Glycine rich sequences with pharmacokinetic enhancing properties of PEG polymers

描述(申请人提供)：蛋白质药物已被批准用于许多治疗适应症，并代表着制药行业的一个快速增长的部分。然而，许多已批准的蛋白质药物和正在开发的候选药物由于不太理想的药代动力学特性和免疫原性问题而未能达到其潜在疗效。这些特性包括较短的循环半衰期、较短的保质期、较低的溶解度、快速的肾脏清除和对蛋白质降解的敏感性。用聚乙二醇类的亲水性化学聚合物修饰蛋白质是一种经过临床验证的解决这些局限性的方法。然而，与连接这些聚合物所需的化学修饰程序相关的挑战带来了巨大的挑战。我们的最终目标是生成模拟亲水性化学聚合物(如聚乙二醇类)的物理化学性质的氨基酸序列。我们的建议是基于观察到富含甘氨酸的序列(GRS)不会折叠成紧凑的三维结构，而是采用类似于聚乙二醇大流体动力学半径的随机构象。我们假设，当它们附着到治疗性蛋白质上时，它们将获得类似的药代动力学改善。这些序列可以使用传统的重组技术连接到蛋白质上，从而完全消除了化学修饰步骤的需要。我们根据人类蛋白质中存在的序列合成了一个198个氨基酸的富含甘氨酸的序列。我们的目标是表达该蛋白，并系统地检测其与药代动力学增强相关的理化和生物学特性。我们的具体目标是：1)在大肠杆菌表达系统中表达5 mg纯化的GRS蛋白，用于下游的鉴定和研究。2)对GRS蛋白的血清稳定性、抗蛋白酶活性和生物物理性质进行表征。3)研究GRS蛋白在动物模型中的血浆药代动力学和免疫原性。在第二阶段，我们将针对GRS的高水平表达、血浆半衰期延长和免疫原性降低进行详细的优化。我们的目标是将优化的GRS与干扰素-α或G-CSF等药物活性蛋白融合在一起，用于动物和临床研究。我们的最终目标是验证这种方法，并使其易于应用于治疗性蛋白质。我们的项目旨在产生富含甘氨酸的序列，这些序列可以重组连接到治疗性蛋白质上，以改善它们的药代动力学特性。这种方法将绕过与用聚乙二醇亲水聚合物修饰蛋白质相关的困难。

DESCRIPTION (provided by applicant): Protein drugs have been approved for many therapeutic indications and represent a rapidly growing segment of the pharmaceutical industry. However, many approved protein drugs and candidates in development fail to reach their potential efficacy due to suboptimal pharmacokinetic properties and immunogenicity concerns. These properties include short circulating half-lives, short shelf lives, low solubility, rapid kidney clearance and susceptibility to proteolytic degradation. The modification of proteins with hydrophilic chemical polymers like polyethylene glycol (PEG) is a clinically validated approach to addressing these limitations. However, the challenges associated with chemical modification procedures required for the attachment of these polymers present significant challenges. Our ultimate goal is to generate amino acid sequences that mimic the physiochemical properties of hydrophilic chemical polymers like PEG. Our proposal is based on the observation that glycine rich sequences (GRS) which contain few hydrophobic amino acids will not fold into compact 3-dimensional structures but will adopt random conformations with large hydrodynamic radii similar to PEG. We hypothesize that they will confer similar pharmacokinetic improvements when attached to therapeutic proteins. These sequences can be attached to proteins using conventional recombinant technology and thus completely obviates the need for chemical modifications steps. We have synthesized a 198 amino acid glycine rich sequence based on sequences that occur in human proteins. We aim to express this protein and systematically test its physiochemical and biological properties relevant to pharmacokinetic enhancement. Our specific aims are: 1) Produce 5 mg of a purified GRS protein in E. coli expression system for downstream characterization and studies. 2) Characterize serum stability, protease resistance and biophysical properties of the GRS protein. 3) Characterize plasma pharmacokinetics and immunogenic potential of the GRS protein in animal models. In Phase II, we will perform detailed optimization of GRS for high-level expression, plasma half-life extension and reduced immunogenicity. We aim to advance optimized GRS which are fused to pharmaceutically active proteins like interferon-alpha or G-CSF into animal and clinical studies. Our ultimate goal is to validate and make this method readily applicable to therapeutic proteins. Our project aims to generate glycine rich sequences that can be attached recombinantly to therapeutic proteins to improve their pharmacokinetic properties. This approach would circumvent the difficulties associated with the modifying proteins with hydrophilic polymers like PEG.