TREATMENT OF LIVER INJURY AND FIBROSIS: SAFETY PHARMACOLOGY AND TOXICOLOGY

不同来源的肝肌成纤维细胞(LMF)激活与肝纤维化的发生有关 所有原因的慢性肝病和值得注意的是，LMF通过细胞凋亡清除可能阻止发展 治疗肝纤维化和肝损伤，并可能使肝纤维化逆转后恢复。抑制或逆转 肌成纤维细胞的激活(治疗性细胞靶点)是治疗肝纤维化的关键。两者都有 防止肝纤维化的进展，并可能防止肝纤维化的消退，尽管肝脏持续存在 正如我们在临床前研究中所记录的那样，损伤被认为是患者的重要临床目标 晚期肝纤维化和肝硬变。最后，阻止肝纤维化的进展将会减少 由于大多数肝细胞癌发生在肝硬变，导致了原发性肝癌的发生。的基础 我们的研发是开发一种新型的人源化治疗多肽(XFB-19)。我们 创建了一个使用模拟合成的库，以改善人类治疗的潜在陷阱。我们已经在 逐步分析以选择最安全和最有效的人源化多肽(包括药用多肽 化学，人血浆和人肝微粒体的稳定性分析，激活的细胞凋亡分析 原代人肝脏肌成纤维细胞，无细胞半胱氨酸天冬氨酸氨基转移酶8激活分析，肝损伤/纤维化模型 药代动力学，生物测定，CYP-450抑制研究，人T细胞和小鼠的免疫原性分析， 人干细胞来源的心肌细胞的心脏毒性检测和丙型肝炎病毒感染的毒理学检测 原代人肝细胞、正常小鼠和肝硬变小鼠)。 在失代偿性肝硬变的动物模型中，XFB-19肽挽救了肝细胞死亡和肝脏 失败，显著地防止了从第16周到第32周45%的动物死亡率。 我们已经开发出一种新型的(一流的位点特异性磷酸化抑制剂)和高效的抗 动物模型中的纤维性多肽，没有免疫原性的证据，在人类中具有特殊的稳定性 微粒体系统和人体血浆。XFB-19在水中具有良好的溶解性。这些功能应该 通过皮下注射促进给药，在临床试验期间具有良好的生物利用度 聚乙二醇-XFB-19在血浆中的稳态释放。聚乙二醇-XFB-19对小鼠无毒 是治疗剂量的100倍。没有证据表明CYP-450同工酶对心脏有毒性或抑制作用。 为这项SBIR提出的目标是完成支持IND的FDA授权研究。没有 FDA批准的治疗肝纤维化的药物，目前没有处于临床研究中的药物 靶向直接激活的肌成纤维细胞。

Activation of liver myofibroblasts (LMF) of different origins is responsible for the development of liver fibrosis in chronic liver diseases of all causes and remarkably, LMF clearance by apoptosis may prevent development of liver fibrosis and liver injury, and possibly allow recovery from reversal of liver fibrosis. Inhibiting o reversing myofibroblast activation (the therapeutic cellular target) is critical for the treatment of liver fibrosis. Both preventing progression of liver fibrosis as well as possibly, regression of liver fibrosis despite continued liver injury, as we documented in our pre-clinical studies, are considered important clinical targets for patients with advanced liver fibrosis and cirrhosis. Finally, blocking the progression of liver fibrosis would decrease development of primary liver cancer since most hepatocellular carcinomas arise in cirrhotic livers. The basis for our Research and Development is the development of a novel ‘humanized’ therapeutic peptide (XFB-19). We created a library using analog synthesis to improve potential pitfalls for human therapy. We have performed in a step-wise manner assays to select the safest and most efficient ‘humanized’ peptide (including medicinal chemistry, stability assays in human plasma and human liver microsomes, apoptosis assays in activated primary human liver myofibroblasts, cell-free caspase 8 activation assays, liver injury/fibrogenesis models, pharmacokinetics, bioassay, CYP-450 inhibition studies, immunogenicity assays in human T-cells and in mice, cardiotoxicity assays in human stem cell-derived cardiomyocytes, and toxicology assays in HCV-infected primary human hepatocytes and in normal and cirrhotic mice). In an animal model of decompensated cirrhosis, the XFB-19 peptide rescues hepatocyte cell death and liver failure, and remarkably prevents by 45 % animal mortality from week-16 to week-32. We have developed a novel (first-in-class inhibitor of a site-specific phosphorylation) and highly effective anti- fibrotic peptide in animal models, with no evidences of immunogenicity, and with exceptional stability in human microsomal systems and human plasma. XFB-19 has excellent solubility in water. These features should facilitate administration by subcutaneous injection with excellent bioavailability during clinical trials judging by the steady-state release in plasma of XFB-19 from the PEG-XFB-19. The PEG-XFB-19 was not toxic to mice at 100-fold the therapeutic dose. There was no evidence of cardiotoxicity or inhibition of CYP-450 isoenzymes. The aims that are proposed for this SBIR are to complete IND-enabling, FDA-mandated studies. There is no FDA-approved medication for the treatment of liver fibrosis, and none of the drugs currently in Clinical Studies target directly activated myofibroblasts.