BACKGROUND Acute myeloid leukemia (AML) is the most common type of adult leukemia. Several studies have demonstrated that oncogenesis in AML is enhanced by kinase signaling pathways such as Src family kinases (SFK) including Src and Lyn, spleen tyrosine kinase (SYK), and bruton's tyrosine kinase (BTK). Recently, the multi-kinase inhibitor ArQule 531 (ARQ 531) has demonstrated potent inhibition of SFK and BTK that translated to improved pre-clinical in vivo activity as compared with the irreversible BTK inhibitor ibrutinib in chronic lymphocytic leukemia (CLL) models. Given the superior activity of ARQ 531 in CLL, and recognition that this molecule has a broad kinase inhibition profile, we pursued its application in pre-clinical models of AML. METHODS The potency of ARQ 531 was examined in vitro using FLT3 wild type and mutated (ITD) AML cell lines and primary samples. The modulation of pro-survival kinases following ARQ 531 treatment was determined using AML cell lines. The effect of SYK expression on ARQ 531 potency was evaluated using a SYK overexpressing cell line (Ba/F3 murine cells) constitutively expressing FLT3-ITD. Finally, the in vivo activity of ARQ 531 was evaluated using MOLM-13 disseminated xenograft model. RESULTS Our data demonstrate that ARQ 531 treatment has anti-proliferative activity in vitro and impairs colony formation in AML cell lines and primary AML cells independent of the presence of a FLT3 ITD mutation. We demonstrate decreased phosphorylation of oncogenic kinases targeted by ARQ 531, including SFK (Tyr416), BTK, and fms-related tyrosine kinase 3 (FLT3), ultimately leading to changes in down-stream targets including SYK, STAT5a, and ERK1/2. Based upon in vitro drug synergy data, we examined ARQ 531 in the MOLM-13 AML xenograft model alone and in combination with venetoclax. Despite ARQ 531 having a less favorable pharmacokinetics profile in rodents, we demonstrate modest single agent in vivo activity and synergy with venetoclax. CONCLUSIONS Our data support consideration of the application of ARQ 531 in combination trials for AML targeting higher drug concentrations in vivo.

中文翻译：

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新型酪氨酸激酶抑制剂 ArQule 531 对急性髓系白血病的临床前疗效。

背景急性髓性白血病(AML)是最常见的成人白血病类型。几项研究表明，AML 中的肿瘤发生通过激酶信号通路增强，例如 Src 家族激酶 (SFK)，包括 Src 和 Lyn、脾酪氨酸激酶 (SYK) 和布鲁顿酪氨酸激酶 (BTK)。最近，在慢性淋巴细胞白血病 (CLL) 模型中，多激酶抑制剂 ArQule 531 (ARQ 531) 已经证明了对 SFK 和 BTK 的有效抑制，与不可逆的 BTK 抑制剂依鲁替尼相比，这转化为改善的临床前体内活性。鉴于 ARQ 531 在 CLL 中的优越活性，并认识到该分子具有广泛的激酶抑制特性，我们将其应用于 AML 的临床前模型。方法 使用 FLT3 野生型和突变 (ITD) AML 细胞系和原始样品在体外检查 ARQ 531 的效力。使用 AML 细胞系确定 ARQ 531 处理后促存活激酶的调节。使用组成型表达 FLT3-ITD 的 SYK 过表达细胞系（Ba/F3 鼠细胞）评估 SYK 表达对 ARQ 531 效力的影响。最后，使用 MOLM-13 播散异种移植模型评估 ARQ 531 的体内活性。结果我们的数据表明，ARQ 531 治疗在体外具有抗增殖活性，并且会损害 AML 细胞系和原代 AML 细胞的集落形成，而与 FLT3 ITD 突变的存在无关。我们证明 ARQ 531 靶向的致癌激酶磷酸化降低，包括 SFK (Tyr416)、BTK 和 fms 相关酪氨酸激酶 3 (FLT3)，最终导致下游目标的变化，包括 SYK、STAT5a 和 ERK1/2。基于体外药物协同数据，我们在 MOLM-13 AML 异种移植模型中单独和与 venetoclax 联合检查了 ARQ 531。尽管 ARQ 531 在啮齿动物中的药代动力学特征较差，但我们证明了适度的单药体内活性和与 venetoclax 的协同作用。结论我们的数据支持考虑将 ARQ 531 应用于针对体内更高药物浓度的 AML 联合试验。我们证明了适度的单药体内活性和与 venetoclax 的协同作用。结论我们的数据支持考虑将 ARQ 531 应用于针对体内更高药物浓度的 AML 联合试验。我们证明了适度的单药体内活性和与 venetoclax 的协同作用。结论我们的数据支持考虑将 ARQ 531 应用于针对体内更高药物浓度的 AML 联合试验。