First-in-human intraoperative near-infrared fluorescence imaging of glioblastoma using cetuximab-IRDye800

Introduction

Maximizing extent of surgical resection with the least morbidity remains critical for survival in glioblastoma patients, and we hypothesize that it can be improved by enhancements in intraoperative tumor detection. In a clinical study, we determined if therapeutic antibodies could be repurposed for intraoperative imaging during resection.

Methods

Fluorescently labeled cetuximab-IRDye800 was systemically administered to three patients 2 days prior to surgery. Near-infrared fluorescence imaging of tumor and histologically negative peri-tumoral tissue was performed intraoperatively and ex vivo. Fluorescence was measured as mean fluorescence intensity (MFI), and tumor-to-background ratios (TBRs) were calculated by comparing MFIs of tumor and histologically uninvolved tissue.

Results

The mean TBR was significantly higher in tumor tissue of contrast-enhancing (CE) tumors on preoperative imaging (4.0 ± 0.5) compared to non-CE tumors (1.2 ± 0.3; p = 0.02). The TBR was higher at a 100 mg dose than at 50 mg (4.3 vs. 3.6). The smallest detectable tumor volume in a closed-field setting was 70 mg with 50 mg of dye and 10 mg with 100 mg. On sections of paraffin embedded tissues, fluorescence positively correlated with histological evidence of tumor. Sensitivity and specificity of tumor fluorescence for viable tumor detection was calculated and fluorescence was found to be highly sensitive (73.0% for 50 mg dose, 98.2% for 100 mg dose) and specific (66.3% for 50 mg dose, 69.8% for 100 mg dose) for viable tumor tissue in CE tumors while normal peri-tumoral tissue showed minimal fluorescence.

Conclusion

This first-in-human study demonstrates the feasibility and safety of antibody based imaging for CE glioblastomas.

Recurrently Mutated Genes Differ between Leptomeningeal and Solid Lung Cancer Brain Metastases

When compared with solid brain metastases from NSCLC, leptomeningeal disease (LMD) has unique growth patterns and is rapidly fatal. Patients with LMD do not undergo surgical resection, limiting the tissue available for scientific research. In this study we performed whole exome sequencing on eight samples of LMD to identify somatic mutations and compared the results with those for 26 solid brain metastases. We found that taste 2 receptor member 31 gene (TAS2R31) and phosphodiesterase 4D interacting protein gene (PDE4DIP) were recurrently mutated among LMD samples, suggesting involvement in LMD progression. Together with a retrospective review of the charts of an additional 44 patients with NSCLC LMD, we discovered a surprisingly low number of KRAS mutations (n = 4 [7.7%]) but a high number of EGFR mutations (n = 33 [63.5%]). The median interval for development of LMD from NSCLC was shorter in patients with mutant EGFR (16.3 months) than in patients with wild-type EGFR (23.9 months) (p = 0.017). Targeted analysis of recurrent mutations thus presents a useful complement to the existing diagnostic tool kit, and correlations of EGFR in LMD and KRAS in solid metastases suggest that molecular distinctions or systemic treatment pressure underpin the differences in growth patterns within the brain.

A Neuro-oncologist's Perspective on Management of Brain Metastases in Patients with EGFR Mutant Non-small Cell Lung Cancer

Management of non-small cell lung cancer (NSCLC) with brain metastasis (BrM) has been revolutionized by identification of molecular subsets that have targetable oncogenes. Historically, survival for NSCLC with symptomatic BrM was weeks to months. Now, many patients are surviving years with limited data to guide treatment decisions. Tumors with activating mutations in epidermal growth factor receptor (EGFRact+) have a higher incidence of BrM, but a longer overall survival. The high response rate of both systemic and BrM EGFRact+ NSCLC to tyrosine kinase inhibitors (TKIs) has led to the rapid incorporation of new therapies but is outpacing evidence-based decisions for BrM in NSCLC. While whole brain radiation therapy (WBRT) was the foundation of management of BrM, extended survival raises concerns for the subacute and late effects radiotherapy. We favor the use of TKIs and delaying the use of WBRT when able. At inevitable disease progression, we consider alternative dosing schedules to increase CNS penetration (such as pulse dosing of erlotinib) or advance to next generation TKI if available. We utilize local control options of surgery or stereotactic radiosurgery (SRS) for symptomatic accessible lesions based on size and edema. At progression despite available TKIs, we use pemetrexed-based platinum doublet chemotherapy or immunotherapy if the tumor has high expression of PDL-1. We reserve the use of WBRT for patients with more than 10 BrM and progression despite TKI and conventional chemotherapy, if performance status is appropriate.

