Tyrosine kinase inhibitors for the treatment of childhood AML

描述（由申请人提供）：尽管超过80%的急性髓性白血病（AML）患儿通过使用大剂量化疗或移植获得完全缓解，但其长期生存率约为50%。单独使用常规治疗无法进一步显著改善长期预后。因此，需要新的药物和将新药物添加到常规治疗中的研究设计。受体酪氨酸激酶在正常生理过程中发挥重要作用，并控制细胞增殖、分化和存活等基本细胞活动。对AML生物学的日益了解暗示了异常酪氨酸激酶激活在白血病发生过程中。因此，针对致癌性酪氨酸激酶信号传导的新疗法对成人AML有很大的热情。我们的中心假设是酪氨酸激酶抑制剂（TKIs）将有效治疗儿童AML。由于阿糖胞苷（Ara-C）是治疗AML最有效的药物之一，因此被包括在每个现代AML治疗方案中，新型药物如TKIs将与阿糖胞苷为基础的方案一起施用。治疗AML的新药物不能干扰细胞对Ara-C的摄取和保留以及细胞毒性活性。在当前的提案中，我们概述了三组相关研究，这些研究将解决临床前和临床药理学方面的空白，以便将来合理地结合一种有前途的多激酶抑制剂索拉非尼治疗儿童AML。(1)明确索拉非尼联合Ara-C在AML小鼠模型体内有效的药代动力学和药效学。(2)确定索拉非尼增强AML中Ara-C积累和抗肿瘤活性的机制。(3)表征索拉非尼在接受以阿糖胞苷为基础的急性髓系白血病（AML）患儿中的药代动力学（PK）和药效学（PD）。本研究项目描述的工作概述了将索拉非尼和其他新型药物整合到儿童AML治疗中的策略，重点是优化全身和肿瘤内药物暴露，最终提高儿童AML患者的生存率。

DESCRIPTION (provided by applicant): Despite greater than 80% of children with acute myelogenous leukemia (AML) experiencing complete remission with the use of high-dose chemotherapy or transplantation, the long-term survival rate is approximately 50%. Further significant improvements in long-term outcome are not expected with conventional therapy alone. Thus novel agents and study designs in which new agents are added to conventional therapy will be needed. Receptor tyrosine kinases play important roles in normal physiological processes and control fundamental cellular activities including cell proliferation, differentiation, and survival. The increasing understanding of the biology of AML has implicated aberrant tyrosine kinase activation in the leukemogenic process. Thus, there has been substantial enthusiasm in adult AML for novel therapies that target oncogenic tyrosine kinase signaling. Our central hypothesis is that tyrosine kinase inhibitors (TKIs) will be effective for the treatment of childhood AML. Since cytarabine (Ara-C) is one of the most effective agents for the treatment of AML and is therefore included in every modern AML treatment regimen, novel agents such as TKIs will be administered with cytarabine-based regimens. New agents in AML must not interfere with the cellular uptake and retention of Ara-C and cytotoxic activity. In the current proposal, we outline three sets of related studies that will address the gaps in preclinical and clinical pharmacology to allow for the future rational incorporation of a promising multikinase inhibitor, sorafenib, in childhood AML. (1) To define the pharmacokinetics and pharmacodynamics of sorafenib in combination with Ara-C that is effective in vivo in murine models of AML. (2) To identify mechanisms by which sorafenib enhances the accumulation and antitumor activity of Ara-C in AML. (3) To characterize the pharmacokinetics (PK) and pharmacodynamics (PD) of sorafenib in children with AML receiving cytarabine-based regimens. The work described in this research project outlines a strategy to integrate sorafenib and other novel agents in the treatment of childhood AML, with an emphasis on optimal systemic and intratumoral drug exposure, and ultimately improve the survival of children with AML. PUBLIC HEALTH RELEVANCE: Despite greater than 80% of children with acute myelogenous leukemia (AML) experiencing complete remission with the use of high-dose chemotherapy or transplantation, the long-term survival rate is approximately 50%. Further significant improvements in long-term outcome are not expected with conventional therapy alone. Our studies are of direct human relevance as they will lead to the rational incorporation of a novel tyrosine kinase inhibitor, sorafenib, in childhood AML.