State of the Art in Low-Grade Glioma Management: Insights From Isocitrate Dehydrogenase and Beyond.

Low-grade gliomas present a formidable challenge in neuro-oncology because of the challenges imposed by the blood-brain barrier, predilection for the young adult population, and propensity for recurrence. In the past two decades, the systematic examination of genomic alterations in adults and children with primary brain tumors has uncovered profound new insights into the pathogenesis of these tumors, resulting in more accurate tumor classification and prognostication. It also identified several common recurrent genomic alterations that now define specific brain tumor subtypes and have provided a new opportunity for molecularly targeted therapeutic intervention. Adult-type diffuse low-grade gliomas are frequently associated with mutations in isocitrate dehydrogenase 1 and 2 (IDH1/2), resulting in production of 2-hydroxyglutarate, an oncometabolite important for tumorigenesis. Recent studies of IDH inhibitors have yielded promising results in patients at early stages of disease with prolonged progression-free survival (PFS) and delayed time to radiation and chemotherapy. Pediatric-type gliomas have high rates of alterations in BRAF, including BRAF V600E point mutations or BRAF-KIAA1549 rearrangements. BRAF inhibitors, often combined with MEK inhibitors, have resulted in radiographic response and improved PFS in these patients. This article reviews emerging approaches to the treatment of low-grade gliomas, including a discussion of targeted therapies and how they integrate with the current treatment modalities of surgical resection, chemotherapy, and radiation.

Tumor Volume Growth Rates and Doubling Times during Active Surveillance of IDH-mutant Low-Grade Glioma.

PURPOSE: Isocitrate dehydrogenase-mutant (IDH-mt) gliomas are incurable primary brain tumors characterized by a slow-growing phase over several years followed by a rapid-growing malignant phase. We hypothesized that tumor volume growth rate (TVGR) on MRI may act as an earlier measure of clinical benefit during the active surveillance period. EXPERIMENTAL DESIGN: We integrated three-dimensional volumetric measurements with clinical, radiologic, and molecular data in a retrospective cohort of IDH-mt gliomas that were observed after surgical resection in order to understand tumor growth kinetics and the impact of molecular genetics. RESULTS: Using log-linear mixed modeling, the entire cohort (n = 128) had a continuous %TVGR per 6 months of 10.46% [95% confidence interval (CI), 9.11%-11.83%] and a doubling time of 3.5 years (95% CI, 3.10-3.98). High molecular grade IDH-mt gliomas, defined by the presence of homozygous deletion of CDKN2A/B, had %TVGR per 6 months of 19.17% (95% CI, 15.57%-22.89%) which was significantly different from low molecular grade IDH-mt gliomas with a growth rate per 6 months of 9.54% (95% CI, 7.32%-11.80%; P < 0.0001). Using joint modeling to comodel the longitudinal course of TVGR and overall survival, we found each one natural logarithm tumor volume increase resulted in more than a 3-fold increase in risk of death (HR = 3.83; 95% CI, 2.32-6.30; P < 0.0001). CONCLUSIONS: TVGR may be used as an earlier measure of clinical benefit and correlates well with the WHO 2021 molecular classification of gliomas and survival. Incorporation of TVGR as a surrogate endpoint into future prospective studies of IDH-mt gliomas may accelerate drug development.

Inaugural Results of the Individualized Screening Trial of Innovative Glioblastoma Therapy: A Phase II Platform Trial for Newly Diagnosed Glioblastoma Using Bayesian Adaptive Randomization.

