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复虫引起 在人体红细胞内感染和发育的寄生虫。寄生虫会传播到 人类通过蜱媒介，肩突硬蜱，也可以通过输血引入。贝斯虫 治疗选择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， 输血后，这种疾病在老年人或免疫功能低下的患者中可能是致命的。为了发展 为了更好地治疗和诊断人类巴贝虫病，我们开发了一种短期体外增殖 测试四种目前临床使用的药物以及已知具有 对其他原生动物的作用。我们的研究证明了内皮素样喹诺酮类（ELQs）的有效活性 和阿托伐醌对抗B。microti和表明有限的活动，其他药物用于巴贝虫病治疗。在 体内功效研究鉴定了2种化合物ELQ-271和ELQ-316，其具有针对B的有效活性。田鼠 LabS1菌株。然而，我们发现， 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的类似物或合适的治疗策略， 导致根治。值得注意的是，我们发现阿托伐醌和前药组成的联合治疗 ELQ-316，ELQ-334，在低至2.5 ± 2.5的剂量下导致小鼠实验性巴贝虫病的根治 mg/kg.生物化学分析表明抑制了B的活性。Microti细胞色素bc1复合物 ELQ和对ELQ或阿托伐醌耐药的寄生虫分析鉴定了B中的单一突变。 microti细胞色素B（BmCytB）基因。根据这些数据，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种结构不同的ELQ的活性和选择性。 将使用生物化学测定来表征其对B的活性。MicroTi和人BC 1复合物， 细胞培养试验将用于评估它们对寄生虫的功效，并评估它们对 哺乳动物细胞将进一步检查具有最大治疗指数的化合物在以下方面的效力： 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， 选自目标1的有效ELQ。产生最大口服生物利用度的ELQ-前药策略将是 与ELQ-334+阿托伐醌组合相比，与阿托伐醌组合测试。在目标3中，我们 将进行生化和遗传分析，以阐明ELQ的作用机制，确定可能的 药物失败的途径，并设计最佳的治疗策略，以实现根治性 疗方拟议研究的成功将为未来的临床试验创造一种治疗方法奠定基础 治疗人类巴贝虫病的安全方案，并达到根治。