Clinical Evaluation of Chlorotoxin-redirected Chimeric Antigen Receptor (CAR) T cells for Treatment of Glioblastoma

项目摘要 尽管越来越积极的护理标准治疗，但胶质母细胞瘤（GBM）患者的预后较差。 这是一种几十年来一直保持不变的预后，这代表了一种基本的未满足的医疗需求。 在广泛的肿瘤类型中的免疫治疗的进展为免疫方法提供了希望， 包括CAR T细胞疗法，可能会改善GBM患者的预后。这是由以下能力支持的： 靶向CD 19的CAR T细胞消除中枢神经系统（CNS）中的B细胞恶性肿瘤，以及 早期临床经验显示CAR T细胞在GBM中的安全性和疾病修饰活性。一个主要 GBM免疫治疗的挑战是GBM肿瘤的表型异质性， 可靶向的肿瘤相关抗原。作为应对这一挑战的一种方法，我们开发了一种新颖的 CAR，其利用氯毒素（CLTX）的选择性和广泛的GBM结合特性。CLTX是36-氨基 蝎毒的酸性肽成分，特异性结合GBM和其他肿瘤， 对非恶性细胞的反应性。以前的早期临床试验已经确定了CLTX在使用时的安全性 作为GBM靶向肽用于成像和放射治疗。我们的临床前研究表明，CLTX-CAR T细胞在体外和体内介导有效的抗肿瘤活性，对正常人没有可观察到的效应子活性。 人细胞或当过继转移到交叉反应小鼠模型中时。我们现在的目标是，在这项建议中， 临床上测试CLTX-CAR T细胞将是安全的并介导抗肿瘤作用的假设， 局部区域递送至GBM患者的CNS。目标1将评估可行性、安全性和反应 CLTX-CAR T细胞在1期临床试验中复发性GBM患者中的比率。CLTX-CAR T细胞将在 通过瘤内[ICT]和脑室内[ICV]导管局部递送。目标2将评估 CAR介导的免疫学变化与应答和抗性相关。利用我们 基于导管的局部区域输送策略允许在整个治疗过程中采集CSF样本，我们将 监测CAR T细胞活性的替代标志物，包括CAR T细胞的持续性和炎症反应的变化。 细胞因子和内源性免疫亚群。我们还将比较不同的 自体CAR T细胞产物具有临床应答。目的3研究胶质母细胞瘤的耐药途径 以及治疗前和治疗后CAR诱导的肿瘤演变，研究抗原逃逸途径和适应性 CAR T治疗的免疫抑制机制。蝎源性CLTX在肿瘤治疗中的创新应用 靶向将是临床上基于天然肽的CAR的第一个例子， 设计超越基于抗体和配体的靶向结构域。CLTX-CAR T细胞靶向广泛的 单个肿瘤中的GBM细胞是重要的，因为它将扩大我们的医疗设备，并可能有助于 限制抗原逃逸并增强肿瘤根除，从而改善GBM患者的结局。

PROJECT SUMMARY Despite increasingly aggressive standard of care treatments, patients with glioblastoma (GBM) have a poor prognosis that has remained unchanged for decades, and this represents a fundamental unmet medical need. Progress in immunotherapy across a broad range of tumor types provides hope that immunological approaches, including CAR T cell therapy, may improve outcomes for patients with GBM. This is supported by the ability of CD19-targeted CAR T cells to eliminate B cell malignancies in the central nervous system (CNS), as well as early clinical experiences showing safety and disease-modifying activity of CAR T cells in GBM. One major challenge for GBM immunotherapies is the phenotypic heterogeneity of GBM tumors coupled with the scarcity of targetable tumor-associated antigens. As an approach to address this challenge we have developed a novel CAR that exploits the selective and broad GBM-binding properties of chlorotoxin (CLTX). CLTX is a 36-amino acid peptide component of scorpion venom that binds specifically to GBM and other tumors with minimal cross- reactivity to non-malignant cells. Previous early phase clinical trials have established safety of CLTX when used as a GBM-targeting peptide for imaging and radiotherapy. Our preclinical studies demonstrate that CLTX-CAR T cells mediate potent antitumor activity in vitro and in vivo, with no observable effector activity against normal human cells or when adoptively transferred into cross-reactive mouse models. We now aim, in this proposal, to clinically test the hypothesis that CLTX-CAR T cells will be safe and mediate antitumor effects when locoregionally delivered to the CNS in patients with GBM. Aim 1 will evaluate the feasibility, safety and response rates of CLTX-CAR T cells in patients with recurrent GBM in a phase 1 clinical trial. CLTX-CAR T cells will be delivered locoregionally via intratumoral [ICT] and intracerebroventricular [ICV] catheters. Aim 2 will assess CAR-mediated immunological changes associated with response and resistance. Taking advantage of our catheter-based locoregional delivery strategy that allows sampling of the CSF throughout treatment, we will monitor surrogate markers of CAR T cell activity, including CAR T cell persistence and changes in inflammatory cytokines and endogenous immune subsets. We will also compare the intrinsic characteristics across different autologous CAR T cell products with clinical response. Aim 3 will investigate pathways of GBM tumor resistance and CAR-induced tumor evolution pre- and post-therapy, investigating antigen escape pathways and adaptive immunosuppressive mechanisms to CAR T treatment. The innovative use of scorpion-derived CLTX for tumor targeting would be the first example of a natural peptide−based CAR in the clinic, potentially expanding CAR designs beyond antibody- and ligand-based targeting domains. CLTX-CAR T cell targeting of a wide range of GBM cells within individual tumors is significant in that it will expand our armamentarium and potentially help to limit antigen escape and enhance tumor eradication, thereby improving outcomes for patients with GBM.