Yi Jonathan Zhang

HER2-Specific T Cells Target Primary Glioblastoma Stem Cells and Induce Regression of Autologous Experimental Tumors

Purpose: Glioblastoma multiforme (GBM) is the most aggressive human primary brain tumor and is currently incurable. Immunotherapies have the potential to target GBM stem cells, which are resistant to conventional therapies. Human epidermal growth factor receptor 2 (HER2) is a validated immunotherapy target, and we determined if HER2-specific T cells can be generated from GBM patients that will target autologous HER2-positive GBMs and their CD133-positive stem cell compartment. Experimental Design: HER2-specific T cells from 10 consecutive GBM patients were generated by transduction with a retroviral vector encoding a HER2-specific chimeric antigen receptor. The effector function of HER2-specific T cells against autologous GBM cells, including CD133-positive stem cells, was evaluated in vitro and in an orthotopic murine xenograft model. Results: Stimulation of HER2-specific T cells with HER2-positive autologous GBM cells resulted in T-cell proliferation and secretion of IFN-γ and interleukin-2 in a HER2-dependent manner. Patients HER2-specific T cells killed CD133-positive and CD133-negative cells derived from primary HER2-positive GBMs, whereas HER2-negative tumor cells were not killed. Injection of HER2-specific T cells induced sustained regression of autologous GBM xenografts established in the brain of severe combined immunodeficient mice. Conclusions: Gene transfer allows the reliable generation of HER2-specific T cells from GBM patients, which have potent antitumor activity against autologous HER2-positive tumors including their putative stem cells. Hence, the adoptive transfer of HER2-redirected T cells may be a promising immunotherapeutic approach for GBM. Clin Cancer Res; 16(2); 474–85

Combinational targeting offsets antigen escape and enhances effector functions of adoptively transferred T cells in glioblastoma.

Preclinical and early clinical studies have demonstrated that chimeric antigen receptor (CAR)-redirected T cells are highly promising in cancer therapy. We observed that targeting HER2 in a glioblastoma (GBM) cell line results in the emergence of HER2-null tumor cells that maintain the expression of nontargeted tumor-associated antigens. Combinational targeting of these tumor-associated antigens could therefore offset this escape mechanism. We studied the single-cell coexpression patterns of HER2, IL-13Rα2, and EphA2 in primary GBM samples using multicolor flow cytometry and immunofluorescence, and applied a binomial routine to the permutations of antigen expression and the related odds of complete tumor elimination. This mathematical model demonstrated that cotargeting HER2 and IL-13Rα2 could maximally expand the therapeutic reach of the T cell product in all primary tumors studied. Targeting a third antigen did not predict an added advantage in the tumor cohort studied. We therefore generated bispecific T cell products from healthy donors and from GBM patients by pooling T cells individually expressing HER2 and IL-13Rα2-specific CARs and by making individual T cells to coexpress both molecules. Both HER2/IL-13Rα2-bispecific T cell products offset antigen escape, producing enhanced effector activity in vitro immunoassays (against autologous glioma cells in the case of GBM patient products) and in an orthotopic xenogeneic murine model. Further, T cells coexpressing HER2 and IL-13Rα2-CARs exhibited accentuated yet antigen-dependent downstream signaling and a particularly enhanced antitumor activity.Preclinical and early clinical studies have demonstrated that chimeric antigen receptor (CAR)-redirected T cells are highly promising in cancer therapy. We observed that targeting HER2 in a glioblastoma (GBM) cell line results in the emergence of HER2-null tumor cells that maintain the expression of nontargeted tumor-associated antigens. Combinational targeting of these tumor-associated antigens could therefore offset this escape mechanism. We studied the single-cell coexpression patterns of HER2, IL-13Rα2, and EphA2 in primary GBM samples using multicolor flow cytometry and immunofluorescence, and applied a binomial routine to the permutations of antigen expression and the related odds of complete tumor elimination. This mathematical model demonstrated that cotargeting HER2 and IL-13Rα2 could maximally expand the therapeutic reach of the T cell product in all primary tumors studied. Targeting a third antigen did not predict an added advantage in the tumor cohort studied. We therefore generated bispecific T cell products from healthy donors and from GBM patients by pooling T cells individually expressing HER2 and IL-13Rα2-specific CARs and by making individual T cells to coexpress both molecules. Both HER2/IL-13Rα2-bispecific T cell products offset antigen escape, producing enhanced effector activity in vitro immunoassays (against autologous glioma cells in the case of GBM patient products) and in an orthotopic xenogeneic murine model. Further, T cells coexpressing HER2 and IL-13Rα2-CARs exhibited accentuated yet antigen-dependent downstream signaling and a particularly enhanced antitumor activity.