Abstract 1598: Single agent NKTR-214, a biased IL2 pathway agonist, increases immune cell infiltrates in brain tumors and prolongs survival in rodent (rattus) glioblastoma (GBM)

Background: Immunotherapy is an attractive option for brain tumor therapy if a robust infiltrative T cell response can be elicited in the tumor. NKTR-214 is a CD122-biased cytokine agonist conjugated with multiple releasable chains of polyethylene glycol and designed to provide sustained signaling through the heterodimeric IL-2 receptor pathway (IL-2Rβγ) to preferentially activate and expand effector CD8+ T and NK cells over Tregs. To assess the potential activity of single agent NKTR-214 in GBM, we used an orthotopic rat glioblastoma survival model.

Methods:NKTR-214 was administered at 0.1 or 0.3 mg/kg q2w iv to Sprague-Dawley rats starting 2 or 7 days (D2, D7) post (p)-implantation of 106 C6 glioma cells into the right striatum. The model requires euthanasia by ~D14 due to tumor burden. Brain tumors were characterized by magnetic resonance (MR) and immunohistochemistry (IHC) for infiltration of CD4+ and CD8+ T cells and for retention of PEG polymer in brain tumor.

Results: Compared to rats receiving vehicle (n = 15), survival was significantly prolonged after NKTR-214 treatment (n = 43, mean 17.2 vs. 10.0 days (P < 0.001) with 15% of rats across all groups alive and tumor-free at Day 50 when the study was terminated. Both doses were equally effective and well tolerated. Surprisingly, treated rats bearing large MR-detectable D7 tumors survived significantly longer compared to rats bearing microscopic D2 tumors (6/21 or ~30% versus 0/21 or 0% respectively at D50, mean 23.1 vs. 12 days, P < 0.004). Concordantly, CD8+ T cells in D7 tumors were significantly increased after NKTR-214 therapy compared to vehicle and D2 tumors, while CD4+ remained low with no significant difference between groups. PEG polymer was detected in the tumor at least 72 hours p-injection.

Conclusions: NKTR-214 is well tolerated, prolongs survival and induces immunological activity in the brain when administered to rats harboring orthotopic GBM. While there was no significant dose dependence, a marked increase in survival was observed when larger D7 tumors were treated with NKTR-214 compared to microscopic D2 tumors, associated with increased intratumoral CD8+ T cells. Levels of CD4+ were unchanged, consistent with the mechanism of CD-122 biased activation of the IL2 pathway. While requiring further study, it is intriguing that the increased sensitivity of larger tumors also corresponds to onset of angiogenesis and rapid tumor growth in this model. NKTR-214 is currently being evaluated in an outpatient Phase 1 / 2 clinical trial for the treatment of solid tumors. The results presented suggest a potential role for NKTR-214 in the treatment of patients afflicted with GBM.

Citation Format: Lawrence Recht, Seema Nagpal, Taichang Jang, Milton Merchant, Irene Choi, Ute Hoch, Deborah Charych. Single agent NKTR-214, a biased IL2 pathway agonist, increases immune cell infiltrates in brain tumors and prolongs survival in rodent (rattus) glioblastoma (GBM) [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 1598. doi:10.1158/1538-7445.AM2017-1598

Optimizing bevacizumab dosing in glioblastoma: less is more

Compared to traditional chemotherapies, where dose limiting toxicities represent the maximum possible dose, monoclonal antibody therapies are used at doses well below maximum tolerated dose. However, there has been little effort to ascertain whether there is a submaximal dose at which the efficacy/complication ratio is maximized. Thus, despite the general practice of using Bevacizumab (BEV) at dosages of 10 mg/kg every other week for glioma patients, there has not been much prior work examining whether the relatively high complication rates reported with this agent can be decreased by lowering the dose without impairing efficacy. We assessed charts from 80 patients who received BEV for glioblastoma to survey the incidence of complications relative to BEV dose. All patients were treated with standard upfront chemoradiation. The toxicity was graded based on the NCI CTCAE, version 4.03. The rate of BEV serious related adverse events was 12.5% (n = 10/80). There were no serious adverse events (≥grade 3) when the administered dose was (<3 mg/kg/week), compared to a 21% incidence in those who received higher doses (≥3 mg/kg/week) (P < 0.01). Importantly, the three patient deaths attributable to BEV administration occurred in patients receiving higher doses. Patients who received lower doses also had a better survival rate, although this did not reach statistical significance [median OS 39 for low dose group vs. 17.3 for high dose group (P = 0.07)]. Lower rates of serious BEV related toxicities are noted when lower dosages are used without diminishing positive clinical impact. Further work aimed at optimizing BEV dosage is justified.

