Preclinical and Clinical Study of CNGb3 Acromatopsia and Treatment with CNTF

CNGb3 肢端视障及 CNTF 治疗的临床前和临床研究

• 批准号: 8565513
• 负责人: Paul Sieving
• 金额: $ 81.17万
• 依托单位: NATIONAL INSTITUTE ON DEAFNESS AND OTHER COMMUNICATION DISORDERS
• 依托单位国家: 美国
• 资助国家: 美国
• 起止时间: 至
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/8565513
• 关键词: Accounting; Address; Adult; Adverse effects; Adverse event; Affect; Age; Animal Model; Animals; Aqueous Humor; Biological; Blindness; Blood - brain barrier anatomy; Blood Circulation; Blood-Retinal Barrier; Bolus Infusion; Canis familiaris; Cell Death; Cells; Ciliary Neurotrophic Factor; Clinical; Clinical Protocols; Clinical Research; Clinical Trials; Color Visions; Devices; Discrimination; Electroretinography; Encapsulated; Enrollment; Eye; Genes; Human; Image; Implant; Individual; Inherited; Injection of therapeutic agent; Knockout Mice; Light; Lighting; Measures; Membrane; Modeling; Molecular; Mutation; Neuraxis; Nonexudative age-related macular degeneration; Operative Surgical Procedures; Optical Coherence Tomography; Organelles; Outcome Measure; Participant; Pathologic Nystagmus; Patients; Penetration; Performance; Phase; Phase I Clinical Trials; Photophobia; Photoreceptors; Phototransduction; Polymers; Population Study; Proteins; Rattus; Recovery; Research Design; Retina; Retinal; Retinal Cone; Retinal Degeneration; Retinal Diseases; Retinal Dystrophy; Retinitis Pigmentosa; Risk; Safety; Severities; Signal Transduction; Staging; Structure; Study Subject; System; Technology; Testing; Therapeutic; Therapeutic Agents; Therapeutic Effect; Time; Toxic effect; Vertebrate Photoreceptors; Vision; Visual; Visual Acuity; Work; achromatopsia; autosomal recessive trait; base; capsule; cyclic-nucleotide gated ion channels; design; effective therapy; follow-up; gene therapy; implantable device; implantation; improved; intravitreal injection; mouse model; neurotrophic factor; phase 2 study; preclinical study; prevent; primary outcome; prospective; research study; response; retinal rods; safety study; secondary outcome; vector

Achromatopsia is a monogenic congenital retinal dystrophy that causes reduced visual acuity, extremely limited color vision discrimination, nystagmus and photophobia. It is inherited as an autosomal recessive trait. Four genes currently are known to cause the condition; CNGA3 and CNGB3 encoding the alpha- and beta-subunits, respectively, of the cyclic nucleotide gated channel type 3 (CNG3) on cone photoreceptors are responsible for the vast majority of the achromatopsia cases. Mutations in the CNGB3 genes alone account for more than 50% of individuals with achromatopsia, a retinal disorder that affects approximately 1 in every 33,000 individuals. The CNGA3 and CNGB3 proteins cooperate to form the heteromeric CNG3 conductance channel on the cone outer segment membrane. CNG3 channels are essential for converting light stimulation to activation of the cone photoreceptors and ultimately to daylight vision. In the absence of cone function, human vision is limited to rod function which is achromatic, resulting in poor acuity and saturation in bright illumination. Although achromatopsia historically was thought to be a condition in which cones were lacking or present in extremely reduced numbers, recent human studies show that a number of cones are still present even in older subjects with achromatopsia. Studies of CNGB3 and CNGA3 animal models also show that cones are present but have significant morphologic changes and progressive functional reduction with age. If cone function could be improved or restored in these subjects, they might recover augmented visual function. Gene therapy experiments have successfully treated achromat animal models, including both the naturally occurring CNGB3 mutation canine model and the CNGB3 knockout mouse model. A surprising observation was made during the gene therapy study of the CNGB3 dog achromat model: gene therapy could partially restore cone function on ERG testing in adult dogs, but only if animals were pretreated with ciliary neurotrophic factor (CNTF). Without prior treatment with CNTF, gene therapy was successful only for quite young dogs. This indicated that CNTF facilitated inducing a biological state in the adult cones in which they were receptive to gene rescue. More surprising was the finding that a bolus intravitreal injection of CNTF protein, without the CNGB3 gene vector, gave functional rescue of cones, and rescue persisted for several weeks until the CNTF from the bolus injection cleared. So, administration