Development of Chimeric Antigen Receptors Targeting Multiple Myeloma

我工作的一个重要重点是为多发性骨髓瘤开发嵌合抗原受体T细胞疗法，多发性骨髓瘤是一种通常无法治愈的浆细胞恶性肿瘤。我的团队是第一个设计和制造专门识别B细胞成熟抗原(BCMA)的汽车。BCMA在正常组织中的表达模式非常有限，但在多发性骨髓瘤的恶性浆细胞上表达。我们构建的BCMA特异性CARS在体外特异性识别多发性骨髓瘤细胞系和原代骨髓瘤细胞，并根除小鼠骨髓瘤。应用免疫组织化学和定量聚合酶链式反应对BCMA在正常人体组织中的表达进行了广泛的分析。免疫组织化学显示，除正常浆细胞表达外，BCMA在正常人体器官中均未见表达。抗BCMA-CAR转导的T细胞治疗晚期多发性骨髓瘤的首个临床试验于2014年9月开放登记。詹姆斯·科琴德费尔是这项试验的首席调查员。在这项试验中，26名患者接受了治疗。在这项试验中有令人印象深刻的反应，这是第一个证明用CAR T细胞消除可测量的多发性骨髓瘤的例子。这项工作导致2016年在《血液》杂志上发表了一篇文章。与蓝鸟生物公司合作，我们开发了一种新的反BCMA汽车，蓝鸟从NCI获得了许可。这辆新车是在我的实验室里开发的，由蓝鸟生物公司改装而成。这款新车正在由Celgene公司进行的全球第一阶段和第二阶段多中心试验中进行测试。我是这款车第一阶段试验的现场PI。这项试验持续最长的完全缓解时间为3年。他的试验结果于2019年5月发表在《新英格兰医学杂志》上；詹姆斯·科琴德费尔是这篇论文的资深作者。CARS T细胞疗法治疗多发性骨髓瘤的另一个总体研究领域是改进CARS的设计。我们有一个项目，着眼于CARS铰链区域结构的变化如何在确定CARS的体内疗效方面起到相当重要的作用。我们已经证明，抗BCMA CAR T细胞铰链区的微小变化可以影响CAR T细胞的体内功能。我们设计了具有完全人类重链唯一抗原识别结构域的新型汽车，并正在进行一项临床试验，测试其中一辆汽车，命名为FHVH33-CD8BBZ。我们假设，与具有单链可变片段抗原识别结构域的传统CARS相比，全人类仅含重链的抗BCMA CAR T细胞的免疫原性较低。在这项临床试验中，有12名患者接受了治疗，其中10名患者有客观反应。我们还在设计针对BCMA以外的抗原的CAR，因为多发性骨髓瘤在许多情况下是一种表型不同的恶性肿瘤，因此靶向不止一个抗原可能是有效地诱导多发性骨髓瘤的长时间无进展间隔所必需的。我们设计了包含靶向信号淋巴细胞激活分子家族成员7(SLAMF7)的CAR结构。我们已经完成了一种编码抗SLAMF7汽车和自杀基因的结构的临床前开发。自杀基因允许按需消除表达CAR的T细胞。自杀基因由一种名为Rimiducid的二聚体试剂激活。二聚化后，caspase9被激活，导致表达CAR的T细胞发生凋亡。抗SLAMF7p；lus自杀基因构建体命名为IC9-Luc90-CD828Z。我们已经启动了IC9-Luc90-CD828Z T细胞的临床试验。

An important focus of my work is development of chimeric antigen receptor T cell therapies for multiple myeloma, which is a usually incurable malignancy of plasma cells. My group was the first to design and construct CARs that specifically recognize B-cell maturation antigen (BCMA). BCMA has a very restricted expression pattern in normal tissues, but BCMA is expressed on the malignant plasma cells of multiple myeloma. The BCMA specific CARs that we have constructed specifically recognize multiple myeloma cell lines and primary myeloma cells in vitro and eradicate myeloma tumors in mice. An extensive analysis of BCMA expression in normal human tissues by immunohistochemistry and quantitative PCR has been conducted. Except for expression by normal plasma cells, BCMA expression was not detected in nomal human organs by immunohistochemistry. The first clinical trial of anti-BCMA-CAR-transduced T cells for treating advanced multiple myeloma was opened for enrollment in September, 2014. James Kochenderfer was Principle Investigator of this trial. Twenty -six patients were treated on this trial. There have been impressive responses on this trial, which were the first demonstrated examples of elimination of measurable multiple myeloma by CAR T cells. This work led to a publication in the journal Blood in 2016. In conjunction with Bluebird Bio, Inc. We have developed a new anti-BCMA CAR that Bluebird licensed from the NCI. This new CAR was developed in my laboratory and modified by bluebird bio. This new CAR is being tested in a world-wide phase I and II multicenter trials conducted by Celgene, Inc. I am a site PI of the phase I trial of this CAR. The longest ongoing complete remission from this trial is 3 years in duration. Results from his trial were published in the New England Journal of Medicine in May 2019; James Kochenderfer was senior author of this paper. Another general area of research on CAR T-cell therapies for multiple myeloma is improving the design of CARs. We have a project looking at how changes in the structure of the hinge region of CARs can be quite important in determining in vivo efficacy of CARs. We have shown that very small changes in the hinge region of anti-BCMA CAR T cells can affect the in vivo function of CAR T cells. We have designed novel CARs with fully-human heavy-chain-only antigen-recognition domains, and a clinical trial testing one of these CARs, designated FHVH33-CD8BBZ, is underway. We hypothesize that fully-human heavy-chain-only anti-BCMA CAR T cells will be less immunogenic than traditional CARs with single-chain variable fragment antigen-recognition domains. 12 patients have been treated on this clinical trial, and 10 of the 12 patients have had objective responses. We are also designing CARs against antigens other than BCMA because multiple myeloma is a phenotypically heterogeneous malignancy in many cases, so targeting more than one antigen might be necessary to effectively induce long progression-free intervals of multiple myeloma. We have designed CAR constructs containing a CAR targeting signaling lymphocyte activation molecule family member 7 (SLAMF7). We have completed preclinical development of a construct that encodes an anti-SLAMF7 CAR and a suicide gene. The suicide gene allows on-demand elimination of the CAR-expressing T cells. The suicide gene is activated by a dimerizer agent called Rimiducid. After dimerization, caspase 9 is activated, which leads to apoptosis of the CAR-expressing T cells. The anti-SLAMF7 p;lus suicide gene construct is designated IC9-Luc90-CD828Z. We have initiated a clinical trial of IC9-Luc90-CD828Z T cells..