Data from: Formulation and toxicology evaluation of the intrathecal AYX1 DNA-decoy in Sprague Dawley rats

The longevity of pain after surgery is debilitating and limits the recovery of patients. AYX1 is a double-stranded, unprotected, 23 base-pair oligonucleotide designed to reduce acute post-surgical pain and prevent its chronification with a single intrathecal peri-operative dose. AYX1 mimics the DNA sequence normally bound by EGR1 on chromosomes, a transcription factor transiently induced in the dorsal root ganglia (DRG) - spinal cord network following a noxious input. AYX1 binds to EGR1 and prevents it from launching waves of gene regulation that are necessary to maintain pain over time. A formulation suitable for an intrathecal injection of AYX1 was developed, including a specific ratio of AYX1 and calcium so the ionic homeostasis of the cerebrospinal fluid is maintained and no impact on neuromuscular control is produced upon injection. A GLP toxicology study in naïve Sprague Dawley rats was conducted using 3 dose levels up to the maximum feasible dose. Clinical observations, neurobehavioral observations, clinical pathology and histopathology of the nervous system and peripheral tissues were conducted. An additional non-GLP study was conducted in the spared nerve injury model of chronic neuropathic pain in which EGR1 is induced in the DRG and spinal cord. Similar testing was performed, including a modified Irwin test to assess a potential impact of AYX1 on autonomic nervous system responses, locomotion, activity, arousal, sensorimotor and neuromuscular function. No AYX1-related adverse events were observed in any of the studies and the no-observed-adverse-effect-level (NOAEL) was judged to be the maximum feasible dose.术后疼痛的长期迁延会严重损害患者机能，并制约其康复进程。AYX1是一种双链、未保护的23碱基对寡核苷酸，设计用于通过单次鞘内围手术期给药，减轻急性术后疼痛并预防其转为慢性疼痛。AYX1可模拟染色体上正常结合早期生长应答因子1（EGR1）的DNA序列；EGR1是一种转录因子，在有害刺激传入后，会于背根神经节（dorsal root ganglia, DRG）-脊髓网络中瞬时诱导表达。AYX1可与EGR1结合，阻断其启动维持疼痛长期存在所必需的基因调控级联反应。研究开发了适用于AYX1鞘内注射的制剂，其中AYX1与钙的比例经过精准调控，可维持脑脊液的离子稳态，且给药后不会对神经肌肉控制产生不良影响。针对未接触受试物的斯普拉格-道利大鼠开展了良好实验室规范（Good Laboratory Practice, GLP）毒理学研究，设置3个剂量梯度，最高至最大可行剂量。研究内容涵盖临床观察、神经行为学观察、临床病理学检测，以及神经系统与外周组织的组织病理学检查。此外还开展了一项非GLP研究，采用spared神经损伤慢性神经性疼痛模型——该模型中，EGR1会在背根神经节与脊髓中被诱导表达。本次研究采用了相似的检测方案，包括改良艾尔文试验，以评估AYX1对自主神经系统反应、运动功能、活动度、觉醒状态、感觉运动功能及神经肌肉功能的潜在影响。所有研究中均未观察到与AYX1相关的不良事件，未观察到不良反应水平（no-observed-adverse-effect-level, NOAEL）被判定为最大可行剂量。