Development of a Live Combinational Microbicide for Women

描述(申请人提供)：OSEL，Inc.是一家专门从事细菌疗法开发的生物制药公司。该公司的主导产品LACTIN-V是一种自然产生的人类阴道乳杆菌分离物，目前正在进行第二阶段临床试验，以检验其在预防复发尿路感染(UTIs)和细菌性阴道病(BV)方面的安全性和有效性。尿路感染和BV都与产生过氧化氢(H_2O_2)的乳酸菌的枯竭有关，这种乳酸菌通常可以保护阴道免受机会性病原体的感染。流行病学研究还表明，阴道乳酸菌的丧失与异性传播HIV-1和其他性传播感染的风险增加有关。LACTIN-V代表了一种预防阴道感染的生态方法，方法是用一种定植的、产生过氧化氢的乳杆菌菌株重建保护阴道的菌群。第二代乳杆菌产品目前正在开发中，它是一种产生过氧化氢的詹森乳杆菌的人类阴道分离株，它已经经过基因改造，能够结构性地分泌高水平的单一蛋白质为基础的有效HIV包膜靶向进入抑制剂，一种N-末端修饰的氰基韦林-N(CV-N)(P51G)。这种活的、自我更新的杀微生物剂可能提供一种有效但廉价的方法来提供基于蛋白质的杀微生物剂，并解决女性控制的方法的迫切需要，以阻止艾滋病毒-1的异性传播。在目前正在进行临床试验的杀微生物剂候选药物中，几乎所有的产品都是“性交依赖”的产品，或者是基于单一活性成分开发的配方。需要开发“非性交依赖”的杀微生物剂或在粘膜艾滋病毒感染途径的多个部位起作用的组合杀菌剂，这是杀菌剂开发中的一个重大差距。在这份R21提案中，我们计划开发一种新型的活性组合杀菌剂，通过使用产生过氧化氢的阴道詹森乳杆菌1153进行基因改造，以结构性地分泌N-末端修饰的CV-N(P51G)和有效的CCR5靶向进入抑制剂c1c5-RANTES。后者是一种N末端修饰的RANTES，针对主要的HIV辅助受体CCR5，具有增强的抗病毒和抗炎活性。在这项提案中，我们将探索从单个乳杆菌菌株或从两个菌株的混合物中输送Cv-N和C1C5-RANTES的可能性，每个菌株提供一个单一的抑制剂。我们将从一组生物工程菌株中选择一种杀菌剂开发候选菌株，这些菌株包含稳定整合到简氏乳杆菌染色体上的优化表达盒。R33阶段将在成功完成R21阶段提案中的拟议里程碑之后进行。对于R33阶段，我们建议在小鼠、兔和非人类灵长类动物上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)模型来进行临床前安全性和有效性研究，包括原位CV-N和C1C5-RANTES的表达、免疫毒性和对抗粘膜病毒传播的有效性。此外，我们建议评估与提供组合杀菌剂的转基因生物的药物开发有关的潜在监管问题，并在IND前与FDA进行磋商。

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.