Retroviral replicating vector for prodrug activator gene therapy

用于前药激活剂基因治疗的逆转录病毒复制载体

• 批准号: 8455803
• 负责人: DOUGLAS J. JOLLY
• 金额: $ 26.9万
• 依托单位: TOCAGEN, INC.
• 依托单位国家: 美国
• 财政年份: 2012
• 资助国家: 美国
• 起止时间: 2012-09-26 至 2016-04-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8455803
• 关键词: Acyclovir; Adverse drug effect; Adverse effects; Affect; Alkylating Agents; Brain Neoplasms; Cancer Patient; Cell Proliferation; Cells; Cessation of life; Characteristics; Chemotherapy-Oncologic Procedure; Clinic; Clinical; Clinical trial protocol document; Combination Drug Therapy; Combined Modality Therapy; Consultations; Cytolysis; Cytosine deaminase; Data; Dose; Drug Combinations; Enrollment; Environment; Event; Flucytosine; Fluorouracil; Future; Ganciclovir; Gene Delivery; Gene Transduction Agent; Gene Transfer; Genes; Glioblastoma; Glioma; Health system; Herpes Simplex Infections; Human; Image; Immune; Immune response; In Vitro; Infection; Inflammation; Injection of therapeutic agent; Los Angeles; Malignant Neoplasms; Malignant neoplasm of brain; Mediating; Metastatic malignant neoplasm to brain; Mitotic; Modeling; Mus; National Comprehensive Cancer Network; Natural Immunity; Normal Cell; Ohio; Oncolytic; One-Step dentin bonding system; Patients; Pharmaceutical Preparations; Phase I Clinical Trials; Principal Investigator; Prodrugs; Proteins; Recurrence; Research Personnel; Retroviral Vector; Safety; San Francisco; Schedule; Simplexvirus; Solid Neoplasm; Taxane Compound; Testing; Therapeutic; Therapeutic Index; Thymidine Kinase; Time; Topoisomerase Inhibitors; Transgenes; Translating; Validation; Viral; Virus; Virus Replication; Xenograft procedure; Yeasts; base; cancer cell; cancer therapy; cell killing; chemotherapeutic agent; chemotherapy; cytotoxic; dosage; gene therapy; gene therapy clinical trial; in vivo; in vivo Model; leukemia; minimally invasive; neoplastic cell; neuro-oncology; neurosurgery; novel; novel strategies; pre-clinical; premature; response; suicide gene; taxane; transduction efficiency; transgene expression; tumor; tumor eradication; valacyclovir; validation studies; vector

DESCRIPTION (provided by applicant): Many strategies for gene therapy of solid tumors involve the use of replication-defective Moloney murine leukemia (MLV)-based retroviral vectors, but efficacy has been limited due to lack of adequate tumor transduction. Gene transfer using replication-competent retroviral vectors would be more efficient, as each transduced tumor cell produces more vectors capable of initiating further infection events. We have devised novel retroviral replicating vectors (RRV) capable of highly efficient gene delivery to solid tumor in vivo. We have demonstrated that vector spread is restricted to the tumor itself due to restriction by innate immunity in normal cells, and the intrinsic inability of the virus to infect ost-mitotic normal cells. We have enrolled 17 subjects with recurrent high grade glioma (HGG) in multi-center Phase I trials (www.clinicaltrials.gov:NCT01156584, NCT01470794). The RRV in these studies, Toca 511 (vocimagene amiretrorepvec, or RRV-CD in this proposal), expresses an optimized yeast cytosine deaminase (CD) which converts the prodrug 5-fluorocytosine (5-FC) into the classic chemotherapy drug 5-fluorouracil (5- FU). 5-FU is often used in chemotherapy combinations, but agents that directly inhibit cell proliferation interfere with vecto spread. We propose to test combinations of different prodrug activator RRV to inhibit tumor without affecting vector spread. This is made feasible by our discovery that RRV infected tumor cells can be reinfected in vivo. We have now constructed RRV expressing an optimized Herpes simplex thymidine kinase (HSV-TK) prodrug activator gene (RRV-TK in this proposal). We propose to perform validation studies with the newly developed RRV-TK vector both in vitro and in glioma models in vivo. We will evaluate the potential for dual RRV gene therapy combining RRV-CD and RRV-TK. We will 1) test the transduction efficiency, transgene expression level, replicative stability, and cytotoxic potency of RRV-TK, in vitro and in vivo, and 2) determine the optimal parameters for combination therapy, using both RRV-CD and RRV-TK, in vitro and in glioma models in vivo. The information from these studies will be used to develop future clinical trial protocols and, like combination chemotherapy, offers the potential for synergistic therapeutic benefit and more efficient tumor eradication than single-agent therapy with either vector alone. Furthermore, as the infected tumor cells themselves produce their own chemotherapeutic drugs, the adverse effects of systemic chemotherapy are avoided. PUBLIC HEALTH RELEVANCE: Many researchers have used 'crippled' viruses (termed 'vectors') that can infect and modify tumor cells as cancer therapies. However such therapies have been shown to have only limited beneficial effects, because too many tumor cells never get infected. We have devised a new approach, using replicating viruses to achieve highly efficient gene transfer to tumor cells in a highly selective manner (i.e., the virus is selective fr cancer cells and will not infect normal cells). The infected tumor cell becomes a virus-producing cell, sustaining further infection. Our first vector is being tested in a multi-center clinical tril in patients with brain tumor. This proposal seeks to develop a second version of this type of vector to be used in combination with the first. These two gene therapy vectors cause the cancer cells to produce their own chemotherapy drugs and the second vector potentially enables non-invasive imaging of vector infection of brain tumors. If successful in these preclincial studies, this approach can be translated into the clinic and has the potential to reduce suffering and death in brain cancer patients. It may also be applicable to brain metastases caused by other malignancies.

