MICA: Targeted Regulatory T Cell Therapy for Inflammatory Bowel Disease

克罗恩病(CD)是一种常见的炎症性肠病，导致严重的慢性并发症和医疗费用。尽管适当地使用了CD药物，许多CD患者仍有持续的肠道炎症或需要手术治疗。这一重大的未得到满足的需求迫使开发新的、有效的治疗方法。胸腺来源的调节性T细胞(TTregs)与小鼠和人类的优势外周耐受有关。在这两个物种中，影响Treg功能的单基因缺陷(例如FOXP3或IL-10R缺陷)会导致包括肠道在内的多系统炎症。同基因Tregs可预防或治愈多种小鼠结肠炎模型。GMP扩展的人类Tregs是安全的，在最近用于GvHD和1型糖尿病的I期研究中显示出希望。我们在临床前研究和GMP级浓缩和扩增Tregs用于细胞移植治疗方面有很好的记录。然而，我们最近发现，从CD患者血液中获得的CD8-CD25+MACs丰富的前体群体中，有相当大比例的tTregs表达促炎细胞因子，这可能在过继转移后授予促炎表型。我们的新数据表明，通过扩增CD患者血液中高度纯净的Tregs亚群，并根据CD4+CD25hiCD127loCD45RA+的表达进行FACS分选，可以避免这种表型。与从富含MACs的前体细胞扩增的tTregs或FACS分选的CD4+CD25hiCD127loCD45RA-前体细胞不同，从CD4+CD25hiCD127loCD45RA+前体细胞扩增的tTregs具有表观遗传稳定的FOXP3表达，这与稳定的tTreg表型和对效应表型的可塑性低相关。这些细胞还抑制自体CD血和粘膜效应T细胞的激活，表达肠道归巢标志，并在带有人小肠的人源化小鼠中定位于人肠道。我们的建议解决了这一未得到满足的医疗需求，将我们的人类临床前数据转换为完整的临床级GMP FACS解决方案，用于从CD患者的血液中制备纯粹的tTregs亚群。在此之后，将进行关键的I/IIa期临床试验，从CD4+CD25hiCD127loCD45RA+前体扩大自体tTregs用于治疗难治性CD。

Crohn's disease (CD) is a common inflammatory bowel disease, causing significant chronic morbidity and healthcare cost. Despite appropriate use of CD medications, many CD patients have on-going intestinal inflammation or require surgery for their disease. This significant unmet need compels the development of novel, effective therapies. Thymically-derived regulatory T cells (tTregs) are associated with dominant peripheral tolerance in mice and humans. In both species, monogenetic defects affecting Treg function (e.g. FOXP3 or IL-10R defects) result in multi-system inflammation, including the intestine. Syngeneic Tregs prevent or cure multiple murine models of colitis. GMP-expanded human Tregs are safe and show promise in recent phase I studies in GvHD and type 1 diabetes. We have a substantial track record in the pre-clinical investigation and GMP-grade enrichment and expansion of Tregs for cell therapy in transplantation. However, we recently found that a significant proportion of tTregs expanded from a CD8-CD25+ MACS-enriched precursor population obtained from CD patients' blood expressed pro-inflammatory cytokines, which may confer a pro-inflammatory phenotype following adoptive transfer. Our new data show that this phenotype can be avoided by expanding a highly pure subpopulation of Tregs from CD patients' blood, enriched by FACS sorting on the basis of CD4+CD25hiCD127loCD45RA+ expression. In contrast to tTregs expanded from MACS-enriched precursors, or FACS sorted CD4+CD25hiCD127loCD45RA- precursors, tTregs expanded from CD4+CD25hiCD127loCD45RA+ precursors have epigenetically stable FOXP3 expression, which is associated with a stable tTreg phenotype and low likelihood of plasticity to an effector phenotype. These cells also suppress activation of autologous CD blood and mucosal effector T cells, express intestinal homing markers and home to human gut in a humanized mouse bearing human small bowel. Our proposal addresses this unmet medical need by translating our human pre-clinical data into a full clinical-grade GMP FACS solution for the preparation of a pure subpopulation of tTregs from the blood of patients with CD. This will be followed by the pivotal phase I/IIa clinical trial of autologous tTregs expanded from CD4+CD25hiCD127loCD45RA+ precursors for the treatment of refractory CD.