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

项目概要/摘要 急性髓性白血病（AML）的生存率（约30%）在过去40年中没有改善， 一些特殊的例子。本研究的长期目标是通过以下方法提高AML的治愈率： 靶向新的细胞存活机制即线粒体（MT）未折叠蛋白的临床实施 响应（mtUPR）。我们建议进行ONC 201的临床1/2期试验， 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，ONC 201在AML中诱导凋亡，但在正常细胞中不诱导凋亡。 重要的是，ONC 201在p53突变的AML中也有很好的疗效，AML是最耐化疗的亚群， 如p53野生型AML。我们的临床前研究进一步证明，ONC 201在功能上消除了 在患者来源的异种移植物中定义白血病干细胞。在MD安德森开展的早期试验显示， ONC 201的耐受性、微摩尔血浆浓度和早期临床反应。我们之前 报道ONC 201诱导由转录因子ATF 4介导的凋亡，ATF 4是整合的细胞凋亡的标志。 应激反应（ISR）。然而，ONC 201并没有诱导与细胞凋亡相关的所有特征性分子变化。 经典ISR（例如，ER应激），表明非典型MOA诱导ATF 4。作为突破性进展 在这次重新提交的报告中，我们发现ONC 201直接结合并激活线粒体 蛋白酶，ClpP，导致选择性线粒体蛋白水解。由此产生的mt蛋白池的减少 诱导所谓的mt蛋白折叠应激（mtPFS）和针对mtPFS的保护性转录应答 称为mt未折叠蛋白反应（mtUPR）。重要的是，已知ATF 4通过mtUPR诱导， 以不同于经典ISR的方式将我们先前对ATF 4的发现联系起来。我们在此假设 AML祖细胞和干细胞比正常细胞对mtPFS更敏感，ONC 201靶向 AML病理生物学中的一个新的脆弱点。拟议中的白血病临床试验提供了一个独特的 有机会彻底调查这个假设。我们将在AML中进行ONC 201的I/II期研究 (Aim 1），并评估潜在的MOA（目标2）。1期试验将确定安全性和初步 ONC 201的疗效和2期的总体缓解率。ATF 4、mtUPR效应蛋白、mt 还将使用标准免疫印迹和PCR方法研究AML细胞中的功能和生物发生 作为新的工具，包括CyTOF（单细胞蛋白质组学）。我们还将确定ClpP、ATF 4和mtUPR是否 效应蛋白是对ONC 201的临床应答的潜在生物标志物。克隆结构的变化将 通过流式细胞术和单细胞DNA测序进行监测。还将进行全基因组RNAseq 以进一步阐明MOA和潜在抗性。我们希望这些研究，这是在尖端的， 我们不断发展的线粒体病理生理学知识，将发展成为一个高效和新颖的 治疗AML的概念。

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.