Development of an Ad5-CEA/Brachyury Vector Approach for Cancer Treatment

描述（由申请人提供）：随着与肿瘤发展相关的新生物标志物的发现，许多肿瘤相关抗原（TAA）被用于免疫治疗模式，旨在诱导抗肿瘤的细胞毒性免疫反应。越来越清楚的是，这些TAA中的任何一种都不足以作为单一实体开发免疫治疗治疗剂。因此，我们的工作重点是开发针对TAA的多靶点免疫治疗方法。目前项目的总体目标是扩大我们的免疫治疗方法，使用多靶向方法治疗转移性结直肠癌（mCRC）。Drs。国家癌症研究所的Jeffery Schlom和James Gully同意与我们合作实现这一目标。我们的Ad5 [E1-， E2b-]- cea (6D) （ETBX-011）免疫治疗单药在mCRC患者中获得了安全性、剂量反应和总生存率的提高。我们相信，添加抗癌干细胞（CSC）方法可以提高疗效，特别是针对肿瘤转移。因此，我们将Brachyury添加为TAA CSC目标。Brachyury代表了一个相对较新的但有吸引力的免疫治疗靶点。它是T-box转录因子家族的一员，在早期发育中起关键作用，主要是在正常中胚层的形成和分化中，其特征是一个高度保守的dna结合域，称为t结构域。近年来，上皮-间质转化（epithelial-mesenchymal transition， EMT）被认为是原发性肿瘤向转移状态发展的关键步骤，Brachyury在其中起着至关重要的作用。肿瘤EMT已被证明与csc样特征的获得有关，包括csc样特征的获得和维持，对常规治疗、化疗和放疗以及一些小分子靶向治疗的耐药性。Brachyury在人癌细胞中的过度表达诱导了EMT特征的改变，包括间充质标记上调，上皮标记下调，细胞迁移和侵袭增加。重要的是，Brachyury具有免疫原性，体外扩增的Brachyury特异性CD8+ T细胞可以裂解表达Brachyury的肿瘤细胞。这些特点使其成为一种更有吸引力的TAA，可广泛用于免疫治疗目的，特别是用于mCRC。Brachyury被纳入我们的重组Ad5 [E1-， E2b-]平台，用于多种免疫治疗方法治疗mCRC。我们相信，该平台将实现多种免疫，从功能上增强对该靶点的免疫反应，并可能防止转移。我们将把Brachyury整合到我们的重组Ad5 [E1-， E2b-]平台中，以生产一种新的更有效的针对原代和mCRC干细胞的mCRC免疫治疗药物。我们相信这两个TAA靶点作为单一递送免疫治疗剂，将通过靶向CSC增强我们的Ad5 [E1-， E2b-]- CEA（6D）方法的临床反应，并将导致mCRC患者的总生存期增加。

DESCRIPTION (provided by applicant): With the discovery of new biomarkers associated with tumor development, many of these tumor-associated antigens (TAA) are being utilized in immunotherapeutic modalities designed to induce anti-tumor directed cytotoxic immune responses. It is increasingly clear that not any one of these TAA is sufficient, as a single entity to develop an immunotherapeutic treatment agent. Consequently, our efforts are being focused on developing multi-targeted immunotherapeutic approach against TAA. The overall goal of the current project is to expand our immunotherapeutic approach for the treatment of metastatic colorectal cancer (mCRC) using a multiple targeted approach. Drs. Jeffery Schlom and James Gully at the National Cancer Institute have agreed to collaborate with us to reach this goal. We have achieved safety, dose response, and an increased overall survival in mCRC patients using our Ad5 [E1-, E2b-]-CEA(6D) (ETBX-011) immunotherapeutic as a single agent. We believe that adding an anti-cancer stem cell (CSC) approach can lead to increased efficacy particularly against tumor metastases. Thus, we have added Brachyury as a TAA CSC target. Brachyury represents a relatively new but attractive target for immunotherapy. It is a member of the T-box family of transcription factors that play key roles during early development, mostly in the formation and differentiation of normal mesoderm and is characterized by a highly conserved DNA-binding domain designated as T-domain. Recently, epithelial-mesenchymal transition (EMT) has been recognized as a key step during the progression of primary tumors into a metastatic state in which Brachyury plays a crucial role. Tumor EMT has been demonstrated to be associated with the acquisition of CSC-like features that includes acquisition and maintenance of CSC-like characteristics, resistance to conventional therapeutics, chemotherapy and radiation, and to some small-molecule targeted therapies. Over-expression of Brachyury in human carcinoma cells induces changes characteristic of EMT, including up-regulation of mesenchymal markers, down-regulation of epithelial markers, and an increase in cell migration and invasion. Importantly, Brachyury is immunogenic and Brachyury-specific CD8+ T cells expanded in vitro can lyse Brachyury expressing tumor cells. These features make it one of the more attractive TAA that can be utilized broadly for immunotherapeutic purposes but especially for mCRC. Brachyury is incorporated into our recombinant Ad5 [E1-, E2b-] platform for use in the multiple immunotherapy approach to treat mCRC. We believe that this platform will enable multiple immunizations that will functionally boost the immune response to this target and may prevent metastases. We will incorporate Brachyury into our recombinant Ad5 [E1-, E2b-] platform to produce a new and more potent immunotherapeutic for mCRC that will target primary and mCRC stem cells. We believe these two TAA targets as a single delivery immunotherapeutic agent, will enhance the clinical responses of our Ad5 [E1-, E2b-]- CEA(6D) approach by targeting CSC and will result in an increased overall survival of patients with mCRC.