Developing CRM1 inhibitors in AML

描述(由申请人提供)：急性髓系白血病(AML)的预后很差，突出了对新的治疗方法的迫切需要。CRM1是一种核输出受体，参与将肿瘤抑制因子(TS)[如P53]主动转运出细胞核，导致其失活。CRM1蛋白的过度表达在AML中已被描述。使用口服选择性抑制剂靶向CRM1导致P53的显著核积聚，进而导致AML细胞株和患者原始细胞高度凋亡、细胞周期停滞和髓系分化。基于这些初步数据，我们假设CRM1抑制剂将是安全和耐受的，并将在AML患者中显示出单药抗白血病活性。KPT-330(最后一代口服CRM1抑制剂)在难治性/复发和新诊断的不适合老年人(&gt；65岁)AML中的第一阶段研究已经开始，目的是评估这种化合物的安全性、耐受性和初步疗效。在具体目标1中，我们建议使用KPT-330在AML患者中的第一阶段临床试验的样本进行相关研究(PK和PD)，目的是：1)确定与临床反应和药物活性相关的预处理分子/细胞遗传学生物标志物；2)评估PD终点；3)评估PK和PD终点之间的关系。由于AML是一种临床和分子复杂的疾病，不太可能用单一药物治愈，因此很可能需要将KPT-330与AML的其他有效方案结合使用，才能达到最大的抗白血病活性。我们小组最近报道了一种相对有效且无毒的单药地西他滨治疗老年AML患者的方案。我们的初步数据支持，用地西他滨启动AML细胞可以增加KPT-330的抗白血病效果。我们推测这一效应是由地西他滨引起的TS核积聚所致。在具体目标2中，我们建议在新诊断的不适合的老年(&gt；60)或难治/复发AML患者中进行地西他滨和KPT-330的第一阶段临床试验，以确定：1)该方案的安全性和耐受性；2)第二阶段的推荐剂量；3)初步疗效；4)PD终点，包括CRM1依赖靶点的表达、甲基组、转录组和miRNA图谱使用下一代测序。最后，由于用CRM1抑制剂治疗可导致白血病细胞中p53和拓扑异构酶(TOPO)IIα(TOPO II抑制剂诱导�裂解复合体和细胞死亡所需的关键酶)的上调和核积聚，我们推测，恢复P53的表达和TOPO II DNA的核定位可能会增加难治性/复发性急性髓细胞白血病细胞对阿糖胞苷/拓扑异构酶II抑制剂的化疗敏感性。我们的数据支持KPT-330与阿糖胞苷和伊达比星有协同作用的假设。在具体目标3中，我们建议通过联合或序贯使用KPT-330来增强阿糖胞苷和/或TOPO IIα抑制剂的抗白血病作用，以克服难治性/复发性急性髓细胞白血病细胞的化疗耐药性。这项提案的主要目标是开发口服CRM1抑制剂治疗AML。

DESCRIPTION (provided by applicant): The prognosis of acute myeloid leukemia (AML) is poor, highlighting the urgent need for novel therapeutic approaches. CRM1 is a nuclear export receptor involved in the active transport of tumor suppressors (TS) [e.g. p53] out of the nucleus resulting in their inactivation. Over-expression of CRM1 protein has been described in AML. Targeting CRM1 using oral selective inhibitors resulted in significant nuclear accumulation of p53 and in turn high degree of apoptosis, cell-cycle arrest and myeloid differentiation in AML cell lines and patient blasts. Based on these preliminary data we hypothesize that CRM1 inhibitors will be safe and tolerated and will show single agent anti-leukemic activity in AML patients. A Phase 1 study of KPT-330 (last generation oral CRM1 inhibitors) in refractory/relapsed and newly diagnosed unfit elderly (>65 years) AML was started with the goal to assess safety, tolerability and preliminary efficacy of this compound. In specific aim 1, we propose to perform correlative studies (PK and PD) using specimens from the Phase 1 clinical trial of KPT-330 in AML patients with the intent to: 1) identify pretreatment molecular/cytogenetic biomarkers associated with clinical response and drug activity, 2) evaluate PD endpoints and 3) asses the relationship between PK and PD endpoints. Because AML is a clinically and molecularly complex disease that is unlikely to be cured with a single agent, it is likely that to achieve maximal anti-leukemia activity we need to combine KPT-330 with other active regimens in AML. Our group recently reported a relatively effective and non toxic single agent decitabine treatment schedule for older AML patients. Our preliminary data support that priming AML blasts with decitabine increases KPT-330 anti-leukemic effects. We hypothesize that this effect is caused by the nuclear accumulation of TS previously induced by decitabine. In specific aim 2, we propose to conduct a Phase 1 clinical trial of decitabine followed by KPT-330 in newly diagnosed unfit elderly (>60) or refractory/relapsed AML patients in order to determine: 1) the safety and tolerability of the regimen; 2) the Phase 2 recommended dose; 3) preliminary efficacy and 4) PD endpoints including CRM1 dependent targets expression, methylome, transcriptome and miRNA profiling using next generation sequencing. Last, since treatment with CRM1 inhibitors results in up-regulation and nuclear accumulation of p53 and Topoisomerase (Topo) IIα (a key enzyme that is required for Topo II inhibitors to induce DNA-cleavage complexes and cell death) in AML blasts, we hypothesize that restoring p53 expression and nuclear localization of Topo II� may increase chemotherapy sensitivity to cytarabine/topo II inhibitors in refractory/relapsed AML blasts. Our data support the hypothesis that KPT-330 synergizes with cytarabine and idarubicin. In specific aim 3 we propose to overcome chemotherapy resistance in refractory/relapsed AML blasts by enhancing cytarabine and/or Topo IIα inhibitors anti-leukemic effects using concomitant or sequential treatment with KPT-330. The main goal of this proposal is to develop oral CRM1 Inhibitors treatment for AML.