Personalized Adoptive T-cell Therapy for AML

摘要/项目摘要 发展扩增和激活AML特异性T细胞的策略至关重要。我们有 开发了一种个性化的癌症疫苗，其中患者来源的肿瘤细胞与自体融合 树突状细胞(DC)，呈现一系列广泛的抗原，捕捉白血病细胞的异质性 种群，包括共有抗原和新抗原。我们已经完成了II期临床试验，在该试验中，患者 接受DC/AML融合的系列疫苗接种化疗后获得缓解。值得注意的是， 尽管中位年龄为63岁，但71%的患者仍未患病，中位随访时间为5年。接种疫苗是 与针对自身AML细胞和白血病相关的T细胞的扩增相关 抗原。DC/AML疫苗可作为产生活化的白血病特异性T细胞的平台。 用于过继免疫治疗的活体。通过这种方式，可以产生白血病特异性的效应细胞， 捕获肿瘤的异质性，并在体外激活以获得功能合格的表型。我们 已经证明，在IL7/IL-15背景下的疫苗刺激导致中枢神经系统水平升高 记忆细胞对反应的长期持续至关重要。虽然疫苗的产生刺激了 白血病特异性T细胞在体内是有效靶向AML细胞的一种有前途的策略， 肿瘤微环境的免疫抑制特性仍然是记忆发展的障碍 应对和长期保护。我们对缓解期的骨髓进行了转录组分析。 与早期相比，接种疫苗以确定可预测持久应答的生物标志物的时间 DC/AML融合疫苗接种后复发。值得注意的是，转化生长因子-β在骨骼中的表达减少 骨髓微环境与持久缓解有关。这些结果与以前的结果一致 报道认为转化生长因子-β是肿瘤免疫原性、T细胞活化和侵袭的负性调节因子 进入肿瘤病床。因此，有很强的理由以转化生长因子β为靶点来提高疫苗效力。在 在这项研究中，我们将创造一种新的策略，通过疫苗介导的过继T细胞治疗 抗原特异性T细胞的刺激、选择和体外扩增。功能特征将是 在具有免疫功能的小鼠白血病模型中进行了检测。然后我们将检查转化生长因子-β抑制的效果。 疫苗下游沉默刺激的T细胞对疫苗应答和转化生长因子的抑制作用 效应器Smad2。在第二个目标中，T细胞产品的特征是针对共享的靶向 和新抗原靶标、寡克隆扩增和保留曲目的多样性、标记的表达 向肿瘤床迁移所需的激活、衰竭、衰老和趋化因子。在第三个目标中， 我们将进行一项I期研究，在这项研究中，急性髓系白血病完全缓解的患者将接受 疫苗刺激的T细胞过继治疗。

Abstract/Project Summary The development of strategies to expand and activate AML specific T cells is of critical importance. We have developed a personalized cancer vaccine in which patient derived tumor cells are fused with autologous dendritic cells (DCs), presenting a broad array of antigens that capture the heterogeneity of the leukemia cell population, including shared and neoantigens. We have completed a phase II clinical trial in which patients that achieve remission following chemotherapy undergo serial vaccination with DC/AML fusions. Remarkably, despite a median age of 63, 71% remained free of disease with a median follow up of 5 years. Vaccination was associated with the expansion of T cells targeting both autologous AML cells and leukemia associated antigens. The DC/AML vaccine can be used as a platform to generate activated leukemia-specific T cells ex- vivo for adoptive immunotherapy. In this way, effector cells may be generated that are leukemia specific, capture tumor heterogeneity, and are activated ex vivo to achieve a functionally competent phenotype. We have demonstrated that vaccine stimulation in the context of IL7/IL-15 results in enhanced levels of central memory cells critical for long term persistence of response. While the generation of vaccine stimulated leukemia specific T cells ex vivo represents a promising strategy to effectively target AML cells in vivo, the immunosuppressive nature of the tumor microenvironment remains a barrier to the development of a memory response and long-term protection. We performed transcriptome analysis in the remission bone marrow at time of vaccination to identify biomarkers that were predictive of durable response as compared to early relapse following vaccination with DC/AML fusions. Of note, decreased expression of TGF-β in the bone marrow microenvironment was associated with durable remission. These results are consistent with prior reports suggesting TGF-β as a negative regulator of tumor immunogenicity, T cell activation and infiltration into the tumor bed. As such there is strong rationale to target TGFβ to enhance vaccine efficacy. In the present study, we will create a novel strategy for adoptive T cell therapy generated by vaccine mediated stimulation, selection of antigen specific T cells and ex vivo expansion. Functional characteristics will be examined in an immunocompetent murine leukemia model. We will then examine the effect of TGF-β inhibition on vaccine response and TGF inhibition within vaccine stimulated T cells by silencing of the downstream effector SMAD2. In the second aim, the T cell product will be characterized with respect to targeting of shared and neo-antigen targets, oligoclonal expansion and diversity of the repertoire, expression of markers of activation, exhaustion, senescence, and chemokines needed for migration into the tumor bed. In the third aim, we will conduct a Phase I study in which patients with AML who achieve complete remission will undergo adoptive therapy with vaccine stimulated T cells.