描述（由申请人提供）：实体瘤基因治疗的许多策略涉及使用基于复制缺陷型莫洛尼鼠白血病（MLV）的逆转录病毒载体，但由于缺乏足够的肿瘤转导，疗效有限。使用可复制的逆转录病毒载体进行基因转移将更有效，因为每个转导的肿瘤细胞产生更多能够引发进一步感染事件的载体。我们设计了一种新型的逆转录病毒复制载体（RRV），能够高效地将基因递送到体内实体瘤中。我们已经证明，由于正常细胞中先天免疫的限制，以及病毒感染有丝分裂正常细胞的固有能力，载体传播仅限于肿瘤本身。我们在多中心I期试验中招募了17名患有复发性高级别胶质瘤（HGG）的受试者（www.clinicaltrials.gov：NCT 01156584、NCT 01470794）。这些研究中的RRV Toca 511（vocimagene amiretrorepvec，或本提案中的RRV-CD）表达一种优化的酵母胞嘧啶脱氨酶（CD），可将前药5-氟胞嘧啶（5-FC）转化为经典化疗药物5-氟尿嘧啶（5- FU）。5-FU常用于化疗组合，但直接抑制细胞增殖的药物会干扰载体扩散。我们建议测试不同前药活化剂RRV的组合以抑制肿瘤而不影响载体扩散。我们发现RRV感染的肿瘤细胞可以在体内再感染，这使其可行。我们现在已经构建了表达优化的单纯疱疹胸苷激酶（HSV-TK）前药激活剂基因（本提案中为RRV-TK）的RRV。我们建议在体外和体内胶质瘤模型中使用新开发的RRV-TK载体进行验证研究。我们将评估联合RRV-CD和RRV-TK的双重RRV基因治疗的潜力。我们将1）在体外和体内测试RRV-TK的转导效率、转基因表达水平、复制稳定性和细胞毒性效力，以及2）在体外和体内胶质瘤模型中使用RRV-CD和RRV-TK两者确定联合治疗的最佳参数。来自这些研究的信息将用于开发未来的临床试验方案，并且与联合化疗一样，提供了比单独使用任一载体的单药治疗更有效的协同治疗益处和肿瘤根除的潜力。此外，由于受感染的肿瘤细胞本身产生它们自己的化疗药物，因此避免了全身化疗的副作用。 公共卫生相关性：许多研究人员使用“残废”病毒（称为“载体”），可以感染和修饰肿瘤细胞作为癌症疗法。然而，这种疗法已被证明只有有限的有益效果，因为太多的肿瘤细胞永远不会被感染。我们已经设计了一种新的方法，使用复制病毒以高度选择性的方式实现高效的基因转移到肿瘤细胞（即，该病毒选择性地抵抗癌细胞，并且不会感染正常细胞）。受感染的肿瘤细胞成为病毒产生细胞，持续进一步感染。我们的第一个载体正在脑肿瘤患者的多中心临床试验中进行测试。本提案旨在开发这类载体的第二个版本，以便与第一个版本结合使用。这两种基因治疗载体使癌细胞产生它们自己的化疗药物，并且第二种载体潜在地使得能够对脑肿瘤的载体感染进行非侵入性成像。如果在这些临床前研究中取得成功，这种方法可以转化为临床，并有可能减少脑癌患者的痛苦和死亡。它也可能适用于其他恶性肿瘤引起的脑转移。