HER2-Specific Chimeric Antigen Receptor–Modified Virus-Specific T Cells for Progressive Glioblastoma: A Phase 1 Dose-Escalation Trial

Importance Glioblastoma is an incurable tumor, and the therapeutic options for patients are limited. Objective To determine whether the systemic administration of HER2-specific chimeric antigen receptor (CAR)–modified virus-specific T cells (VSTs) is safe and whether these cells have antiglioblastoma activity. Design, Setting, and Participants In this open-label phase 1 dose-escalation study conducted at Baylor College of Medicine, Houston Methodist Hospital, and Texas Children’s Hospital, patients with progressive HER2-positive glioblastoma were enrolled between July 25, 2011, and April 21, 2014. The duration of follow-up was 10 weeks to 29 months (median, 8 months). Interventions Monotherapy with autologous VSTs specific for cytomegalovirus, Epstein-Barr virus, or adenovirus and genetically modified to express HER2-CARs with a CD28.&zgr;-signaling endodomain (HER2-CAR VSTs). Main Outcomes and Measures Primary end points were feasibility and safety. The key secondary end points were T-cell persistence and their antiglioblastoma activity. Results A total of 17 patients (8 females and 9 males; 10 patients ≥18 years [median age, 60 years; range, 30-69 years] and 7 patients <18 years [median age, 14 years; range, 10-17 years]) with progressive HER2-positive glioblastoma received 1 or more infusions of autologous HER2-CAR VSTs (1u2009×u2009106/m2 to 1u2009×u2009108/m2) without prior lymphodepletion. Infusions were well tolerated, with no dose-limiting toxic effects. HER2-CAR VSTs were detected in the peripheral blood for up to 12 months after the infusion by quantitative real-time polymerase chain reaction. Of 16 evaluable patients (9 adults and 7 children), 1 had a partial response for more than 9 months, 7 had stable disease for 8 weeks to 29 months, and 8 progressed after T-cell infusion. Three patients with stable disease are alive without any evidence of progression during 24 to 29 months of follow-up. For the entire study cohort, median overall survival was 11.1 months (95% CI, 4.1-27.2 months) from the first T-cell infusion and 24.5 months (95% CI, 17.2-34.6 months) from diagnosis. Conclusions and Relevance Infusion of autologous HER2-CAR VSTs is safe and can be associated with clinical benefit for patients with progressive glioblastoma. Further evaluation of HER2-CAR VSTs in a phase 2b study is warranted as a single agent or in combination with other immunomodulatory approaches for glioblastoma.

Middle cerebral artery aneurysms: A single-center series comparing endovascular and surgical treatment

OBJECTIVEnThe optimal treatment for middle cerebral artery (MCA) aneurysms is controversial. MCA aneurysms have been considered more conducive to surgical treatment. Recent technology has led to successful endovascular treatment of MCA aneurysms. The objective of this study was to analyze the outcomes of endovascular and surgical treatment of MCA aneurysms as experienced by a single tertiary center.nnnMETHODSnWe retrospectively reviewed 90 MCA aneurysms in 84 patients treated from 2005 to 2010. They were separated into 2 groups: endovascular coiling, with 50 (59.5%) patients, and surgical clipping, with 34 (40.5%) patients. Outcome was based on complications, procedural morbidity and mortality, clinical and angiographic outcomes, and retreatment rates. Patients were further separated into ruptured and unruptured aneurysm groups.nnnRESULTSnRuptured aneurysms were 10 of 50 (20%) and 9 of 34 (26.5%) patients in the endovascular and surgical groups, respectively. Procedure-related complications were 16% and 0% for the endovascular and surgical groups (P = .01), respectively. Overall rate of complete or near-complete occlusion at angiographic follow-up was 86% and 95% for the endovascular and surgical groups (P = .16), respectively. Proportion of patients with modified Rankin scale of 3 to 6 at 6 months follow-up was 10% and 5.9% for the endovascular and surgical groups (P = .5), respectively. The mean angiographic follow-up was 9.02 months (range 0 to 5.2 years). Retreatment rates were 14% and 0% for the endovascular and surgical groups, respectively (P = .01).nnnCONCLUSIONSnIn this nonrandomized sample of 90 MCA aneurysms treated with endovascular coiling or neurosurgical clipping, we observed a similar clinical outcome based on the modified Rankin scale and angiographic occlusion. Complication and retreatment rates were higher but not significant for the endovascular group. Both treatment modalities are good alternatives and should be individualized based on aneurysm angioarchitecture and the patients general conditions.

