Glycine rich sequences with pharmacokinetic enhancing properties of PEG polymers

描述（由申请人提供）：基于蛋白质的生物制药市场正在迅速扩大。然而，许多蛋白质的临床效用受到其短血清半衰期的限制，需要频繁注射。改善血清半衰期的最常见方法是PEG化。聚乙二醇（PEG）与治疗性蛋白质的化学偶联通常会产生包含非活性异构体的产品混合物，并降低产品的总体效力。蛋白质的化学聚乙二醇化显著增加了制造成本，需要精确的过程控制和分析测定来确保产品组成的再现性。目前的项目描述了模仿化学PEG的物理化学性质的多肽链（称为rPEG）。rPEG是亲水性的并且具有非常大的流体动力学半径。最重要的是，rPEG可以重组融合到治疗性蛋白质中，从而产生均质产物。rPEG与生物制药的融合预计将提供与化学PEG化类似的益处（长血清半衰期，降低免疫原性），同时提供改善的产品效力，均一性和显著降低的制造成本。该项目的第一阶段非常成功，证明了rPEG技术的可行性。开发了紧密模拟化学PEG性质的rPEG序列。我们证明，20 kDa的rPEG序列具有180 kDa的表观分子量。rPEG与模型蛋白GFP的融合将其在大鼠中的血清半衰期从1-3小时增加到约10小时，与化学PEG化的效果相似。此外，这种rPEG-GFP融合物在大鼠中仅引起非常弱的免疫应答。我们的第二阶段目标是将rPEG技术应用于人生长激素（hGH）。hGH目前用于治疗儿童侏儒症。2006年销售额超过30亿美元。由于其快速血浆消除，hGH治疗需要每天注射。hGH的长效形式尚未获得批准，并且由于形成含有非活性异构体的混合物，hGH的化学PEG化的成功有限。我们的目标是开发用于生产、纯化和配制rPEG-hGH的方法。将在体外和体内对所得产品进行全面表征。由此产生的数据包将允许rPEG-hGH进入临床开发。该项目期间开发的方法和数据将验证rPEG技术，并使其能够广泛应用于其他蛋白质药物。 公共卫生相关性：许多生物药物的效用受到其短血清半衰期的限制，这需要频繁注射。该项目的目标是开发模拟聚乙二醇性质的重组肽链（称为rPEG）。这些rPEG可以直接与蛋白质药物融合，以增加其血清半衰期。我们将通过开发用于治疗儿童侏儒症的长效人类生长激素来验证rPEG技术。

DESCRIPTION (provided by applicant): The market for protein-based biopharmaceuticals is rapidly expanding. However, the clinical utility of many proteins is limited by their short serum half-life, requiring frequent injections. The most common approach to improve serum half-life is PEGylation. The chemical conjugation of Polyethylene glycol (PEG) to therapeutic proteins typically results in product mixtures that include inactive isomers and reduce the overall potency of the product. The chemical PEGylation of proteins significantly increases manufacturing costs, requiring precise process control and analytical assays to ensure reproducibility of product composition. The current project describes polypeptide chains (called rPEGs) that mimic the physicochemical properties of chemical PEG. rPEGs are hydrophilic and have very large hydrodynamic radii. Most importantly, rPEGs can be recombinantly fused to therapeutic proteins resulting in homogeneous products. The fusion of rPEGs to biopharmaceutical is expected to provide benefits that are similar to chemical PEGylation (long serum half-life, reduced immunogenicity) while offering improved product potency, homogeneity, and significantly reduced manufacturing costs. Phase I of this project was extremely successful and demonstrated the feasibility of the rPEG technology. rPEG sequences that closely mimic the properties of chemical PEG were developed. We demonstrated that a 20 kDa rPEG sequence has an apparent molecular weight of 180 kDa. Fusion of rPEG to the model protein GFP increased its serum half-life in rats from 1-3 h to approximately 10 h, similar to the effect of chemical PEGylation. Furthermore, this rPEG-GFP fusion elicited only a very weak immune response in rats. Our phase II goal is to apply rPEG technology to human growth hormone (hGH). hGH is currently used for the treatment of dwarfism in children. 2006 sales exceeded $3B. Due to its rapid plasma elimination, hGH treatment requires daily injections. No long-acting form of hGH has been approved and chemical PEGylation of hGH had limited success due to the formation of mixtures containing inactive isomers. We aim to develop methods for the production, purification, and formulation of rPEG-hGH. The resulting product will be thoroughly characterized in vitro and in vivo. The resulting data package will allow rPEG- hGH to enter clinical development. The methods and data developed during the project will validate rPEG technology and enable its broad application to other protein pharmaceuticals. PUBLIC HEALTH RELEVANCE: The utility of many biopharmaceuticals is limited by their short serum half-life, which requires frequent injections. The goal of this project is to develop recombinant peptide chains (called rPEG) that mimic the properties of polyethylene glycol. These rPEGs can be directly fused to protein pharmaceuticals to increase their serum half-life. We will validate rPEG technology by developing a long-acting version of human growth hormone for the treatment of dwarfism in children.