of CNTF protein alone, and without prior or subsequent gene vector delivery, supported recovery of light-stimulated activity of the cone photoreceptors in the CNGB3 achromat dog. CNTF is among the class of macro-biomolecules called neurotrophic factors which have been demonstrated to retard loss of photoreceptor cells during retinal degeneration. CNTF is effective in retarding vision loss from photoreceptor cell death in 13 animal models. A Phase 1 safety study in 2003-2006 was conducted at the NEI to investigate ocular delivery of CNTF in 10 subjects with end-stage retinitis pigmentosa. It passed appropriate safety milestones to mount Phase 2 studies, and the study indicated that CNTF possibly improved acuity performance in some subjects. The Phase 1 clinical trial observations and the animal studies provided the impetus for mounting a Phase 2 efficacy study for subjects with retinitis pigmentosa and dry AMD. The study design and outcome measures were based on the premise that CNTF could possibly improve visual function of cone photoreceptor cells. One major challenge is the delivery of this potentially therapeutic CNTF agent to the retina. The blood-retinal barrier prevents or inhibits the penetration of macro-molecules to the neurosensory retina, similar to the action of the blood-brain barrier in limiting transfer between the systemic circulation and the central nervous system. To address this issue, Neurotech USA, Inc., developed encapsulated cell technology (ECT) to provide controlled, sustained delivery of therapeutic agents directly into the intraocular fluids and thereby providing direct access to the retina. Cells within the ECT device are transfected with the CNTF gene and produce CNTF protein which exits through a semi-permeable polymer capsule membrane directly into the vitreous. The Neurotech NT-501 ECT device measures approximately 1mm x 6 mm and can readily be retrieved from the eye, providing an added level of safety. The previous Phase 1 and Phase 2 studies in RP and AMD have clearly demonstrated that CNTF is released by the implanted device and have also demonstrated that CNTF reaches and modifies the retina. To further explore the efficacy of CNTF in achromatopsia, we are delivering CNTF by intravitreal injection to the mouse model, which has a deletion of the CNGB3 gene. The model shows a severe and early reduction in cone function, while maintaining relatively good rod function as measured by the electrotretinogram (ERG). We previously showed that intravitreal injection of CNTF into normal rat eye suppresses rod function by down-regulating molecular mechanisms involved in converting light to visual signals (phototransduction). However, as mentioned above, it protects photoreceptors in several inherited and light induced models of retinal degeneration. Recently, it was shown that CNTF also protects cones from degeneration in one of these models, and actually partially restores the functional organelle for light reception, the cone outer segment. This indicates the possible anatomical basis for the recovery of cone function in humans and and CNGB3 dogs mentioned above. Using the CNGB3 mouse model of achromatopsia will allow us to explore potential mechanisms of cone rescue as well as conditions that enhance and prolong this affect. Clinical protocol: CNTF Implants for CNGB3 Achromatopsia ClinicalTrials.gov identifier: NCT01648452 Objective: The objective of this study is to evaluate the safety of ocular NT-501 device with encapsulated NT-201 cells releasing Ciliary Neurotrophic Factor (CNTF) to the retina of participants affected with CNGB3 achromatopsia. Study Population: Five participants affected with CNGB3 achromatopsia will be enrolled, with one eye treated per participant. Design: This is a Phase I/II, prospective, single-center study. One eye of each participant will receive a vitreous NT-501 device implant releasing CNTF. The study will be completed once the final participant has received three years of follow-up. Outcome Measures: The primary outcome is the number and severity of adverse events and systemic and ocular toxicities at six months post-implantation. Additional safety of ocular CNTF implants in participants with CNGB3 achromatopsia will be determined from assessment of retinal function, ocular structure and occurrence of adverse events at all time points. Secondary outcomes include changes in visual function including visual acuity and color vision, electroretinogram (ERG) responses, and retinal imaging with optical coherence tomography (OCT).

