Molecular basis and protective efficacy of cross-neutralizing antibodies against four major respiratory viruses

项目概要/摘要 全世界每年有数以万计的致命癌症被造血干细胞治愈 移植（HCT），但不幸的是，超过十分之一的患者会出现病毒性下呼吸道感染 感染，其中近一半患者死于感染。如果体内没有完整的免疫系统 移植后的最初几个月，这些危及生命的感染抵消了潜在生命带来的益处 保存移植。超过一半的感染是由四种病毒引起的：RSV、HMPV、HPIV3 和 HPIV1， 目前没有任何药物干预措施可用于 HCT 后的治疗或预防。虽然 成年人在儿童时期普遍感染这些病毒，HCT 接受者失去了免疫力，使他们 容易出现严重并发症。使用单克隆抗体 (mAb) 进行被动免疫代表 降低这些感染风险的策略。虽然一些抗 RSV mAb 候选药物已取得进展 在临床试验中，它们的使用仅限于 RSV 导致几乎所有肺部感染病例的婴儿。 然而，这些单克隆抗体在 HCT 患者中的临床疗效预计会大幅降低，因为其他药物 HMPV、HPIV3 和 HPIV1 等重要病毒对疾病有显着影响。填补这一临床空白 对于 HCT 患者，我们发现了两种交叉中和单克隆抗体：一种同时针对 RSV 和 HMPV， 另一个针对 HPIV3 和 HPIV1。这些单克隆抗体可以组合在一起同时保护 对抗 HCT 后导致大多数肺部感染的四种病毒。为了测试功效，我们将管理这些 单克隆抗体对免疫功能正常和免疫功能低下的动物具有预防和治疗作用。我们还将 测试这些单克隆抗体的药代动力学，并进行修改，以延长半衰期和肺功能 生物利用度，这样单剂量就可以弥补移植后的整个脆弱期。另一个 将新型抗体疗法引入临床时经常被忽视的陷阱是潜在的耐药性。最近 抗 RSV 单克隆抗体临床试验的失败表明，逃逸变异的出现可能会削弱临床试验的能力 发展。在候选人进入临床前阶段之前，如何预测临床前阶段的成功或失败 临床试验是一个重要的问题，其答案可以节省大量的资源、精力和成本。 时间。为了填补这一知识空白，我们开发了一种称为深度突变扫描的创新方法 它提供了病毒突变景观的全面图景，从而实现了前所未有的临床前研究 电阻的评估。由于本提案中描述的两种交叉中和单克隆抗体结合到保守的 表位，这些和类似的单克隆抗体可能具有很高的耐药屏障。准备和对抗阻力 通过未来的病毒变体，我们将利用完整突变图谱的预测来识别下一个- 一代单克隆抗体，使我们能够领先病毒进化几步。这些新型交叉中和单克隆抗体 我们开发的创新和严格的审查方法可以提供新的标准 护理 HCT 患者，并为其他候选人的设计和测试提供最大的成功机会。

PROJECT SUMMARY/ABSTRACT Tens of thousands of otherwise deadly cancers are cured worldwide each year by hematopoietic stem cell transplantation (HCT), but unfortunately over one in ten patients will develop a viral lower respiratory tract infection, with almost half of these patients succumbing to the infection. Without an intact immune system in the first few months after transplant, these life-threatening infections offset the benefit derived from potentially life- saving transplant. Over half of these infections are caused by four viruses: RSV, HMPV, HPIV3, and HPIV1, none of which currently have any pharmacologic interventions for treatment or prevention after HCT. Although adults are universally infected with these viruses in childhood, HCT recipients lose their immunity, making them vulnerable to severe complications. Passive immunization with monoclonal antibodies (mAbs) represents a strategy to reduce the risk of these infections. While several anti-RSV mAb candidates have progressed through clinical trials, their use is limited to infants in whom RSV is responsible for virtually all cases of lung infection. However, the clinical efficacy of these mAbs is expected to be substantially lower in HCT patients because other important viruses like HMPV, HPIV3, and HPIV1 contribute significantly to disease. To fill this clinical gap for HCT patients, we have discovered two cross-neutralizing mAbs: one that targets both RSV and HMPV and another that targets both HPIV3 and HPIV1. Together, these mAbs could be combined to simultaneously protect against the four viruses that cause most lung infections after HCT. To test efficacy, we will administer these mAbs prophylactically and therapeutically to immunocompetent and immunocompromised animals. We will also test the pharmacokinetics of these mAbs with modifications designed for increased half-life and lung bioavailability, such that a single dose could bridge the entire period of vulnerability after transplant. Another often neglected pitfall in bringing novel antibody therapies to the bedside is the potential for resistance. Recent failed clinical trials of anti-RSV mAbs have shown that the emergence of escape variants can cripple clinical development. How to predict success or failure during the preclinical phase before candidates progress into clinical trials is an important question, and the answers could save massive amounts of resources, effort, and time. To fill this knowledge gap, we have developed an innovative approach called deep mutational scanning that provides a comprehensive picture of the viral mutational landscape, allowing an unprecedented preclinical evaluation of resistance. Since the two cross-neutralizing mAbs described in this proposal bind to conserved epitopes, these and similar mAbs may have a high barrier of resistance. To prepare for and counter resistance by future viral variants, we will leverage predictions from our complete mutational maps to identify next- generation mAbs, allowing us to stay a few steps ahead of viral evolution. These novel cross-neutralizing mAbs and the innovative and rigorous approaches we have developed to vet them could provide a new standard of care for HCT patients and inform the design and testing of other candidates with the greatest chance for success.