Convection-Enhanced Delivery of a First-in-Class Anti-β1 Integrin Antibody for the Treatment of High-Grade Glioma Utilizing Real-Time Imaging

Introduction: OS2966 is a first-in-class, humanized and de-immunized monoclonal antibody which targets the adhesion receptor subunit, CD29/β1 integrin. CD29 expression is highly upregulated in glioblastoma and has been shown to drive tumor progression, invasion, and resistance to multiple modalities of therapy. Here, we present a novel Phase I clinical trial design addressing several factors plaguing effective treatment of high-grade gliomas (HGG). Study Design: This 2-part, ascending-dose, Phase I clinical trial will enroll patients with recurrent/progressive HGG requiring a clinically indicated resection. In Study Part 1, patients will undergo stereotactic tumor biopsy followed by placement of a purpose-built catheter which will be used for the intratumoral, convection-enhanced delivery (CED) of OS2966. Gadolinium contrast will be added to OS2966 before each infusion, enabling the real-time visualization of therapeutic distribution via MRI. Subsequently, patients will undergo their clinically indicated tumor resection followed by CED of OS2966 to the surrounding tumor-infiltrated brain. Matched pre- and post-infusion tumor specimens will be utilized for biomarker development and validation of target engagement by receptor occupancy. Dose escalation will be achieved using a unique concentration-based accelerated titration design. Discussion: The present study design leverages multiple innovations including: (1) the latest CED technology, (2) 2-part design including neoadjuvant intratumoral administration, (3) a first-in-class investigational therapeutic, and (4) concentration-based dosing. Trial registration: A U.S. Food and Drug Administration (FDA) Investigational New Drug application (IND) for the above protocol is now active.

The Meningioma Enhancer Landscape Delineates Novel Subgroups and Drives Druggable Dependencies

Meningiomas are the most common primary intracranial tumor with current classification offering limited therapeutic guidance. Here, we interrogated meningioma enhancer landscapes from 33 tumors to stratify patients based upon prognosis and identify novel meningioma-specific dependencies. Enhancers robustly stratified meningiomas into three biologically distinct groups (adipogenesis/cholesterol, mesodermal, and neural crest) distinguished by distinct hormonal lineage transcriptional regulators. Meningioma landscapes clustered with intrinsic brain tumors and hormonally responsive systemic cancers with meningioma subgroups, reflecting progesterone or androgen hormonal signaling. Enhancer classification identified a subset of tumors with poor prognosis, irrespective of histologic grading. Superenhancer signatures predicted drug dependencies with superior in vitro efficacy to treatment based upon the NF2 genomic profile. Inhibition of DUSP1, a novel and druggable meningioma target, impaired tumor growth in vivo. Collectively, epigenetic landscapes empower meningioma classification and identification of novel therapies. SIGNIFICANCE: Enhancer landscapes inform prognostic classification of aggressive meningiomas, identifying tumors at high risk of recurrence, and reveal previously unknown therapeutic targets. Druggable dependencies discovered through epigenetic profiling potentially guide treatment of intractable meningiomas.This article is highlighted in the In This Issue feature, p. 1611.

Deep neural network to locate and segment brain tumors outperformed the expert technicians who created the training data

Purpose: Deep learning (DL) algorithms have shown promising results for brain tumor segmentation in MRI. However, validation is required prior to routine clinical use. We report the first randomized and blinded comparison of DL and trained technician segmentations.

Approach: We compiled a multi-institutional database of 741 pretreatment MRI exams. Each contained a postcontrast T1-weighted exam, a T2-weighted fluid-attenuated inversion recovery exam, and at least one technician-derived tumor segmentation. The database included 729 unique patients (470 males and 259 females). Of these exams, 641 were used for training the DL system, and 100 were reserved for testing. We developed a platform to enable qualitative, blinded, controlled assessment of lesion segmentations made by technicians and the DL method. On this platform, 20 neuroradiologists performed 400 side-by-side comparisons of segmentations on 100 test cases. They scored each segmentation between 0 (poor) and 10 (perfect). Agreement between segmentations from technicians and the DL method was also evaluated quantitatively using the Dice coefficient, which produces values between 0 (no overlap) and 1 (perfect overlap).

Results: The neuroradiologists gave technician and DL segmentations mean scores of 6.97 and 7.31, respectively (p<0.00007). The DL method achieved a mean Dice coefficient of 0.87 on the test cases.

