Electroporation-Mediated Gene Therapy with IFN-b for MS

描述(申请人提供)：多发性硬化症(MS)最广泛的处方治疗是需要经常给予重组β-干扰素(干扰素-β)的延长治疗。虽然这种疗法在减少复发的MS患者的疾病进展和恶化率方面有效，但也有重要的局限性，包括成本高、需要重复注射、频繁的副作用以及在一些患者中产生中和抗体。肌肉内传递编码治疗蛋白的基因序列是直接给药蛋白质本身的一种潜在的替代方法。基于基因的方法的主要好处是，一次给药能够提供相对稳定、持续几个月的蛋白质生产。该项目的长期目标是开发一种基于基因的干扰素-β传递方法，显著降低成本和注射频率，临床疗效和副作用可与目前的重组蛋白疗法相媲美或更好。在第一阶段，Ichor证明了电穿孔介导的肌肉注射干扰素-β3基因的基本可行性。该程序在小鼠体内诱导了干扰素-β的持续表达至少3个月，没有毒性证据。干扰素-β在脾中的诱导生物标志物显著上调，表明干扰素-β具有生物学活性。值得注意的是，基因转移后的干扰素-β生物标记物诱导显著高于重组干扰素-β注射后。因此，这种基于基因的传递所实现的基因表达的大小和持续时间，加上没有显著的毒性，表明这种方法的进一步研究和开发是必要的。拟议第二阶段研究的目的是： 1)研制适合临床应用的干扰素-β表达载体； 2)证明干扰素-β基因治疗对MS的动物模型--小鼠EAE的进展具有与重组干扰素-β同样有效的抑制作用； 3)证明干扰素-β基因转移可以扩大到大鼠和猪，并建立临床剂量水平，以及 4)评估与肌肉内基因转移治疗蛋白传递相关的特定安全/毒理学问题。这些研究将为正式的安全性/毒理学评估和第一阶段人体研究奠定基础，最终目标是为多发性硬化症提供有效的基于基因的干扰素-β疗法。

DESCRIPTION (provided by applicant): The most widely prescribed treatment for multiple sclerosis (MS) is prolonged therapy requiring frequent administration of recombinant interferon-beta (IFN-beta). While effective in reducing disease progression and exacerbation rate in relapsing MS patients, the therapy has important limitations including high cost, need for repeated injections, frequent side effects, and development of neutralizing antibodies in some patients. The intramuscular delivery of gene sequences encoding therapeutic proteins is a potential alternate approach to direct administration of the protein itself. The principle benefit of a gene-based approach is that a single administration is capable of providing relatively stable, sustained production of the protein for several months. The long-term goal of this project is to develop a gene-based method for delivery of IFN-beta that significantly reduces both the cost and injection frequency, with clinical efficacy and side effects comparable to or better than the current recombinant protein therapies. In Phase I, Ichor demonstrated the basic feasibility of electroporation mediated intramuscular delivery of the IFN-beta3 gene. The procedure induced sustained expression of IFN-beta in mice for at least 3 months with no evidence of toxicity. The IFN-beta was biologically active as indicated by significant upregulation of an IFN-beta inducible biomarker in spleen. Notably, IFN-beta biomarker induction was significantly higher following gene transfer than after recombinant IFN-beta administration. Thus, the magnitude and duration of gene expression achieved with this gene based delivery plus the lack of significant toxicity indicate that further investigation and development of this approach is warranted. The aims of the proposed Phase II studies are to: 1) Develop an IFN-beta expression vector appropriate for clinical use; 2) Demonstrate that IFN-beta gene therapy inhibits the progression of murine EAE, an animal model of MS, as effectively as recombinant IFN-beta; 3) Demonstrate that IFN-beta gene transfer can be scaled up to rats and pigs and establish clinical dosage levels, and 4) Evaluate specific safety/toxicology issues relevant to therapeutic protein delivery via intramuscular gene transfer. These studies will set the stage for formal safety/toxicology evaluations and Phase I human studies, with the ultimate goal of providing an effective gene-based IFN-beta therapy for MS.