Effect of BPM31510 on radiosensitivity of temozolomide-resistant glioblastoma cell model and survival in in vivo C6 glioma rat model supporting phase I clinical investigation in GBM

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Background: Glioblastoma (GB) is characterized by dysregulated metabolism, utilizing glycolysis for energy production to support unrestricted growth. BPM 31510, an ubidecarenone containing lipid nanodispersion effectuates a switch in cancer energy sourcing from glycolysis towards mitochondrial OXPHOS, i.e. reverses Warburg effect, providing rationale for its potential utility in treatment of GB. The current study investigated utility of BPM31510 alone and in combination with temozolomide. Methods: In vitro (U251-MG human GB cell line) and in vivo (C6 glioma rat model) preclinical models of GB were used to assess the anti-cancer activity of BPM 31510 alone (100 mg/kg/d) and combination with TMZ/bevacizumab (BEV). In addition, an in vitro model of acquired TMZ chemo-resistance was established by progressive adaptation of parental U251-MG cells to increasing doses of TMZ. Parental and resistant subclones (TMZ-R) were used to define activity of BPM31510 in the TMZ-refractory setting. Results: In vitro results demonstrated that BPM 31510 has anti-cancer activity in both parental and TMZ-R U251-MG cells with EC50 values of ~400 µM and 800 µM, respectively. Importantly, BPM 31510 treatment also resensitized TMZ-R cell lines to TMZ. In vivo, BPM 31510 treatment was associated with increasing duration of survival; one fifth of the rats treated achieved survival greater than 15 days post implantation, a response not observed in the control or irradiation arms of the study. Assessment of the combination of BPM 31510 with TMZ or BEV in the in vivoC6 glioma rat model is ongoing. A phase I open-label, non-randomized clinical trial to evaluate the safety and tolerability of BPM31510 in patients with recurrent BEV-refractory GB, as well as the changes in GB metabolism by SUV-PET imaging in response to treatment is under investigation. Conclusions: Preclinical data demonstrate that BPM 31510 has potential anti-cancer activity alone and in combination with standard therapy regimens and alleviates TMZ chemo-resistance in preclinical models of GB. These results provide support of a Phase 1 clinical study of BPM31510 in GB; this study is actively enrolling.

Association of SDF1 inhibition with local control and relative cerebral blood volume of glioblastoma

2058

Background: Glioblastoma is the most common and aggressive primary brain tumor, with 75-85% of patients historically having recurrence within the original tumor site. We have shown in preclinical studies that inhibition of the SDF1/CXCR4 pathway by the CXCR4 inhibitor Plerixafor increases tumor response to irradiation by inhibition of the recovery of tumor blood vessels. Methods: Newly diagnosed glioblastoma patients were enrolled to the clinical trial using the investigational agent Plerixafor after standard radiation therapy and temozolomide (NCT01977677). To date, 28 patients out of the planned accrual of 29 have been enrolled to this study. Normalized relative cerebral blood volume (rCBV) ratios were calculated by the mean rCBV within the 95% isodose radiation field one month post-radiation as compared to contralateral white matter outside of the radiation field. Our imaging analysis compares patients treated with Plerixafor compared to a control group receiving standard therapy (chemo-RT). Results: There was a significant reduction in rCBV measured by DSC-MRI within the 95% isodose field one month after radiation therapy in patients receiving Plerixafor compared to control (p < 0.02). The rCBV out of the radiation field was similar between patients receiving Plerixafor compared to control patients one-month post radiation therapy. As of February 7, 2017, only 2 of the total of 9 recurrences occurred within the irradiated field. The rate of out of field recurrence (77%) was therefore much higher than expected (20%), with statistical significance (p < 0.03, Fisher’s exact test). Conclusions: We show that Plerixafor has a meaningful impact on local control of glioblastoma. Furthermore, DSC-MRI could be a useful biomarker of its efficacy.

Study of microbial growth on silicone tubes after transcanalicular laser-assisted dacryocystorhinostomy and correlation with patency

INTRODUCTION

Intubation in primary transcanalicular laser assisted dacryocystorhinostomy (TCLADCR) is performed to increase the success rates. However, the associated inflammation and infection can have adverse effects.

OBJECTIVE

To study the microbial infection and drug susceptibility of extubated silicone tubes and final anatomical patency in patients undergoing TCLADCR.

