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

该项目结合了自体抗CD 19嵌合抗原受体转导T细胞输注的临床试验和对从接受嵌合抗原受体转导T细胞输注的患者中获得的细胞进行的实验室实验。在2012年期间，该项目导致了在Blood上发表的全体会议论文，标题为“抗CD 19嵌合抗原受体转导T细胞临床试验中B细胞耗竭和免疫抑制沿着细胞因子相关毒性的缓解”。该项目还产生了一个摘要，作为口头报告在世界上最重要的血液学会议，美国血液学会年会。本节的其余部分总结了该项目。对于化疗耐药的B细胞恶性肿瘤，需要新的疗法。经遗传工程改造以表达特异性识别B细胞抗原CD 19的嵌合抗原受体（汽车）的T细胞的连续转移是治疗B细胞恶性肿瘤的有希望的新方法。我们正在进行一项临床试验，患者接受自体T细胞的输注，这些T细胞被编码抗CD 19 CAR的γ逆转录病毒转导。CAR由抗CD 19抗体的可变区、CD 28分子的一部分和CD 3-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，然后输注抗CD 19-CAR转导的T细胞。我们在这项临床试验中治疗了21名患者。患者患有慢性淋巴细胞白血病（CLL）或非霍奇金淋巴瘤。为所有患者产生特异性识别表达CD 19的靶细胞的抗CD 19-CAR转导的T细胞。在最近14例接受当前版本方案治疗的患者中，5例获得持续完全缓解。这14例患者中有8例获得部分缓解。21名患者中有2人死亡。11例可评价患者中有9例发生了显著的CD 19 + B系细胞耗竭。这种B细胞耗竭持续长达18个月。由于B细胞耗竭持续时间长，不能归因于患者接受的化疗。例如，滤泡性淋巴瘤患者在我们的方案治疗前多克隆血液B细胞水平正常。治疗6个月后，他的血液B细胞计数为每微升1个（正常范围为每微升61-321个B细胞）。一名CLL患者在化疗和CAR转导的T细胞给药后的前32天内淋巴结肿大消退。通过定量PCR在所有8名患者的血液中检测到CAR转导的细胞。含有CAR基因的外周血单核细胞（PBMC）的百分比变化很大。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%。患者在CAR转导的T细胞输注后的前10天内具有显著的毒性。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名患者的血液中检测到CAR转导的细胞。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精氨酸介导的毒性。

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.