The Role of Endoscopic Third Ventriculostomy in the Treatment of Communicating Hydrocephalus

OBJECTIVEnTo elucidate the role of endoscopic third ventriculostomy (ETV) in patients with secondary and idiopathic communicating hydrocephalus (HCP).nnnMETHODSnA series of 36 patients with communicating HCP (21 men and 15 women) were treated by ETV between November 2007 and February 2010. The patients age ranged from 19 to 81 years old (mean 52 years), and had a follow-up of 6 to 36 months (mean 9.2 months). The patients were divided into a group of 29 patients with secondary communicating HCP and a group of 7 patients with normal pressure HCP. Sixteen (44.4%) of the patients had a previous ventriculoperitoneal shunt placement that presented with shunt malfunction.nnnRESULTSnThe etiology of secondary HCP was subarachnoid hemorrhage, meningitis, trauma, neoplasm, and others. Etiology was not possible to determine in some patients. The outcome of ETV was considered successful in 27/36 patients (75%). A Kaplan-Meier analysis revealed that the successful proportion of ETVs in secondary communicating HCP at 0.5, 1, and 3 months of follow-up was 0.83, 0.8, and 0.77, respectively; in the idiopathic normal pressure HCP group it was 0.83 initially and became stable at 0.66 after the first month. Overall, the successful proportion of ETV in communicating HCP was at 0, 0.5, 1, and 3 months of follow-up was 0.97, 0.83, 0.78, and 0.75.nnnCONCLUSIONSnETV is a good option in the management of secondary communicating HCP, normal pressure HCP, and replacing malfunctioning ventriculoperitoneal shunts. The indications of ETV as a first-line treatment in communicating HCP needs further study; however, results are promising.

Quantitative comparison of hemodynamic parameters from steady and transient CFD simulations in cerebral aneurysms with focus on the aneurysm ostium

Objective To quantitatively compare hemodynamics simulated with steady-state and transient computational fluid dynamics (CFD) simulations in cerebral aneurysms with single inflow, with focus at the aneurysm ostium. Methods Transient and steady-state CFD simulations were performed in 10 cerebral aneurysms. Distributions and average values for pressure, helicity, vorticity, and velocity were qualitatively compared at proximal and distal parent artery locations, at the ostium plane, and in the aneurysm, and scaling factors between the two kinds of simulations were determined. Relative inflow and outflow areas at the ostium were compared, as were average inflow and outflow velocities. In addition, values for the pressure-loss coefficient (PLC), a recently introduced parameter to assess aneurysm rupture risk, were compared for both kinds of simulation. Results Distributions of hemodynamic parameters had a similar shape but were lower for transient than for steady-state simulations. Averaged scaling factors over cases and anatomical locations showed differences for hemodynamic parameters (0.485±0.01 for pressure, 0.33±0.02 for helicity, 0.58±0.06 for vorticity and 0.56±0.04 for velocity). Good agreement between ratios of inflow and outflow areas at the aneurysm ostium was obtained (Pearson correlation coefficient >0.97, p<0.001) and for the PLC (linear regression slope 0.73±0.14, R2=0.75). Conclusions Steady-state simulations are a quick alternative to transient simulation for visualizing and quantifying inflow and outflow areas at the aneurysm ostium, potentially of value when planning flow diverter treatment and for quantifying the PLC, a potential indicator of aneurysm rupture.

Quantification of speed-up and accuracy of multi-CPU computational flow dynamics simulations of hemodynamics in a posterior communicating artery aneurysm of complex geometry.

Background Towards the translation of computational fluid dynamics (CFD) techniques into the clinical workflow, performance increases achieved with parallel multi-central processing unit (CPU) pulsatile CFD simulations in a patient-derived model of a bilobed posterior communicating artery aneurysm were evaluated while simultaneously monitoring changes in the accuracy of the solution. Methods Simulations were performed using 2, 4, 6, 8, 10 and 12 processors. In addition, a baseline simulation was obtained with a dual-core dual CPU computer of similar computational power to clinical imaging workstations. Parallel performance indices including computation speed-up, efficiency (speed-up divided by number of processors), computational cost (computation time × number of processors) and accuracy (velocity at four distinct locations: proximal and distal to the aneurysm, in the aneurysm ostium and aneurysm dome) were determined from the simulations and compared. Results Total computation time decreased from 9u2005h 10u2005min (baseline) to 2u2005h 34u2005min (10u2005CPU). Speed-up relative to baseline increased from 1.35 (2u2005CPU) to 3.57 (maximum at 10u2005CPU) while efficiency decreased from 0.65 to 0.35 with increasing cost (33.013 to 92.535). Relative velocity component deviations were less than 0.0073% and larger for 12u2005CPU than for 2u2005CPU (0.004±0.002%, not statistically significant, p=0.07). Conclusions Without compromising accuracy, parallel multi-CPU simulation reduces computing time for the simulation of hemodynamics in a model of a cerebral aneurysm by up to a factor of 3.57 (10u2005CPUs) to 2u2005h 34u2005min compared with a workstation with computational power similar to clinical imaging workstations.

