EGFRvIII-positive Tumor Research Articles

IMMU-05. A PHASE I STUDY IN PROGRESS OF HEGFRVIII-CD3 BI-SCFV (BRITE) IN PATIENTS WITH WHO GRADE IV MALIGNANT GLIOMA

Abstract INTRODUCTION Approximately 30% of glioblastomas harbor the tumor specific EGFRvIII mutation. hEGFRvIII-CD3 bi-scFv (Brain Bi-Specific T Cell Engager - BRiTE) is a novel bispecific antibody construct which can redirect a patient’s entire repertoire of T cells (TCR-agnostic) to specifically lyse EGFRvIII-positive tumor cells. Compared to CAR-T therapy, it offers a highly potent yet off-the-shelf approach for glioblastoma. BRiTE is now entering Phase I clinical trials (NCT04903795) and will be trialed as a monotherapy or with autologous T cell infusion. Migration of T cell binding macromolecules across the blood-brain barrier may be facilitated by activated T cells which adhere to the microvascular endothelium and enter the brain parenchyma. Concurrent administration of activated T cells could therefore enhance trafficking of BRiTE and other antibody-based macromolecules into the intracerebral compartment. HYPOTHESIS We hypothesize that treatment of EGFRvIII-positive WHO grade IV malignant glioma with BRiTE alone or with peripheral T-cell infusion is safe and can induce objective tumor shrinkage at tolerable doses. TRIAL DESIGN/OBJECTIVES A maximum of 18 patients with newly diagnosed or recurrent WHO grade IV malignant EGFRvIII+ glioma will be enrolled after undergoing standard of care treatment. The primary objective will be evaluating the safety of BRiTE alone and with autologous T cell infusion. Patients will receive a single BRiTE infusion, followed 14 days later by an infusion of activated autologous T cells and a second bolus BRiTE infusion. Dose escalation and de-escalation will be managed using a Bayesian optimal interval design. Secondary objectives will be to describe clinical benefit as determined by objective response rate per mRANO criteria, and to evaluate BRiTE pharmacokinetics in serum. CONCLUSION We describe a first-in-human trial of bispecific T cell engager therapy for glioblastoma. We also describe our novel approach for enhancing intracranial penetration of BRiTE using autologous T cell infusion.

Self-Assembled Nanoparticles Prepared from Low-Molecular-Weight PEI and Low-Generation PAMAM for EGFRvIII-Chimeric Antigen Receptor Gene Loading and T-Cell Transient Modification.

BackgroundThe complex preparation procedures and severe toxicities are two major obstacles facing the wide use of chimeric antigen receptor-modified T (CAR-T) cells in clinical cancer immunotherapy. The nanotechnology-based T cell temporary CAR modification may be a potential approach to solve these problems and make the CAR-T cell-based tumor therapy feasible and broadly applicable.MethodsA series of plasmid DNA-loaded self-assembled nanoparticles (pDNA@SNPsx/y) prepared from adamantane-grafted polyamidoamine (Ad-PAMAM) dendrimers of different generations (G1 or G5) and cyclodextrin-grafted branched polyethylenimine (CD-PEI) of different molecular weights (800, 2000, or 25,000 Da) were characterized and evaluated. The detailed physicochemical properties, cellular interaction, and cytotoxicity of selected pDNA@SNPG1/800 were systematically investigated. Thereafter, the epidermal growth factor receptor variant III (EGFRvIII) CAR-expression plasmid vector (pEGFRvIII-CAR) was constructed and encapsulated into SNPG1/800. The resulting pEGFRvIII-CAR@SNPG1/800 was used for Jurkat cell transient transfection, and the EGFRvIII-CAR expressed in transfected cells was measured by flow cytometry and Western blot. Finally, the response of EGFRvIII CAR-positive Jurkat T cell to target tumor cell was evaluated.ResultsThe pDNA@SNPG1/800 showed the highest efficacy in Jurkat cell gene transfection and exhibited low cytotoxicity. pEGFRvIII-CAR@SNPG1/800 can efficiently deliver pEGFRvIII-CAR into Jurkat T cells, thereby resulting in transient EGFRvIII-CAR expression in transfected cells. EGFRvIII-CAR that is present on the cell membrane enabled Jurkat T cells to recognize and bind specifically with EGFRvIII-positive tumor cells.ConclusionThese results indicated that pEGFRvIII-CAR@SNPG1/800 can effectively achieve T-cell transient CAR modification, thereby demonstrating considerable potential in CAR-T cancer therapy.