Conclusions: This was the first objective comparison of automated and human segmentation using a blinded controlled assessment study. Our DL system learned to outperform its “human teachers” and produced output that was better, on average, than its training data.

Stereotactic radiosurgery with concurrent HER2-directed therapy is associated with improved objective response for breast cancer brain metastasis

BACKGROUND

Patients with breast cancer positive for human epidermal growth factor receptor 2 (HER2) remain at high risk of intracranial relapse following treatment and experience increased rates of intracranial failure after stereotactic radiosurgery (SRS). We hypothesized that the addition of concurrent lapatinib to SRS would improve intracranial complete response rates.

METHODS

Patients with newly diagnosed HER2-amplified breast cancer brain metastases from 2005-2014 who underwent SRS were included and divided into 2 cohorts based on timing of treatment with lapatinib. Outcome variables included the proportion of patients who achieved an intracranial complete response or progressive disease according to the RECIST 1.1 criteria, as well as individual lesion response rates, distant intracranial failure, and radiation necrosis.

RESULTS

Eighty-four patients with 487 brain metastases met inclusion criteria during the study period. Over 138 treatment sessions, 132 lesions (27%) were treated with SRS and concurrent lapatinib, while 355 (73%) were treated with SRS without lapatinib. Compared with patients treated with SRS alone, patients treated with concurrent lapatinib had higher rates of complete response (35% vs 11%, P = 0.008). On a per-lesion basis, best objective response was superior in the concurrent lapatinib group (median 100% vs 70% reduction, P < 0.001). Concurrent lapatinib was not associated with an increased risk of grade 2+ radiation necrosis (1.0% with concurrent lapatinib vs 3.5% without, P = 0.27). Lapatinib had no protective effect on distant intracranial failure rates (48% vs 49%, P = 0.91).

CONCLUSION

The addition of concurrent lapatinib to SRS was associated with improved complete response rates among patients with HER2-positive brain metastases.

Imaging and diagnostic advances for intracranial meningiomas

The archetypal imaging characteristics of meningiomas are among the most stereotypic of all central nervous system (CNS) tumors. In the era of plain film and ventriculography, imaging was only performed if a mass was suspected, and their results were more suggestive than definitive. Following more than a century of technological development, we can now rely on imaging to non-invasively diagnose meningioma with great confidence and precisely delineate the locations of these tumors relative to their surrounding structures to inform treatment planning. Asymptomatic meningiomas may be identified and their growth monitored over time; moreover, imaging routinely serves as an essential tool to survey tumor burden at various stages during the course of treatment, thereby providing guidance on their effectiveness or the need for further intervention. Modern radiological techniques are expanding the power of imaging from tumor detection and monitoring to include extraction of biologic information from advanced analysis of radiological parameters. These contemporary approaches have led to promising attempts to predict tumor grade and, in turn, contribute prognostic data. In this supplement article, we review important current and future aspects of imaging in the diagnosis and management of meningioma, including conventional and advanced imaging techniques using CT, MRI, and nuclear medicine.

Recent developments and future directions in adult lower-grade gliomas: Society for Neuro-Oncology (SNO) and European Association of Neuro-Oncology (EANO) consensus

The finding that most grades II and III gliomas harbor isocitrate dehydrogenase (IDH) mutations conveying a relatively favorable and fairly similar prognosis in both tumor grades highlights that these tumors represent a fundamentally different entity from IDH wild-type gliomas exemplified in most glioblastoma. Herein we review the most recent developments in molecular neuropathology leading to reclassification of these tumors based upon IDH and 1p/19q status, as well as the potential roles of methylation profiling and deletional analysis of cyclin-dependent kinase inhibitor 2A and 2B. We discuss the epidemiology, clinical manifestations, benefit of surgical resection, and neuroimaging features of lower-grade gliomas as they relate to molecular subtype, including advanced imaging techniques such as 2-hydroxyglutarate magnetic resonance spectroscopy and amino acid PET scanning. Recent, ongoing, and planned studies of radiation therapy and both cytotoxic and targeted chemotherapies are summarized, including both small molecule and immunotherapy approaches specifically targeting the mutant IDH protein.

