TREATMENT OF LIVER INJURY AND FIBROSIS: SAFETY PHARMACOLOGY AND TOXICOLOGY

不同来源的肝肌成纤维细胞（LMF）的激活是导致肝纤维化发展的原因。 值得注意的是，通过细胞凋亡清除LMF可以防止所有原因的慢性肝病的发展。 肝纤维化和肝损伤，并可能允许从肝纤维化逆转中恢复。抑制o逆转 肌成纤维细胞活化（治疗性细胞靶标）对于肝纤维化的治疗是关键的。两 预防肝纤维化的进展以及可能的肝纤维化的消退，尽管持续的肝纤维化， 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化。最后，阻断肝纤维化的进展将减少 原发性肝癌的发展，因为大多数肝细胞癌发生在肝硬化。的基础 我们的研究和开发是开发一种新的“人源化”治疗肽（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 逐步的方式测定以选择最安全和最有效的“人源化”肽（包括药用肽）， 化学、人血浆和人肝微粒体中的稳定性试验、活化细胞中的细胞凋亡试验 原代人肝肌成纤维细胞，无细胞半胱天冬酶8活化测定，肝损伤/纤维化模型， 药代动力学、生物测定、IFN-450抑制研究、人T细胞和小鼠中的免疫原性测定， 人干细胞衍生的心肌细胞中的心脏毒性测定，以及HCV感染的 原代人肝细胞以及正常和痴呆小鼠）。 在失代偿性肝硬化的动物模型中，XFB-19肽拯救肝细胞死亡和肝脏 失败，并且从第16周至第32周显著地防止了45%的动物死亡。 我们已经开发了一种新的（第一次在类抑制剂的位点特异性磷酸化）和高效的抗- 纤维化肽在动物模型中，没有免疫原性的证据，在人体中具有特殊的稳定性 微粒体系统和人血浆。XFB-19在水中具有良好的溶解性。这些特征应当 从临床试验来看，方便皮下注射给药，生物利用度良好 XFB-19在血浆中从PEG-XFB-19的稳态释放。PEG-XFB-19对小鼠无毒性 是治疗剂量的100倍没有证据表明存在心脏毒性或抑制α-450同工酶。 本SBIR的拟定目标是完成IND授权的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.