VLA-4–targeted 67Cu-LLP2A preconditioning enhances efficacy of T-cell-based adoptive immunotherapy

项目概要和摘要 包括嵌合抗原受体（CAR）T细胞的免疫性T细胞疗法（ACT）是新型免疫疗法 取得了空前的成功，尤其是在白血病患者身上。然而，它们在固体中的功效有限。 肿瘤的成功的一个障碍是ACT穿透实体瘤微环境（TME）的能力， 其中过继性T细胞经常遇到常驻的抑制性免疫细胞谱系。管理 化疗形式的淋巴细胞清除预处理，氟达拉滨/环磷酰胺（FLU/CY）， T细胞的输注是确保T细胞植入和持久性的关键步骤。增加全身 对FLU/CY的照射（TBI）可进一步增强淋巴细胞耗竭，但以脱靶毒性为代价。 因此，使用可以更选择性地淋巴细胞清除的药剂可以改善ACT的功效，而不需要额外的治疗。 增加脱靶毒性。LLP2A是一种肽模拟小分子，对极晚期抗原具有高亲和力， 4（VLA-4），在淋巴细胞和几种癌症（包括黑色素瘤和 神经母细胞瘤在这里，我们建议测试VLA-4靶向67Cu-LLP2A放射性核素治疗（TRT）作为单一的治疗。 在两种同基因实体瘤模型中，ACT前，药物或与剂量降低（DR）-FLU/CY联合给药 （pmel-1/hgp100 B16黑色素瘤和GD2 CAR/NXS-2神经母细胞瘤模型）。我们假设 67Cu-LLP2A + DR-FLU/CY联合方案比FLU/CY单用方案更有效 （假设1）。我们还假设67Cu-LLP2A TRT可以通过直接辐射降低肿瘤负荷- 诱导细胞死亡，并可促进T细胞介导的杀伤。我们假设这种新的67Cu-LLP2A 预处理方案将延长用ACT治疗的具有表达VLA-4的实体瘤的小鼠的存活 通过在实体瘤中过继性T细胞的更大渗透和活性（假设2）。为了证明这一点，在 目的1，我们将使用最先进的剂量测定和生物分布研究，以确定剂量，其中67铜- LLP2A作为单药或与DR-FLU/CY联合使用可实现ACT的充分淋巴细胞清除， 引起毒性以及通过直接细胞毒性作用降低肿瘤负荷。在第二章中，我们将考察 全身施用67Cu-LLP2A增强ACT在两种同系固体中的功效的能力 肿瘤模型在完成这些目标后，我们将证明67Cu-LLP2A TRT有潜力 重新定义目前ACT的预处理方法，并改善实体瘤患者的预后。

Project Summary & Abstract Adoptive T cell therapies (ACT) including chimeric antigen receptor (CAR) T cells are novel immunotherapies with unparalleled successes, especially in patients with leukemia. However, they have limited efficacy in solid tumors. One barrier to success is the ability of ACT to penetrate the solid tumor microenvironment (TME), where adoptive T cells often encounter resident suppressive immune cell lineages. The administration of lymphodepleting conditioning in the form of chemotherapy, fludarabine/cyclophosphamide (FLU/CY) prior to the infusion of T cells is a critical step to ensure T cell engraftment and persistence. The addition of total body irradiation (TBI) to FLU/CY can further enhance lymphodepletion but comes at a cost of off-target toxicity. Thus, the use of an agent that can more selectively lymphodeplete may improve the efficacy of ACT without increased off-target toxicity. LLP2A is a peptidomimetic small molecule with a high affinity for very late antigen- 4 (VLA-4), expressed at high levels in lymphocytes and several cancers including melanoma and neuroblastoma. Here, we propose to test VLA-4–targeted 67Cu-LLP2A radionuclide therapy (TRT) as a single agent or in combination with dose-reduced (DR)-FLU/CY prior to ACT in two syngeneic solid tumor models (pmel-1/hgp100 B16 melanoma and GD2 CAR/NXS-2 neuroblastoma model). We hypothesize that the combination of 67Cu-LLP2A + DR-FLU/CY is a more effective lymphodepleting regimen than FLU/CY alone (Hypothesis 1). We also hypothesize that 67Cu-LLP2A TRT can reduce tumor burden through direct radiation- induced cell death and can facilitate T-cell mediated killing. We hypothesize that this new 67Cu-LLP2A conditioning regimen will extend the survival of mice with VLA-4–expressing solid tumors treated with ACT through greater penetration and activity of adoptive T cells within solid tumors (Hypothesis 2). To prove this, in Aim 1, we will use state-of-the-art dosimetry and biodistribution studies to determine the dose where 67Cu- LLP2A as a single agent or combined with DR-FLU/CY can achieve adequate lymphodepletion for ACT without causing toxicity as well reduce tumor burden through direct cytotoxic effects. Then in Aim 2, we will examine the ability of systemically administered 67Cu-LLP2A to enhance the efficacy of ACT in two syngeneic solid tumor models. After completion of these aims, we will demonstrate that 67Cu-LLP2A TRT has the potential to redefine current conditioning approaches for ACT and improve the outcomes of patients with solid tumors.