Glioblastoma Myeloid-Derived Suppressor Cell Subsets Express Differential Macrophage Migration Inhibitory Factor Receptor Profiles That Can Be Targeted to Reduce Immune Suppression

The application of tumor immunotherapy to glioblastoma (GBM) is limited by an unprecedented degree of immune suppression due to factors that include high numbers of immune suppressive myeloid cells, the blood brain barrier, and T cell sequestration to the bone marrow. We previously identified an increase in immune suppressive myeloid-derived suppressor cells (MDSCs) in GBM patients, which correlated with poor prognosis and was dependent on macrophage migration inhibitory factor (MIF). Here we examine the MIF signaling axis in detail in murine MDSC models, GBM-educated MDSCs and human GBM. We found that the monocytic subset of MDSCs (M-MDSCs) expressed high levels of the MIF cognate receptor CD74 and was localized in the tumor microenvironment. In contrast, granulocytic MDSCs (G-MDSCs) expressed high levels of the MIF non-cognate receptor CXCR2 and showed minimal accumulation in the tumor microenvironment. Furthermore, targeting M-MDSCs with Ibudilast, a brain penetrant MIF-CD74 interaction inhibitor, reduced MDSC function and enhanced CD8 T cell activity in the tumor microenvironment. These findings demonstrate the MDSC subsets differentially express MIF receptors and may be leveraged for specific MDSC targeting.

MDNA55 survival in recurrent glioblastoma (rGBM) patients expressing the interleukin-4 receptor (IL4R) as compared to a matched synthetic control

2513

Background: MDNA55 is an engineered IL-4 fused to pseudomonas exotoxin A being developed for GBM, an aggressive, universally fatal disease. No curative therapy exists and 75% of patients are not eligible for resection at recurrence. MDNA55 targets IL4R overexpressed in GBM, the immunosuppressive tumor microenvironment, and high expression is associated with poor survival outcomes in GBM. A Ph 2b trial of MDNA55 was completed in rGBM using convection-enhanced delivery to bypass the BBB. Here we report results from the Ph 2b trial and comparison against a matched Synthetic Control Arm (SCA). Methods: MDNA55-05 is an open-label, single-arm study of intratumoral delivery of ≤ 240 μg MDNA55 as a single treatment via ≤ 4 catheters in de novo GBM without IDH1/2 mutation at 1st or 2nd recurrence not eligible for resection, tumors ≤ 4 cm, KPS ≥ 70. IL4R expression in GBM tissues was determined by H-Score using a validated IHC assay. 1o endpoint is median overall survival (mOS); 2o endpoint includes the impact of IL4R status on mOS. An eligibility-matched SCA was identified retrospectively from patient registries at major neurosurgery centers with access to GBM tumor tissue banks under IRB-approved protocols. Results: 44 subjects comprise the MDNA55 per protocol analysis population: median age 56 (35 - 77); median dose 177 mg (range 18 – 240 mg), 50% had KPS ≤ 80. No systemic toxicities observed, drug-related AEs were primarily neurological and characteristic of GBM, no deaths attributed to MDNA55. Median OS was 11.6 months (95% CI 7.9 – 15.2). When stratified by IL4R expression, mOS in IL4R High (n = 21) was 15 vs. 8.4 months in IL4R Low (n = 19); p = 0.2175. OS12 is 57% vs. 33%. When compared to the SCA (n = 81), MDNA55 subjects survived significantly longer: mOS 12.4 vs. 7.7 months; p = 0.0077. When comparing IL4R High groups, mOS in MDNA55 (n = 21) was 15.8 vs. 6.2 months in the SCA (n = 17); p = 0.0626. Subgroup analysis in unmethylated MGMT subjects also show better survival with MDNA55 (n = 23) than the SCA (n = 31); mOS 12.3 vs. 7.7 months (p = 0.0268), indicating that MDNA55 may be beneficial in patients resistant to temozolomide. Conclusions: MDNA55 subjects represent a difficult to treat population ( de novo GBM, IDH wild-type, not eligible for surgery at recurrence). Single treatment with MDNA55 prolongs survival by nearly 10 months in a subset of rGBM expressing high levels of IL4R when compared to a matched SCA, providing an unprecedented outcome for this highly lethal disease. Clinical trial information: NCT02858895 .

