Development of endochin-like quinolones for babesiosis therapy

用于治疗巴贝虫病的类内啡肽喹诺酮类药物的开发

• 批准号: 9392521
• 负责人: CHOUKRI BEN MAMOUN
• 金额: $ 66.94万
• 依托单位: YALE UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2016
• 资助国家: 美国
• 起止时间: 2016-12-01 至 2020-11-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/9392521
• 关键词: Adverse effects; Anaplasmosis; Antimalarials; Azithromycin; Babesia microti; Babesiosis; Biochemical; Biochemical Genetics; Biological Assay; Biological Availability; Black-legged Tick; Blood; Blood Transfusion; Borrelia microti; Case Fatality Rates; Cell Culture Techniques; Chemicals; Clindamycin; Clinical; Clinical Research; Clinical Trials; Combined Modality Therapy; Complex; Cytochrome bc1 Complex; Cytochromes b; Data; Development; Diagnostic tests; Disease; Dose; Drug Kinetics; Drug Targeting; Drug usage; Elderly; Enzyme Inhibition; Enzymes; Erythrocytes; Excision; Failure; Formulation; Future; Genes; Genetic Polymorphism; Genetic study; Genomics; Human; Immunocompromised Host; In Vitro; Infection; Lead; Lyme Disease; Malaria; Mammalian Cell; Measures; Mitochondria; Mus; Mutation; Oral; Oral Administration; Parasite resistance; Parasitemia; Parasites; Patients; Pharmaceutical Preparations; Pharmacodynamics; Pharmacology; Phenotype; Prodrugs; Production; Property; Protozoa; Qi; Quinine; Quinolones; Recrudescences; Reporting; Research; Route; Safety; Site; Specificity; Testing; Therapeutic; Therapeutic Index; Ticks; Toxic effect; Transfusion; Treatment Protocols; United States; Virulence; analog; atovaquone; base; comparative efficacy; design; efficacy study; efficacy testing; enzyme activity; experience; granulocyte; in vivo; in vivo evaluation; individual patient; inhibitor/antagonist; mouse model; mutant; pathogen; success; treatment strategy; vector

Human babesiosis is a malaria-like multisystem disease caused primarily by an emerging apicomplexan parasite Babesia microti that infects and develops within human erythrocytes. The parasite is transmitted to humans by the tick vector, Ixodes scapularis and can also be introduced through blood transfusion. Babesiosis treatment options consist of two combinations of antimalarials, azithromycin+atovaquone or clindamycin+quinine. However, even with these drugs and other supportive measures such as exchange transfusion, the disease can be fatal in elderly individuals or immunocompromised patients. In order to develop better therapies and diagnostic tests for human babesiosis, we developed a short-term ex vivo proliferation assay to test the efficacy of the four currently clinically used drugs as well as compounds known to have activity against other protozoa. Our studies demonstrated potent activity of endochin-like quinolones (ELQs) and atovaquone against B. microti and indicated limited activity of other drugs used in babesiosis therapy. In vivo efficacy studies identified 2 compounds ELQ-271 and ELQ-316 with potent activity against the B. microti LabS1 strain following oral administration at 10mg/kg. However, we found that monotherapy involving either ELQs or atovaquone was always accompanied by recrudescence 9 to 16 days post-drug removal, emphasizing the need to identify better analogs of these compounds or a suitable therapeutic strategy that can lead to radical cure. Remarkably, we found that a combination therapy consisting of atovaquone and a prodrug of ELQ-316, ELQ-334, results in radical cure of experimental babesiosis in mice at doses as low as 2.5+2.5 mg/kg. Biochemical assays demonstrated inhibition of the activity of the B. microti cytochrome bc1 complex by ELQ, and analysis of parasites resistant to either ELQs or atovaquone identified single mutations in the B. microti Cytochrome b (BmCytb) gene. Building upon these data, we propose the following three specific aims. In Aim 1, we will characterize the activity and selectivity of ELQ-316 and 30 structurally diverse ELQs. Biochemical assays will be used to characterize their activity against the B. microti and human bc1 complex, and cell culture assays will be used to assess their efficacy against the parasite and evaluate their toxicity on mammalian cells. Compounds with the greatest therapeutic indices will be further examined for their potency in mice and ability to clear infection without recrudescence. In Aim 2, we will synthesize prodrugs of the 2 most potent ELQs selected from aim 1. The ELQ-prodrug strategy that yields the greatest oral bioavailability will be tested in combination with atovaquone in comparison to the ELQ-334+Atovaquone combination. In Aim 3, we will perform biochemical and genetic assays to elucidate the mechanism of action of ELQs, identify possible routes for drug failure and design the best therapeutic strategy for an ideal formulation that achieves radical cure. The success of the proposed studies will set the stage for future clinical trials to create a treatment regimen for human babesiosis that is safe and achieves radical cure.

