Development of PTI-125-DX, a blood-based diagnostic for Alzheimer's disease

摘要 PTI正在开发PTI-125-DX，一种新的基于血液的定量诊断候选药物 阿尔茨海默病(AD)。迫切需要一种非侵入性和廉价的AD诊断方法， 尤其是有能力在认知之前发现早期病变的人 症状。PTI-125-DX测量血浆中两个蛋白质片段的比率，是一种 我们的候选治疗药物PTI-125的配套诊断/生物标志物。PTI-125中断和 阻止细丝蛋白A(Flna)S与α7-烟碱型乙酰胆碱受体(α7nAChR)的结合， 哪个淀粉样β1-42(Aβ42)劫持了过度磷酸化的tau蛋白。我们已经测试过了 220个血浆样本，并显示出两个数量级的显著差异 有AD诊断(经影像或脑脊液标志物确认)和年龄匹配的正常对照组。 区分这两组的准确率为98-100%。在两项盲法研究之一中，PTI- 125-DX鉴别确诊为AD病理的MCI(MCI-AD)和疑似非AD的MCI 淀粉样变性病理(MCI-SNAP)的准确率为92%；在另一种情况下，这种区分需要 通过成像进行确认。在本提案中，我们将比较其他MCI-AD和MCI-SNAP 并通过检测存档的血浆样本来确定该方法的疾病特异性 路易体痴呆、额颞叶痴呆和帕金森病患者 与AD、MCI-AD、MCI-SNAP、早发性家族性AD(FAD)、癌症和老年人或年轻人一起 控制。由于PTI-125-DX目前为蛋白质印迹形式，我们将开发一种ELISA检测方法，并 将其与使用ProteinSimple的WES™的自动蛋白质印迹格式进行比较。在第二阶段，我们会 用精心挑选的多肽和重组人免疫产生专有抗体 蛋白质；将对这些多克隆抗体进行筛选和测试，以确定最佳 组合。然后，相应的免疫原将被用于开发单克隆性 抗体。我们设想的夹心ELISA法将捕获所有感兴趣的片段，并分别 检测两个特定的蛋白质片段。用最终的单抗和最终的ELISA(或WES) 选定的格式，我们将对多达250个未确认的血浆样本进行新的盲法研究 来自AIBL的研究。在这项工作结束时，PTI-125-DX将准备好 商业化或合作。

Abstract PTI is developing PTI-125-DX, a novel, quantitative blood-based diagnostic candidate for Alzheimer's disease (AD). A non-invasive and inexpensive AD diagnostic is sorely needed, particularly one with the ability to detect early pathological changes that precede cognitive symptoms. PTI-125-DX measures the ratio of two protein fragments in plasma and is a companion diagnostic/biomarker for our therapeutic candidate PTI-125. PTI-125 disrupts and prevents filamin A (FLNA)'s association with the α7-nicotinic acetylcholine receptor (α7nAChR), which amyloid beta 1-42 (Aβ42) hijacks to hyperphosphorylate tau protein. We have tested over 220 plasma samples and show two orders of magnitude significant differences between patients with AD diagnoses (confirmed by imaging or CSF markers) and age-matched normal controls. These two groups are distinguished with 98-100% accuracy. In one of two blinded studies, PTI- 125-DX distinguished MCI with confirmed AD pathology (MCI-AD) from MCI with suspected non- amyloid pathology (MCI-SNAP) with 92% accuracy; in the other, this distinction needs confirmation by imaging. In this proposal, we will compare additional MCI-AD and MCI-SNAP samples and determine disease specificity of the assay by testing archived plasma samples from patients with dementia with Lewy bodies, Frontotemporal Dementia and Parkinson's disease alongside AD, MCI-AD, MCI-SNAP, early-onset familial AD (FAD), cancer and elderly or young controls. As PTI-125-DX is currently in Western blot format, we will develop an ELISA assay and compare it to an automated Western blot format using ProteinSimple's Wes™. In Phase II, we will generate proprietary antibodies by immunizing with carefully selected peptides and recombinant proteins; these polyclonal antibodies will be screened and tested to determine optimal combinations. The corresponding immunogens will then be used to develop monoclonal antibodies. The sandwich ELISA we envision will capture all fragments of interest and separately detect two specific protein fragments. With final monoclonal antibodies and a final ELISA (or Wes) format selected, we will perform a new blinded study of up to 250 de-identified plasma samples from the AIBL study. At the conclusion of this work, PTI-125-DX will be ready for commercialization or partnering.