PURPOSE: The Individualized Screening Trial of Innovative Glioblastoma Therapy (INSIGhT) is a phase II platform trial that uses response adaptive randomization and genomic profiling to efficiently identify novel therapies for phase III testing. Three initial experimental arms (abemaciclib [a cyclin-dependent kinase [CDK]4/6 inhibitor], neratinib [an epidermal growth factor receptor [EGFR]/human epidermal growth factor receptor 2 inhibitor], and CC-115 [a deoxyribonucleic acid-dependent protein kinase/mammalian target of rapamycin inhibitor]) were simultaneously evaluated against a common control arm. We report the results for each arm and examine the feasibility and conduct of the adaptive platform design. PATIENTS AND METHODS: Patients with newly diagnosed O6-methylguanine-DNA methyltransferase-unmethylated glioblastoma were eligible if they had tumor genotyping to identify prespecified biomarker subpopulations of dominant glioblastoma signaling pathways (EGFR, phosphatidylinositol 3-kinase, and CDK). Initial random assignment was 1:1:1:1 between control (radiation therapy and temozolomide) and the experimental arms. Subsequent Bayesian adaptive randomization was incorporated on the basis of biomarker-specific progression-free survival (PFS) data. The primary end point was overall survival (OS), and one-sided P values are reported. The trial is registered with ClinicalTrials.gov (identifier: NCT02977780). RESULTS: Two hundred thirty-seven patients were treated (71 control; 73 abemaciclib; 81 neratinib; 12 CC-115) in years 2017-2021. Abemaciclib and neratinib were well tolerated, but CC-115 was associated with ≥ grade 3 treatment-related toxicity in 58% of patients. PFS was significantly longer with abemaciclib (hazard ratio [HR], 0.72; 95% CI, 0.49 to 1.06; one-sided P = .046) and neratinib (HR, 0.72; 95% CI, 0.50 to 1.02; one-sided P = .033) relative to the control arm but there was no PFS benefit with CC-115 (one-sided P = .523). None of the experimental therapies demonstrated a significant OS benefit (P > .05). CONCLUSION: The INSIGhT design enabled efficient simultaneous testing of three experimental agents using a shared control arm and adaptive randomization. Two investigational arms had superior PFS compared with the control arm, but none demonstrated an OS benefit. The INSIGhT design may promote improved and more efficient therapeutic discovery in glioblastoma. New arms have been added to the trial.

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.).

Preclinical and clinical evaluation of Buparlisib (BKM120) in recurrent/refractory Central Nervous System Lymphoma.

Central Nervous System (CNS) Lymphomas are aggressive brain tumors with limited treatment options. Targeting the phosphoinositide 3-kinase (PI3K) pathway yields promising responses across B-cell malignancies, but its therapeutic potential in CNS lymphomas remains unexplored. We present pre-clinical and clinical data on the pan-PI3K inhibitor Buparlisib in CNS lymphomas. In a primary CNS lymphoma-patient-derived cell line, we define the EC50. Four patients with recurrent CNS lymphoma were enrolled in a prospective trial. We evaluated Buparlisib plasma and cerebrospinal fluid pharmacokinetics, clinical outcomes, and adverse events. Treatment was well tolerated. Common toxicities include hyperglycemia, thrombocytopenia, and lymphopenia. The presence of Buparlisib in plasma and CSF was confirmed 2h post-treatment with a median CSF concentration below the EC50 defined in the cell line All four patients were evaluated for response and the median time to progression was 39 days. Buparlisib monotherapy did not lead to meaningful responses and the trial was prematurely stopped.Clinical Trial Registration: NCT02301364.

Moving Spatially Resolved Multiplexed Protein Profiling toward Clinical Oncology.

The shift in cancer therapy from broadly cytotoxic agents toward "personalized" treatments that target specific alterations in each patient's tumor requires diagnostic pathology approaches that are quantitative and biospecimen-friendly. Novel multiplexed antibody-based imaging technologies can measure single-cell expression of over 60 proteins in intact tumor sections and hold promise for clinical oncology.

Glioblastoma and Other Primary Brain Malignancies in Adults: A Review.

