CASPALLO: A PHASE I STUDY EVALUATING THE USE OF ALLODEPLETED T CELLS TRANSDUCED

这个子项目是许多研究子项目中利用 资源由NIH/NCRR资助的中心拨款提供。子项目和 调查员(PI)可能从NIH的另一个来源获得了主要资金， 并因此可以在其他清晰的条目中表示。列出的机构是 该中心不一定是调查人员的机构。 T细胞耗竭干细胞移植(SCT)后供者T细胞回输可加速免疫重建，有效对抗复发恶性肿瘤。单倍体相合SCT后，移植物抗宿主病(GvHD)的高风险基本上排除了这一选择。因此，我们一直在使用CD25免疫毒素耗尽供者T细胞的同种异体反应性前体细胞。我们的方法似乎是有效的，在不增加GvHD的情况下，只需5×104/kg的同种异体半相合供体细胞就能显著加速受者的抗病毒免疫恢复(血液全书[1])。给予较高剂量的细胞是获得抗白血病效果所必需的，而且在一些患者中，这些剂量的细胞即使在同种异体耗尽后也足以引发GvHD，这几乎是不可避免的。因此，我们建议通过在同种异体耗尽的T细胞中加入自杀基因--诱导型caspase 9(ICasp9)来增加我们的方法的安全性，允许在给药有不良反应的情况下破坏它们。ICasp9由促凋亡分子人caspase 9连接到人FK506结合蛋白的药物结合域，加入小分子合成药物导致caspase 9同源二聚化，激活caspase途径，并在24小时内导致转导细胞凋亡。二聚体AP1903已经成功地完成了人体志愿者的安全测试。我们已经产生了编码iCasp9的逆转录病毒载体和一个可选择的标记(截短的CD19)，使转导细胞能够浓缩到90%的纯度。我们计划给表达iCasp9的同种异体耗竭细胞注入不断增加的剂量，从即使对未经修饰的同种异体耗竭细胞也是安全的剂量开始。我们的假设是，任何发生在较高剂量水平的GVHD都会对AP1903的应用产生反应，因为基因修饰的异基因耗竭细胞被破坏。如果我们的假设是正确的，这种方法将能够安全地给予更大剂量和更有效的供体细胞，以优化大多数抗肿瘤和抗病毒的免疫重建，同时确保少数发生GVHD的人可以得到有效的治疗。

This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. Addback of donor T cells following T cell-depleted stem cell transplantation (SCT) can accelerate immune reconstitution and be effective against relapsed malignancy. After haploidentical SCT, a high risk of graft-versus-host disease (GvHD) had essentially precluded this option. We have therefore been depleting donor T cells of alloreactive precursor cells, using a CD25 immunotoxin. Our method appeared effective and as few as 5 x 104/kg allodepleted haploidentical donor cells substantially accelerated anti-viral immune recovery in the recipient, without increasing GvHD (Blood Plenary Paper[1]). Administration of higher doses of cells will be necessary to obtain an antileukemic effect, and it is almost inevitable that in some patients, these doses of cells will be sufficient to trigger GvHD even after allodepletion. We therefore propose to increase the safety of our approach by incorporating a suicide gene, inducible caspase 9 (iCasp9), in the allodepleted T cells, permitting their destruction should administration have adverse effects. iCasp9 consists of a pro-apoptotic molecule, human caspase 9, joined to a drug-binding domain derived from human FK506-binding protein; addition of a small molecule synthetic drug leads to homodimerization of caspase 9, activation of the caspase pathway and apoptosis of the transduced cells within 24 hours. The dimerizer, AP1903, has successfully completed safety-testing in human volunteers. We have generated a retroviral vector encoding iCasp9 and a selectable marker (truncated CD19) to enable enrichment of transduced cells to >90% purity. We plan to infuse escalating doses of iCasp9-expressing allodepleted cells, starting at doses that are safe even for unmodified allodepleted cells. Our hypothesis is that any GVHD that develops at higher dose levels will respond to administration of AP1903 because of destruction of the gene-modified allodepleted cells If our hypothesis is correct, this approach will enable safe administration of larger and more effective doses of donor cells for optimal anti-tumor and anti-viral immune reconstitution in the majority, while ensuring that the minority who develop GVHD can be effectively treated.