COMBINATION CHEMOTHERAPY FOR PANDEMIC INFLUENZA

描述（由申请人提供）：潜在的灾难性流感大流行是不可避免的。此外，现在的技术允许在实验室制造高致病性流感病毒。做好准备至关重要，需要最佳地利用现有疫苗和抗病毒药物。虽然疫苗能最好地控制流感，但生产一种菌株特异性疫苗至少需要6个月的时间。因此，抗病毒药物可能是最好的立即可用的策略。我们假设，两类针对不同病毒蛋白并发挥不同机制的抗流感药物联合治疗将提供临床和战略优势。这一假设将通过三个具体目标来检验。1)为了建立一种可靠的检测方法，我们将首先评估新开发的MDCK-SAIT1细胞的适用性，MDCK-SAIT1细胞增加了人样唾液酸（alpha2-6 gal连接）受体的表达，用于检测不同亚型（包括高致病性病毒）的新发和耐药变体的药物敏感性。2)我们将在MDCK-SAIT1细胞中测试NA抑制剂与M2阻滞剂金刚乙胺联合抗甲型流感病毒感染，并在小鼠模型中表征它们对人类和新出现的高致病性H5N1和H9N2流感病毒的相互作用模式（加性、增效或拮抗）。3)我们将确定联合抗病毒治疗对耐药变异的出现和耐药菌株临床重要特性（如毒力和传播力）的影响。我们建议分析从不同宿主和不同致病性分离的流感病毒的广谱。我们将包括最近从香港分离的样本，因为强有力的实验证据表明，人类大流行性流感病毒的前体起源于中国南方。这些发现将表明：1)联合抗病毒治疗作为对天然或人为高致病性流感病毒的反应是否在临床上具有优势；2)该策略是否为抗病毒药物的储存和大规模使用提供实用、经济和公共卫生优势。

DESCRIPTION (provided by applicant): A potentially catastrophic influenza pandemic is inevitable. Further, technology now allows the laboratory creation of highly pathogenic influenza viruses. Preparedness is vital, and it requires optimal use of the available vaccines and antivirals. Although vaccines offer the best control of influenza, at least 6 months is needed for production of a strain-specific vaccine. Therefore, antiviral drugs may be the best immediately available strategy. We hypothesize that combination therapy with two classes of anti-influenza drugs that target different viral proteins and exert different mechanisms will offer clinical and strategic advantages. This hypothesis will be tested by three specific aims. 1) To establish a reliable assay method, we will first evaluate the suitability of newly developed MDCK-SAIT1 cells, which have increased expression of humanlike sialic acid (alpha2-6 Gal-linked) receptors, for detecting drug sensitivity of emerging and resistant variants of different subtypes, including highly pathogenic viruses. 2) We will test combinations of NA inhibitors with the M2 blocker rimantadine against influenza A virus infection in MDCK-SAIT1 cells, and we will characterize their mode of interaction (additive, synergistic, or antagonistic) against human and emerging highly pathogenic H5N1 and H9N2 influenza viruses in a mouse model. 3) We will determine the effect of combination antiviral therapy on the emergence of drug-resistant variants and on clinically important properties of resistant strains, such as virulence and transmissibility. We propose to analyze a wide spectrum of influenza viruses isolated from various hosts and differing in pathogenicity. We will include recent isolates from Hong Kong, because of strong experimental evidence that the precursors of human pandemic influenza viruses originate in southern China. These findings will show 1) whether combination antiviral treatment is clinically advantageous as a response to natural or manmade highly pathogenic influenza viruses and 2) whether this strategy offers practical, economic, and public health advantages for the stockpiling and large-scale use of antivirals.