ATIM-49 (LTBK-01). AMG 596, A NOVEL ANTI-EGFRVIII BISPECIFIC T CELL ENGAGER (BITE®) MOLECULE FOR THE TREATMENT OF GLIOBLASTOMA (GBM): PLANNED INTERIM ANALYSIS IN RECURRENT GBM (RGBM)

Abstract OBJECTIVES The class III variant of the epidermal growth factor receptor (EGFRvIII) represents the most common EGFR mutation in GBM. AMG 596 is a bispecific T cell engager (BiTE®) molecule designed to engage a patient’s own CD3-positive T cells to EGFRvIII-positive tumor antigens. This is the first clinical data readout for AMG 596. METHODS This phase 1, first-in-human, open-label, sequential dose-escalation/expansion study evaluates continuous intravenous AMG 596 in patients with EGFRvIII-positive GBM or malignant glioma in recurrent (Group 1) or newly diagnosed in maintenance treatment (Group 2) settings. Eligible patients: adults with EGFRvIII-positive GBM or malignant glioma; ≤2 mg/day dexamethasone, ECOG performance status ≤1; life expectancy ≥3 months; and acceptable renal, hematological, and hepatic function. The primary objective evaluates safety and tolerability. Additional assessments include objective response rate per modified Response Assessment in Neuro-Oncology (RANO) Criteria. RESULTS As of June 2019, 15 rGBM patients (Group 1) were enrolled; 14 patients received ≥1 dose AMG 596. 14/15 (93.3%) patients were evaluable at time of analysis (safety analysis set). Median age was 54.5 years (range, 44–68); 50% were male. Seven patients discontinued for progressive disease (PD). AEs occurred in all patients and were serious in 7/14 (50%). None resulted in discontinuation; two (14.3%) fatal AEs were related to PD. Headache and depressed consciousness (both n=2, 14.3%) were the most common grade ≥3 treatment emergent AEs. In patients with sufficient follow-up to assess response (n=8), 1 (12.5%) achieved partial response, 2 (25%) had stable disease, 4 (50%) had PD at initial scan, and 1 (12.5%) discontinued treatment for PD. Semi-quantitative EGFRvIII expression analysis revealed a median H-score of 115 (range, 8–280). CONCLUSION This interim analysis suggests a first indication that AMG 596 may be well-tolerated and offer anti-tumor activity in patients with rGBM. Enrollment is ongoing and additional data will be presented. NCT03296696.

Novel anti-EGFRvIII bispecific T cell engager (BiTE) antibody construct in glioblastoma (GBM): Trial in progress of AMG 596 in patients with recurrent or newly diagnosed disease.

TPS2071 Background: GBM is the most aggressive primary brain tumor in adults and is extremely difficult to treat. Patients with GBM tend to progress rapidly within weeks or months. Median overall survival is only 12–15 months despite aggressive treatment, and less than 5% of patients survive 5 years. GBM also severely impacts quality of life and cognitive function. Approximately 50% of GBM tumors test positive for amplification or mutation of the epidermal growth factor receptor (EGFR), the most common of which is the EGFRvIII gain-of-function mutation. AMG 596 is a bispecific T cell engager (BiTE®) antibody construct designed to crosslink and engage CD3-positive T cells to EGFRvIII-positive tumor cells, inducing tumor cell lysis and T cell proliferation. A clinical trial is being conducted for this novel immunotherapy agent in patients with EGFRvIII-positive GBM. Methods: NCT03296696 is a phase 1, first-in-human, open-label, sequential dose-escalation and dose-expansion study evaluating the safety, tolerability, and pharmacokinetics and pharmacodynamics (PK/PD) of AMG 596 in patients with EGFRvIII-positive GBM. AMG 596 is administered via continuous intravenous infusion. The study is expected to enroll approximately 82 patients total and comprises two groups (Group 1: patients with recurrent GBM; Group 2: patients with newly diagnosed GBM in the maintenance treatment phase after standard of care). Key inclusion criteria include: male or female; ≥ 18 years of age; with pathologically documented and diagnosed grade IV GBM; Eastern Cooperative Oncology Group performance status ≤ 1; life expectancy ≥ 3 months per study investigator; and acceptable renal, hematological, and hepatic function. The primary endpoint evaluates the safety and tolerability of AMG 596 via collection of treatment-emergent adverse events. Additional endpoints include objective response rate per modified Response Assessment in Neuro-Oncology Criteria and PK/PD analyses of AMG 596 in serum. The study began enrolling patients in April 2018 and enrollment is ongoing. For more information, please contact Amgen Medical Information: medinfo@amgen.com. Clinical trial information: NCT03296696.

