sc-rAAV8 via Lumbar Puncture as Spinal Analgesic Drug Delivery Systems

描述(申请人提供)：腰椎穿刺术(LP)是向神经系统提供新疗法的一种有吸引力的途径，因为它在患者身上是安全的；在床边进行；FDA批准用于传统药物。然而，到目前为止，它在基因传递方面的应用一直是无效的，不符合安全原则，也没有针对神经元。我们利用8型重组腺相关病毒(sc-rAAV8)，通过鞘内(IT)将基因高效地转移到背根神经节(DRGs)的初级感觉神经元。在大鼠慢性神经病理性疼痛模型中，单次注射表达止痛基因前内啡肽(pp？EP)或大鼠抗炎基因白介素10(rIL10/F129S)突变形式的sc-rAAV8可显著(p&lt；0.0001)缓解3个月的症状，这是一项重要的功能结果。这项应用的假设是，sc-rAAV8 Via LP是一种可用于治疗顽固性慢性疼痛的可行的基因传递产品，可供专业研究中心以外的临床医生使用。为了研究/建立临床翻译的潜力，我们提出了以下具体目标：目的1.通过体视学对封闭与开放IT空间中的DRG转导进行量化，表征对IT载体的血清学免疫学特性，并确定器官分布。目的2.确定神经病理性疼痛模型中最强的候选治疗基因，并确定与传统疼痛治疗是否存在药理协同作用。目的3.在一种新的反映不治之癌患者疼痛的大鼠模型中，测试该方法的抗伤害性效果，这可能是未来的临床试验场景。目的4.检测ITsc-rAAV8是否能有效地转导大鼠背根神经节神经元。意义和未来展望：慢性疼痛影响着5000万美国人，仅在美国每年就会产生1000亿美元的成本(如PA-07-282所述)。这项申请提出了一种基因治疗方法，如果研究计划成功，这种方法将成为晚期恶性肿瘤患者严重疼痛的临床开发候选。IT sc-rAAV8可以作为机制验证试验的工具，例如验证小胶质细胞激活作为人类治疗靶点的有效性，也可能成为治疗其他难治性慢性疼痛的新药。 公共卫生相关性：慢性疼痛影响着5000万美国人，仅在美国每年就造成1000亿美元的成本(如PA-07-282所述)。脊椎抽吸是一种有吸引力的途径，可以为神经系统提供治疗各种疾病的新疗法，尤其是治疗疼痛。原因是脊髓的功能是一个“痛门”，能够大开，从而促进疼痛信号的传递或“关闭”，从而控制疼痛。脊椎抽液对患者是安全的；在床边进行；FDA批准用于传统药物。我们已经开发出一种基因治疗方法，通过脊椎抽吸来管理新的基因载体，从而控制疼痛。具体地说，我们在老鼠模型中发现，通过我们的方法，一种严重的疼痛类型-慢性神经病理性疼痛可以控制3个月。在这项申请中提出的研究中，我们希望进一步研究和改进我们的方法，以便评估它是否是一种可行的治疗方法，用于未来的人类开发，特别是关注晚期癌症的剧烈疼痛。

DESCRIPTION (provided by applicant): Lumbar puncture (LP) is an attractive route for delivering novel therapies to the nervous system because it is safe in patients; performed at the bedside; and FDA-approved for conventional drugs. However, its use for gene delivery has to date been ineffective; has not met safety principles; and has failed to target neurons. We have developed highly effective gene transfer to the primary sensory neurons of the dorsal root ganglia (DRGs) via LP, i.e. intrathecally (IT), using self-complementary recombinant adeno-associated virus serotype 8 (sc-rAAV8). A single administration of sc-rAAV8 expressing the analgesic gene prepro-¿-endorphin (pp¿EP) or a mutant form of the rat anti- inflammatory gene interleukin-10 (rIL10/F129S) led to highly significant (p<0.0001) relief of symptoms for =3 months in a rat chronic neuropathic pain model, an important functional outcome. The hypothesis of this application is that sc-rAAV8 via LP is a viable gene delivery product for intractable chronic pain usable by clinicians outside of specialized research centers. In order to investigate/establish the potential for clinical translation, we propose the following Specific Aims: Aim 1. To quantify DRG transduction by stereology in the "closed" vs. "open" IT space, characterize serological immunity to the IT vector, and determine organ distribution. Aim 2. To identify the strongest candidate therapeutic gene in the neuropathic pain model and to define if there is pharmacological synergy with conventional pain treatments. Aim 3. To test the antinociceptive efficacy of the approach in a new rat model reflecting pain in patients with incurable cancer, a possible future clinical trial-scenario. Aim 4. To test if IT sc-rAAV8 effectively transduces DRG neurons in large animals. Significance & future perspective: Chronic pain affects 50 million Americans and incurs costs of >$100 billion/year in the US alone (as stated in PA-07-282). This application proposes a gene therapy approach, which, if the Research Plan succeeds, will become a candidate for clinical development in patients with severe pain from advanced malignancies. IT sc-rAAV8 may serve as a tool for proof-of-mechanism trials, e.g. to validate microglial activation as therapeutic target in humans, and may also become a new drug for otherwise intractable chronic pain. Public Health Relevance: Chronic pain affects 50 million Americans and incurs costs of >$100 billion/year in the US alone (as stated in PA-07-282). Spinal tap is an attractive route for delivering novel therapies to the nervous system for a variety of diseases but particularly for pain. The reason is that the spinal cord functions as a "pain gate" able to open wide and thereby to facilitate pain signal transfer or to "close" and thereby control pain. A spinal tap is is safe in patients; performed at the bedside; and FDA-approved for conventional drugs. We have developed a gene therapy method administering new gene vectors by spinal tap, which control pain. Specifically, we find in a rat model that a severe type of pain, chronic neuropathic pain can be controlled for >3 months by our approach. In the research proposed in this application, we wish to study and improve our approach further in order to evaluate, whether it is a viable treatment approach for future development for human use with a special focus on severe pain from advanced cancer.