Solmaz Sahebjam

Emerging Biomarkers in Glioblastoma

Glioblastoma, the most common primary brain tumor, has few available therapies providing significant improvement in survival. Molecular signatures associated with tumor aggressiveness as well as with disease progression and their relation to differences in signaling pathways implicated in gliomagenesis have recently been described. A number of biomarkers which have potential in diagnosis, prognosis and prediction of response to therapy have been identified and along with imaging modalities could contribute to the clinical management of GBM. Molecular biomarkers including O(6)-methlyguanine-DNA-methyltransferase (MGMT) promoter and deoxyribonucleic acid (DNA) methylation, loss of heterozygosity (LOH) of chromosomes 1p and 19q, loss of heterozygosity 10q, isocitrate dehydrogenase (IDH) mutations, epidermal growth factor receptor (EGFR), epidermal growth factor, latrophilin, and 7 transmembrane domain-containing protein 1 on chromosome 1 (ELTD1), vascular endothelial growth factor (VEGF), tumor suppressor protein p53, phosphatase and tensin homolog (PTEN), p16INK4a gene, cytochrome c oxidase (CcO), phospholipid metabolites, telomerase messenger expression (hTERT messenger ribonucleic acid [mRNA]), microRNAs (miRNAs), cancer stem cell markers and imaging modalities as potential biomarkers are discussed. Inclusion of emerging biomarkers in prospective clinical trials is warranted in an effort for more effective personalized therapy in the future.

Clinical outcomes of melanoma brain metastases treated with stereotactic radiosurgery and anti-PD-1 therapy, anti-CTLA-4 therapy, BRAF/MEK inhibitors, BRAF inhibitor, or conventional chemotherapy

BACKGROUND The effect of immunologic and targeted agents on intracranial response rates in patients with melanoma brain metastases (MBMs) is not yet clearly understood. This report analyzes outcomes of intact MBMs treated with single-session stereotactic radiosurgery (SRS) and anti-PD-1 therapy, anti-CTLA-4 therapy, BRAF/MEK inhibitors(i), BRAFi, or conventional chemotherapy. PATIENTS AND METHODS Patients were included if MBMs were treated with single-session SRS within 3 months of receiving systemic therapy. The primary end point of this study was distant MBM control. Secondary end points were local MBM control defined as a >20% volume increase on follow-up MRI, systemic progression-free survival, overall survival (OS) from both SRS and cranial metastases diagnosis, and neurotoxicity. Images were reviewed alongside two neuro-radiologists at our institution. RESULTS Ninety-six patients were treated to 314 MBMs over 119 SRS treatment sessions between January 2007 and August 2015. No significant differences were noted in age (P = 0.27), gender (P = 0.85), treated gross tumor volume (P = 0.26), or the diagnosis-specific graded prognostic assessment (P = 0.51) between the treatment cohorts. Twelve-month Kaplan-Meier (KM) distant MBM control rates were 38%, 21%, 20%, 8%, and 5% (P = 0.008) for SRS with anti-PD-1 therapies, anti-CTLA-4 therapy, BRAF/MEKi, BRAFi, and conventional chemotherapy, respectively. No significant differences were noted in the KM local MBM control rates among treatment groups (P = 0.25). Treatment with anti-PD-1 therapy, anti-CTLA-4 therapy, or BRAF/MEKi significantly improved OS on both univariate and multivariate analyses when compared with conventional chemotherapy. CONCLUSION In our institutional analysis of patients treated with SRS and various systemic immunologic and targeted melanoma agents, significant differences in distant MBM control and OS are noted. Prospective evaluation of the potential synergistic effect between these agents and SRS is warranted.

Nivolumab with or without ipilimumab in patients with recurrent glioblastoma: results from exploratory phase I cohorts of CheckMate 143

