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

描述（由申请人提供）：目前克罗恩病（CD）的治疗方案并不令人满意，这一点可以通过该疾病的高比例并发症来证明，通常需要进行衰弱性肠切除术。CD被认为是由致病性Th1/Th17细胞过量和耐受诱导抗原（Ag）特异性T调节性CD4+细胞，特别是Tr1细胞（FOXp3-CD25-IL-10high，FOXp3-CD25-IL-4high）缺乏引起的。在缺乏适当水平的调节性T细胞的情况下，致病性Th1/Th17细胞的影响是不可抵抗的，导致粘膜炎症和损伤。超过粘膜完整性的阈值损失，发生肠腔的细菌移位，然后引发粘膜下感染、炎症、组织损伤和更大屏障功能障碍的正反馈循环。为了满足这一需求，Radikal Therapeutics正在开发一种新型融合蛋白（hR-411），该蛋白可在抗原（Ag）特异性活化T细胞中诱导靶向免疫耐受。hR-411由Ig-Fc和CXCL11构建，CXCL11是一种CXCR3结合配体，最近被鉴定为反调节趋化因子。使用mR-411（hR-411的鼠同源物）的治疗深刻地抑制实验性过敏性脑脊髓炎（EAE）（啮齿动物中的经典自身免疫模型系统），即使在疾病发作后开始治疗时也是如此。此外，从用mR-411体内处理的EAE供体中分离的Ag特异性效应Th1细胞将其极化重定向为Tr1细胞，并在过继转移实验中抑制EAE。与泛抑制性免疫调节剂相反，mR-411诱导对活动性疾病具有抗原特异性的耐受性，但保留对先前遇到的抗原的全身免疫力。第1阶段具体目标：在肠道炎症的过继性T细胞转移模型中确定mR-411剂量依赖性地减弱已建立的结肠炎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，所述小鼠通过过继性转移CD4 + CD45RB高T细胞而引起结肠炎。过继性T细胞转移后开始4周开始mR-411或地塞米松治疗。预期mR-411剂量依赖性地改善肠道组织学评分并防止中性粒细胞浸润。第2阶段具体目标：确定hR-411的临床前安全性，如大鼠和灵长类动物毒理学和安全药理学GLP研究所证明。我们将开发：1）用于在无血清培养基中生产hR-411的高产CHO细胞系，2）经验证的分析方法，以支持生产过程中和放行检测，以及3）GMP级hR-411原料药和产品批次，以支持GLP毒理学和安全药理学研究以及GCP临床试验。然后，我们将在绒猴非人灵长类动物中进行急性安全药理学和亚急性及慢性毒理学研究。 公共卫生相关性：克罗恩病仍然是现有疗法的障碍，高比例的患者持续反复发作的炎症和肠道损伤。我们正在开发一种新的药物，专门阻断这种情况下的炎症过程，但不会干扰一般免疫力。我们将在自身免疫性结肠炎的临床相关动物模型中测试这种药物。

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.