Anti-AAV Antibodies as an Obstacle to Cardiac AAV Gene Therapy

抗 AAV 抗体是心脏 AAV 基因治疗的障碍

• 批准号: 9176405
• 负责人: Roger J. Hajjar
• 金额: $ 83.44万
• 依托单位: ICAHN SCHOOL OF MEDICINE AT MOUNT SINAI
• 依托单位国家: 美国
• 财政年份: 2016
• 资助国家: 美国
• 起止时间: 2016-07-01 至 2020-04-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/9176405
• 关键词: Accounting; Address; Adsorption; Age; Animal Model; Antibodies; Antigens; Bacterial Transformation; Biological Assay; Blood; Bypass; Ca(2+)-Transporting ATPase; Calcium; Capsid; Cardiac; Cardiac Myocytes; Cardiovascular Diseases; Cells; Cessation of life; Clinic; Coronary; Coupled; Data; Dependovirus; Development; Diagnosis; Directed Molecular Evolution; Disease; Escherichia coli; Exclusion Criteria; Failure; Family suidae; Future; Gene Delivery; Gene therapy trial; Genes; Goals; Heart Diseases; Heart failure; Human; Immunoglobulins; In Vitro; Infusion procedures; Libraries; Methods; Mission; Modeling; National Heart, Lung, and Blood Institute; Nude Rats; Outcome; Patients; Percutaneous Administrations; Phase; Plasmapheresis; Protein Isoforms; Pump; Resistance; Rodent; SERCA2a; Sarcoplasmic Reticulum; Serotyping; Serum; Survival Rate; Techniques; Testing; Therapeutic; Treatment Efficacy; Tropism; Up-Regulation; Variant; Viral; Virion; Virus; adeno-associated viral vector; base; design; gene therapy; improved; in vitro Assay; in vivo; innovation; lifetime risk; meetings; neutralizing antibody; novel; novel strategies; prevent; research study; therapeutic gene; transgene expression; treatment strategy; vector

Recently, Adeno-Associated Virus (AAV)-based vectors have emerged as promising gene delivery vehicles for a wide array of diseases, including cardiovascular disorders. Despite early encouraging results, the CUPID (Calcium Upregulation by Percutaneous Administration of Gene Therapy in Cardiac Disease) trial using an AAV serotype 1 vector encoding the sarcoplasmatic calcium ATPase SERCA2a failed to meet both its primary and secondary endpoints. These results were surprising because in porcine models of HF AAV1.SERCA2a improved cardiac function. Preliminary results suggest that the disappointing outcome was due to a failure of AAV1.SERCA2a to deliver efficiently the SERCA2a gene. One possible explanation for the poor gene delivery is that neutralizing antibodies (NAbs) against AAV1 were not detected with the in vitro NAb assay used in the CUPID trial, but that these NAbs prevented transduction. In Aim 1 of this application we will test in a porcine HF model the hypothesis that extremely low levels of NAbs, which can only be detected by a more sensitive in vivo NAb assay, can prevent transduction and therapeutic efficacy of AAV1.SERCA2a. Conversely, if in vitro NAb assays are sufficiently sensitive, we will determine the maximal NAb levels that are still compatible with efficient transduction and therapeutic efficacy of AAV1.SERCA2a (in pigs). An alternative explanation for the negative results of the CUPID trial is that AAV1 displays specie-specific tropism, i.e. that AAV1 can efficiently transduce pig but not human cardiomyocytes. To bring cardiac AAV gene therapy to the clinic, it will be critical to isolate AAV variants that 1) Can efficiently transduce human cardiac cells and 2) Show increased resistance to NAbs. The isolation of such variants is the goal of Aim 2. Unfortunately, it seems unlikely that AAV variants that can efficiently transduce human cardiomyocytes and that are also resistant to very high levels of NAbs against the naturally occurring AAV serotypes can be isolated. Therefore, in Aim 3, we will test an approach to deplete NAbs from the blood by plasmapheresis coupled with immunadsorption with columns with immobilized AAV particles. With the successful completion of this proposal, we will have established whether an in vitro NAb assay is sensitive enough to serve as an exclusion criterion for cardiac AAV gene therapy trials where AAV is delivered by intracoronary infusion, or if a more sensitive in vivo assay must be used. We will have isolated novel AAV variants with tropism for human cardiomyocytes and increased resistance to NAbs. Finally, we will have established whether plasmapheresis coupled with immunadsorption on AAV columns can be used to deplete NAbs from blood. These parameters will be critical in the design and execution of future gene therapy trials for cardiovascular diseases.

最近，与腺相关的病毒（AAV）基于腺相关的载体已成为有前途的基因递送车辆 用于多种疾病，包括心血管疾病。尽管有早期令人鼓舞的结果，但 丘比特（通过经皮钙在心脏病中的基因疗法的钙上调）试验 编码肌浆钙ATPASE SERCA2A的AAV血清型1向量无法满足其 主要和次要端点。这些结果令人惊讶，因为在HF的猪模型中 AAV1.serca2a改善了心脏功能。初步结果表明，令人失望的结果是 由于AAV1.serca2a未能有效传递SERCA2A基因。一个可能的解释 基因递送差是未检测到针对AAV1的中和抗体（NAB）用体外NAB检测到 丘比特试验中使用的测定法，但这些NABS阻止了转导。在本应用程序的目标1中，我们将 在猪HF模型中测试的假设是，极低水平的Nabs，只能通过A检测到 更敏感的体内NAB分析可以防止AAV1.serca2a的转导和治疗功效。 相反，如果体外NAB测定足够敏感，我们将确定最大的NAB水平 仍然与AAV1.serca2a（猪）的有效转导和治疗功效兼容。 丘比特试验负面结果的另一种解释是AAV1显示了特定于特定的 向西主义，即AAV1可以有效地转导猪而不是人类心肌细胞。 要将心脏AAV基因疗法带到诊所，分离AAV变体至关重要。1）可以 有效地转导人类心细胞，2）表现出对NABS的耐药性。这种隔离 变体是目标2的目标。 不幸的是，似乎不太可能有效地转导人类心肌细胞的AAV变体 并且对天然AAV血清型的NABS也可以抵抗非常高的NABS 孤立。因此，在AIM 3中，我们将测试一种通过血浆置换从血液中耗尽Nabs的方法 与固定的AAV颗粒的色谱柱与免疫吸附结合。 随着该提案的成功完成，我们将确定是否是体外NAB测定法 敏感足以作为心脏AAV基因疗法试验的排除标准，其中AAV交付 如果必须使用更敏感的体内测定法，则通过秋季内输注。我们将有孤立的小说AAV 对人类心肌细胞的向流主义的变体和对NABS的耐药性。最后，我们将有 确定血浆置换是否与AAV色谱柱上的免疫吸附结合可以用来耗尽 血液中的nabs。这些参数对于未来基因治疗试验的设计和执行至关重要 心血管疾病。