Repolarization of Activated Th1 Cells: a Novel Means to Treat IBD

描述(由申请人提供)：克罗恩病(CD)目前的治疗方案并不令人满意，该疾病并发症的比例很高，经常需要进行虚弱的肠道切除。CD被认为是由于致病的Th1/Th17细胞过多和耐受诱导抗原(Ag)特异性调节性T细胞，特别是TR1细胞(Foxp3-CD25-IL-10高，Foxp3-CD25-IL-4高)的缺乏所致。在缺乏适当水平的调节性T细胞的情况下，致病的Th1/Th17细胞的影响是无对抗的，导致粘膜炎症和损伤。超过了粘膜完整性的阈值损失，肠腔的细菌移位发生，然后引起粘膜下感染、炎症、组织损伤和更大的屏障功能障碍的正反馈循环。为了满足这一需求，Radikal Treeutics正在开发一种新型融合蛋白(HR-411)，它可以在抗原(Ag)特异性激活的T细胞中诱导靶向免疫耐受。HR-411是由Ig-FC和CXCL11构建的，CXCL11是一种CXCR3结合配体，最近被发现是一种反调节趋化因子。用HR-411的小鼠同源物MR-411治疗，即使在疾病发作后开始治疗，也能深刻抑制实验性变态反应性脑脊髓炎(EAE)，这是啮齿动物的一种经典自身免疫模型系统。此外，在过继转移实验中，MR-411体内处理的EAE供者体内分离的Ag特异性效应Th1细胞将其极化重定向至TR1细胞，并抑制EAE。与泛抑制性免疫调节剂不同，MR-411诱导对活动期疾病具有抗原特异性的耐受性，同时保持对先前遇到的抗原的普遍免疫力。第一阶段的具体目标：在肠道炎症的T细胞转移模型中建立MR-411剂量依赖地减轻已建立的结肠炎的模型我们将在重组酶激活基因-1缺陷(RAG-/-)小鼠中进行MR-411的剂量递增安慰剂对照研究，小鼠通过过继转移CD4+CD45RBHigh T细胞而发生结肠炎。使用MR-411或地塞米松治疗将在过继T细胞转移后4周开始。MR-411有望剂量依赖性地改善肠道组织学评分，防止中性粒细胞渗入。第二阶段的具体目标：建立HR-411的临床前安全性，如GLP对大鼠和灵长类动物的毒理学和安全药理学研究所证明的那样。我们将开发：1)在无血清介质中生产HR-411的高产CHO细胞系，2)经过验证的分析方法，以支持生产过程中和释放测试，以及3)GMP级批次的HR-411药物物质和产品，以支持GLP毒理学和安全性药理学研究以及GCP临床试验。然后，我们将对Marmoset非人类灵长类动物进行急性安全性药理学和亚急性和慢性毒理学研究。 与公共卫生相关：克罗恩病仍然对现有的治疗方法持顽固态度，有很高比例的患者忍受着反复发作的炎症和肠道损伤。我们正在开发一种新药，专门阻止这种情况下的炎症过程，但不会干扰全身免疫。我们将在自身免疫性结肠炎的临床相关动物模型中测试该制剂。

DESCRIPTION (provided by applicant): Current treatment regimens for Crohn's Disease (CD) are unsatisfactory, as evidenced by the high percentage of complications in the disease, frequently necessitating debilitating intestinal resection. CD is thought to result from both an excess of pathogenic Th1/Th17 cells and a deficiency of tolerance-inducing antigen (Ag) specific T regulatory CD4+ cells, in particular Tr1 cells (FOXp3-CD25-IL-10high, FOXp3-CD25-IL-4high). In the absence of suitable levels of regulatory T-cells, the impact of pathogenic Th1/Th17 cells is unopposed, resulting in mucosal inflammation and injury. Beyond a threshold loss of mucosal integrity, bacterial translocation from the gut lumen takes place, which then elicits a positive feedback loop of submucosal infection, inflammation, tissue injury, and greater barrier dysfunction. To meet this need, Radikal Therapeutics is developing a novel fusion protein (hR-411) that induces targeted immune tolerance in antigen (Ag)-specific activated T-cells. hR-411 is constructed from Ig-Fc and CXCL11, a CXCR3-binding ligand that has been recently identified as a counter- regulatory chemokine. Therapy with mR-411, the murine homologue of hR-411, profoundly suppresses experimental allergic encephalomyelitis (EAE), a classic autoimmune model system in rodents, even when treatment is initiated after disease onset. Moreover, Ag-specific effector Th1 cells isolated from EAE donors treated in vivo with mR-411 redirect their polarization into Tr1 cells and suppress EAE in adoptive transfer experiments. In contrast to pan-suppressive immunomodulators, mR-411 induces tolerance that is Ag-specific for the active disease yet preserves generalized immunity to previously encountered antigens. Phase 1 Specific Aim: Establish that mR-411 dose-dependently attenuates established colitis in an adoptive T-cell transfer model of intestinal inflammation We will carry out a dose-escalation placebo-controlled investigation of mR-411 in recombinase-activating gene-1 deficient (RAG-/-) mice rendered colitic via the adoptive transfer of CD4+CD45RBhigh T-cells. Treatment with mR-411 or dexamethasone will begin 4 weeks after adoptive T-cell transfer. mR-411 is expected to dose-dependently improve gut histology score and prevent neutrophil infiltration. Phase 2 Specific Aim: Establish the pre-clinical safety of hR-411, as demonstrated by GLP studies of toxicology and safety pharmacology in rats and primates. We will develop: 1) a high-producing CHO cell line for production of hR-411 in serum-free media, 2) validated analytical methods to support manufacturing in- process and release testing, and 3) GMP-grade batches of hR-411 drug substance and product to support GLP toxicology and safety pharmacology studies and GCP clinical trials. We will then undertake acute safety pharmacology and subacute and chronic toxicology investigations in Marmoset non-human primates. PUBLIC HEALTH RELEVANCE: Crohn's Disease remains recalcitrant to existing therapies, with a high percentage of patients enduring recurrent bouts of inflammation and intestinal damage. We are developing a novel drug that specifically blocks the inflammatory process in this condition yet does not interfere with general immunity. We will test this agent in a clinically-relevant animal model of autoimmune colitis.