Strategies to target BCR-ABL1 compound mutants in CML and Ph+ ALL

CML 和 Ph ALL 中针对 BCR-ABL1 复合突变体的策略

• 批准号: 10523439
• 负责人: Michael W. Deininger
• 金额: $ 36.99万
• 依托单位: VERSITI WISCONSIN, INC.
• 依托单位国家: 美国
• 财政年份: 2021
• 资助国家: 美国
• 起止时间: 2021-11-10 至 2025-12-31
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10523439
• 关键词: ABL1 gene; Acute Myelocytic Leukemia; Address; Affinity; Alleles; Allosteric Site; American; Binding; Binding Sites; Biochemical; Biophysics; Blast Phase; Bypass; Cessation of life; Chronic Myeloid Leukemia; Chronic-Phase Myeloid Leukemia; Clinical; Clinical Trials; Communication; Complex; Dasatinib; Dependence; Distant; Dose; Enzyme Inhibition; Event; Exhibits; FDA approved; Foundations; Gatekeeping; Imatinib; Knowledge; Laboratory Study; Leukemic Cell; Malignant Neoplasms; Malignant neoplasm of lung; Medical; Medicine; Methods; Molecular Conformation; Mutation; Non-Small-Cell Lung Carcinoma; Patient-Focused Outcomes; Patients; Ph+ ALL; Pharmaceutical Preparations; Philadelphia Chromosome; Phosphotransferases; Physiological; Prevalence; Protac; Proto-Oncogene Proteins c-abl; Protocols documentation; Recurrent disease; Refractory; Regulatory Element; Reporting; Residual state; Resistance; Sampling; Signal Transduction; Site; Site-Directed Mutagenesis; System; Technology; Testing; Therapeutic; Treatment Failure; Tyrosine Kinase Inhibitor; Work; Xenograft procedure; base; clinical development; effective therapy; improved; inhibitor; leukemia; melanoma; mouse model; mutant; novel therapeutic intervention; optimal treatments; research clinical testing; resistance mechanism; resistance mutation; targeted treatment

Abstract: Philadelphia chromosome-positive (Ph+) leukemia is caused by BCR-ABL1, a constitutively active fusion kinase. Tyrosine kinase inhibitors (TKIs) targeting the ATP site of BCR-ABL1 are effective in treating chronic-phase chronic myeloid leukemia (CP-CML) yet minimally effective at treating blast-phase CML and Ph+ acute lymphoblastic leukemia. In the 20 years since the approval of the first TKI in all of medicine, imatinib, TKIs have dramatically improved survival of patients with CP-CML, resulting in a projected increase of CML prevalence from 70,000 Americans in 2010 to 180,000 in 2050. Despite this progress, TKI-resistant CML remains a challenge, with >1,000 deaths annually in the U.S. At least 50% of TKI treatment failure arises through mutations in BCR-ABL1. Laboratory studies on the five FDA-approved BCR-ABL1 TKIs have established their mutational profiles against the >30 mutations observed in patients. In aggregate, these TKIs cover the clinical spectrum of BCR-ABL1 single point mutants. Ponatinib is the only TKI that is clinically effective against the T315I gatekeeper mutant. However, BCR-ABL1 compound mutants, defined as 2 mutations in the same BCR-ABL1 allele, that include T315I with any second mutation are resistant to all approved TKIs, including ponatinib, leaving these patients with no further treatment options. Asciminib is the first inhibitor in clinical development that binds the BCR-ABL1 myristoyl site, an allosteric site distant from the ATP site, to enforce an autoinhibited, inactive conformation. We established that asciminib, like ponatinib, is not effective against T315I-inclusive compound mutants, yet combining ponatinib (but not nilotinib or dasatinib) with asciminib is extremely effective at inhibiting many T315I-inclusive compound mutant forms of BCR-ABL1. This discovery provides the basis for a novel therapeutic strategy to address an entirely unmet medical need and is the foundation of this proposal. In Aim 1, we will use computational, biophysical and crystallographic methods to decipher how ponatinib re-sensitizes compound mutant BCR-ABL1 to asciminib. We will test the combination in relevant mouse models and in primary leukemia samples. In Aim 2A, we will develop a therapeutic strategy for clinically resistant BCR-ABL1 compound mutants that are not inhibited by the combination of ponatinib with asciminib. Instead, we will target these mutants for proteasomal degradation using an asciminib proteolysis targeting chimera (PROTAC) strategy. Unlike TKIs, PROTACs are effective even upon transient or weak binding. We will test the hypothesis that ponatinib-induced stabilization of the myristoyl site is the initiating event that allows subsequent binding of an asciminib-PROTAC and proteasomal degradation of compound mutant BCR-ABL1. In Aim 2B, we will develop a ponatinib-PROTAC strategy for compound mutants carrying a myristoyl site resistance mutation. Our work will provide a rationale for clinical evaluation of ponatinib combined with asciminib as a therapy for currently untreatable BCR-ABL1 compound mutant leukemia. Compound mutations are also a major cause of resistance in acute myeloid leukemia, melanoma, and lung cancer, and our study will provide a blueprint for treating these malignancies.