Achrompopsia是一种单基因性视网膜营养不良，可引起视力降低，彩色视觉区分极有限，眼球震颤和恐惧症。 它被继承为常染色体隐性特征。目前已知四个基因会导致这种情况。锥形光感受器上的环状核苷酸门型3（CNG3）的CNGA3和CNGB3分别编码α-和β-亚基型的α和β-亚基均负责绝大多数achromomopsia病例。仅CNGB3基因中的突变占Achromomatia患者的50％以上，这是一种视网膜疾病，每33,000个个体中大约会影响1个。 CNGA3和CNGB3蛋白在锥外段膜上合作形成异元CNG3电导通道。 CNG3通道对于将光刺激转化为激活锥形感受器，并最终转化为日光视觉至关重要。在没有锥体功能的情况下，人类的视力仅限于棒功能，这是具有色素的杆功能，导致明亮照明的敏锐度和饱和度差。 尽管历史上认为是锥虫缺乏锥体或存在极度降低的锥体的疾病，但最近的人类研究表明，即使在患有Achromomatia的较旧受试者中，许多锥体仍然存在。 CNGB3和CNGA3动物模型的研究还表明，锥体存在，但具有显着的形态变化和随着年龄的增长的逐渐降低。如果可以在这些受试者中改善或恢复锥功能，则它们可能会恢复增强的视觉功能。 基因疗法实验已成功治疗了Achromat动物模型，包括天然存在的CNGB3突变犬模型和CNGB3敲除小鼠模型。在CNGB3狗Achromat模型的基因治疗研究中进行了令人惊讶的观察：基因治疗可以部分恢复成年犬的ERG测试的锥体功能，但前提是用纤毛神经营养因子预处理动物（CNTF）。没有事先使用CNTF治疗，基因疗法仅针对年轻的狗而成功。这表明CNTF促进在他们接受基因救援的成年锥体中诱导生物学状态。更令人惊讶的是，发现没有CNGB3基因载体的CNTF玻璃体内注射CNTF蛋白给出了锥体的功能拯救，并且拯救持续了几周，直到清除了CNTF。因此，单独使用CNTF蛋白，并且没有事先或随后的基因载体递送，就支持CNGB3 Achromat狗中锥形感受器的光刺激活性的恢复。 CNTF是一种称为神经营养因子的宏观生物分子类，这些因子已证明在视网膜变性过程中延迟了感光细胞的丧失。 CNTF在13个动物模型中有效地延迟了感光细胞死亡的视力丧失。 2003 - 2006年在NEI进行了一项1阶段的安全研究，以研究10名具有色素末期视网膜炎的受试者的CNTF的眼部递送。它将适当的安全里程碑传递给了第2阶段的研究，研究表明，CNTF可能会改善某些受试者的敏锐性表现。第1阶段的临床试验观察和动物研究为具有视网膜炎色素和干燥AMD的受试者安装2期疗效研究提供了动力。研究设计和结果度量是基于CNTF可能改善锥形感光细胞视觉功能的前提。 一个主要的挑战是将这种潜在的治疗性CNTF代理传递给视网膜。血液 - 视网膜屏障可防止或抑制宏观分子对神经感觉视网膜的穿透，类似于血脑屏障在限制系统性循环和中枢神经系统之间的转移中的作用。为了解决这个问题，Neurotech USA，Inc。开发了封装的细胞技术（ECT），以直接将治疗剂的受控递送到眼内流体，从而直接进入视网膜。 ECT装置中的细胞用CNTF基因转染并产生CNTF蛋白，该蛋白通过半渗透的聚合物胶囊膜直接进入玻璃体。 Neurotech NT-501 ECT设备的测量约为1mm x 6 mm，可以轻松从眼睛中检索，从而增加了安全水平。先前的RP和AMD中的第1阶段和第2阶段研究清楚地表明，CNTF由植入的装置释放，还证明了CNTF覆盖范围并修改了视网膜。 为了进一步探索CNTF在Achromomatia中的疗效，我们通过玻璃体内注射将CNTF输送到小鼠模型，该模型的cngb3基因缺失。 该模型显示出严重和早期的锥体功能，同时保持相对良好的杆功能，如用电视图（ERG）测量。我们先前表明，玻璃体内注射CNTF在正常的大鼠眼中，通过下调参与将光转换为视觉信号的分子机制（PhototRansduction）来抑制棒功能。但是，如上所述，它保护了几种遗传和光感应的视网膜变性模型中的光感受器。最近，显示CNTF还保护锥体免受这些模型的变性，实际上部分恢复了功能细胞器，以进行光接收，即锥外段。这表明在人类和上述CNGB3狗中恢复锥功能的解剖基础。使用CNGB3小鼠的Achromomopia模型将使我们能够探索锥体救援的潜在机制以及增强和延长这种影响的条件。 临床方案： CNGB3 ACHROMOMOPIA的CNTF植入物 临床标识符：NCT01648452 目的：这项研究的目的是用封装的NT-2011细胞评估眼部NT-501设备的安全性，这些NT-2011细胞释放了睫状神经营养因子（CNTF），以对受CNGB3 Achromopsia影响的参与者的视网膜释放。 研究人群：将招募五名受CNGB3 Achromoptia影响的参与者，每名参与者进行一只眼睛的治疗。 设计：这是I/II期，前瞻性，单中心研究。每个参与者的一只眼睛将收到玻璃NT-501设备植入CNTF的植入物。一旦最终参与者接受了三年的随访，该研究将完成。 结果指标：主要结果是在植入后六个月时不良事件的数量和严重性以及全身和眼毒性的数量和严重性。 CNGB3 Achromomatia参与者中的眼CNTF植入物的额外安全性将从评估视网膜功能，眼结构的评估和不良事件的发生。次要结果包括视觉功能的变化，包括视觉敏锐度和色觉，电视图（ERG）响应（ERG）响应以及具有光学相干断层扫描（OCT）的视网膜成像。