Caisson Biotech, LLC, 655 Research Parkway, Suite 525, Oklahoma City, OK 73104, USA.
University of Oklahoma Health Sciences Center, Department of Biochemistry and Molecular Biology, University of Oklahoma Health Sciences Center, Oklahoma City, OK 73126, USA.
Glycobiology. 2017 Nov 1;27(11):1052-1061. doi: 10.1093/glycob/cwx072.
Many injectable drugs require delivery strategies for enhancing their pharmacokinetics due to rapid loss via renal filtration if possess low molecular weight (<60-70 kDa) and/or clearance by the body's components (e.g., proteases, antibodies, high-efficiency receptors) in their native form. FDA-approved polyethylene glycol (PEG) is a vehicle for improving therapeutics, but artificial polymers have potential biocompatibility and immunogenicity liabilities. Here, we utilized a natural vertebrate carbohydrate, heparosan (HEP), the biosynthetic precursor of heparan sulfate and heparin, to enhance performance of a biologic drug. The HEP polysaccharide was stable with a long half-life (~8 days for 99-kDa chain) in the nonhuman primate bloodstream, but was efficiently degraded to very short oligosaccharides when internalized by cells, and then excreted into urine and feces. Several HEP-modified human granulocyte-colony stimulating factor (G-CSF) conjugates were synthesized with defined quasi-monodisperse HEP polysaccharide chains. Single dosing of 55- or 99-kDa HEP-G-CSF in rats increased blood neutrophil levels comparable to PEG-G-CSF conjugates. Repeated dosing of HEP-G-CSF or HEP alone for 2 weeks did not cause HEP-specific toxic effects in rats. HEP did not possess the anticoagulant behavior of its daughter, heparin, based on testing in rats or clinical diagnostic assays with human plasma. Neither anti-HEP IgG nor IgM antibodies were detected in a long-term (9 doses over 7 months) immunogenicity study of the HEP-drug conjugate with rats. These proof-of-concept experiments with HEP-G-CSF indicate that it is a valid drug candidate for neutropenia and suggest the potential of this HEP-based platform as a safe alternative delivery vehicle for other therapeutics.
许多注射用药物由于其低分子量（<60-70 kDa）或在天然形式下被身体成分（如蛋白酶、抗体、高效受体）清除，因此需要通过输送策略来增强其药代动力学。经美国食品和药物管理局批准的聚乙二醇（PEG）是一种改善治疗方法的载体，但人工聚合物具有潜在的生物相容性和免疫原性缺陷。在这里，我们利用了一种天然脊椎动物碳水化合物肝素聚糖（HEP），它是肝素硫酸和肝素的生物合成前体，来增强生物药物的性能。HEP 多糖在非人类灵长类动物的血液中具有稳定性，半衰期长（99 kDa 链的半衰期约为 8 天），但当被细胞内化时，它会迅速降解为非常短的寡糖，然后被排泄到尿液和粪便中。用具有明确准单分散 HEP 多糖链的方法合成了几种 HEP 修饰的人粒细胞集落刺激因子（G-CSF）缀合物。在大鼠中单次给予 55 或 99 kDa 的 HEP-G-CSF 可使血液中性粒细胞水平增加，与 PEG-G-CSF 缀合物相当。在大鼠中重复给予 HEP-G-CSF 或 HEP 2 周不会引起 HEP 特异性毒性作用。HEP 不会因其女儿肝素而具有抗凝作用，这是基于在大鼠中进行的测试或用人类血浆进行的临床诊断测定。在大鼠中进行的 HEP-药物缀合物的长达 9 次（7 个月）的长期免疫原性研究中，均未检测到抗 HEP IgG 或 IgM 抗体。HEP-G-CSF 的这些概念验证实验表明，它是中性粒细胞减少症的有效候选药物，并表明基于 HEP 的平台作为其他治疗方法的安全替代输送载体的潜力。
