GALV-Based Retroviral Replicating Vectors for Glioma Gene Therapy

用于神经胶质瘤基因治疗的基于 GALV 的逆转录病毒复制载体

• 批准号: 10443010
• 负责人: NORIYUKI KASAHARA
• 金额: $ 40.37万
• 依托单位: UNIVERSITY OF CALIFORNIA, SAN FRANCISCO
• 依托单位国家: 美国
• 财政年份: 2019
• 资助国家: 美国
• 起止时间: 2019-08-01 至 2022-07-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/10443010
• 关键词: GALV; Based; Retroviral; Replicating; Vectors

Glioblastoma multiforme (GBM), the most common primary brain tumor in adults, carries a dismal prognosis. Clinical trials with non-replicating retroviral vectors for gene therapy of GBM showed inadequate gene transfer, without therapeutic benefit. Hence we developed a unique strategy with retroviral replicating vectors (RRV) for more efficient & tumor-selective delivery of prodrug activator (`suicide') genes, without spread to normal tissues. In intracranial glioma models, this enabled tumor-localized activation of an anti-cancer drug from a systemically administered non-toxic prodrug, achieving long-term survival without systemic myelotoxicity. Supported by prior NINDS U01 funding, an optimized RRV expressing the yeast cytosine deaminase suicide gene (RRV-CD, `Toca 511') was developed, and first-in-human Phase I trials for recurrent high-grade glioma have shown radiographic complete responses and significantly increased survival compared to contemporaneous external controls, leading to FDA `Breakthrough Therapy' designation, and a pivotal Phase III trial that is now underway. Ideally, this approach may be augmented by using RRV to deliver 2 or more suicide genes in combination, analogous to combination chemotherapy, but generated within the tumor itself, without systemic myelotoxicity. As viral packaging capacity limits us to a single suicide gene per virus, we developed a second RRV delivering another suicide gene, Herpes simplex thymidine kinase (TK), which activates anti-herpetic prodrugs such as ganciclovir by phosphorylation, and acts as a super-antigen. Also, as RRV encoated with the same envelope compete for binding to the same cell surface receptors, we encoated RRV-TK with Gibbon ape leukemia virus (GALV) envelope to avoid such interference with the current clinical vector RRV-CD, and enable combined use of both viruses. However, since GALV-encoated RRV may show unwanted transduction of hematopoietic cells, here we propose studies to validate the safety and efficacy of this new RRV. As the GALV envelope binds a cellular receptor conserved on human and rat (but not mouse) cells, for intracranial tumor models to evaluate tumor transduction, biodistribution, and genotoxicity, we propose to establish both (a) human glioma xenografts in immunodeficient mice with humanized hematopoiesis, and (b) syngeneic gliomas in immunocompetent rats. To mitigate potential genotoxicity, we also propose to evaluate a novel strategy to restrict RRV by incorporation of the target sequence for microRNA miR-142-3p, which is known to be highly abundant in hematopoietic cells. In the R21 Phase, we will first examine replicative efficiency and selectivity of the newly developed GALV- encoated RRV in glioma vs. hematopoietic cells in vitro (Aim 1), and optimize the above in vivo models (Aim 2). In the R33 Phase, we will employ these models to evaluate tumor selectivity and transduction efficiency of GALV-encoated RRV (Aim 1), and to evaluate its efficacy for suicide gene therapy and activation of anti-tumor immunity (Aim 2). If successful, we will establish a lead candidate for further clinical translation of GALV-encoated RRV-TK, as a single agent by itself and/or combined with RRV-CD, through the CREATE Program.

多形性胶质母细胞瘤（GBM）是成人最常见的原发性脑肿瘤，预后不良。 用非复制型逆转录病毒载体进行GBM基因治疗的临床试验显示基因转移不足， 没有治疗效果。因此，我们用逆转录病毒复制载体（RRV）开发了一种独特的策略， 前药激活物（“自杀”）基因的更有效和肿瘤选择性递送，而不扩散到正常组织。 在颅内神经胶质瘤模型中，这使得肿瘤局部激活抗癌药物， 给药无毒前药，实现长期存活而无全身性骨髓毒性。得到之前的支持 NINDS U 01资助，一种表达酵母胞嘧啶脱氨酶自杀基因的优化RRV（RRV-CD，“Toca 511“），首次在人类I期临床试验的复发性高级别胶质瘤的放射学显示， 与同期外部对照相比，完全反应和显著增加的存活率， 导致FDA“突破性疗法”的认定，以及目前正在进行的关键III期试验。 理想情况下，这种方法可以通过使用RRV组合递送2个或更多个自杀基因来增强， 类似于联合化疗，但在肿瘤本身内产生，没有全身性骨髓毒性。 由于病毒包装能力限制我们每个病毒只能有一个自杀基因，我们开发了第二种RRV， 另一种自杀基因，单纯疱疹胸苷激酶（TK），其激活抗疱疹前药， 更昔洛韦通过磷酸化作用，并作为超抗原。另外，由于RRV包裹的信封 为了与相同的细胞表面受体竞争结合，我们将RRV-TK与巨猿白血病病毒包被， （GALV）包膜，以避免与当前临床载体RRV-CD的这种干扰，并使得能够组合使用 这两种病毒。然而，由于GALV包被的RRV可能显示出造血细胞的不希望的转导， 在这里，我们建议进行研究，以验证这种新的RRV的安全性和有效性。由于GALV包膜结合了 人和大鼠（但不是小鼠）细胞上保守的细胞受体，用于颅内肿瘤模型评估 肿瘤转导、生物分布和遗传毒性，我们建议建立（a）人胶质瘤异种移植物 在具有人源化造血的免疫缺陷小鼠中，和（B）在免疫活性大鼠中的同基因胶质瘤。 为了减轻潜在的遗传毒性，我们还建议评估一种新的策略，以限制RRV的掺入 microRNA miR-142- 3 p的靶序列，已知其在造血细胞中高度丰富。 在R21阶段，我们将首先研究新开发的GALV的复制效率和选择性， 目的1：体外研究RRV在胶质瘤和造血细胞中的表达，并优化上述体内模型（目的2）。 在R33阶段，我们将使用这些模型来评估肿瘤的选择性和转导效率。 目的1研究GALV包裹的RRV（Aim 1）在自杀基因治疗和激活抗肿瘤细胞中的作用 豁免（目标2）。如果成功，我们将建立一个主要候选人，用于进一步的临床翻译GALV编码的 RRV-TK，作为单独的单药和/或与RRV-CD组合，通过CREATE程序。