Myeloid-derived suppressor cell subset heterogeneity drives glioblastoma progression in a sex-dependent manner

Immunosuppression is a major factor facilitating glioblastoma (GBM) progression and therapeutic resistance. We previously demonstrated that myeloid-derived suppressor cells (MDSCs) expand in GBM patients, but the mechanisms by which MDSC subsets promote tumorigenesis remain unknown. Using multiple syngeneic mouse GBM models, we show that monocytic MDSCs (mMDSCs) accumulate in tumors of males and associate with poor prognosis. Consistent with preclinical observations, males, who constitute 60% of GBM patients and have a worse prognosis than females, had significantly more tumor-infiltrating mMDSCs. In contrast, female tumor-bearing mice had a two-fold increase in circulating granulocytic MDSC (gMDSC) frequency, and a high gMDSC gene signature correlated with poor prognosis of female patients. Male-to-female bone marrow transplantation indicated that immune cell-intrinsic discrepancies drive the sex differences in GBM survival. In line with the differential MDSC localization, targeting gMDSCs with anti-Ly6G neutralizing antibodies extended the lifespan of female mice without affecting males. However, mMDSCs were protected from the anti-Ly6C depletion strategy due to their systemic and local proliferation, as indicated by ex vivo Ki-67 staining and subsequently confirmed by gene expression analysis. Drug-prediction using the differential expression profiles and subsequent pre-clinical testing established that mMDSCs can be targeted by chemotherapies, while IL-1 inhibitors are effective against gMDSCs. These findings indicate that MDSC subset variation represents an opportunity for improved immunotherapy efficacy while accounting for sex as a biological variable.

Anticonvulsant prophylaxis and steroid use in adults with metastatic brain tumors: summary of SNO and ASCO endorsement of the Congress of Neurological Surgeons guidelines

BACKGROUND

The Congress of Neurological Surgeons (CNS) has developed a series of guidelines on the treatment of adults with metastatic brain tumors, including systemic therapy and supportive care topics. ASCO has a policy and set of procedures for endorsing clinical practice guidelines that have been developed by other professional organizations.

METHODS

Two CNS Guidelines were reviewed for developmental rigor by methodologists and an independent multi-disciplinary Expert Panel was formed to review the content and assess agreement with the recommendations. The expert panel voted to endorse the two guidelines and ASCO and SNO independently reviewed and approved the ASCO/SNO guideline endorsement.

RESULTS

The ASCO/SNO Expert Panel determined that the recommendations from the CNS anticonvulsants and steroids guidelines, published January 9, 2019, are clear, thorough, and based upon the most relevant scientific evidence. ASCO/SNO endorsed these two CNS guidelines, with minor alterations.

CONCLUSIONS

Key recommendations include: prophylactic anti-epileptic drugs were not recommended for routine use; corticosteroids (specifically dexamethasone) were recommended for temporary symptomatic relief in patients with neurologic symptoms and signs related to mass effect from brain metastases.

Stereotactic radiosurgery with concurrent lapatinib is associated with improved local control for HER2-positive breast cancer brain metastases

OBJECTIVE

With increasing survival for patients with human epidermal growth factor receptor 2-positive (HER2+) breast cancer in the trastuzumab era, there is an increased risk of brain metastasis. Therefore, there is interest in optimizing intracranial disease control. Lapatinib is a small-molecule dual HER2/epidermal growth factor receptor inhibitor that has demonstrated intracranial activity against HER2+ breast cancer brain metastases. The objective of this study was to investigate the impact of lapatinib combined with stereotactic radiosurgery (SRS) on local control of brain metastases.

METHODS

Patients with HER2+ breast cancer brain metastases who underwent SRS from 1997-2015 were included. The primary outcome was the cumulative incidence of local failure following SRS. Secondary outcomes included the cumulative incidence of radiation necrosis and overall survival.

RESULTS

One hundred twenty-six patients with HER2+ breast cancer who underwent SRS to 479 brain metastases (median 5 lesions per patient) were included. Among these, 75 patients had luminal B subtype (hormone receptor-positive, HER2+) and 51 patients had HER2-enriched histology (hormone receptor-negative, HER2+). Forty-seven patients received lapatinib during the course of their disease, of whom 24 received concurrent lapatinib with SRS. The median radiographic follow-up among all patients was 17.1 months. Concurrent lapatinib was associated with reduction in local failure at 12 months (5.7% vs 15.1%, p < 0.01). For lesions in the ≤ 75th percentile by volume, concurrent lapatinib significantly decreased local failure. However, for lesions in the > 75th percentile (> 1.10 cm3), concurrent lapatinib did not significantly improve local failure. Any use of lapatinib after development of brain metastasis improved median survival compared to SRS without lapatinib (27.3 vs 19.5 months, p = 0.03). The 12-month risk of radiation necrosis was consistently lower in the lapatinib cohort compared to the SRS-alone cohort (1.3% vs 6.3%, p < 0.01), despite extended survival.

