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)正被用于免疫治疗方式，旨在诱导抗肿瘤导向的细胞毒性免疫反应。越来越清楚的是，作为一个单一实体，这些TAA中的任何一个都不足以开发免疫治疗治疗剂。因此，我们的努力集中在开发针对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，使用多靶点方法治疗转移性结直肠癌(MCRC)。国家癌症研究所的Jeffery Schlom博士和James Gully博士已经同意与我们合作实现这一目标。使用我们的Ad5[E1-，E2b-]-CEA(6D)(ETBX-011)免疫疗法作为单一药物，我们已经在mCRC患者中实现了安全性、剂量反应和总存活率的增加。我们相信，增加一种抗癌干细胞(CSC)方法可以提高疗效，特别是对肿瘤转移的疗效。因此，我们增加了短视作为TAA CSC的目标。短视是一种相对较新但很有吸引力的免疫治疗靶点。它是转录因子T-box家族中的一员，在早期发育过程中发挥关键作用，主要在正常中胚层的形成和分化中发挥作用，其特征是具有一个高度保守的DNA结合结构域，称为T-结构域。近年来，上皮-间充质转化(EMT)被认为是原发肿瘤向转移状态发展的关键步骤，而短暂性细胞在其中起着至关重要的作用。肿瘤EMT已被证明与CSC样特性的获得有关，包括CSC样特性的获取和维持，对传统治疗、化疗和放射的抵抗，以及一些小分子靶向治疗。人癌细胞过表达短链蛋白可导致EMT特征的改变，包括间质标志物表达上调，上皮标志物表达下调，细胞迁移和侵袭增加。重要的是，短瘤具有免疫原性，体外扩增的短瘤特异性CD8T细胞可以溶解短瘤表达的肿瘤细胞。这些特点使其成为更具吸引力的TAA之一，可广泛用于免疫治疗目的，尤其是对mCRC。Brachyury被整合到我们的重组Ad5[E1-，E2B-]平台中，用于治疗mCRC的多重免疫治疗方法。我们相信，这一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。我们将在我们的重组Ad5[E1-，E2b-]平台中加入短毛刺激素，以生产一种针对原代和mCRC干细胞的新的、更有效的mCRC免疫疗法。我们相信，这两个TAA靶点作为一种单次递送的免疫治疗剂，将通过靶向CSC来增强我们的Ad5[E1-，E2b-]-CEA(6D)方法的临床反应，并将导致mCRC患者的总体存活率增加。

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.