EGFRvIII Is Expressed in Cellular Areas of Tumor in a Subset of Glioblastoma.

Epidermal growth factor receptor variant III (EGFRvIII) is a tumor-specific cell surface antigen often expressed in glioblastoma and has drawn much attention as a possible therapeutic target. We performed immunohistochemistry on histology sections of surgical specimens taken from 67 cases with glioblastoma, isocitrate dehydrogenase-wild type, and evaluated the morphological characteristics and distribution of the EGFRvIII-positive tumor cells. We then evaluated the localization of EGFRvIII-expression within the tumor and peritumoral areas. EGFRvIII immunopositivity was detected in 15 specimens taken from 13 patients, including two recurrent specimens taken from the same patient at relapse. Immunofluorescence staining demonstrated that EGFRvIII-positive cells were present in cells positive for glial fibrillary acidic protein (GFAP), and some showed astrocytic differentiation with multiple fine processes and others did not shown. The EGFRvIII-positive cells were located in cellular areas of the tumor, but not in the invading zone. In the two recurrent cases, EGFRvIII-positive cells were markedly decreased in one case and retained in the other. With regard to overall survival, univariate analysis indicated that EGFRvIII-expression in patients with glioblastoma was not significantly associated with a favorable outcome. Double-labeling immunofluorescence staining of EGFRvIII and GFAP showed that processes of large, well differentiated, GFAP-positive glia extend to and surround less differentiated, EGFRvIII-positive glial cells in cellular areas of tumor. However, in the tumor periphery, EGFRvIII-positive tumor cells were not observed. This finding suggests that EGFRvIII is involved in tumor proliferation, but that invading glioma cells lose their EGFRvIII expression.

The Effect of and Mechanism Underlying Autophagy in Hepatocellular Carcinoma Induced by CH12, a Monoclonal Antibody Directed Against Epidermal Growth Factor Receptor Variant III

Background/Aims: Epidermal growth factor receptor variant III (EGFRvIII), the most frequent EGFR variant, is constitutively activated without binding to EGF and is correlated with a poor prognosis. CH12, a human-mouse chimeric monoclonal antibody, has been developed in our laboratory and selectively binds to overexpressed EGFR and EGFRvIII. A previous study had reported that EGFR could influence autophagic activity, and autophagy is closely related to tumor development and the response to drug therapy. In this study, we aimed to elucidate the effect of CH12 on autophagy and efficacy of combining CH12 with an autophagy inhibitor against EGFRvIII-positive tumors. Methods: EGFRvIII was overexpressed in liver cancer, glioblastoma and breast cancer, and the change in the autophagy-relevant protein levels was analyzed by western blot assays, LC3 punctate aggregation was analyzed by immunofluorescence. The interaction of Beclin-1 and Rubicon was assessed by co-immunoprecipitation (Co-IP) after CH12 treatment. The efficacy of ATG7 or Beclin-1 siRNA in combination with CH12 in Huh-7-EGFRvIII cells was assessed by CCK-8 assays. The autophagy and apoptosis signaling events in Huh-7-EGFRvIII cells upon treatment with control, CH12, siRNA or combination for 48 h were assessed by western blot assays. Results: Our results showed that, in cancer cell lines overexpressing EGFRvIII, only the liver cancer cell lines Huh-7 and PLC/PRF/5 suggested autophagy activation. We then investigated the mechanism of autophagy activation after EGFRvIII overexpression. The results showed that EGFRvIII interacted with Rubicon, an autophagy inhibition protein, and released Beclin-1 to form the inducer complex, thus contributing to autophagy. In addition, CH12, via inhibiting the phosphorylation of EGFRvIII, promoted the interaction of EGFRvIII with Rubicon, further inducing autophagy. In vitro assays suggested that knocking down the expression of the key proteins ATG7 or Beclin-1 in the autophagy pathway with siRNA inhibits tumor cell proliferation. Combining autophagy-related proteins 7 (ATG7) or Beclin-1 siRNA with CH12 in Huh-7-EGFRvIII cells showed better inhibition of cell proliferation. Conclusion: EGFRvIII could induce autophagy, and CH12 treatment could improve autophagy activity in EGFRvIII-positive liver cancer cells. The combination of CH12 with an autophagy inhibitor or siRNA against key proteins in the autophagy pathway displayed more significant efficacy on EGFRvIII-positive tumor cells than monotherapy, and induced cell apoptosis.