Relationships and redundancies of selected hemodynamic and structural parameters for characterizing virtual treatment of cerebral aneurysms with flow diverter devices

BACKGROUND AND PURPOSEnTo quantify the relationship and to demonstrate redundancies between hemodynamic and structural parameters before and after virtual treatment with a flow diverter device (FDD) in cerebral aneurysms.nnnMETHODSnSteady computational fluid dynamics (CFD) simulations were performed for 10 cerebral aneurysms where FDD treatment with the SILK device was simulated by virtually reducing the porosity at the aneurysm ostium. Velocity and pressure values proximal and distal to and at the aneurysm ostium as well as inside the aneurysm were quantified. In addition, dome-to-neck ratios and size ratios were determined. Multiple correlation analysis (MCA) and hierarchical cluster analysis (HCA) were conducted to demonstrate dependencies between both structural and hemodynamic parameters.nnnRESULTSnVelocities in the aneurysm were reduced by 0.14m/s on average and correlated significantly (p<0.05) with velocity values in the parent artery (average correlation coefficient: 0.70). Pressure changes in the aneurysm correlated significantly with pressure values in the parent artery and aneurysm (average correlation coefficient: 0.87). MCA found statistically significant correlations between velocity values and between pressure values, respectively. HCA sorted velocity parameters, pressure parameters and structural parameters into different hierarchical clusters. HCA of aneurysms based on the parameter values yielded similar results by either including all (n=22) or only non-redundant parameters (n=2, 3 and 4).nnnCONCLUSIONnHemodynamic and structural parameters before and after virtual FDD treatment show strong inter-correlations. Redundancy of parameters was demonstrated with hierarchical cluster analysis.

Four-Dimensional Phase Contrast Magnetic Resonance Imaging Protocol Optimization Using Patient-Specific 3-Dimensional Printed Replicas for In Vivo Imaging Before and After Flow Diverter Placement

OBJECTIVEnHemodynamics in cerebral aneurysms are currently investigated toward clinical efficacy using nonstandardized computational simulation techniques. At the same time, flow patterns and velocities are accessible by 4-dimensional phase contrast magnetic resonance imaging (4D pcMRI). Complexity of protocol design and imaging duration has limited the use of this technique in clinical imaging. A new approach is presented to overcome these limitations.nnnMETHODSnThree-dimensional (3D) replicas of 2 cerebral aneurysms were fabricated by fused deposition prototyping (3D printing) and imaged using 4D pcMRI while connected to a magnetic resonance imaging-compatible continuous flow loop. Acquisition parameters were optimized with imaging times not to exceed 10 minutes. Six patients harboring cerebral aneurysms with sizes ranging from 4.7 to 13.8 mm were imaged with the optimized 4D pcMRI protocol. After treatment with the pipeline embolization device (PED), 4D pcMRI examinations were repeated in 3 patients.nnnRESULTSnIn all cases, major flow patterns were visualized well; smaller aneurysms posed a challenge because of limited spatial resolution, whereas larger aneurysms contained regions of low velocity resulting in limited contrast in the flow-sensitive images. After PED placement, ordered aneurysmal flow was disrupted and intra-aneurysmal velocity was reduced on average by 24.5% (range, 12.9-31.5%). Exploratory statistical analysis yielded a positive significant correlation (P < 0.01) between changes in inflow velocity and posttreatment intra-aneurysmal flow velocity.nnnCONCLUSIONSn4D pcMRI flow imaging in cerebral aneurysms within a time frame suitable for clinical imaging applications is feasible with optimized acquisition parameters, thereby enabling quantification of intra-aneurysmal flow changes after flow diverter device treatment.

Desmoplastic non-infantile ganglioglioma in late adulthood

Desmoplastic infantile ganglioglioma (DIG) is an uncommon supratentorial neuroepithelial brain tumor that typically occurs in infants younger than 24xa0months. Desmoplastic non-infantile ganglioglioma (DNIG) is a rare variant of this intracranial neoplasm. There are only 16 DNIG cases reported in the literature, with all patients under the age of 25 at the time of presentation. These DIG and DNIG cases were radiologically and histologically similar, with good outcome after treatment. Despite the size and high mitotic index for patients with DNIG, the prognosis is generally favorable and gross total resection is sufficient. We present a case of a 59-year-old woman with a DNIG. To the best of our knowledge, this is the first case reported of DNIG in late adulthood. Clinical presentation, histological and radiological findings are discussed.