Improving the disposition of antileukemic asparaginase after drug-induced immunotoxicity

项目摘要 天冬酰胺酶(ASNase)是治疗儿童急性淋巴细胞白血病的主要药物之一 白血病(ALL)。ASNase最常见的不良反应是形成一种免疫反应， 可能会危及药物暴露，并导致更糟糕的治疗结果。因此，治疗策略 预防或克服对ASNase的免疫反应和保持足够的药物暴露是迫切需要的。 聚乙二醇化天冬氨酸氨基转移酶(PEG-ASNase)是用于所有治疗的一线药物，它仍然容易发生 治疗过程中的免疫毒性。 我们的初步结果表明：1)ASNase诱导的免疫反应可以减少药物暴露 通过直接药物中和和加速ASNase的药代动力学清除；2)治疗 药物浓度可以在对聚乙二醇天冬氨酸氨基转移酶敏化后达到，但可能需要比在幼稚中更高的药物剂量 患者达到类似的治疗效果；3)携带者患ASNase过敏症的风险更高 活化的T细胞核因子，胞浆钙调神经磷酸酶依赖性2(NFATC2)rs6021191变异体， 这导致参与免疫反应调节的转录因子的高表达；4) Ig G和Ig E抗原特异性抗体均参与了ASNase过敏症的发病机制 将被用来促进以细胞为基础的方法的发展，以监测PEG-ASNase的免疫原性；以及 5)建立了两种可移植的B细胞小鼠模型，均可用于药物疗效的研究 和毒性。 基于这些观察，我们假设(1)可以克服免疫的预处理策略 阻断过敏介质和恢复药物对聚乙二醇-天冬氨酸氨基转移酶的反应 浓度可以保持聚乙二醇天冬氨酸氨基转移酶的抗白血病特性。(2)遗传和 NFATC2的药理抑制作用可阻止或减弱对聚乙二醇天冬氨酸氨基转移酶的增敏作用。(3)免疫球蛋白 和/或IgE介导的外周血细胞(PBCs)与聚乙二醇天冬氨酸氨基转移酶的结合可作为生物标志物 免疫毒性。我们提出了三个具体目标来验证我们的假设：1)确定组合 阻断超敏反应介质和聚乙二醇天冬氨酸氨基转移酶剂量调整的前处理药物可以 利用两种聚乙二醇天冬氨酸酶小鼠模型克服免疫反应并保持抗白血病效果 超敏反应和B细胞ALL；2)确定抑制NFAT通路是否可以防止致敏 以维持抗白血病的疗效；以及3)确定致敏的外周血细胞是否可以被识别 用流式细胞术在体外通过它们与荧光标记的聚乙二醇酶-天冬氨酸酶结合。 拟议的工作将确定克服、预防和监测对聚乙二醇胺的免疫反应的策略。 ASNase。这三个目标并不是相互依存的，但在逻辑上与改善聚乙二醇的单一重点有关- 天冬氨酸氨基转移酶疗法。该项目的长期目标是通过克服或提高儿童ALL的存活率 预防药物诱导的免疫反应，确保患者获得足够的聚乙二醇天冬氨酸酶 在所有治疗过程中暴露。

Project Summary Asparaginase (ASNase) is one of the main drugs used for the treatment of pediatric acute lymphoblastic leukemia (ALL). The most common adverse reaction of ASNase is the development of an immune response that can compromise drug exposure and lead to worse treatment outcome. Therefore, therapeutic strategies that prevent or overcome the immune response to ASNase and retain sufficient drug exposure are urgently needed. PEGylated ASNase (PEG-ASNase) is the first-line agent used for ALL therapy, and it remains prone to immunotoxicity during treatment. Our preliminary results showed that: 1) ASNase-induced immune responses can decrease drug exposure through direct drug neutralization and by accelerating the pharmacokinetic clearance of ASNase; 2) therapeutic drug levels can be attained after sensitization to PEG-ASNase but may require drug doses higher than in naïve patients to achieve similar therapeutic effects; 3) there is a higher risk of ASNase hypersensitivity among carriers of the nuclear factor of activated T-cells, cytoplasmic, calcineurin-dependent 2 (NFATC2) rs6021191 variant, which leads to higher expression of this transcription factor involved in the regulation of immune responses; 4) both IgG and IgE antigen-specific antibodies are involved in the mechanism of ASNase hypersensitivity, which will be used to facilitate the development of a cell-based approach to monitor PEG-ASNase immunogenicity; and 5) we have established two mouse models of transplantable B cell ALL that can be used to study drug efficacy and toxicity. Based on these observations, we hypothesize that (1) pretreatment strategies that can overcome immune responses to PEG-ASNase by blocking the mediators of hypersensitivity and restoring drug concentrations can maintain the antileukemic properties of PEG-ASNase. (2) Genetic and pharmacological inhibition of NFATC2 can prevent or attenuate sensitization to PEG-ASNase. (3) IgG and/or IgE-mediated binding of peripheral blood cells (PBCs) to PEG-ASNase can be used as a biomarker of immunotoxicity. We propose three specific aims to test our hypotheses: 1) to determine whether combining pretreatment drugs that block the mediators of hypersensitivity and PEG-ASNase dose adjustments can overcome immune responses and retain antileukemic efficacy using two murine models of PEG-ASNase hypersensitivity and B cell ALL; 2) to determine whether inhibition of the NFAT pathway can prevent sensitization to PEG-ASNase and maintain antileukemic efficacy; and 3) to determine if sensitized PBCs can be identified through their binding to fluorescently labeled PEG-ASNase ex vivo using flow cytometry. The proposed work will identify strategies to overcome, prevent, and monitor the immune response to PEG- ASNase. The three aims are not interdependent but are logically related with a singular focus on improving PEG- ASNase therapy. The long-term goal of this project is to improve pediatric ALL survival by overcoming or preventing the drug-induced immune response and ensuring that patients receive adequate PEG-ASNase exposure during ALL treatment.