Prevention of corneal transplant rejection using AAV-HLA-G combination therapy

联系PD/PI：GILGER，BRIAN C 摘要 角膜盲是全球失明的主要原因，同种异体角膜移植（CT）是治疗角膜盲的最佳方法。 这是世界上最常见的组织移植形式。尽管大约有18万例CT手术 目前每年约有1270万人等待捐献角膜接受手术。尽管如此，CT 手术伴随着高的失败率：多达20-30%的角膜移植物在第一次手术中被排斥。 5年，在一般人群中，在高风险病例中，占人口的20%以上，几乎所有 移植物在3年内被排斥。CT失败给已经有限的供体角膜供应带来了压力， 每需要70个角膜，大约只有一个角膜可用。无论是由于缺乏访问权限，还是 由于干预不成功，绝大多数角膜盲病例未经治疗， 活动受限、福尔斯风险增加、情绪困扰和死亡率增加。当前方法 为了减轻角膜移植排斥，涉及局部和全身皮质类固醇和免疫抑制剂， 但这些方法都有严重的缺点，已知皮质类固醇会诱发视力， 损失，而免疫抑制剂除了引起严重的潜在副作用外，价格也很高。 为了满足减少移植失败和提高移植物长期成功率的方法的迫切需求， 同种异体人CT，Bedrock Therapeutics提出使用腺相关病毒（AAV）介导的 转导以将HLA-G同种型递送至供体角膜移植物， 这是一种有效的治疗方法，可以防止人类受体的反应，并防止CT后的排斥反应。第一阶段提案的重点是前任 影响角膜外植体的AAV载体转导的鉴定变量的体内优化。治疗 有效性和可行性将通过追求两个具体目标来瞄准：1）AAV-HLA-1的优化。 Gcombo离体转导变量（即，载体生产、剂量和孵育时间），和2）评价 高危兔同种异体CT模型中AAV-HLA-Gcombo离体转导功效。基岩疗法 以前的研究已经证明了使用AAV 8 G9将HLA-G同种型转染到供体中的可行性 角膜和由此产生的在同种异体CT的动物模型中移植排斥的成功预防。 在移植前将HLA-G转导到兔角膜中导致完全预防了角膜移植术后的角膜炎。 同种异体移植物在80天内的排斥反应与对照角膜在10天内的排斥反应。成功 该方法的应用将为获得免疫耐受的角膜提供平台，解决高比率的角膜移植。 角膜移植排斥反应和改善目前组织短缺的问题。完成拟议工作 将为更多的临床前和临床研究铺平道路，最终目标是将我们的平台应用于 人类CT，以改善成千上万的患者的生活质量，经历角膜排斥反应 每年. 项目摘要/摘要第6页

Contact PD/PI: GILGER, BRIAN C Abstract Corneal blindness is a leading cause of global blindness, with allogeneic corneal transplantation (CT) being the most common form of tissue transplantation worldwide. Though approximately 180,000 CT surgeries are carried out each year, around 12.7 million are currently awaiting a donor cornea to undergo the operation. Still, CT surgery is accompanied by a high failure rate: as many as 20–30% of corneal grafts are rejected within the first 5 years in the general population, and in high-risk cases, which represent over 20% of the population, almost all grafts are rejected within 3 years. CT failure puts a strain on the already-limited supply of donor corneas, for which there is approximately only one cornea available for every 70 needed. Whether by lack of access or unsuccessful intervention, the vast majority of cases of corneal blindness go untreated, leaving patients with limited mobility, an increased risk of falls, emotional distress, and an increase in mortality. Current approaches to mitigate corneal graft rejection involve topical and systemic corticosteroids and immunosuppressive agents, but these methods are all burdened with acute disadvantages; corticosteroids have been known to induce vision loss, and immunosuppressive agents, besides incurring serious potential side effects, also come at a high price. To address the critical need for methods to reduce graft failure and improve the long-term success of allogeneic human CT, Bedrock Therapeutics proposes to use adeno-associated virus (AAV)-mediated transduction to deliver HLA-G isoforms to donor corneal grafts to ultimately modulate the immunologic response of a human recipient and prevent rejection following CT. This Phase I proposal focuses on the ex vivo optimization of identified variables that affect AAV vector transduction of corneal explants. Treatment efficacy and feasibility will be targeted through the pursuit of two specific aims: 1) optimization of AAV-HLA- Gcombo ex vivo transduction variables (i.e., vector production, dose, and incubation time), and 2) evaluation of AAV-HLA-Gcombo ex vivo transduction efficacy in a high-risk rabbit allogenic CT model. Bedrock Therapeutics' previous studies have demonstrated the feasibility of using AAV8G9 to transduce HLA-G isoforms into donor corneas and the resulting successful prevention of graft rejection in animal models of allogeneic CT. Transduction of HLA-G into rabbit corneas prior to transplantation resulted in complete prevention of allogeneic graft rejection over an 80-day period vs. rejection at 10 days in control corneas. Successful application of this method will provide a platform for obtaining immune-tolerant corneas, addressing the high rate of corneal graft rejection and ameliorating current tissue shortage problems. Completion of the proposed work will pave the way for additional preclinical and clinical studies with an eventual goal of applying our platform to human CT in order to improve the quality of life of the thousands of patients that experience corneal rejection each year. Project Summary/Abstract Page 6