Whereas stereochemical purity in drugs has become the standard for small molecules, stereoisomeric mixtures containing as many as a half million components persist in antisense oligonucleotide (ASO) therapeutics because it has been feasible neither to separate the individual stereoisomers, nor to synthesize stereochemically pure ASOs. Here we report the development of a scalable synthetic process that yields therapeutic ASOs having high stereochemical and chemical purity. Using this method, we synthesized rationally designed stereopure components of mipomersen, a drug comprising 524,288 stereoisomers. We demonstrate that phosphorothioate (PS) stereochemistry substantially affects the pharmacologic properties of ASOs. We report that Sp-configured PS linkages are stabilized relative to Rp, providing stereochemical protection from pharmacologic inactivation of the drug. Further, we elucidated a triplet stereochemical code in the stereopure ASOs, 3′-SpSpRp, that promotes target RNA cleavage by RNase H1 in vitro and provides a more durable response in mice than stereorandom ASOs.

中文翻译：

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控制硫代磷酸酯立体化学可显着提高反义寡核苷酸的功效

药物中的立体化学纯度已成为小分子的标准，而反义寡核苷酸（ASO）治疗剂中仍含有多达五百万种成分的立体异构混合物，因为分离单个立体异构体或合成立体化学纯的ASO都是不可行的。在这里，我们报告了可扩展的合成工艺的发展，该工艺可产生具有高立体化学和化学纯度的治疗性ASO。使用这种方法，我们合成了合理设计的米泊美森的立体纯组分，该药物包括524,288立体异构体。我们证明，硫代磷酸酯（PS）立体化学实质上影响了ASO的药理特性。我们报告说S p配置的PS链接相对于R是稳定的p，提供立体化学保护以防止药物的药理学失活。此外，我们阐明了立体纯ASO中的三联体立体化学密码3'- S p S p R p，它在体外可促进RNase H1裂解靶RNA ，并在小鼠中提供比立体随机ASO更持久的响应。