CONCLUSIONS

For patients with HER2+ breast cancer brain metastases, the use of lapatinib concurrently with SRS improved local control of brain metastases, without an increased rate of radiation necrosis. Concurrent lapatinib best augments the efficacy of SRS for lesions ≤ 1.10 cm3 in volume. In patients who underwent SRS for HER2+ breast cancer brain metastases, the use of lapatinib at any time point in the therapy course was associated with a survival benefit. The use of lapatinib combined with radiosurgery warrants further prospective evaluation.

Myeloid-Derived Suppressor Cell Subsets Drive Glioblastoma Growth in a Sex-Specific Manner

Myeloid-derived suppressor cells (MDSC) that block antitumor immunity are elevated in glioblastoma (GBM) patient blood and tumors. However, the distinct contributions of monocytic (mMDSC) versus granulocytic (gMDSC) subsets have yet to be determined. In mouse models of GBM, we observed that mMDSCs were enriched in the male tumors, whereas gMDSCs were elevated in the blood of females. Depletion of gMDSCs extended survival only in female mice. Using gene-expression signatures coupled with network medicine analysis, we demonstrated in preclinical models that mMDSCs could be targeted with antiproliferative agents in males, whereas gMDSC function could be inhibited by IL1β blockade in females. Analysis of patient data confirmed that proliferating mMDSCs were predominant in male tumors and that a high gMDSC/IL1β gene signature correlated with poor prognosis in female patients. These findings demonstrate that MDSC subsets differentially drive immune suppression in a sex-specific manner and can be leveraged for therapeutic intervention in GBM. SIGNIFICANCE: Sexual dimorphism at the level of MDSC subset prevalence, localization, and gene-expression profile constitutes a therapeutic opportunity. Our results indicate that chemotherapy can be used to target mMDSCs in males, whereas IL1 pathway inhibitors can provide benefit to females via inhibition of gMDSCs.See related commentary by Gabrilovich et al., p. 1100.This article is highlighted in the In This Issue feature, p. 1079.

Management of brain metastases in breast cancer: a review of current practices and emerging treatments

PURPOSE

Breast cancer brain metastases (BCBM) are becoming an increasingly common diagnosis due to improved systemic control and more routine surveillance imaging. Treatment continues to require a multidisciplinary approach managing systemic and intracranial disease burden. Although, improvements have been made in the diagnosis and management of BCBM, brain metastasis patients continue to pose a challenge for practitioners.

METHODS

In this review, a group of medical oncologists, radiation oncologists, radiologists, breast surgeons, and neurosurgeons specializing in the treatment of breast cancer reviewed the available published literature and compiled a comprehensive review on the current state of BCBM.

RESULTS

We discuss the pathogenesis, epidemiology, diagnosis, treatment options (including systemic, surgical, and radiotherapy treatment modalities), and treatment response evaluation for BCBM. Furthermore, we discuss the ongoing prospective trials enrolling BCBM patients and their biologic rationale.

CONCLUSIONS

BCBM management is an increasing clinical concern. Multidisciplinary management combining the strengths of surgical, systemic, and radiation treatment modalities with prospective trials incorporating knowledge from the basic and translational sciences will ultimately lead to improved clinical outcomes for BCBM patients.

The effect of Gamma Knife radiosurgery on large posterior fossa metastases and the associated mass effect from peritumoral edema

OBJECTIVE

Gamma Knife radiosurgery (GKRS) as monotherapy is an option for the treatment of large (≥ 2 cm) posterior fossa brain metastases (LPFMs). However, there is concern regarding possible posttreatment increase in peritumoral edema (PTE) and associated compression of the fourth ventricle. This study evaluated the effects and safety of GKRS on tumor and PTE control in LPFM.

METHODS

The authors performed a single-center retrospective review of 49 patients with 51 LPFMs treated with GKRS. Patients with at least 1 clinical and radiological follow-up visit were included. Tumor, PTE, and fourth ventricle volumetric measurements were used to assess efficacy and safety. Overall survival was a secondary outcome.