Background Immunotherapies have demonstrated efficacy across a diverse set of tumors supporting further evaluation in glioblastoma. The objective of this study was to evaluate the safety/tolerability and describe immune-mediated effects of nivolumab ± ipilimumab in patients with recurrent glioblastoma. Exploratory efficacy outcomes are also reported. Methods Patients were randomized to receive nivolumab 3 mg/kg every 2 weeks (Q2W; NIVO3) or nivolumab 1 mg/kg + ipilimumab 3 mg/kg every 3 weeks (Q3W) for 4 doses, then nivolumab 3 mg/kg Q2W (NIVO1+IPI3). An alternative regimen of nivolumab 3 mg/kg + ipilimumab 1 mg/kg Q3W for 4 doses, then nivolumab 3 mg/kg Q2W (NIVO3+IPI1) was investigated in a nonrandomized arm. Results Forty patients were enrolled (NIVO3, n = 10; NIVO1+IPI3, n = 10; NIVO3+IPI1, n = 20). The most common treatment-related adverse events (AEs) were fatigue (NIVO3, 30%; NIVO1+IPI3, 80%; NIVO3+IPI1, 55%) and diarrhea (10%, 70%, 30%, respectively). AEs leading to discontinuation occurred in 10% (NIVO3), 30% (NIVO1+IPI3), and 20% (NIVO3+IPI1) of patients. Three patients achieved a partial response (NIVO3, n = 1; NIVO3+IPI1, n = 2) and 8 had stable disease for ≥12 weeks (NIVO3, n = 2; NIVO1+IPI3, n = 2; NIVO3+IPI1, n = 4 [Response Assessment in Neuro-Oncology criteria]). Most patients (68%) had tumor-cell programmed death ligand-1 expression ≥1%. Immune-mediated effects mimicking radiographic progression occurred in 2 patients. Conclusions Nivolumab monotherapy was better tolerated than nivolumab + ipilimumab; the tolerability of the combination was influenced by ipilimumab dose. These safety and exploratory findings merit further investigation of immunotherapies in glioblastoma.

Baseline pretreatment contrast enhancing tumor volume including central necrosis is a prognostic factor in recurrent glioblastoma: evidence from single- and multicenter trials

Background. The prognostic significance of baseline contrast enhancing tumor prior to second- or third-line therapy in recurrent glioblastoma (GBM) for overall survival (OS) remains controversial, particularly in the context of repeated surgical resection and/or use of anti-angiogenic therapy. In the current study, we examined recurrent GBM patients from both single and multicenter clinical trials to test whether baseline enhancing tumor volume, including central necrosis, is a significant prognostic factor for OS in recurrent GBM. Methods. Included were 497 patients with recurrent GBM from 4 data sources: 2 single-center sites (University of Toronto, University of California Los Angeles) and 2 phase II multicenter trials (AVF3708G, Bevacizumab ± Irinotecan, NCT00345163; XL184-201, Cabozantinib, NCT00704288). T1 subtraction maps were used to define volume of contrast enhancing tumor, including central necrosis. Cox multivariable and univariate analyses were used to evaluate the relationship between tumor volume prior to second- or third-line therapy and OS. Results. Both continuous measures of baseline tumor volume and tumors dichotomized into large (≥15cc) and small (<15cc) tumors were significant predictors of OS (P<.0001), independently of age and treatment. Univariate analysis demonstrated significant OS differences (P<.05) between large (≥15cc) and small (<15cc) tumors in patients under all therapeutic scenarios. Only patients treated with cabozantinib who previously failed anti-angiogenic therapy did not show an OS dependence on baseline tumor volume. Conclusions. Baseline tumor volume is a significant prognostic factor in recurrent GBM. Clinical trial treatment arms must have a balanced distribution of tumor size, and tumor size should be considered when interpreting therapeutic efficacy.

Outcomes targeting the PD-1/PD-L1 axis in conjunction with stereotactic radiation for patients with non-small cell lung cancer brain metastases.

Anti-PD-1/PD-L1 therapies have demonstrated activity in patients with advanced stage non-small cell lung cancer (NSCLC). However, little is known about the safety and feasibility of patients receiving anti-PD-1/PD-L1 therapy and stereotactic radiation for the treatment of brain metastases. Data were analyzed retrospectively from NSCLC patients treated with stereotactic radiation either before, during or after anti-PD-1/PD-L1 therapy with nivolumab (anti-PD-1) or durvalumab (anti-PD-L1). Seventeen patients treated with stereotactic radiosurgery (SRS) or fractionated stereotactic radiation therapy (FSRT) to 49 brain metastases over 21 sessions were identified. Radiation was administered prior to, during and after anti-PD-1/PD-L1 therapy in 22 lesions (45%), 13 lesions (27%), and 14 lesions (29%), respectively. The 6 months Kaplan–Meier (KM) distant brain control rate was 48% following stereotactic radiation. Six and 12 month KM rates of OS from the date of stereotactic radiation and the date of cranial metastases diagnosis were 48/41% and 81/51%, respectively. The 6 month rate of distant brain control following stereotactic radiation for patients treated with stereotactic radiation during or prior to anti-PD-1/PD-L1 therapy was 57% compared to 0% among patients who received anti-PD-1/PD-L1 therapy before stereotactic radiation (p = 0.05). A Karnofsky Performance Status (KPS) of <90 was found to be predictive of worse OS following radiation treatment on both univariate and multivariate analyses (MVA, p = 0.01). In our series, stereotactic radiation to NSCLC brain metastases was well tolerated in patients who received anti-PD-1/PD-L1 therapy. Prospective evaluation to determine how these two modalities can be used synergistically to improve distant brain control and OS is warranted.

