Novel targeted CAR-T multiple myeloma therapy

项目摘要 多发性骨髓瘤（MM）是浆细胞（PC）的恶性肿瘤，在美国和美国， 全球每年有11.7万人死亡。目前，美国有超过91，000人，全球有超过300，000人患有 毫米尽管在过去的二十年中取得了重大的治疗进展，但MM仍然是不可治愈的，并且大多数MM患者 死于潜在的恶性肿瘤通过嵌合抗原受体-T细胞（CAR-Ts）重定向T细胞的最新疗法 靶向B细胞成熟抗原（BCMA）的抗体或双特异性抗体已经显著改善了患有 既往治疗难治性疾病。然而，几乎所有的MM患者都经历疾病进展， 对这些靶向BCMA的T细胞疗法是难治的。因此，迫切需要制定新的目标， 这些有效的T细胞导向的MM疗法。该1期SBIR应用解决了新的单克隆抗体的需求。 antibody（mAb）denoted MM3. MM 3属于一类新的抗体，可变淋巴细胞受体B（VLRB） 由无颌脊椎动物、七鳃鳗和八目鳗的B细胞产生的抗体，并特异性结合一种独特的形式 一种经过充分验证的MM治疗靶点，CD 38细胞表面蛋白的多聚体形式，无可检测的结合 到CD 38单体。CD 38多聚体由PC和MM肿瘤独特表达，而CD 38单体由PC和MM肿瘤特异表达。 由许多其他正常细胞类型表达，包括NK和T细胞免疫效应子。CAR-T细胞利用MM 3作为 因此，靶向识别结构域避免了与单体结合相关潜在的“中靶/肿瘤外”毒性 CD 38，表达单体CD 38和CAR抗原结合结构域的CAR-T细胞中的“杀兄弟”， 单体CD 38，以及NK和T细胞免疫效应物的耗竭。肿瘤高度表达多聚体CD 38 蛋白酶体和/或免疫调节剂药物难治的复发-难治性MM（RRMM）患者的细胞。虽然 CD 38表达的下调是抗CD 38单克隆抗体治疗抗性的几种机制之一，例如， 达雷妥尤单抗、高水平CD 38和多聚体CD 38表达在抗CD 38 mAb治疗3 - 6个月内恢复 停药后，超过87%的RRMM患者的MM肿瘤细胞表达高水平的CD 38多聚体， MM3。MM 3人CAR-T细胞已经产生，并在体外试验中显示仅对细胞直接CAR-T杀伤 表达多聚体CD 38。本申请将通过以下方式扩展那些结果：（1）用T细胞产生MM 3 CAR-T细胞， 来自健康人类志愿者和抗BCMA CAR-T治疗后复发的患者的制剂， 评价针对来自人的MM细胞系和自体MM肿瘤细胞的体外靶特异性活化和细胞毒性， 抗BCMA CAR-T复发的MM患者，和（2）评估MM 3 CAR-T细胞的体内抗肿瘤功效， 移植有人MM肿瘤细胞系的MISTRG 6“人源化”小鼠。这些I期研究之后将进行 2例用RRMM患者T细胞产生的MM 3 CAR-T针对来自相同患者的肿瘤的体内评价， MISTRG 6模型和通过GMP生产MM 3 CAR慢病毒和MM 3 CAR-T细胞，以及IND使能 药理学/毒理学研究，以支持这种新的CAR-T治疗MM患者的首次人体临床试验， 其他疗法都失败了

PROJECT SUMMARY Multiple myeloma (MM), a malignancy of plasma cells (PCs), is responsible for over 12,500 deaths in the US and over 117,000 deaths worldwide annually. Over 91,000 individuals in the US and over 300,000 worldwide currently live with MM. In spite of major therapeutic advances in the past two decades, MM remains incurable and most MM patients succumb to the underlying malignancy. Recent therapies redirecting T cells via chimeric antigen receptor-T cells (CAR-Ts) or bispecific antibodies that target B Cell Maturation Antigen (BCMA) have significantly improved survival of patients with disease refractory to prior therapies. However, nearly all MM patients experience disease progression and become refractory to these BCMA-targeted T cell therapies. There is therefore an urgent unmet need to develop new targets for these potent T cell-directed MM therapies. This phase 1 SBIR application addresses that need with a novel monoclonal antibody (mAb) designated MM3. MM3 belongs to a new class of antibodies, Variable Lymphocyte Receptor B (VLRB) antibodies produced by the B cells of jawless vertebrates, lamprey and hagfish, and specifically binds to a distinctive form of a well-validated MM therapeutic target, multimeric forms of the CD38 cell surface protein, with no detectable binding to CD38 monomers. CD38 multimers are uniquely expressed by PCs and MM tumors, whereas CD38 monomers are expressed by numerous other normal cell types, including NK and T cell immune effectors. CAR-T cells that utilize MM3 as target recognition domain therefore avoid potential “on-target/off-tumor” toxicity associated with binding to monomeric CD38, “fratricide” among CAR-T cells that express both monomeric CD38 and CAR antigen binding domains that bind monomeric CD38, and depletion of NK and T cell immune effectors. Multimeric CD38 is highly expressed by the tumor cells of relapsed-refractory MM (RRMM) patients refractory to proteasome and/or immunomodulator drugs. Although downregulation of CD38 expression is one of several mechanisms of resistance to anti-CD38 mAb therapy, e.g., daratumumab, high levels of CD38 and multimeric CD38 expression return within 3 to 6 months of anti-CD38 mAb therapy discontinuation, and MM tumor cells of over 87% of RRMM patients express high levels of CD38 multimers detected with MM3. MM3 human CAR-T cells have been produced and shown with in vitro assays to direct CAR-T killing only to cells that express multimeric CD38. This application will extend those results by: (1) producing MM3 CAR-T cells with T cell preparations derived from healthy human volunteers and from patients relapsed following anti-BCMA CAR-T therapy and evaluating in vitro target-specific activation and cytotoxicity against a MM cell line and autologous MM tumor cells from anti-BCMA CAR-T relapsed MM patients, and (2) evaluating the in vivo anti-tumor efficacy of MM3 CAR-T cells with MISTRG6 “humanized” mice engrafted with a human MM tumor cell line. These phase 1 studies will be followed by phase 2 in vivo evaluations of MM3 CAR-Ts produced with RRMM patient T cells against tumors from those same patients in the MISTRG6 model and by GMP production of MM3 CAR lentivirus and MM3 CAR-T cells, and IND-enabling pharmacology/toxicology studies to support first in human clinical trials of this new CAR-T therapy for MM patients that have failed all other therapies.