Development of a Live Combinational Microbicide for Women

简介（由申请人提供）：Osel, Inc.是一家专门从事细菌治疗药物开发的生物制药公司。该公司的主要产品LACTIN-V是一种天然存在的人类阴道分离物，目前正在进行II期临床试验，以检查其预防复发性尿路感染（uti）和细菌性阴道病（BV）的安全性和有效性。UTIs和BV都与产生过氧化氢（H2O2）的乳酸菌的消耗有关，这种乳酸菌通常保护阴道免受机会性病原体的感染。流行病学研究还表明，阴道乳酸菌的缺失与异性传播HIV-1和其他性传播感染的风险增加有关。LACTIN-V代表了一种生态方法，通过重新建立保护性阴道菌群，产生h2o2的乳酸杆菌菌株来预防阴道感染。目前正在开发的第二代乳杆菌产品是一种能产生h2o2的延森乳杆菌的人阴道分离物，该产品经过基因修饰，可组成性分泌高水平的基于单一蛋白的强效HIV包膜靶向进入抑制剂，即n端修饰的cyanovirin-N (CV-N) （P51G）。这种活的、自我更新的杀微生物剂可能提供了一种有效而廉价的方法来提供基于蛋白质的杀微生物剂，并解决了对女性控制方法的迫切需求，以阻止HIV-1的异性传播。在目前临床试验的候选杀菌剂中，几乎所有的杀菌剂都是“依赖性交”的产品，或者是基于单一活性成分的配方用于开发。需要开发“非性交依赖”的杀微生物剂或在粘膜HIV感染途径的多个位点起作用的组合杀微生物剂，这代表了杀微生物剂开发中的一个重大空白。在这项R21提案中，我们计划开发一种新型的活组合杀微生物剂，该杀微生物剂通过对产生h2o2的阴道L. jensenii 1153进行基因修饰，组成性地分泌n端修饰的CV-N （P51G）和有效的CCR5靶向进入抑制剂C1C5-RANTES。后者是一种n端修饰的RANTES，靶向主要的HIV共受体CCR5，具有增强的抗病毒和抗炎活性。在本提案中，我们将探索从单一乳酸菌菌株或从两种菌株的混合物中递送CV-N和C1C5-RANTES的可能性，每种菌株递送一种抑制剂。我们将从一系列生物工程菌株中选择一种杀菌剂开发候选菌株，这些菌株含有优化的表达盒，可以稳定地整合到L. jensen染色体中。R33阶段将在R21阶段提案中建议的里程碑成功完成后进行。对于R33期，我们建议在小鼠、家兔和非人类灵长类动物中进行临床前动物安全性和有效性研究。我们将使用中国恒河猴（Macaca mulatta）模型进行临床前安全性和有效性研究，包括原位CV-N和C1C5-RANTES表达、免疫毒性和对粘膜病毒传播的有效性。此外，我们建议评估与提供组合杀微生物剂的转基因生物药物开发相关的潜在监管问题，并与FDA进行ind前咨询。

DESCRIPTION (provided by applicant): Osel, Inc. is a biopharmaceutical company specializing in the development of bacterial therapeutics. The company's lead product, LACTIN-V, is a naturally occurring human vaginal isolate of Lactobacillus crispatus presently undergoing phase II clinical trials to examine its safety and efficacy in preventing recurrent urinary tract infections (UTIs) and bacterial vaginosis (BV). Both UTIs and BV are associated with a depletion of hydrogen peroxide (H2O2)-producing lactobacilli that normally protect the vagina from infection by opportunistic pathogens. Epidemiological studies also suggest that loss of vaginal lactobacilli is associated with an increased risk of heterosexual HIV-1 transmission and other sexually transmitted infections. LACTIN-V represents an ecological approach to prevent vaginal infections by re-establishing the protective vaginal flora with a colonizing, H2O2-producing Lactobacillus strain. A second-generation Lactobacillus product, currently under development, is a human vaginal isolate of H2O2-producing L. jensenii that has been genetically modified to constitutively secrete high levels of a single protein-based potent HIV envelope-targeted entry inhibitor, an N-terminally modified cyanovirin-N (CV-N) (P51G). This live, self-renewing microbicide may afford an efficacious, yet inexpensive means to deliver a protein-based microbicide and address the urgent need for female-controlled approaches to block heterosexual transmission of HIV-1. Among the microbicide candidates currently in clinical trials, almost all of them are "coital dependent" products, or are being formulated for development based on a single active ingredient. The need to develop "non-coital dependent" microbicides or combinational microbicides that act at multiple sites of the mucosal HIV infection pathway represents a significant gap in microbicide development. In this R21 proposal, we plan to develop a novel live combinational microbicide by employing an H2O2-producing vaginal L. jensenii 1153 genetically modified to constitutively secrete the N-terminally modified CV-N (P51G) and an effective CCR5- targeted entry inhibitor, C1C5-RANTES. The latter is an N-terminally modified RANTES that targets the major HIV co-receptor CCR5 with an increased antiviral and anti-inflammatory activity. In this proposal, we will explore the possibility of delivering CV-N and C1C5-RANTES from a single strain of Lactobacillus, or from a mixture of two strains, each delivering a single inhibitor. We will select a microbicide development candidate from a collection of bioengineered strains that contain optimized expression cassettes stably integrated into the L. jensenii chromosome. The R33 phase will follow after a successful completion of the proposed milestones in the R21 phase proposal. For the R33 phase, we propose to conduct preclinical animal safety and efficacy studies in mouse, rabbit, and non-human primates. We will employ a Chinese rhesus macaque (Macaca mulatta) model that allows persistent vaginal colonization of L. jensenii to conduct preclinical safety and efficacy studies, including in situ CV-N and C1C5-RANTES expression, immunotoxicity, and efficacy against mucosal viral transmission. Furthermore, we propose to evaluate potential regulatory issues concerning the pharmaceutical development of a genetically modified organism which delivers combinational microbicides and to have a pre-IND consultation with FDA.