Anaplastic oligodendroglioma: advances and treatment options.

Opinion statementThe optimal treatment strategy for anaplastic oligodendroglial (AO) tumors is evolving. Molecular profiling of oligodendrogliomas have shown distinctive genetic patterns characterized by combined deletions of chromosome arms 1p and 19q, O(6)-methylguanine methyltransferase (MGMT) methylation, and isocitrate dehydrogenase 1 (IDH1) mutations; they are all prognostic factors for patients with AO. In addition, a strong association has also been found between the CpG island hypermethylation phenotype (CIMP) status and MGMT promoter methylation. Long term follow up data of the Radiation Therapy Oncology Group (RTOG) 9402 and the European Organisation for Research and Treatment of Cancer (EORTC) 26951 studies demonstrate clear evidence that for patients with codeleted 1p19q AO, early chemotherapy with radiation offers a significant improvement in overall survival compared with early radiation, even with salvage chemotherapy at tumor relapse, and thus establishes the 1p19q allelic loss as a predictive marker distinct from tumors without the chromosome change. Radiotherapy alone is no longer considered an adequate treatment for this patient population. In cases with no 1p19q deletion, most neuro-oncologists recommend incorporating radiotherapy into the upfront treatment strategy. However, there are still unanswered questions regarding whether upfront chemotherapy, omitting/deferring radiotherapy, in the desire to avoid late neurocognitive toxicity of radiotherapy should be the initial therapy for AO tumors with codeleted 1p19q, or whether temozolomide, an oral agent with a better toxicity profile, can be substituted for procarbazine, lomustine, and vincristine (PCV). Further studies are warranted and the increasing understanding of molecular pathways involved may lead to more selective therapeutic targets in the future.

Outcomes Following Hypofractionated Stereotactic Radiotherapy in the Management of Brain Metastases.

Objective:To evaluate the outcomes of patients treated with hypofractionated stereotactic radiotherapy (HSRT) for radiosensitive and radioresistant brain metastases. Methods:Between August 2006 and July 2013, a total of 56 lesions in 44 patients with brain metastases were treated with HSRT. Twenty-three (41.1%) lesions were radioresistant. Patients were treated to a total dose of 24 to 30 Gy in 3 to 5 fractions. Median planning target volume was 6.18 cm3. The primary endpoint for this study was local control with secondary endpoints of overall survival, distant failure, performance status, and treatment toxicity. Results:The median follow-up for all patients was 5 months (range, 0.4 to 58.3 mo). Six- and 12-month Kaplan-Meier estimates of local control for all lesions were 85.6% and 79.4%, respectively. Radioresistant tumors had a 6- and 12-month local control rate of 87.0%, whereas radiosensitive tumors had a 6- and 12-month local control rate of 82.5% and 72.2%, respectively (P=0.41). Six- and 12-month distant brain control rates were 56.8% and 46.9%, respectively. Overall survival was significantly associated with recursive partitioning analysis classes I, II, and III (P=0.0003) and graded prognostic assessment classes 2 to 3 and 1 to 1.5 (P=0.041). Conclusions:HSRT is a safe and feasible alternative to single-session stereotactic radiosurgery for brain metastases. No difference was observed in local control rates between radioresistant and radiosensitive tumors.

