A Cytomegalovirus-based therapeutic vaccine against oncogenic human papillomaviruses

摘要 高危人类乳头瘤病毒(HPV)会导致宫颈癌，这是全球第二常见的肿瘤 全球女性，以及口咽癌的很大比例。尽管针对HPV的预防性疫苗 实际上，它们没有治疗效果，因此不会使数百万已经感染的人受益。因此， HPV靶向治疗性疫苗既有医学上的需要，也有商业机会。终极的 因此，该项目的目标是在临床试验中评估持续的HPV特异性效应记忆T 传播缺陷巨细胞病毒(CMV)载体诱导和维持的细胞(TEM)反应可以克服 在持续性HPV中观察到的免疫学无知并通过 宫颈上皮内瘤变(CIN)到癌。巨细胞病毒载体疫苗已经显示出前所未有的 在非人类灵长类动物(NHP)模型系统中对艾滋病毒/艾滋病的有效性，包括第一个有文献记载的免疫... 介导清除已建立的慢病毒感染。因此，NHP中的这些综合研究非常有力 提示CMV载体可以对整合到宿主中的持久性病毒起到治疗作用 人类乳头瘤病毒等基因组。CMV载体是唯一无限期保持高频率的疫苗平台 TEM在循环中，即使使用已被修改为限制的安全增强的载体也能观察到这一点 分泌、传播和重新激活。此外，巨细胞病毒载体可以被改造来诱导强大的免疫。 对新表位的反应，诱导CD8+T细胞对亚显性MHC-I-、MHC-E-和MHC-II限制性 在自然感染或常规疫苗接种中未发现的多肽。重要的是，可以使用CMV载体 在CMV阳性宿主中反复出现，但没有失去免疫原性，这是一个关键特征，因为发病率很高 巨细胞病毒在人类中的传播。由于未能清除HPV感染与T细胞虚弱和狭窄有关 我们假设广泛的广度、频率和通过非持续循环 CMV诱导的TEM淋巴组织(包括宫颈)将随着时间的推移清除HPV感染的细胞，并提供 持久的保护。在第一阶段的原则证明研究中，我们在小鼠肿瘤模型中证明了 巨细胞病毒载体诱导T细胞清除表达HPV癌基因E6和E7的肿瘤细胞。正在进行中 我们进一步评估了恒河猴巨细胞病毒对E6和E7的T细胞应答的广度和限制性 NHP中的HPV。为促进基于巨细胞病毒的高危HPV16和HPV16免疫治疗的临床开发 18我们建议设计和构建表达多种安全性的人CMV载体E6/E7 功能。我们将比较两个包含专利修改的专有HCMV载体骨架与 关于它们的体外生长特性以及它们在NHP中诱导HPV特异性T细胞反应的能力。这个 下选的人乳头瘤病毒/人乳头状瘤病毒候选疫苗将在NHP中进一步表征安全性并用于制备 根据现行良好制造规范(CGMP)规定，用于制造的媒介种子库存，因此 启用IND备案和临床测试。

Abstract High-risk human papillomaviruses (HPV) cause cervical cancer, the second most common neoplasm among women globally, and a large proportion of oropharyngeal cancers. Although prophylactic vaccines to HPV are effective they have no therapeutic effect and thus do not benefit the millions of individuals already infected. Thus, there is both a medical need and a commercial opportunity for a HPV-targeting therapeutic vaccine. The ultimate goal of this project is therefore to evaluate in clinical trials whether sustained HPV-specific effector memory T cell (TEM) responses elicited and maintained by spread-deficient cytomegalovirus (CMV)-vectors can overcome the immunological ignorance observed in persistent HPV and terminate the multistep progression through cervical intraepithelial neoplasia (CIN) to cancer. CMV-vectored vaccines have demonstrated unprecedented effectiveness in non-human primate (NHP) model systems for HIV/AIDS including the first documented immune- mediated clearance of an established lentivirus infection. These comprehensive studies in NHP thus strongly suggest that CMV-vectors can provide a therapeutic effect against persistent viruses that integrate into the host genome such as HPV. CMV-vectors are the only vaccine platform that indefinitely maintains high frequencies of TEM in circulation and this is observed even with safety-enhanced vectors that have been modified to limit secretion, dissemination and reactivation. Moreover, CMV-vectors can be engineered to induce robust immune response to novel epitopes, eliciting CD8+ T cells to sub-dominant MHC-I-, MHC-E- and MHC-II-restricted peptides not found in natural infection or upon conventional vaccination. Importantly, CMV vectors can be used repeatedly and in CMV-positive hosts without loss of immunogenicity, a critical feature given the high prevalence of CMV in the human population. Since failure to clear HPV infection correlates with weak and narrow T cell responses we hypothesize that the extensive breadth, frequency and continuous circulation through non- lymphoid tissues (including the cervix) of TEM elicited by CMV will clear HPV-infected cells over time and provide lasting protection. In a proof-of-principle phase I study we demonstrated in a murine tumor model that murine CMV-vectors induce T cells that eliminate tumor cells expressing the HPV oncogenes E6 and E7. In ongoing studies we further evaluate the breadth and restriction of T cell responses elicited by rhesus CMV to E6 and E7 of HPV in NHP. To advance the clinical development of a CMV-based immunotherapy for high risk HPV16 and 18 we propose here to design and construct E6/E7 expressing human CMV vectors displaying multiple safety features. We will compare two proprietary HCMV vector backbones containing patented modifications with respect to their in vitro growth characteristics and their ability to elicit HPV-specific T cell responses in NHP. The down-selected HCMV/HPV vaccine candidate will be further characterized for safety in NHP and used to prepare vector seed stocks for manufacturing under current good manufacturing practice (cGMP) regulations, thus enabling IND-filing and clinical testing.