摘要：费城染色体阳性（Ph+）白血病是由 BCR-ABL1 引起的，BCR-ABL1 是一种组成型活性蛋白。 靶向 BCR-ABL1 ATP 位点的融合激酶抑制剂 (TKI) 可有效治疗。 慢性期慢性粒细胞白血病 (CP-CML) 但对治疗急变期 CML 和 Ph+ 效果甚微 自从所有药物中第一个 TKI 伊马替尼 (imatinib) 获批以来的 20 年里。 显着提高了 CP-CML 患者的生存率，导致 CML 预计增加 美国人的患病率从 2010 年的 70,000 人增加到 2050 年的 180,000 人。尽管取得了这一进展，但 TKI 耐药性 CML 仍然存在 这是一个挑战，美国每年有超过 1,000 例死亡。至少 50% 的 TKI 治疗失败是由于 对 FDA 批准的五种 BCR-ABL1 TKI 进行的实验室研究已经确定了 BCR-ABL1 的突变。 总的来说，这些 TKI 涵盖了临床中观察到的超过 30 种突变。 BCR-ABL1 单点突变谱是临床上唯一对 T315I 有效的 TKI。 然而，BCR-ABL1 复合突变体，定义为相同 BCR-ABL1 中的 pp2 个突变。 等位基因，包括具有任何第二个突变的 T315I，对所有批准的 TKI 具有耐药性，包括 ponatinib，从而使 这些患者没有进一步的治疗选择。阿西米尼是临床开发中第一个结合的抑制剂。 BCR-ABL1 肉豆蔻酰位点（远离 ATP 位点的变构位点）可强制执行自动抑制、失活 我们确定阿西米尼（asciminib）与普纳替尼（ponatinib）一样，对包含 T315I 的化合物无效。 突变体，但将 ponatinib（但不是 nilotinib 或 dasatinib）与 asciminib 组合在抑制方面非常有效 许多包含 T315I 的 BCR-ABL1 复合突变体形式这一发现为新的发现提供了基础。 解决完全未满足的医疗需求的治疗策略是本提案的基础。 我们将使用计算、生物物理和晶体学方法来破译 ponatinib 如何重新敏化 我们将在相关小鼠模型和原代试验中测试复合突变体 BCR-ABL1 与阿西米尼的组合。 在目标 2A 中，我们将为临床耐药的 BCR-ABL1 化合物开发治疗策略。 相反，我们将针对这些突变体。 使用 asciminib 蛋白水解靶向嵌合体 (PROTAC) 策略进行蛋白酶体降解，与 TKI 不同， PROTAC 即使在短暂或弱结合时也是有效的，我们将测试 ponatinib 诱导的假设。 肉豆蔻酰位点的稳定是允许随后结合 asciminib-PROTAC 的起始事件 以及复合突变体 BCR-ABL1 的蛋白酶体降解 在目标 2B 中，我们将开发 ponatinib-PROTAC。 我们的工作将为携带肉豆蔻酰位点抗性突变的复合突变体提供一个基本原理。 用于帕纳替尼联合阿西米尼治疗目前无法治疗的 BCR-ABL1 的临床评估 复合突变白血病 复合突变也是急性髓性白血病耐药的主要原因。 白血病、黑色素瘤和肺癌，我们的研究将为治疗这些恶性肿瘤提供蓝图。