MATERIALS AND METHODS

A non-randomised prospective interventional study was conducted in a tertiary care eye centre. The study included twenty consecutive adult patients with primary nasolacrimal duct obstruction. They underwent TCLADCR with bicanalicular silicone intubation. The stents were removed at 2 months and subjected to culture sensitivity, followed by administration of appropriate antimicrobial agents. Main outcome measures studied were the microbial spectrum on the cultured tubes, their sensitivity profile and its correlation with final anatomical patency.

RESULTS

A positive culture was obtained in 100% cases, comprising of normal commensals and pathogenic organisms. Of the total 24 isolates, 16 (66.6%) Gram positive bacteria (75% Staphylococcus aureus) and 8 (33.3%) Gram negative bacteria (commonest E.coli) were found, with 4 tubes having more than one isolate. No fungal growth was seen. Ninety percent success rate was achieved at one year following appropriate antimicrobial therapy except in 2 patients with gram negative isolates who had failed to take the prescribed antibiotics following sensitivity reports. There was no correlation between multiple infections and success rate. However, by using the Fisher exact test, a positive correlation was obtained between appropriate antibiotic treatment and the final anatomical patency (p less than 0.05).

CONCLUSION

Silicone intubation predisposes to microbial growth, which if neglected, can lead to failure of TCLADCR.

History and current state of immunotherapy in glioma and brain metastasis

Malignant brain tumors such as glioblastoma (GBM) and brain metastasis have poor prognosis despite conventional therapies. Successful use of vaccines and checkpoint inhibitors in systemic malignancy has increased the hope that immune therapies could improve survival in patients with brain tumors. Manipulating the immune system to fight malignancy has a long history of both modest breakthroughs and pitfalls that should be considered when applying the current immunotherapy approaches to patients with brain tumors. Therapeutic vaccine trials for GBM date back to the mid 1900s and have taken many forms; from irradiated tumor lysate to cell transfer therapies and peptide vaccines. These therapies were generally well tolerated without significant autoimmune toxicity, however also did not demonstrate significant clinical benefit. In contrast, the newer checkpoint inhibitors have demonstrated durable benefit in some metastatic malignancies, accompanied by significant autoimmune toxicity. While this toxicity was not unexpected, it exceeded what was predicted from pre-clinical studies and in many ways was similar to the prior trials of immunostimulants. This review will discuss the history of these studies and demonstrate that the future use of immune therapy for brain tumors will likely need a personalized approach that balances autoimmune toxicity with the opportunity for significant survival benefit.

Phase 1/2 Trial of 5-Fraction Stereotactic Radiosurgery With 5-mm Margins With Concurrent and Adjuvant Temozolomide in Newly Diagnosed Supratentorial Glioblastoma: Health-Related Quality of Life Results

PURPOSE

We report a longitudinal assessment of health-related quality of life (HRQOL) in patients with glioblastoma (GBM) treated on a prospective dose escalation trial of 5-fraction stereotactic radiosurgery (25-40 Gy in 5 fractions) with concurrent and adjuvant temozolomide.

METHODS

HRQOL was assessed using the European Organization for Research and Treatment of Cancer (EORTC) quality of life questionnaire core-30 (QLQ-C30) general, the EORTC quality of life questionnaire-brain cancer specific module (QLQ-BN20), and the M.D. Anderson Symptom Inventory-Brain Tumor (MDASI-BT). Questionnaires were completed at baseline and at every follow-up visit after completion of radiosurgery. Changes from baseline for 9 predefined HRQOL measures (global quality of life, physical functioning, social functioning, emotional functioning, motor dysfunction, communication deficit, fatigue, insomnia, and future uncertainty) were calculated at every time point.

RESULTS

With a median follow-up time of 10.4 months (range, 0.4-52 months), 139 total HRQOL questionnaires were completed by the 30 patients on trial. Compliance with HRQOL assessment was 76% at 12 months. Communication deficit significantly worsened over time, with a decline of 1.7 points per month (P=.008). No significant changes over time were detected in the other 8 scales of our primary analysis, including global quality of life. Although 8 patients (27%) experienced adverse radiation effects (ARE) on this dose escalation trial, it was not associated with a statistically significant decline in any of the primary HRQOL scales. Disease progression was associated with communication deficit, with patients experiencing an average worsening of 13.9 points per month after progression compared with 0.7 points per month before progression (P=.01).

CONCLUSION

On this 5-fraction dose escalation protocol for newly diagnosed GBM, overall HRQOL remained stable and appears similar to historical controls of 30 fractions of radiation therapy. Tumor recurrence was associated with worsening communication deficit, and ARE did not correlate with a decline in HRQOL.