Importance: Malignant primary brain tumors cause more than 15 000 deaths per year in the United States. The annual incidence of primary malignant brain tumors is approximately 7 per 100 000 individuals and increases with age. Five-year survival is approximately 36%. Observations: Approximately 49% of malignant brain tumors are glioblastomas, and 30% are diffusely infiltrating lower-grade gliomas. Other malignant brain tumors include primary central nervous system (CNS) lymphoma (7%) and malignant forms of ependymomas (3%) and meningiomas (2%). Symptoms of malignant brain tumors include headache (50%), seizures (20%-50%), neurocognitive impairment (30%-40%), and focal neurologic deficits (10%-40%). Magnetic resonance imaging before and after a gadolinium-based contrast agent is the preferred imaging modality for evaluating brain tumors. Diagnosis requires tumor biopsy with consideration of histopathological and molecular characteristics. Treatment varies by tumor type and often includes a combination of surgery, chemotherapy, and radiation. For patients with glioblastoma, the combination of temozolomide with radiotherapy improved survival when compared with radiotherapy alone (2-year survival, 27.2% vs 10.9%; 5-year survival, 9.8% vs 1.9%; hazard ratio [HR], 0.6 [95% CI, 0.5-0.7]; P < .001). In patients with anaplastic oligodendroglial tumors with 1p/19q codeletion, probable 20-year overall survival following radiotherapy without vs with the combination of procarbazine, lomustine, and vincristine was 13.6% vs 37.1% (80 patients; HR, 0.60 [95% CI, 0.35-1.03]; P = .06) in the EORTC 26951 trial and 14.9% vs 37% in the RTOG 9402 trial (125 patients; HR, 0.61 [95% CI, 0.40-0.94]; P = .02). Treatment of primary CNS lymphoma includes high-dose methotrexate-containing regimens, followed by consolidation therapy with myeloablative chemotherapy and autologous stem cell rescue, nonmyeloablative chemotherapy regimens, or whole brain radiation. Conclusions and Relevance: The incidence of primary malignant brain tumors is approximately 7 per 100 000 individuals, and approximately 49% of primary malignant brain tumors are glioblastomas. Most patients die from progressive disease. First-line therapy for glioblastoma is surgery followed by radiation and the alkylating chemotherapeutic agent temozolomide.

Vorasidenib and ivosidenib in IDH1-mutant low-grade glioma: a randomized, perioperative phase 1 trial.

Vorasidenib and ivosidenib inhibit mutant forms of isocitrate dehydrogenase (mIDH) and have shown preliminary clinical activity against mIDH glioma. We evaluated both agents in a perioperative phase 1 trial to explore the mechanism of action in recurrent low-grade glioma (IGG) and select a molecule for phase 3 testing. Primary end-point was concentration of D-2-hydroxyglutarate (2-HG), the metabolic product of mIDH enzymes, measured in tumor tissue from 49 patients with mIDH1-R132H nonenhancing gliomas following randomized treatment with vorasidenib (50 mg or 10 mg once daily, q.d.), ivosidenib (500 mg q.d. or 250 mg twice daily) or no treatment before surgery. Tumor 2-HG concentrations were reduced by 92.6% (95% credible interval (CrI), 76.1-97.6) and 91.1% (95% CrI, 72.0-97.0) in patients treated with vorasidenib 50 mg q.d. and ivosidenib 500 mg q.d., respectively. Both agents were well tolerated and follow-up is ongoing. In exploratory analyses, 2-HG reduction was associated with increased DNA 5-hydroxymethylcytosine, reversal of 'proneural' and 'stemness' gene expression signatures, decreased tumor cell proliferation and immune cell activation. Vorasidenib, which showed brain penetrance and more consistent 2-HG suppression than ivosidenib, was advanced to phase 3 testing in patients with mIDH LGGs. Funded by Agios Pharmaceuticals, Inc. and Servier Pharmaceuticals LLC; ClinicalTrials.gov number NCT03343197.

Integrated clinical and genomic analysis identifies driver events and molecular evolution of colitis-associated cancers.

