A combination strategy to target pathophysiology of chronic lymphocytic leukemia

项目总结 慢性淋巴细胞白血病(CLL)细胞的存活在很大程度上是由于B细胞受体(BCR)信号转导和 Bcl2家族蛋白的抗细胞凋亡作用。Bcr途径对细胞的增殖、维持、 和B细胞的存活。Bruton‘s酪氨酸激酶(BTK)在BCR轴中起关键作用，当BCR 受到刺激。由于它在BCR轴信号转导中的关键作用以及BCR通路在B细胞中的重要性，BTK是 一个有吸引力的治疗靶点和伊布鲁替尼(IBR)被批准用于CLL。CLL细胞对bcl-2的依赖性 2生存蛋白使bcl2拮抗剂如VEN成为BTK的最佳组合伙伴 抑制剂。阿卡拉布替尼(acalabrutinib，ACA)是第二代更具选择性的BTK抑制剂，它不可逆转地与 Cys-481位于BTK激活区，并能有效地阻断其酶活性。ACA展示了令人信服的 在临床和I期试验中的活性，很明显，这种口服药物非常有效， 选择性优于第一代缓蚀剂IBR。然而，在临床上，患者很少能完全缓解。 (Cr)或治愈，以及持续使用药物或联合使用策略。类似于BCR目标， Bcl2抑制剂VEN在临床上有效，但CRS有限。基于我们的临床前调查和 在三个不同的理论基础上，我们设计并启动了一项结合IBR和VEN治疗CLL的临床试验。基本原理 包括IBR治疗后CLL细胞中MCL-1存活蛋白的下降，CLL细胞从 IBR后淋巴转移到循环血液，并潜在地降低VEN诱导的肿瘤溶解的发生率 IBR肿瘤摘除所致的综合征。数据显示，与 IBR或VEN单一疗法以及三分之二的患者实现了无法检测到的残留疾病 以前没有治疗过的病人。基于这些数据，我们假设更具选择性的BTK抑制剂ACA 联合VEN可能是治疗CLL的更有效的策略，有更高的有效率。一份临床方案 (NCT04169737)已经建立并启动，以评估与或 没有接受Obinutuzumab治疗--幼稚的和以前接受过治疗的队列。在这份提案中，我们将只关注 ACA+VEN联合用药(即不含奥昔单抗)。通过这次试验，我们将在治疗过程中获得样本 评估对治疗反应有贡献的成分。在目标1中，我们将进行药效学 治疗期间的分析以确定VEN对ACA的影响。各药的血浆药代动力学 药物将被测量，分子终点将使用RNAseq和蛋白质组学分析进行比较。为 目的2比较ACA/VEN组合与IBR/VEN组合的非劣性。这些 分析将包括药效学分析、组学和使用回顾数据的生物标记物比较 来自IBR/VEN结合正在进行的ACA/VEN临床试验。我们有来自未经治疗的患者(n=120)的先前数据 80例在IBR/VEN试验中接受过治疗的CLL患者。归根结底，该提案的目标是确定 反应和耐药的标志和生物标志物，可能导致更有效的CLL治疗。

PROJECT SUMMARY Survival of chronic lymphocytic leukemia (CLL) cells is largely due to B-cell receptor (BCR) signaling and to the anti-apoptotic function of BCL-2 family proteins. The BCR pathway is critical for the proliferation, maintenance, and survival of B-cells. Bruton’s tyrosine kinase (BTK) is pivotal in the BCR axis and is activated when BCR is stimulated. Due to its critical role in BCR axis signaling and importance of the BCR pathway in B-cells, BTK is an attractive therapeutic target and ibrutinib (IBR) was approved for CLL. The dependency of CLL cells on BCL- 2 protein for survival makes BCL-2 antagonists such as venetoclax (VEN) optimal combination partners for BTK inhibitors. Acalabrutinib (ACA) is a second-generation more selective BTK inhibitor that irreversibly binds to Cys-481 in the BTK kinase domain and potently blocks its enzymatic activity. ACA demonstrated compelling activity in the clinic and during Phase I trials, and it became clear that this oral drug is highly effective with greater selectivity than first-generation inhibitor IBR. However, clinically, patients rarely achieve complete remissions (CR) or cures, and continuous use of the drug or combination strategies are needed. Similar to BCR targeting, BCL-2 inhibitor, VEN, was effective in the clinic but with limited CRs. Based on our preclinical investigations and three distinct rationales, we designed and initiated a clinical trial combining IBR and VEN in CLL. Rationales included decline in MCL-1 survival protein in CLL cells following IBR treatment, mobilization of CLL cells from lymph nodes to circulating blood after IBR, and potential decreased incidence of VEN-induced tumor lysis syndrome due to debulking of tumor by IBR. Data demonstrated a dramatic increase in CR rates compared with IBR or VEN monotherapy as well as achievement of undetectable measurable residual disease in 2/3 of previously untreated patients. Based on this data we hypothesized that more selective BTK inhibitor ACA combined with VEN may be more effective strategy for CLL with greater response rates. A clinical protocol (NCT04169737) has been established and initiated to evaluate the efficacy of the combination treatment with or without obinutuzumab treatment-naïve and previously treated cohorts. In this proposal, we will focus only on the ACA+VEN combination (i.e. without obinutuzumab). Through this trial, we will obtain samples during treatment to evaluate the components that contribute to response to therapy. In Aim 1, we will conduct pharmacodynamic analyses during therapy to determine the impact of VEN addition to ACA. Plasma pharmacokinetics of each drug will be measured, and molecular endpoints will be compared using RNAseq and proteomics analyses. For Aim 2, we will compare the combination of ACA/VEN combination against IBR/VEN for non-inferiority. These analyses will include pharmacodynamic analysis, -omics and biomarker comparisons using retrospective data from IBR/VEN combination with the ongoing ACA/VEN clinical trial. We have prior data from untreated (n=120) and previously treated (n=80) CLL patients on IBR/VEN trial. Ultimately, the goals of this proposal are to identify hallmarks and biomarkers of response and resistance that may lead to more effective treatment of CLL.