RESULTS

Fifty-one lesions in 49 consecutive patients were identified; 57.1% of patients were male. At the time of GKRS, the median age was 61.5 years, and the median Karnofsky Performance Status score was 90. The median number of LPFMs and overall brain metastases were 1 and 2, respectively. The median overall tumor, PTE, and fourth ventricle volumes at diagnosis were 4.96 cm3 (range 1.4-21.1 cm3), 14.98 cm3 (range 0.6-71.8 cm3), and 1.23 cm3 (range 0.3-3.2 cm3), respectively, and the median lesion diameter was 2.6 cm (range 2.0-5.07 cm). The median follow-up time was 7.3 months (range 1.6-57.2 months). At the first follow-up, 2 months posttreatment, the median tumor volume decreased by 58.66% (range -96.95% to +48.69%, p < 0.001), median PTE decreased by 78.10% (range -99.92% to +198.35%, p < 0.001), and the fourth ventricle increased by 24.97% (range -37.96% to +545.6%, p < 0.001). The local control rate at first follow-up was 98.1%. The median OS was 8.36 months. No patient required surgical intervention, external ventricular drainage, or shunting between treatment and first follow-up. However, 1 patient required a ventriculoperitoneal shunt at 23 months from treatment. Posttreatment, 65.30% received our general steroid taper, 6.12% received no steroids, and 28.58% required prolonged steroid treatment.

CONCLUSIONS

In this retrospective analysis, patients with LPFMs treated with GKRS had a statistically significant posttreatment reduction in tumor size and PTE and marked opening of the fourth ventricle (all p < 0.001). This study demonstrates that GKRS is well tolerated and can be considered in the management of select cases of LPFMs, especially in patients who are poor surgical candidates.

High-risk Meningioma: Initial Outcomes From NRG Oncology/RTOG 0539

BACKGROUND

Phase 2 cooperative group meningioma trial assessing the safety and efficacy of risk-adaptive management strategies. This is the initial analysis of the high-risk cohort.

METHODS AND MATERIALS

High-risk patients were those with a new or recurrent World Health Organization (WHO) grade III meningioma of any resection extent, recurrent WHO grade II of any resection extent, or new WHO grade II after subtotal resection. Patients received intensity-modulated radiotherapy (IMRT) using a simultaneous integrated boost technique (60 Gy high dose and 54 Gy low dose in 30 fractions). Three-year progression-free survival (PFS) was the primary endpoint. Adverse events (AEs) were scored per NCI Common Terminology Criteria for Adverse Events version 3.

RESULTS

Of 57 enrolled patients, 53 received protocol treatment. Median follow-up was 4.0 years (4.8 years for living patients). Two patients withdrew without progression before year 3; for the remaining 51 patients, 3-year PFS was 58.8%. Among all 53 protocol-treated patients, 3-year PFS was 59.2%. Three-year local control was 68.9%, and overall survival was 78.6%. Of 51 patients, 1 patient (1.9%) experienced a late grade-5 necrosis-related AE. All other acute (23 of 53 patients) and late (21 of 51 patients) AEs were grades 1 to 3.

CONCLUSIONS

Patients with high-risk meningioma treated with IMRT (60 Gy/30) experienced 3-year PFS of 58.8%. Combined acute and late AEs were limited to grades 1 to 3, except for a single necrosis-related grade 5 event. These results support postoperative IMRT for high-risk meningioma and invite ongoing investigations to improve outcomes further.

Outcomes and prognostic stratification of patients with recurrent glioblastoma treated with salvage stereotactic radiosurgery

OBJECTIVE

Glioblastoma (GBM) is the most malignant form of astrocytoma. The average survival is 6-10 months in patients with recurrent GBM (rGBM). In this study, the authors evaluated the role of stereotactic radiosurgery (SRS) in patients with rGBMs.

METHODS

The authors performed a retrospective review of their brain tumor database (1997-2016). Overall survival (OS) and progression-free survival (PFS) after salvage SRS were the primary endpoints evaluated. Response to SRS was assessed using volumetric MR images.

RESULTS

Fifty-three patients with rGBM underwent salvage SRS targeting 75 lesions. The median tumor diameter and volume were 2.55 cm and 3.80 cm3, respectively. The median prescription dose was 18 Gy (range 12-24 Gy) and the homogeneity index was 1.90 (range 1.11-2.02). The median OS after salvage SRS was estimated to be 11.0 months (95% CI 7.1-12.2) and the median PFS after salvage SRS was 4.4 months (95% CI 3.7-5.0). A Karnofsky Performance Scale score ≥ 80 was independently associated with longer OS, while small tumor volume (< 15 cm3) and less homogeneous treatment plans (homogeneity index > 1.75) were both independently associated with longer OS (p = 0.007 and 0.03) and PFS (p = 0.01 and 0.002, respectively). Based on these factors, 2 prognostic groups were identified for PFS (5.4 vs 3.2 months), while 3 were identified for OS (median OS of 15.2 vs 10.5 vs 5.2 months).