Glioblastoma cellular cross-talk converges on NF-κB to attenuate EGFR inhibitor sensitivity

In glioblastoma (GBM), heterogeneous expression of amplified and mutated epidermal growth factor receptor (EGFR) presents a substantial challenge for the effective use of EGFR-directed therapeutics. Here we demonstrate that heterogeneous expression of the wild-type receptor and its constitutively active mutant form, EGFRvIII, limits sensitivity to these therapies through an interclonal communication mechanism mediated by interleukin-6 (IL-6) cytokine secreted from EGFRvIII-positive tumor cells. IL-6 activates a NF-κB signaling axis in a paracrine and autocrine manner, leading to bromodomain protein 4 (BRD4)-dependent expression of the prosurvival protein survivin (BIRC5) and attenuation of sensitivity to EGFR tyrosine kinase inhibitors (TKIs). NF-κB and survivin are coordinately up-regulated in GBM patient tumors, and functional inhibition of either protein or BRD4 in in vitro and in vivo models restores sensitivity to EGFR TKIs. These results provide a rationale for improving anti-EGFR therapeutic efficacy through pharmacological uncoupling of a convergence point of NF-κB-mediated survival that is leveraged by an interclonal circuitry mechanism established by intratumoral mutational heterogeneity.

Highly Specific and Effective Targeting of EGFRvIII-Positive Tumors with TandAb Antibodies.

To harness the cytotoxic capacity of immune cells for the treatment of solid tumors, we developed tetravalent, bispecific tandem diabody (TandAb) antibodies that recognize EGFRvIII, the deletion variant III of the epidermal growth factor receptor (EGFR), and CD3 on T-cells, thereby directing immune cells to eliminate EGFRvIII-positive tumor cells. Using phage display, we identified scFv antibodies selectively binding to EGFRvIII. These highly EGFRvIII-specific, fully human scFv were substantially improved by affinity maturation, achieving KDs in the picomolar range, and were used to construct a set of bispecific EGFRvIII-targeting TandAbs with a broad range of binding and cytotoxic properties. These antibodies exhibited an exquisite specificity for a distinguished epitope in the N-terminal portion of EGFRvIII, as shown on recombinant antigen in Western Blot, SPR, and ELISA, as well as on antigen-expressing cells in FACS assays, and did not bind to the wild-type EGFR. High-affinity EGFRvIII/CD3 TandAbs were most potent in killing assays, displaying cytotoxicity toward EGFRvIII-expressing CHO, F98 glioma, or human DK-MG cells with EC50 values in the range of 1–10 pM in vitro. They also demonstrated dose-dependent growth control in vivo in an EGFRvIII-positive subcutaneous xenograft tumor model. Together with the tumor-exclusive expression of EGFRvIII, the EGFRvIII/CD3 TandAbs’ high specificity and strictly target-dependent activation with no off-target activity provide an opportunity to target tumor cells and spare normal tissues, thereby reducing the side effects associated with other anti-EGFR therapies. In summary, EGFRvIII/CD3 TandAbs are highly attractive therapeutic antibody candidates for selective immunotherapy of EGFRvIII-positive tumors.

