESULTS To date, a total of 61 patients have enrolled and initiated treatment with abemaciclib. Cohort A enrolled 9 patients with IDH-wildtype WHO grade II and III astrocytomas. Cohort B enrolled 10 patients with astrocytomas of varying IDH-status. Cohort C is a diverse group of 42 patients including 22 treatment-refractory meningiomas, 10 IDH-mutant gliomas (5 astrocytomas, 5 oligodendrogliomas), 3 ependymomas, 3 primary CNS lymphomas, 2 pituitary tumors, 1 glioneuronal rosette forming tumor, and 1 diffuse midline glioma. A total of 7 grade 3 toxicities occurred in 6 patients: fatigue (3), neutropenia (2), colitis (1) and seizure (1); no grade 4 toxicities occurred. CONCLUSIONS We present the results of a novel CNS basket trial looking at the efficacy of abemaciclib across multiple recurrent primary brain tumors. Efficacy results will be presented, highlighting an update on promising results in the 22 patients with recurrent meningiomas.

This study explores the repeated use of glucarpidase following HD-MTX in patients with CNSL. HD-MTX requires aggressive hydration and inpatient monitoring to prevent toxicity. Glucarpidase 50 units(u)/kg for delayed MTX clearance results in a reduction of systemic MTX levels without crossing the blood brain barrier. This study explores the use of 1000 or 2000 units of glucarpidase following repeated cycles of MTX 3–8 g/m2. Eligible adult patients had isolated CNSL, CrCl ≥ 60 mL/min, and KPS ≥ 50. Rituximab with MTX was administered for eight cycles. Glucarpidase was given 24 hours after each MTX infusion. MTX concentrations were monitored in serum and cerebrospinal fluid (CSF). Twelve patients enrolled to date and data are available for 50 doses of MTX (3 g/m2 (20), 6 g/m2 (21), 8 g/m2 (9)). Glucarpidase 1000u (14) or 2000u (36) resulted in at least a 95% reduction in serum MTX levels within 15 minutes following 49/50 doses. A 93% decrease was seen with the remaining dose. Glucarpidase was not detected in the CSF of 7 patients analyzed. Potentially cytotoxic MTX concentrations (10–6 M) were observed in CSF 1 hour (7/7) and 6 hours (4/7) after glucarpidase administration. Radiographic responses are evaluable in 9 patients: complete response (5), partial response (2), stable disease (1), and progressive disease (1). No grade 3 events were attributed to glucarpidase; one grade 4 event of anaphylaxis occurred. Anti-glucarpidase antibodies were detected in 2/5 patients analyzed. In summary, administration of low-dose glucarpidase 24 hours after MTX 3–8 g/m2 results in a reproducible rapid reduction in serum MTX levels in non-renally impaired patients. CSF MTX levels remain therapeutic and clinical response expected from MTX-based therapy does not appear compromised. Anti-glucarpidase antibodies may develop though significance remains unclear. Study is ongoing. Future directions will explore glucarpidase use for reduction of inpatient stay with HD-MTX.