CAR-T cell control through orthogonal antibody-based switches

项目概要/摘要： 嵌合抗原受体T（CAR-T）细胞疗法在癌症的临床试验中取得了显著的效果; 为复发性难治性急性淋巴细胞白血病患者提供完全缓解， 患者对治愈的希望是现实的。然而，与无法控制CAR-T细胞相关的挑战是， 输注到患者体内会引起严重的安全性问题。这包括永久性B细胞再生障碍性贫血和致死性病例 细胞因子释放综合征此外，恶性细胞上抗原表达的丧失使得常规的免疫治疗变得困难。 CAR-T细胞对复发性疾病无效，并且已归因于在癌症患者中的大量复发。 ALL和CLL白血病的早期临床试验。相应地，控制机制的发展 CAR-T细胞代表了一种关键和紧急的未满足的医疗需求，需要进行彻底的研究， 为患者提供安全有效的CAR-T细胞疗法。 为此，该提案描述了一种工程化基于抗体的开关的方法，其使得能够 对CAR-T细胞活性的可调控制。这些开关介导形成正交的免疫学结构。 靶细胞、开关和CAR-T细胞之间的突触，其在结构上、化学计量上和时间上是 定义为启用以前未报告的控制级别。这项工作的长期目标是 了解这些开关如何提高临床的安全性和多功能性。本报告的总体目标 该提案是研究在白血病背景下使用开关控制CAR-T细胞的活性， 淋巴瘤的小鼠模型。我们的中心假设是，基于抗体的开关，控制 体内CAR-T细胞活性的特异性和持续时间将能够控制疗效、持久性和安全性 过继转移的CAR-T细胞。这项研究的基本原理是， 在患者的免疫系统内正交地使用CAR-T细胞疗法比传统的CAR-T细胞疗法更安全，因为它 由基于抗体的开关的剂量控制并且完全依赖于基于抗体的开关的剂量。 为了检验中心假设，目标1将确定可转换CAR-T细胞的重定向， 一种抗原在小鼠模型中模拟疾病复发。目标2将确定基于开关的控制 影响CAR-T细胞表型，这是重要的，因为持续的表型与 在临床试验中完全缓解。目标3将使用一种独特的小鼠模型， 与传统CART-19治疗相关，以证明对严重不良反应的开关控制 方面的影响.这项研究是开发通用CAR构建体的重要一步， 将消除为每个抗原靶点重建新CAR的需要。预计这将大大降低 “从实验室到床边”开发的成本和时间，以及提供标准化的治疗方案， 这在传统的CAR-T细胞中是不可能实现的。

Project Summary/Abstract: Chimeric antigen receptor T (CAR-T) cell therapy has produced remarkable results in clinical trials for cancer; providing complete remissions in patients with relapsed refractory acute lymphoblastic leukemia, and offering patients a realistic hope for a cure. However, challenges related to the inability to control CAR-T cells once infused into the patient pose significant safety concerns. This includes permanent B cell aplasia and fatal cases of cytokine release syndrome. Additionally, loss of antigen expression on malignant cells renders conventional CAR-T cells ineffective against relapsed disease and has been attributed to a significant number of relapses in early stage clinical trials for ALL and CLL leukemia. Correspondingly, the development of mechanisms to control CAR-T cells represents a critical and urgent unmet medical need which warrants thorough investigation to provide a safe and efficacious CAR-T cell therapy for patients. Towards this end, this proposal describes a method of engineering antibody-based switches which enables tunable control over CAR-T cell activity. These switches mediate formation of an orthogonal immunological synapse between the target cell, switch, and CAR-T cell which is structurally, stoichiometrically, and temporally defined to enable a level of control which has not been reported previously. The long term goal of this work is to understand how these switches can improve safety and versatility in the clinic. The overall objective of this proposal is to investigate the use of switches to control activity of CAR-T cells in the context of leukemia and lymphoma using mouse models. Our central hypothesis is that antibody-based switches which control the specificity and duration of CAR-T cell activity in vivo will enable control over the efficacy, persistence, and safety of adoptively transferred CAR-T cells. The rationale for this research is that a sCAR-T cell which functions orthogonally within the patient’s immune system is safer than conventional CAR-T cell therapy because it is controlled by, and entirely dependent on, dosing of the antibody-based switch. To test the central hypothesis, aim 1 will determine the redirection of switchable CAR-T cells to more than one antigen in mouse models which mimic disease relapse. Aim 2 will determine how switch-based control effects CAR-T cell phenotype which is significant because persistent phenotypes are strongly associated with complete remissions in clinical trials. Aim 3 will use a unique mouse model which recapitulates the toxicity associated with conventional CART-19 therapy to demonstrate switch-based control over severe adverse side effects. The proposed research is a significant step in the development of a universal CAR construct which would obviate the need to reconstruct a new CAR for each antigen target. This is expected to substantially lower the cost and time of “bench to bedside” development, as well as provide a standardized treatment regimen which is not yet possible with conventional CAR-T cells.