Novel Small Molecules For Acute Liver Failure

描述（由申请人提供）：急性肝衰竭（ALF）对临床医生和科学家来说都是一个挑战。通常与酒精-对乙酰氨基酚综合征有关，其临床过程是不可预测的和两极分化的，在很大比例的病例中以死亡为结果。由于缺乏特异性治疗，器官移植是唯一临床有效的策略。因此，该领域的转化研究已经成熟，可以确定和开发新的治疗策略，以减轻肝细胞死亡，促进肝再生并改善结果。在最好的情况下，这种治疗方法将加速肝脏再生并排除移植的需要；在最严重的情况下，它们将作为“肝桥”直到移植。大量证据表明，散点因子/肝细胞生长因子（SF/HGF）具有直接的肝保护作用，可作为治疗ALF的潜在药物。然而，以基因或蛋白质治疗的形式使用这种生长因子的可行性受到许多后勤问题的影响。模拟SF/HGF活性的低分子量化合物可以克服这些后勤困难并提供有效的治疗。基于SF/HGF受体c-Met的酪氨酸激酶结构域的atp结合位点的三维结构，并使用结合合理药物设计和临床前生物学的产品发现引擎，我们已经确定了SF/HGF样的小分子围绕着酞嗪-1 (2H)- 1支架。Ang 1170是该类中的主要成员，可激活SF/HGF受体c-Met，并在迄今为止的所有测试中重现了SF/HGF的生物活性。根据I期项目进行的原理验证研究表明，Ang 1170激活肝细胞SF/HGF/c-Met通路，减轻氧化应激诱导的肝细胞死亡，加速部分肝切除边缘肝脏的再生。在哺乳动物ALF模型中，Ang 1170全身预处理可降低死亡率，并减轻肝损伤。我们的初步研究结果具有潜在的重要临床意义，即延迟使用Ang 1170治疗可减轻ALF患者的肝细胞死亡、刺激肝脏再生、降低死亡率并减轻肝功能障碍。重要的是，Ang 1170对衰竭的边缘肝有治疗作用。初步安全性研究表明，Ang 1170治疗是安全且耐受性良好的。在单独资金的支持下，一套正式和全面的关于Ang 1170基因毒理学、毒理学和安全药理学的监管研究正在进行中。目前的II期申请旨在完成Ang 1170的临床前表征，将充分探索其在ALF临床前模型中的治疗效果；一组针对两个物种的急性、体内重复剂量、剂量递增安全性研究将补充这些疗效研究。成功完成拟议的监管研究将支持向食品和药物管理局提交新药研究申请；该申请的批准将允许我们的SF/HGF模拟物Ang 1170的首次临床研究。公共卫生相关性：急性肝功能衰竭仍然是发病率和死亡率的重要原因。一种具有肝保护和肝再生作用的小分子肝细胞生长因子模拟物具有巨大的临床效益。

DESCRIPTION (provided by applicant): Acute liver failure (ALF) constitutes a challenge to clinicians and scientists alike. Commonly associated with the alcohol-acetaminophen syndrome, its clinical course is unpredictable and polarizing, with death as the outcome in a large percentage of cases. Given the lack of specific therapy, organ transplantation is the only clinically effective strategy. Consequently, the field is ripe for translational studies that identify and develop new therapeutic strategies that attenuate hepatocyte death, promote hepatic regeneration and improve outcome. In a best-case scenario, such therapeutics will accelerate liver regeneration and preclude the need for transplantation; in the most severe cases, they will serve as a "hepatic bridge" until transplantation. Significant evidence suggests that scatter factor / hepatocyte growth factor (SF/HGF), exerts direct hepatoprotective effects and can potentially be used as a therapeutic in ALF. However, the feasibility of using this growth factor in the form of gene or protein therapy is compounded by numerous logistical issues. Low molecular weight compounds that mimic the activity of SF/HGF could overcome these logistical difficulties and provide effective therapy. Based on the 3-dimensional structure of the ATP-binding site of the SF/HGF receptor c-Met's tyrosine kinase domain and using a product discovery engine combining rational drug design with preclinical biology, we have identified SF/HGF-like small molecules centered around a phthalazin-1 (2H)- one scaffold. Ang 1170, the lead member within this class, activates the SF/HGF receptor c-Met and has recapitulated the bioactivity of SF/HGF in every assay tested to date. Proof-of-principle studies conducted under our Phase I program indicate that Ang 1170 activates the hepatocyte SF/HGF/c-Met pathway, attenuates oxidative stress-induced hepatocyte death and accelerates regeneration in partially hepatectomized marginal livers. In a mammalian model of ALF, Ang 1170 systemic pretreatment reduces mortality, and attenuates hepatic injury. Of potentially significant clinical relevance is our preliminary findings that delayed treatment with Ang 1170, attenuates hepatocyte death, stimulates liver regeneration, decreases mortality and attenuates liver dysfunction in ALF. Importantly, Ang 1170 is therapeutic in the failing marginal liver. Pilot safety studies suggest that Ang 1170 treatment is safe and well-tolerated. Supported by separate funding, a formal and comprehensive set of regulatory studies profiling the genotoxicology, toxicology and safety pharmacology of Ang 1170 is underway. The present Phase II application, designed to complete the preclinical characterization of Ang 1170, will explore fully its therapeutic efficacy in preclinical models of ALF; a panel of acute, in vivo repeat dose, dose-escalating safety studies in two species will complement these efficacy studies. Successful completion of the proposed regulatory studies will support an Investigational New Drug application to Food and Drug Administration; approval of this application will allow the first clinical studies of our SF/HGF mimetic, Ang 1170. PUBLIC HEALTH RELEVANCE: Acute liver failure remains a significant cause of morbidity and mortality. A small molecule hepatocyte growth factor mimetic that is hepatoprotective and hepatoregenerative is of tremendous clinical benefit.