Abstract 4417: Characterization of xenograft-derived EGFRvIII-positive GBM cell cultures reveals functional interactions between EGFRvIII, wild-type EGFR, and p53

Abstract In 20% – 30% of all glioblastomas (GBMs), the most common and deadly form of glioma, gene rearrangements in amplified epidermal growth factor receptor (EGFR) cause amplification of a highly oncogenic variant of wild-type EGFR called EGFRvIII. A number of studies demonstrate that EGFRvIII amplification is detected predominantly in GBMs harboring wild-type EGFR amplification or those expressing the wild-type isoform of the tumor suppressor p53. However, it remains unclear why such genetic interactions occur or whether they are advantageous for tumor growth. Our limited understanding of these genetic interactions likely stems from an inability to study the function of amplified EGFRvIII in vitro using currently available model systems. Indeed, there are no immortalized GBM cell lines that express EGFRvIII because prolonged in vitro culture of EGFRvIII-positive GBM tumor cells invariably selects against EGFRvIII amplification. Moreover, the commonly used ectopic EGFRvIII expression models are unlikely to fully recapitulate the function, regulation, and downstream signaling activities of amplified EGFRvIII. Herein, we validate the use of short-term cell cultures derived from GBM xenografts expressing amplified EGFRvIII to study the endogenous function of amplified EGFRvIII. These cells exhibit competency in EGFR signaling, and maintain EGFRvIII expression for up to five months. Further characterization of these cells using small molecule inhibitor and short hairpin RNA approaches reveals three novel observations. First, loss of EGFRvIII expression and activity results in growth arrest and cellular senescence, indicating that EGFRvIII activity is required for cell growth. Second, specific depletion of wild-type EGFR significantly decreases EGFRvIII phosphorylation, demonstrating that high-level wild-type EGFR expression is required for maximal EGFRvIII activation. Third, p53 depletion inhibits growth arrest induced by loss of EGFRvIII activity, strongly suggesting that the growth-promoting activity of EGFRvIII is strictly dependent on p53 function. By showing that EGFRvIII functionally interacts with wild-type EGFR and wild-type p53 in a manner that promotes cell growth, these data provide a functional basis for the commonly observed genetic interactions between amplified EGFRvIII and amplified wild-type EGFR or wild-type p53. Furthermore, our data imply that with help from amplified wild-type EGFR, amplified EGFRvIII functions specifically to overcome the growth inhibitory activity of wild-type p53 in order to promote cell growth. Consistent with this insight, we provide preliminary evidence for the efficacy of a combination therapy involving EGFR and MDM2 inhibitors, which permits concomitant inhibition of EGFR signaling and potentiation of p53 function. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 4417. doi:10.1158/1538-7445.AM2011-4417

Genetically engineered T cells to target EGFRvIII expressing glioblastoma

Glioblastoma remains a significant therapeutic challenge, warranting further investigation of novel therapies. We describe an immunotherapeutic strategy to treat glioblastoma based on adoptive transfer of genetically modified T-lymphocytes (T cells) redirected to kill EGFRvIII expressing gliomas. We constructed a chimeric immune receptor (CIR) specific to EGFRvIII, (MR1-zeta). After in vitro selection and expansion, MR1-zeta genetically modified primary human T-cells specifically recognized EGFRvIII-positive tumor cells as demonstrated by IFN-gamma secretion and efficient tumor lysis compared to control CIRs defective in EGFRvIII binding (MRB-zeta) or signaling (MR1-delzeta). MR1-zeta expressing T cells also inhibited EGFRvIII-positive tumor growth in vivo in a xenografted mouse model. Successful targeting of EGFRvIII-positive tumors via adoptive transfer of genetically modified T cells may represent a new immunotherapy strategy with great potential for clinical applications.

A genetically modified allogeneic cellular vaccine generates MHC class I-restricted cytotoxic responses against tumor-associated antigens and protects against CNS tumors in vivo

An active immunotherapeutic strategy using transfected allogeneic cells for targeting the mutant epidermal growth factor receptor (EGFRvIII) on intracranial tumors was examined. Immunization with allogeneic 300.19/EGFRvIII cells induced CD8 + cytotoxic T-lymphocytes against EGFRvIII bearing syngeneic B16-F10 melanoma or 560 astrocytoma cells (H-2 b), but not against allogeneic NR6 cells (H-2 q) also bearing EGFRvIII significant NK cell activity was also noted in vitro. Vaccination protected against intracranial challenge with EGFRvIII-positive tumor, with 50% long term survival. In vivo depletions of effector cell subsets demonstrated the requirements for both CD8 + and CD4 + T-cells but not NK cells in producing this protective effect. These data demonstrate the generation of significant, antigen-specific and MHC class I-restricted cytotoxic immune responses which are effective against tumors present in the CNS.