Ph1/2 Study of the Imipridone ONC201 for Treatment of AML IND125,203 (12/23/2014)

项目摘要/摘要 存活率(AP.30%)的急性髓系白血病(AML)在过去40年中没有改善，除了 一些特殊的实例。这项研究的长期目标是通过以下途径提高AML的治愈率 靶向一种新的细胞生存机制--线粒体未折叠蛋白的临床应用 回应(MtUPR)。我们建议进行ONC201的1/2期临床试验，这是一种一流的药物 并确认和进一步研究潜在的新的作用机制(MOA)。我们 在广泛的临床前研究中发现，ONC201可诱导AML细胞凋亡，但不能诱导正常细胞凋亡。 重要的是，ONC201对p53突变的AML也有很好的疗效，P53突变的AML也是最耐药的亚群 如P53野生型AML。我们的临床前研究进一步表明，ONC201在功能上消除了- 定义了患者来源的异种移植中的白血病干细胞。MD Anderson启动的早期试验显示非常好 ONC201的耐受性、微摩尔血浆浓度和早期临床反应。我们之前 报道称，ONC201通过转录因子ATF4诱导细胞凋亡，ATF4是整合的标志 应激反应(ISR)。然而，ONC201并没有引起与以下相关的所有特征分子变化 经典的ISR(如内质网应激)，表明非典型的MOA诱导ATF4。随着突破性进展 在这次重新提交的报告中，我们发现ONC201直接结合并激活线粒体 蛋白水解酶，ClpP，导致选择性线粒体蛋白分解。由此导致的mt蛋白库的减少 诱导所谓的mt蛋白折叠应激(MtPFS)和对mtPFS的保护性转录反应 称为线粒体未折叠蛋白反应(MtUPR)。重要的是，已知ATF4是通过mtUPR诱导的， 以一种不同于经典ISR的方式将我们之前在ATF4上的发现联系起来。我们在这里假设 AML祖细胞和干细胞比正常细胞更容易受到mtPFS的影响，ONC201是靶向 急性髓系白血病病理生物学中的一个新的脆弱性。拟议的白血病临床试验提供了一种独特的 彻底研究这一假说的机会。我们将在AML中进行ONC201的1/2期研究 (目标1)，并评估基本的MOA(目标2)。第一阶段试验将确定安全性和初步 ONC201的疗效和2期总缓解率。ATF4、mtUPR效应蛋白、mt AML细胞的功能和生物发生也将使用标准的免疫印迹和聚合酶链式反应方法进行研究 作为包括单细胞蛋白质组学(CyTOF)在内的新工具。我们还将确定ClpP、ATF4和mtUPR是否 效应蛋白是临床对ONC201反应的潜在生物标志物。克隆体系结构的变化将 通过流式细胞仪和单细胞DNA测序进行监测。还将执行全基因组RNAseq 以进一步阐明MOA和潜在的抗性。我们期待着这些研究，它们处于 我们不断进化的线粒体病理生理学知识，将发展成为一种高效和新颖的 急性髓系白血病的治疗理念。

Project Summary/Abstract Survival rates (app. 30 %) of acute myeloid leukemia (AML) have not been improved over 4 decades, except in some specialized instances. The long term aim of this study is to increase the cure rates of AML through clinical implementation of targeting a new cellular survival mechanism, i.e. mitochondrial (mt) unfolded protein response (mtUPR). We are proposing to conduct a clinical Phase 1/2 trial of ONC201, a first-in-class imipridone and to confirm and further investigate the underlying novel mechanism of action (MOA). We discovered in extensive preclinical studies that ONC201 induces apoptosis in AML but not in normal cells. Importantly, ONC201 has great efficacy in p53-mutated AML, the most chemotherapy-resistant subset, as well as in p53 wild-type AML. Our preclinical studies further demonstrate that ONC201 eliminates functionally- defined leukemia stem cells in patient-derived xenografts. Early trials initiated at MD Anderson show excellent tolerability of ONC201, micromolar plasma concentrations, and early clinical responses. We previously reported that ONC201 induces apoptosis mediated by the transcription factor ATF4, a hallmark of integrated stress response (ISR). However, ONC201 did not induce all characteristic molecular changes associated with classical ISRs (e.g., ER stress), suggesting an atypical MOA to induce ATF4. As break through progress reported in this re-submission, we have discovered that ONC201 directly binds and activates the mitochondrial protease, ClpP, resulting in selective mitochondrial proteolysis. The resultant reduction of mt protein pools induces so-called mt protein folding stress (mtPFS) and the protective transcriptional response against mtPFS termed mt unfolded protein response (mtUPR). Importantly, ATF4 is known to be induced through mtUPR, connecting our previous findings on ATF4 in a way different from classical ISRs. We here hypothesize that AML progenitor and stem cells are more susceptible to mtPFS than normal cells, and that ONC201 is targeting a novel point of vulnerability in AML pathobiology. The proposed clinical trial in leukemia provides a unique opportunity to thoroughly investigate this hypothesis. We will conduct a Phase 1/2 study of ONC201 in AML (Aim 1), and evaluate the underlying MOA (Aim 2). The Phase 1 trial will determine the safety and preliminary efficacy of ONC201 and Phase 2 the overall response rate. Changes in ATF4, mtUPR effector proteins, mt function and biogenesis in AML cells will be investigated using standard immunoblot and PCR methods as well as novel tools including CyTOF (single cell proteomics). We will also determine if ClpP, ATF4 and mtUPR effector proteins are potential biomarkers of clinical response to ONC201. Changes in clonal architecture will be monitored by flow cytometry and single-cell DNA sequencing. Genome-wide RNAseq will also be performed to further elucidate MOA and potential resistance. We expect these studies, which are at the cutting edge of our evolving knowledge of mitochondrial pathophysiology, to be developed into a highly effective and novel concept for the treatment of AML.