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）是成人原发性脑肿瘤中最常见的亚型。GB是非常具有攻击性、高度侵入性和浸润性的关键脑结构。尽管化疗、手术和放疗取得了进展，但从诊断开始的平均生存时间为6-12个月。已经尝试利用宿主的免疫系统来开发用于GBM的新疗法。针对神经胶质瘤的全身免疫尚未产生有益效果，因为它受到进行性肿瘤突变和不利于维持免疫应答的脑微环境的限制。从脑实质内引发免疫反应本身受到树突状细胞（DC）缺乏和免疫抑制环境的限制。我们在一个大的同基因啮齿类动物颅内胶质瘤模型中测试了一种联合基因治疗方法，该方法使用表达fms样酪氨酸激酶3配体（FltSL）的第一代重组腺病毒载体。（将DC募集到脑），和单纯疱疹病毒1型胸苷激酶（HSV 1-TK），其通过前药GCV（GCV）的磷酸化诱导肿瘤细胞死亡，使潜在的抗原性肿瘤表位可用于募集到脑中的DC。这种方法成功地根除了一种大型啮齿动物肉眼可见的肿瘤，所有其他单基因疗法都失败了。然而，在生命早期可能已经暴露于腺病毒的人类中，免疫应答可以完全消除第一代腺病毒的表达。因此，我们现在已经表明，这可以通过使用新的高容量腺病毒载体（HC-Ad）来克服。对于该U 01提案，我们将进行实验以严格评估用表达FltSL的HC-Ad与HC-Ad-HSV 1-TK+GCV组合治疗脑肿瘤的效率和潜在的神经病理学、全身性或行为副作用。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。遵循具有特定里程碑的严格时间轴，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，其次在内源性自发犬GBM中测试有效性、安全性、全身生物分布和不可预见的副作用，最后在非人灵长类动物模型的脑中测试安全性和生物分布。在满足所有先前的里程碑后，我们建议在本U 01提案结束时提交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.