Noah James W., Severson William E., Chung Donghoon H., Moore Blake, Jia Fuli, Xu Xiaolin, Maddox Clinton, Rasmussen Lynn, Sosa Melinda Ingrum, Tower Nichole A., Ananthan S., Evans Carrie W., White E. Lucile, Jonsson Colleen, Matharu Daljit S., Flaherty Daniel P., Simpson Denise S., Golden Jennifer E., Aubé Jeffrey
Southern Research Specialized Biocontainment Screening Center; Southern Research Institute, Birmingham, AL
Center for Predictive Medicine, University of Louisville
Respiratory Syncytial Virus (RSV) is the most common cause of bronchiolitis and pneumonia among infants under one year of age. Most children will be infected with RSV prior to their second birthday, leading to 75,000-125,000 hospitalizations and medical costs exceeding $650 million annually. The virus is highly contagious and is associated with substantial morbidity and mortality. Nevertheless, severe lower respiratory tract disease may occur at any age, especially among the elderly or those with compromised cardiac, pulmonary, or immune systems. FDA-approved drugs for the acute infection are ribavirin and the prophylactic humanized monoclonal antibody, Synagis, which is limited to use in high risk pediatric patients. Due to the lack of a vaccine and the presence of toxicological limitations in existing therapies, there is substantial need for effective treatments with an improved profile. Of the 313,816 Molecular Libraries Small Molecule Repository (MLSMR) compounds screened in a cell-based, RSV inhibition assay, 51 compounds were selected based on potency, selectivity and chemical tractability for further evaluation in dose response and secondary assays. Collaboration between the assay provider at the University of Louisville, the screening center at Southern Research Institute and the University of Kansas Specialized Chemistry Center narrowed the structure activity relationship (SAR) focus to three scaffolds. The probe, ML275, resulted from structural modification and optimization of a quinazolinedione chemical series, generating a compound with an antiviral EC value of 0.81 ± 0.75 μM and a 247-fold selectivity index (SI) for antiviral activity over HEp-2 cell cytotoxicity. Additionally, ML275 demonstrated a 6.7 log reduction of viral titer, or reduction by approximately 5,000,000-fold. ML275, determined to be a post-entry inhibitor of viral replication, has been broadly profiled for off-target liabilities and assessed for PAMPA permeability and hepatocyte toxicity.
呼吸道合胞病毒（RSV）是一岁以下婴儿毛细支气管炎和肺炎的最常见病因。大多数儿童在两岁生日前会感染RSV，每年导致75000至125000例住院治疗，医疗费用超过6.5亿美元。该病毒具有高度传染性，与大量发病和死亡相关。然而，严重的下呼吸道疾病可能发生在任何年龄，尤其是老年人或心脏、肺部或免疫系统受损的人群。美国食品药品监督管理局（FDA）批准用于急性感染的药物是利巴韦林和预防性人源化单克隆抗体Synagis，后者仅限于高危儿科患者使用。由于缺乏疫苗且现有疗法存在毒理学局限性，迫切需要疗效更好的有效治疗方法。在基于细胞的RSV抑制试验中筛选的313816种分子文库小分子储存库（MLSMR）化合物中，基于效力、选择性和化学可处理性选择了51种化合物，用于剂量反应和二次试验的进一步评估。路易斯维尔大学的试验提供者、南方研究所的筛选中心和堪萨斯大学专业化学中心之间的合作将结构活性关系（SAR）研究重点缩小到三种支架。探针ML275是对喹唑啉二酮化学系列进行结构修饰和优化后得到的，产生了一种抗病毒EC值为0.81±0.75μM的化合物，其抗病毒活性对人喉表皮样癌细胞（HEp-2）细胞毒性的选择性指数（SI）为247倍。此外，ML275使病毒滴度降低了6.7个对数，即降低了约5000000倍。ML275被确定为病毒复制的进入后抑制剂，已对其脱靶效应进行了广泛分析，并评估了其在平行人工膜渗透试验（PAMPA）中的通透性和肝细胞毒性。