Evaluation of the Safety and Benefit of Phase I Oncology Trials for Patients With Primary CNS Tumors

PURPOSE Patients with high-grade gliomas (HGG) are frequently excluded from first-in-human solid tumor trials because of perceived poor prognosis, excessive toxicities, concomitant drug interactions, and poor efficacy. We conducted an analysis of outcomes from select, single-agent phase I studies in patients with HGG. We compared outcomes to pooled analysis of published studies in solid tumors with various molecular and cytotoxic drugs evaluated as single agents or as combinations. PATIENT AND METHODS Individual records of patients with recurrent HGG enrolled onto Adult Brain Tumor Consortium trials of single-agent, cytotoxic or molecular agents from 2000 to 2008 were analyzed for baseline characteristics, toxicities, responses, and survival. RESULTS Our analysis included 327 patients with advanced, refractory HGG who were enrolled onto eight trials involving targeted molecular (n=5) and cytotoxic (n=3) therapies. At enrollment, patients had a median Karnofsky performance score of 90 and median age of 52 years; 62% were men, 63% had glioblastoma, and the median number of prior systemic chemotherapies was one. Baseline laboratory values were in an acceptable range to meet eligibility criteria. Patients were on the study for a median of two cycles (range, <one to 56 cycles), and 96% were evaluable for primary end points. During cycle 1, grade≥3 nonhematologic and grade≥4 hematologic toxicities were 5% (28 of 565 adverse events) and 0.9% (five of 565 adverse events), respectively, and 66% of these occurred at the highest dose level. There was one death attributed to drug. Overall response rate (complete and partial response) was 5.5%. Median progression-free and overall survival times were 1.8 and 6 months, respectively. CONCLUSION Patients with HGG who meet standard eligibility criteria may be good candidates for solid tumor phase I studies with single-agent molecular or cytotoxic drugs with favorable preclinical rationale and pharmacokinetic properties in this population.

Managing leptomeningeal melanoma metastases in the era of immune and targeted therapy

Melanoma frequently metastasizes to the brain, with CNS involvement being clinically evident in ∼30% of patients (as high as 75% at autopsy). In ∼5% cases melanoma cells also metastasize to the leptomeninges, the sub‐arachnoid space and cerebrospinal fluid (CSF). Patients with leptomeningeal melanoma metastases (LMM) have the worst prognosis and are characterized by rapid disease progression (mean survival 8‐10 weeks) and a death from neurological causes. The recent years have seen tremendous progress in the development of targeted and immune therapies for melanoma that has translated into an increased survival benefit. Despite these gains, the majority of patients fail therapy and there is a suspicion that the brain and the leptomeninges are a “sanctuary” sites for melanoma cells that escape both targeted therapy and immunologic therapies. Emerging evidence suggests that (1) Cancer cells migrating to the CNS may have unique molecular properties and (2) the CNS/leptomeningeal microenvironment represents a pro‐survival niche that influences therapeutic response. In this Mini‐Review, we will outline the clinical course of LMM development and will describe how the intracranial immune and cellular microenvironments offer both opportunities and challenges for the successful management of this disease. We will further discuss the latest data demonstrating the potential use of BRAF inhibitors and immune therapy in the management of LMM, and will review future potential therapeutic strategies for the management of this most devastating complication of advanced melanoma.

Emerging biomarkers in anaplastic oligodendroglioma: implications for clinical investigation and patient management

Oligodendrogliomas are heterogeneous tumors with a variable response to treatment. This clinical variability underlines the urgent need for markers that can reliably aid diagnosis and guide clinical decision-making. Long-term follow-up data from the EORTC 26951 and RTOG 9402 clinical trials in newly diagnosed anaplastic oligodendroglioma have established chromosome 1p19q codeletion as a predictive marker of response to procarbazine, lomustine and vincristine chemotherapy in anaplastic oligodendrogliomas. In addition, MGMT promoter hypermethylation has been strongly associated with glioma CpG island hypermethylation phenotype (G-CIMP+) status, this has been suggested as an epiphenomenon of genome-wide methylation, conferring a more favorable prognosis. Molecular profiling of these tumors has identified several other markers with potential clinical significance: mutations of IDH, CIC, FUBP1 and CDKN2A require further validation before they can be implemented as clinical decision-making tools. Additionally, recent data on the clinical significance of intrinsic glioma subtyping appears promising. Indeed, existing evidence suggests that comprehensive analyses such as intrinsic glioma subtyping or G-CIMP status are superior to single molecular markers. Clearly, with evolving treatment strategies and in the era of individualized therapy, broader omics-based molecular evaluations are required to improve outcome prediction and to identify patients who will benefit from specific treatment strategies.