CONCLUSIONS

SRS is associated with longer OS and/or PFS in patients with good performance status, small-volume tumor recurrences, and heterogeneous treatment plans. The authors propose a prognostic model to identify a cohort of rGBM patients who may benefit from SRS.

Metronomic capecitabine as an immune modulator in glioblastoma patients reduces myeloid-derived suppressor cells

BACKGROUNDMyeloid-derived suppressor cells (MDSCs) are elevated in the circulation of patients with glioblastoma (GBM), present in tumor tissue, and associated with poor prognosis. While low-dose chemotherapy reduces MDSCs in preclinical models, the use of this strategy to reduce MDSCs in GBM patients has yet to be evaluated.METHODSA phase 0/I dose-escalation clinical trial was conducted in patients with recurrent GBM treated 5-7 days before surgery with low-dose chemotherapy via capecitabine, followed by concomitant low-dose capecitabine and bevacizumab. Clinical outcomes, including progression-free and overall survival, were measured, along with safety and toxicity profiles. Over the treatment time course, circulating MDSC levels were measured by multiparameter flow cytometry, and tumor tissue immune profiles were assessed via time-of-flight mass cytometry.RESULTSEleven patients total were enrolled across escalating dose cohorts of 150, 300, and 450 mg bid. No serious adverse events related to the drug combination were observed. Compared with pretreatment baseline, circulating MDSCs were found to be higher after surgery in the 150-mg treatment arm and lower in the 300-mg and 450-mg treatment arms. Increased cytotoxic immune infiltration was observed after low-dose capecitabine compared with untreated GBM patients in the 300-mg and 450-mg treatment arms.CONCLUSIONSLow-dose, metronomic capecitabine in combination with bevacizumab was well tolerated in GBM patients and was associated with a reduction in circulating MDSC levels and an increase in cytotoxic immune infiltration into the tumor microenvironment.TRIAL REGISTRATIONClinicalTrials.gov NCT02669173.FUNDINGThis research was funded by the Cleveland Clinic, Case Comprehensive Cancer Center, the Musella Foundation, B*CURED, the NIH, the National Cancer Institute, the Sontag Foundation, Blast GBM, the James B. Pendleton Charitable Trust, and the Dr. Miriam and Sheldon G. Adelson Medical Research Foundation. Capecitabine was provided in kind by Mylan Pharmaceuticals.

Pathologic Correlation of Cellular Imaging Using Apparent Diffusion Coefficient Quantification in Patients with Brain Metastases After Gamma Knife Radiosurgery

OBJECTIVE

To evaluate the role of apparent diffusion coefficient (ADC) in differentiating radiation necrosis (RN) from recurrent tumor after Gamma Knife radiosurgery (GKRS) for brain metastases (BMs).

METHODS

Forty-one patients with BM who underwent surgical intervention after GKRS at Cleveland Clinic (2006-2017) were included in this retrospective study. The ADC values of the growing lesions and the contralateral hemisphere were calculated using picture archiving and communication system. These values were correlated to the percentage of RN identified on pathologic evaluation of the surgical specimen.

RESULTS

The median age of the patients was 59 years (range, 25-86 years), and lung cancer (63.4%) was the most common malignancy. Median initial (pre-GKRS) target volume of the lesions was 5.4 cc (range, 0.135-45.6 cc), and median GKRS dose was 18.0 Gy. Surgical resection or biopsy was performed at a median of 176 days after GKRS. Two variables were statistically significant predictors of predominate RN (75%-100%) in the surgical specimen: 1) ADC of the lesion on the preresection magnetic resonance imaging (MRI) and 2) initial pre-GKRS target volume. ADC >1.5 × 10^-3 mm²/s within the lesion on MRI predicted significant RN on pathologic evaluation of the lesion (P < 0.05). Similarly, when the target volume before GKRS was large (>10 cc), the risk of identifying significant necrosis in the pathologic specimen was elevated (P < 0.05).

CONCLUSIONS

Our data suggest that the combination of lesion ADC on MRI prior to surgical intervention and the initial target volume can predict RN with reasonable accuracy.

Population description and clinical response assessment for spinal metastases: part 2 of the SPIne response assessment in Neuro-Oncology (SPINO) group report

Background

Approximately 40% of metastatic cancer patients will develop spinal metastases. The current report provides recommendations for standardization of metrics used for spinal oncology patient population description and outcome assessment beyond local control endpoints on behalf of the SPIne response assessment in Neuro-Oncology (SPINO) group.