Inflammation has long been recognized to contribute to cancer development, particularly across the gastrointestinal tract. Patients with inflammatory bowel disease have an increased risk for bowel cancers, and it has been posited that a field of genetic changes may underlie this risk. Here, we define the clinical features, genomic landscape, and germline alterations in 174 patients with colitis-associated cancers and sequenced 29 synchronous or isolated dysplasia. TP53 alterations, an early and highly recurrent event in colitis-associated cancers, occur in half of dysplasia, largely as convergent evolution of independent events. Wnt pathway alterations are infrequent, and our data suggest transcriptional rewiring away from Wnt. Sequencing of multiple dysplasia/cancer lesions from mouse models and patients demonstrates rare shared alterations between lesions. These findings suggest neoplastic bowel lesions developing in a background of inflammation experience lineage plasticity away from Wnt activation early during tumorigenesis and largely occur as genetically independent events.

Isocitrate dehydrogenase (IDH) mutant gliomas: A Society for Neuro-Oncology (SNO) consensus review on diagnosis, management, and future directions.

Isocitrate dehydrogenase (IDH) mutant gliomas are the most common adult, malignant primary brain tumors diagnosed in patients younger than 50, constituting an important cause of morbidity and mortality. In recent years, there has been significant progress in understanding the molecular pathogenesis and biology of these tumors, sparking multiple efforts to improve their diagnosis and treatment. In this consensus review from the Society for Neuro-Oncology (SNO), the current diagnosis and management of IDH-mutant gliomas will be discussed. In addition, novel therapies, such as targeted molecular therapies and immunotherapies, will be reviewed. Current challenges and future directions for research will be discussed.

Combination Olaparib and Temozolomide for the Treatment of Glioma: A Retrospective Case Series.

OBJECTIVES: To report on the tolerability and efficacy of olaparib with temozolomide (TMZ) for glioma METHODS: Single-center retrospective series of glioma patients treated with olaparib/TMZ September 2018-December 2021 RESULTS: 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.

Phase III trial of chemoradiotherapy with temozolomide plus nivolumab or placebo for newly diagnosed glioblastoma with methylated MGMT promoter.

BACKGROUND: Nearly all patients with newly diagnosed glioblastoma experience recurrence following standard-of-care radiotherapy (RT) + temozolomide (TMZ). The purpose of the phase III randomized CheckMate 548 study was to evaluate RT + TMZ combined with the immune checkpoint inhibitor nivolumab (NIVO) or placebo (PBO) in patients with newly diagnosed glioblastoma with methylated MGMT promoter (NCT02667587). METHODS: Patients (N = 716) were randomized 1:1 to NIVO [(240 mg every 2 weeks × 8, then 480 mg every 4 weeks) + RT (60 Gy over 6 weeks) + TMZ (75 mg/m2 once daily during RT, then 150-200 mg/m2 once daily on days 1-5 of every 28-day cycle × 6)] or PBO + RT + TMZ following the same regimen. The primary endpoints were progression-free survival (PFS) and overall survival (OS) in patients without baseline corticosteroids and in all randomized patients. RESULTS: As of December 22, 2020, median (m)PFS (blinded independent central review) was 10.6 months (95% CI, 8.9-11.8) with NIVO + RT + TMZ vs 10.3 months (95% CI, 9.7-12.5) with PBO + RT + TMZ (HR, 1.1; 95% CI, 0.9-1.3) and mOS was 28.9 months (95% CI, 24.4-31.6) vs 32.1 months (95% CI, 29.4-33.8), respectively (HR, 1.1; 95% CI, 0.9-1.3). In patients without baseline corticosteroids, mOS was 31.3 months (95% CI, 28.6-34.8) with NIVO + RT + TMZ vs 33.0 months (95% CI, 31.0-35.1) with PBO + RT + TMZ (HR, 1.1; 95% CI, 0.9-1.4). Grade 3/4 treatment-related adverse event rates were 52.4% vs 33.6%, respectively. CONCLUSIONS: NIVO added to RT + TMZ did not improve survival in patients with newly diagnosed glioblastoma with methylated or indeterminate MGMT promoter. No new safety signals were observed.

