Gutless Adenovirus Mediated Gene Therapy for Glioma

描述(由申请人提供)： 多形性胶质母细胞瘤(GBM)是成人原发脑肿瘤中最常见的亚型。GB具有极强的侵袭性、高度侵袭性，并渗透到关键的大脑结构中。尽管化疗、手术和放射治疗取得了进展，但从确诊之日起的平均生存期为6-12个月。利用宿主的免疫系统来开发治疗基底膜的新方法已经被尝试。由于受到进展性肿瘤突变的限制，以及不利于维持免疫反应的脑微环境，针对胶质瘤的系统免疫并未产生有益的效果。从脑实质内部启动免疫反应本身受到树突状细胞(DC)的缺乏和免疫抑制环境的限制。我们已经在一个大型同基因啮齿动物颅内胶质瘤模型中测试了一种联合基因治疗方法，该方法使用第一代表达FMS样酪氨酸激酶3配体(FltSL)的重组腺病毒载体(以向脑内招募DC)，以及通过前体药物GCV(GCV)的磷酸化而诱导肿瘤细胞死亡的单纯疱疹病毒1型胸苷激酶(HSV1-TK)，使潜在的抗原性肿瘤表位可用于向脑内招募的DC。这种方法成功地根除了一种大型啮齿动物肉眼肿瘤，而所有其他单基因疗法测试都失败了。然而，在可能在生命早期接触过腺病毒的人类中，免疫反应可以完全取消第一代腺病毒的表达。因此，我们现在已经证明，这可以通过使用新型大容量腺病毒载体(HC-Ad)来克服。对于这项U01建议，我们将进行实验，以严格评估表达FltSL的HC-Ad联合HC-Ad-HSV1-TK+GCV治疗脑瘤的有效性和潜在的神经病理、全身或行为副作用。我们的长期目标是将这种基因治疗方法推向I期临床试验。遵循严格的时间表和特定的里程碑，我们建议首先在大型啮齿动物神经胶质瘤中测试我们的HC-Ad方法的安全性和有效性，然后在内源性自发性狗脑胶质瘤中测试有效性、安全性、全身生物分布和不可预见的副作用，最后测试非人类灵长类动物模型的安全性和脑中的生物分布。在达到之前的所有里程碑后，我们建议在这份U01提案接近尾声时提交FDA批准。

DESCRIPTION (provided by applicant): Glioblastoma multiforme (GBM) is the most common subtype of primary brain tumors in adults. GB is very aggressive, highly invasive, and infiltrates critical brain structures. Mean survival time from the time of diagnosis is 6-12 months, in spite of advances in chemotherapy, surgery and radiotherapy. Harnessing the host's immune system to develop novel treatments for GBM has been attempted. Systemic immunization against glioma has not yielded beneficial effects, since it is limited by progressive tumor mutation, and a brain micro-environment not conducive to sustaining immune responses. Priming immune responses from within the brain parenchyma itself is limited by the paucity of dendritic cells (DC) and an immune-suppressive environment. We have tested in a large syngeneic rodent intracranial glioma model a combined gene therapy approach using first generation recombinant adenovirus vectors expressing fms-like tyrosine kinase 3 ligand (FltSL) (to recruit DCs to the brain), and herpes simplex virus type 1 thymidine kinase (HSV1-TK) that through the phosphorylation of the prodrug GCV (GCV) induces tumor cell death, making potentially antigenic tumor epitopes available to the DCs recruited to the brain. This approach was successful in eradicating a large rodent macroscopic tumor, for which all other single gene therapies tested failed. However, in humans who may have been exposed to adenovirus earlier in life, the immune response can completely abolish expression from first generation adenovirus. Therefore, we have now shown that this can be overcome by the use of the novel high capacity adenoviral vectors (HC-Ad). For this U01 proposal, we will perform experiments to stringently assess the efficiency and potential neuropathological, systemic, or behavioral side effects of the treatment of brain tumors with HC-Ad expressing FltSL in combination with HC- Ad- HSV1-TK+GCV. Our long term aim is to move this gene therapy approach towards Phase I clinical trials. Following a stringent timeline with specific milestones, we propose to test our HC-Ad approach first in a large rodent glioma for safety and efficacy, secondly in endogenous spontaneous dog GBMs for efficacy, safety, systemic biodistribution, and unforeseen side effects, and, finally, test safety and biodistribution in the brain of a non-human primate model. Having met all previous milestones, we propose to file for FDA approval towards the end of this U01 proposal.