Methods

The SPINO group survey was conducted in order to determine the preferences for utilization of clinician-based and patient-reported outcome measures for description of patients with spinal metastases. Subsequently, ClinicalTrials.gov registry was searched for spinal oncology clinical trials, and measures for patient description and outcome reporting were identified for each trial. These two searches were used to identify currently used descriptors and instruments. A literature search was performed focusing on the measures identified in the survey and clinical trial search in order to assess their validity in the metastatic spinal tumor patient population. References for this manuscript were identified through PubMed and Medline searches.

Results

Published literature, expert survey, and ongoing clinical trials were used to synthesize recommendations for instruments for reporting of spinal stability, epidural tumor extension, neurological and functional status, and symptom severity.

Conclusions

Accurate description of patient population and therapy effects requires a combination of clinician-based and patient-reported outcome measures. The current report provides international consensus recommendations for the systematic reporting of patient- and clinician-reported measures required to develop trials applicable to surgery for spinal metastases and postoperative spine stereotactic body radiotherapy (SBRT).

Durable complete responses in some recurrent high-grade glioma patients treated with Toca 511 + Toca FC

Background

Vocimagene amiretrorepvec (Toca 511) is an investigational gamma-retroviral replicating vector encoding cytosine deaminase that, when used in combination with extended-release 5-fluorocytosine (Toca FC), results preclinically in local production of 5-fluorouracil, depletion of immune-suppressive myeloid cells, and subsequent induction of antitumor immunity. Recurrent high-grade glioma (rHGG) patients have a high unmet need for effective therapies that produce durable responses lasting more than 6 months. In this setting, relapse is nearly universal and most responses are transient.

Methods

In this Toca 511 ascending-dose phase I trial (NCT01470794), HGG patients who recurred after standard of care underwent surgical resection and received Toca 511 injected into the resection cavity wall, followed by orally administered cycles of Toca FC.

Results

Among 56 patients, durable complete responses were observed. A subgroup was identified based on Toca 511 dose and entry requirements for the follow-up phase III study. In this subgroup, which included both isocitrate dehydrogenase 1 (IDH1) mutant and wild-type tumors, the durable response rate is 21.7%. Median duration of follow-up for responders is 35.7+ months. As of August 25, 2017, all responders remain in response and are alive 33.9+ to 52.2+ months after Toca 511 administration, suggesting a positive association of durable response with overall survival.

Conclusions

Multiyear durable responses have been observed in rHGG patients treated with Toca 511 + Toca FC in a phase I trial, and the treatment will be further evaluated in a randomized phase III trial. Among IDH1 mutant patients treated at first recurrence, there may be an enrichment of complete responders.

Phase I Trial of Radiosurgery Dose Escalation Plus Bevacizumab in Patients With Recurrent/Progressive Glioblastoma

BACKGROUND

The effectiveness of stereotactic radiosurgery (SRS) for recurrent glioblastoma (rGBM) remains uncertain. SRS has been associated with a high risk of radionecrosis in gliomas.

OBJECTIVE

To determine the safety of dose escalation of single-fraction radiosurgery for rGBM in the setting of bevacizumab therapy.

METHODS

We conducted a prospective trial to determine the safety and synergistic benefit of higher doses of SRS administered with bevacizumab for rGBM. A single dose of bevacizumab was given prior to SRS and continued until progression. Dose-limiting toxicity was evaluated in successive cohorts of 3 patients.

RESULTS

Seven males and 2 females entered the study. The maximum linear diameter of the enhancing tumor was 2.58 cm (2.04-3.09). Prescription dose was escalated from 18 to 22 Gy. The radiosurgery target was chosen before the first dose of bevacizumab, about 1 wk prior to SRS treatment. Pre-SRS bevacizumab treatment was associated with a reduction of the mean volume of the enhancing lesion from 4.7 to 2.86 cm3 on the day of SRS (P = .103). No patient developed an acute side effect related to SRS treatment. The combination of SRS and bevacizumab resulted in a partial response in 3 patients and stable disease in 6 patients. Median progression-free and overall survival were 7.5 and 13 mo, respectively.

CONCLUSION

A single dose of bevacizumab prior to SRS permitted safe prescription dose escalation up to 22 Gy for rGBM. Further evaluation of the efficacy of SRS for rGBM should be performed in the setting of bevacizumab treatment.