Novel Approaches to Pretargeted Radioimmunotherapy

预靶向放射免疫治疗的新方法

• 批准号: 6989501
• 负责人: SALLY J DENARDO
• 金额: $ 27.08万
• 依托单位: UNIVERSITY OF CALIFORNIA AT DAVIS
• 依托单位国家: 美国
• 财政年份: 2004
• 资助国家: 美国
• 起止时间: 2004-04-01 至 2007-03-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6989501
• 关键词: athymic mouse; biotechnology; cell line; chemical structure; clearance rate; crosslink; hormone related neoplasm /cancer; immunoconjugates; immunoglobulin structure; immunologic substance development /preparation; immunopathology; metastasis; microarray technology; monoclonal antibody; neoplasm /cancer radioimmunotherapy; organometallic compounds; polyethylene glycols; prostate neoplasms; radiotracer; therapy design /development; yttrium

The goal of this project is to generate a novel PEGylated bispecific, bivalent single chain (scFv) antibody (MAb) construct as part of a new pretargeting delivery strategy that will greatly increase the therapeutic index of radioimmunotherapy (RIT) in metastatic prostate cancer. The underlying hypothesis is that metastatic prostate cancer can be cured without marrow support by systemically targeted radiation therapy as part of combined modality therapy, if the therapeutic index of RIT is increased by a factor of 10. In a Phase I RIT study in patients with androgen-independent metastatic prostate cancer, we have induced therapeutic response using Yttrium-90 (90Y) MAb against an epithelial mucin (MUC-1), but marrow support was needed for effective therapy. In contrast, the strategy for pretargeted RIT (pRIT) disassociates the phase of accumulation of the nonradioactive construct at the sites of prostate cancer from the phase for delivery of the small radioisotope source, thereby dramatically decreasing radiation to normal tissues while preserving the radiation to the cancer. Key issues are addressed for pretargeted therapy, by providing a less immunogenic, modular, specific tumor targeting molecule, and a multivalent radioactive source that will, on subsequent injection, quickly bind and cross link the pretargeted molecules on tumor cells with high avidity. If needed, further strategies have been developed to negate interference from pretargeting molecules that remain in the circulation. Specific Aims have included: 1) select scFv from MUC-1 immune scFv libraries that specifically bind prostate cancer cells using tissue arrays of >300 prostate cancers and an extensive panel of normal tissues; 2) produce an optimized anti-cancedanti-DOTA scFv conjugated PEG ((scFv)4-PEG)); 3) develop an optimized multivalent Y-90 DOTA structure to bind and cross link on tumor, utilizing molecular modeling and biosensor affinity; 4) study the dose/time characteristics of the prostate cancer pretargeting conjugate as In-111 DOTA-(scFv)4-PEG and the multivalent Y-90 DOTA in in vitro and in vivo pharmacokinetic studies to maximize tumor uptake in nude mice bearing human prostate cancers; 5) if needed, implement strategy to negate interference of residual pretargeting molecules in blood; 6) develop protocols and GMP pharmaceuticals for pharmacokinetic studies in prostate cancer patients to be initiated by the next grant period. The investigative team has: the requisite experience, methods and resources. We have made vector modifications allowing site specific scFv conjugation; demonstrated MUC-1 target expression patterns correlating to malignancy and Gleason grade by MAb; selected scFv that selectively stain prostate cancer on tissue arrays. This proposal has a high likelihood of success.

该项目的目标是产生一种新型的聚乙二醇化双特异性双价单链(ScFv)抗体(MAb)，作为新的预靶向递送策略的一部分，该策略将大大提高转移性前列腺癌的放射免疫治疗(RIT)的治疗指数。基本的假设是，如果RIT的治疗指数增加10倍，转移性前列腺癌可以在没有骨髓支持的情况下被治愈，作为综合治疗的一部分，如果RIT的治疗指数增加10倍。在一项针对雄激素非依赖性转移性前列腺癌患者的I期RIT研究中，我们使用Yttrium-90(90Y)抗上皮粘蛋白(MUC-1)的单抗诱导了治疗反应，但有效的治疗需要骨髓支持。相反，前靶向RIT(PRIT)的策略将前列腺癌部位非放射性结构的积聚阶段与前列腺癌的 提供小的放射性同位素源，从而极大地减少对正常组织的辐射，同时保留对癌症的辐射。通过提供免疫原性较低的、模块化的、特定的肿瘤靶向分子和多价放射源，在随后的注射中，将快速结合和交联具有高亲和力的肿瘤细胞上的预靶向分子，从而解决了预靶向治疗的关键问题。如果需要，已经开发了进一步的策略来消除保留在循环中的预靶向分子的干扰。具体目标包括：1)从MUC-1免疫单链抗体文库中筛选与前列腺癌细胞特异结合的单链抗体，利用300例前列腺癌组织阵列和大量正常组织；2)产生优化的抗癌抗DOTA单链抗体偶联聚乙二醇单抗 ((ScFv)4-PEG))；3)利用分子模拟和生物传感器亲和力，开发与肿瘤结合和交联的优化的多价Y-90 DOTA结构；4)研究前列腺癌预靶向偶联物In-111 DOTA-(ScFv)4-PEG和多价Y-90 DOTA的剂量/时间特性，以最大限度地提高荷人前列腺癌裸鼠对肿瘤的摄取；5)如果需要，实施消除血液中残留的前靶向分子干扰的策略；6)开发用于前列腺癌患者药代动力学研究的方案和GMP药物 在下一个授权期之前。调查小组拥有：必要的经验、方法和资源。我们对载体进行了修饰，允许位点特异性的scFv结合；通过单抗证明了与恶性肿瘤和Gleason分级相关的MUC-1靶向表达模式；选择了选择性地将前列腺癌染色到组织阵列上的scFv。这项提议很有可能成功。