人类巴贝西虫病是一种类似疟疾的多系统疾病，主要由一种新出现的顶端复合体引起 寄生虫巴贝虫，感染人类红细胞并在其中发育。寄生虫被传播到 人类通过蜱媒介肩胛硬蜱传播，也可以通过输血传播。巴贝斯虫病 治疗方案包括两种抗疟药组合：阿奇霉素+阿托伐醌或 克林霉素+奎宁。然而，即使有了这些药物和其他支持措施（例如交换） 如果输血，这种疾病对于老年人或免疫功能低下的患者可能是致命的。为了发展 为了更好地治疗人类巴贝斯虫病和诊断测试，我们开发了一种短期离体增殖方法 检测四种目前临床使用的药物以及已知具有以下功效的化合物的功效 对其他原生动物的活性。我们的研究证明了内啡肽样喹诺酮类药物 (ELQ) 的有效活性 和阿托伐醌对抗田鼠芽孢杆菌，并表明用于巴贝斯虫病治疗的其他药物的活性有限。在 体内功效研究确定了 2 种化合物 ELQ-271 和 ELQ-316 对田鼠芽孢杆菌具有有效的活性 口服 10mg/kg 后的 LabS1 菌株。然而，我们发现单一疗法涉及 ELQ 或阿托伐醌总是伴随着药物去除后 9 至 16 天的复发， 强调需要鉴定这些化合物的更好类似物或合适的治疗策略 导致根治。值得注意的是，我们发现由阿托伐醌和前药组成的联合疗法 ELQ-316、ELQ-334，剂量低至 2.5+2.5 即可根治小鼠实验性巴贝西虫病 毫克/公斤。生化测定表明，B. microti 细胞色素 bc1 复合物的活性受到抑制 ELQ 以及对 ELQ 或阿托伐醌耐药的寄生虫的分析发现了 B. microti 细胞色素 b (BmCytb) 基因。基于这些数据，我们提出以下三个具体目标。 在目标 1 中，我们将表征 ELQ-316 和 30 种结构多样的 ELQ 的活性和选择性。 生化测定将用于表征它们针对田鼠和人类 bc1 复合物的活性， 细胞培养测定将用于评估其对寄生虫的功效并评估其对寄生虫的毒性 哺乳动物细胞。具有最大治疗指数的化合物将进一步检查其在以下方面的效力： 小鼠和清除感染而不复发的能力。在目标 2 中，我们将合成 2 个最重要的前药 从目标 1 中选择有效的 ELQ。产生最大口服生物利用度的 ELQ 前药策略将是 与阿托伐醌组合进行测试，并与 ELQ-334+阿托伐醌组合进行比较。在目标 3 中，我们 将进行生化和遗传测定，以阐明 ELQ 的作用机制，识别可能的 药物失败的途径，并设计最佳治疗策略，以实现根治的理想配方 治愈。拟议研究的成功将为未来创造治疗方法的临床试验奠定基础 人类巴贝斯虫病的治疗方案是安全的并且可以实现根治。