Autologous T cells Transduced with an Anti-CD19 Chimeric Antigen Receptor

该项目结合了输注自体抗cd19嵌合抗原受体转导T细胞的临床试验和对输注嵌合抗原受体转导T细胞的患者细胞进行的实验室实验。2012年，该项目在《Blood》杂志上发表了一篇题为“抗cd19嵌合抗原受体转导T细胞临床试验中b细胞耗竭和恶性肿瘤缓解以及细胞因子相关毒性”的全体论文。该项目还产生了一份摘要，作为世界上最重要的血液学会议——美国血液学学会年会上的口头报告。本节的其余部分总结了该项目。化疗耐药的b细胞恶性肿瘤需要新的治疗方法。表达特异性识别b细胞抗原CD19的嵌合抗原受体（CARs）的基因工程T细胞过继转移是治疗b细胞恶性肿瘤的一种有前途的新方法。我们正在进行一项临床试验，患者接受输注自体T细胞，这些细胞被编码抗cd19 CAR的γ -逆转录病毒转导。CAR由抗cd19抗体的可变区域、CD28分子的一部分和CD3-zeta分子的一部分组成。我们的临床方案包括环磷酰胺加氟达拉滨化疗，随后输注抗cd19 - car转导的T细胞。我们在这项临床试验中治疗了21名患者。这些患者患有慢性淋巴细胞白血病（CLL）或非霍奇金淋巴瘤。所有患者都产生了特异性识别表达cd19的靶细胞的抗cd19 car转导T细胞。在最近接受当前版本方案治疗的14名患者中，有5名患者获得了持续的完全缓解。14例患者中有8例获得部分缓解。21名患者中已有两人死亡。在11例可评估的患者中，有9例发生了CD19+ b系细胞的显著缺失。这种b细胞耗竭持续了18个月。由于b细胞耗竭的持续时间较长，这不能归因于患者接受的化疗。例如，一名滤泡性淋巴瘤患者在接受我们的治疗方案之前，其多克隆血B细胞水平正常。治疗6个月后，患者血B细胞计数为1 /微升（正常范围为61-321 /微升）。一名CLL患者在化疗和car -转导T细胞治疗后32天内腺病消退。通过定量PCR检测8例患者血液中car转导细胞。含有CAR基因的外周血单个核细胞（PBMC）的百分比差异很大。在输注后的早期时间点，表达car的T细胞占所有血液T细胞的66%。在car -转导T细胞输注后的前10天，患者出现了明显的毒性。最突出的毒性是低血压和神经毒性。到目前为止，通过定量PCR在所有17例患者的血液中检测到car转导细胞。这些结果表明，表达car的T细胞可以特异性地消除靶细胞，并在人体中引起显著的细胞因子介导的毒性。

This project is a combination of a clinical trial of infusions of autologous anti-CD19 chimeric-antigen-receptor-transduced T cells and laboratory experiments performed on cells obtained from patients that received infusions of the chimeric-antigen-receptor-transduced T cells. During 2012 this project resulted in a Plenary Paper published in Blood entitled "B-cell Depletion and Remissions of Malignancy Along With Cytokine-associated Toxicity in a Clinical Trial of Anti-CD19 Chimeric-antigen-receptor-transduced T cells". The project also resulted in an abstract that was presented as an oral presentation at the most important hematology meeting in the world, the Annual Meeting of the American Society of Hematology. The rest of this section summarizes the project. New therapies are needed for chemotherapy-resistant B-cell malignancies. Adoptive transfer of T cells genetically-engineered to express chimeric antigen receptors (CARs) that specifically recognize the B-cell antigen CD19 is a promising new approach for treating B-cell malignancies. We are conducting a clinical trial in which patients receive infusions of autologous T cells that are transduced with gamma-retroviruses encoding an anti-CD19 CAR. The CAR is made up of the variable regions of an anti-CD19 antibody, a portion of the CD28 molecule, and a portion of the CD3-zeta molecule. Our clinical protocol consists of cyclophosphamide plus fludarabine chemotherapy followed by an infusion of anti-CD19-CAR-transduced T cells. We have treated 21 patients on this clinical trial. The patients had chronic lymphocytic leukemia (CLL) or non-Hodgkin lymphoma. Anti-CD19-CAR-transduced T cells that specifically recognized CD19-expressing target cells were produced for all patients.Of the most recent 14 patients treated on the current version of the protocol, 5 have obtained ongoing complete remissions. Eight of these 14 patients achieved partial remissions. Two of the 21 patients have died. A striking depletion of CD19+ B-lineage cells occurred in 9 of 11 evaluable patients. This B-cell depletion lasted for up to 18 months. Because of the long duration of B-cell depletion, it cannot be attributed to the chemotherapy that the patients received. For example, a patient with follicular lymphoma had a normal level of polyclonal blood B cells before treatment on our protocol. Six months after treatment, he had a blood B cell count of 1 per microliter (normal range 61-321 B cells per microliter). A patient with CLL had a regression of adenopathy in the first 32 days after chemotherapy and CAR-transduced T cell administration. CAR-transduced cells were detected in the blood of all 8 patients by quantitative PCR. The percentage of peripheral blood mononuclear cells (PBMC) containing the CAR gene varied widely. At early time-points after infusion, CAR-expressing T cells constituted up to 66 percent of all blood T cells. Patients had significant toxicities during the first 10 days after CAR-transduced T cell infusion. The most prominent toxicity were hypotension and neurological toxicity. CAR-transduced cells were detected in the blood of all 17 patients studied so far by quantitative PCR. These results demonstrate that CAR-expressing T cells can specifically eliminate targeted cells and cause significant cytokine-mediated toxicity in humans.