Hypothetical generalized framework for a new imaging endpoint of therapeutic activity in early phase clinical trials in brain tumors.

Imaging response assessment is a cornerstone of patient care and drug development in oncology. Clinicians/clinical researchers rely on tumor imaging to estimate the impact of new treatments and guide decision making for patients and candidate therapies. This is important in brain cancer, where associations between tumor size/growth and emerging neurological deficits are strong. Accurately measuring the impact of a new therapy on tumor growth early in clinical development, where patient numbers are small, would be valuable for decision making regarding late-stage development activation. Current attempts to measure the impact of a new therapy have limited influence on clinical development, as determination of progression, stability or response does not currently account for individual tumor growth kinetics prior to the initiation of experimental therapies. Therefore, we posit that imaging-based response assessment, often used as a tool for estimating clinical effect, is incomplete as it does not adequately account for growth trajectories or biological characteristics of tumors prior to the introduction of an investigational agent. Here, we propose modifications to the existing framework for evaluating imaging assessment in primary brain tumors that will provide a more reliable understanding of treatment effects. Measuring tumor growth trajectories prior to a given intervention may allow us to more confidently conclude whether there is an anti-tumor effect. This updated approach to imaging-based tumor response assessment is intended to improve our ability to select candidate therapies for later-stage development, including those that may not meet currently sought thresholds for "response" and ultimately lead to identification of effective treatments.

Incidence of brain metastases in patients with early HER2-positive breast cancer receiving neoadjuvant chemotherapy with trastuzumab and pertuzumab.

The addition of pertuzumab (P) to trastuzumab (H) and neoadjuvant chemotherapy (NAC) has decreased the risk of distant recurrence in early stage HER2-positive breast cancer. The incidence of brain metastases (BM) in patients who achieved pathological complete response (pCR) versus those who do not is unknown. In this study, we sought the incidence of BM in patients receiving HP-containing NAC as well as survival outcome. We reviewed the medical records of 526 early stage HER2-positive patients treated with an HP-based regimen at Memorial Sloan Kettering Cancer Center (MSKCC), between September 1, 2013 to November 1, 2019. The primary endpoint was to estimate the cumulative incidence of BM in pCR versus non-pCR patients; secondary endpoints included disease free-survival (DFS) and overall survival (OS). After a median follow-up of 3.2 years, 7 out of 286 patients with pCR had a BM while 5 out of 240 non-pCR patients had a BM. The 3-year DFS was significantly higher in the pCR group compared to non-pCR group (95% vs 91 %, p = 0.03) and the same trend was observed for overall survival. In our cohort, despite the better survival outcomes of patients who achieved pCR, we did not observe appreciable differences in the incidence of BM by pCR/non-pCR status. This finding suggests that the BM incidence could not be associated with pCR. Future trials with new small molecules able to cross the blood brain barrier should use more specific biomarkers rather than pCR for patients' selection.

Balancing Risk and Efficiency in Drug Development for Rare and Challenging Tumors: A New Paradigm for Glioma.

The process of developing cancer therapies is well established and has enabled the incorporation of many new drugs and classes of agents into the standard of care for common cancers. Clinical drug development is fundamentally different for rare and difficult-to-treat solid tumors, such as glioma or pancreatic cancer. The failure to develop effective new agents for the latter diseases has discouraged the development of therapeutics for these cancers. Using glioma as an example, we describe a process toward obtaining more reliable early-stage signals of drug activity and a process toward translating those signals into clinical benefits with more efficient late-stage development. If linked together, these processes should increase the likelihood of benefit in late-stage settings at a lower cost and encourage more drug development for patients with rare and difficult-to-treat cancers.