Characterization of the peripheral neuropathy associated with brentuximab vedotin treatment of Mycosis Fungoides and Sézary Syndrome

Chemotherapy-induced peripheral neuropathy (CIPN) is common, frequently limits chemotherapy dosing, and negatively impacts quality of life. The National Cancer Institute Common Toxicity Criteria for Adverse Events (CTCAE), version 4.0, and the Total Neuropathy Score clinical version (TNSc) are both validated scores to quantify peripheral neuropathy (PN), with the TNSc being more sensitive to clinical changes. Mycosis fungoides and Sézary syndrome (MF/SS) are characterized by a chronic course, where current therapies are generally non-curative and treatment toxicities have the potential for significant lasting effects. Brentuximab vedotin (BV) is an antibody-drug-conjugate composed of an anti-CD30 monoclonal antibody linked to the microtubule-disrupting agent, monomethyl auristatin E, with a known associated CIPN. In our phase II clinical trial of BV in MF/SS, 25 (69%) of 36 patients developed PN, with 18 (50%) developing Clinically Significant PN, CTCAE v4.0 grade 2 or higher. The median time to grade 2 PN was 15 weeks (range 0.4-48) after the initial dose. By Kaplan-Meier calculation, the median time to improvement from Clinically Significant PN was 30 weeks from the last BV dose. Seventy-four percent had improvement by 24 months. We found that TNSc scores significantly correlated with CTCAE grade, with Spearman correlation coefficient 0.68 (p < 0.001). By logistic regression, for each 100 mg increase in BV total dose, the likelihood of developing Clinically Significant PN increased by 23% (95% CI 4-46%). Improved monitoring of CIPN associated with BV is of paramount importance in the MF/SS population.

Challenges of "Reverse" Aortic Arch Debranching for Repair of the Ascending Aorta by Thoracic Endovascular Aortic Repair

INTRODUCTION

Ascending aortic pathology presents a unique challenge for treatment by thoracic endovascular aortic repair (TEVAR), because of lack of adequate endograft landing zones. This report describes a unique "reverse" extra-anatomical aortic arch debranching procedure performed to enable TEVAR of the ascending aorta.

REPORT

A 71-year-old male presented with a large ascending aortic pseudoaneurysm secondary to previous arch repair anastomosis. This pathology was treated by TEVAR of the ascending aorta. To create a sufficient landing zone for the endovascular stent graft, a "reverse" extra-anatomical aortic arch debranching procedure was performed. This involved a left subclavian artery to left carotid artery bypass, left to right carotid-to-carotid bypass, ligation of proximal left common carotid artery, and embolization of the innominate artery origin.

DISCUSSION

TEVAR of the ascending aorta can be made feasible through a novel debranching procedure that creates sufficient landing zones for the endograft. This surgical approach may prove useful in patients who present with aortic arch pathology and comorbidities that prevent open surgical repair.

Endovascular Repair of a Chronic AV Fistula Presenting as Post-Partum High Output Heart Failure

Introduction

Acute injury to the large vessels is the most feared of diagnoses for a spinal surgeon, but far more common is the delayed presentation of arteriovenous fistula (AVF) formation. The mean time to diagnosis of an AV fistula in this scenario is just over 1 month. Treatment can include both open and endovascular repair.

Report

This study presents a case of an otherwise healthy 39-year-old woman who initially presented with orthopnea, leg edema, and a presumptive diagnosis of post-partum cardiomyopathy. Cardiac investigations revealed high output cardiac failure and an abdominal CT scan confirmed an arterial venous fistula from the left common iliac artery to left common iliac vein. The patient maintained a cardiac output three times normal prior to her definitive treatment. This high flow physiology caused unique challenges for the endovascular procedure as the stent graft collapsed and distorted toward the iliac side wall. The AV fistula was eventually covered successfully and post-operative studies show no further fistula and normal cardiac function. This case demonstrates an unanticipated effect of very high flows of stent graft deployment.

Discussion

Extreme high flow AV fistulas can present as unexpected challenges to endovascular repair. These issues may be ameliorated by techniques such as controlled hypotension, adenosine, ventricular pacing, or proximal balloon occlusion.

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This chronic AV fistula was diagnosed 12 years after lumbar discectomy.

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Only after the normal physiological state of pregnancy, and its elevated high cardiac output requirements did the patient decompensate with orthopnea and edema.

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This otherwise healthy 39-year-old woman had three times the cardiac output expected which was caused by her iliac artery to iliac vein fistula.

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Endovascular treatment is a viable option to cover the fistula, but the high flows can collapse and distort the stent graft during deployment.

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Controlled hypotension, adenosine, ventricular pacing or proximal balloon occlusion may be appropriate if extreme flows are anticipated.