A Novel Microbiome-Based Immune-Modulator that Potentiates Cancer Checkpoint Therapy

项目摘要 本项目的目标是开发一种新的口服药物R-5780，它采用微生物组相关模式 识别受体(PRRs)增强免疫检查点抑制物(ICI)治疗慢性粒细胞白血病的活性 癌症的治疗。R-5780基于一种被称为分泌型抗原A(SAGA)的独特酶，该酶由 我们的研究小组发现的粪肠球菌可以参与微生物群相关的免疫学 肠道通路，并增强PD-1和CTLA4通路靶向剂的作用[19，29，30]。 肠道微生物区系与对宿主健康和疾病的显著影响有关，而离散的物种 共生细菌与改善患者对癌症免疫治疗的反应有关[7-14]。这个 这些有益细菌效应背后的分子机制仍然知之甚少。特别是， 特定的肠球菌株与抗PD-1/PD-L1治疗的改善反应有关 转移性黑色素瘤、肺癌和肾癌的患者，但其作用机制尚未得到证实 既未阐明也未用于改进癌症免疫治疗。我们实验室的最新工作证明 这些有益的肠球菌菌株表达SAGA肽聚糖重塑酶，当 通过一种不内源性表达SAGA的益生菌进行重组，可以增强抗- PD-1检查点治疗在小鼠肿瘤模型研究中的肿瘤效应。肽聚糖代谢物 SAGA直接激活宿主PRRs激活关键的宿主免疫信号通路[19]。 虽然确定的微生物组共生菌株可能提供一种有趣的替代方案来预防和治疗癌症 结合ICI疗法，许多菌株不适合人类使用(包括某些SAGA阳性 肠球菌)，作用机制很难表征，使药物开发具有挑战性。 然而，最近的研究表明，改良的益生菌被设计成携带特定的重组生物 肠道靶向制剂是一种有效的肠道微生物靶向途径。的确，我们的 最近的结果表明，对益生菌进行工程改造或重新编程，以重组表达和 将SAGA传递到肠道可以影响癌症的免疫反应性，并大大增强 ICI治疗的效果。这些抗肿瘤作用是通过肠道PRR参与实现的。我们的目标是开发一种 提供SAGA的新型益生菌菌株(简称R-5780)作为一种口服药物，具有协同作用 与ICI试剂一起提高免疫治疗的效果。主要目标是：1)最终确定R-5780 通过确定第二个肿瘤模型中的活性并证明初步的可制造性来验证，2) 执行必要的放大工艺开发，为GMP生产做准备，3)评估R-5780 剂量递增研究中的活性，并确定可用于临床试验的新生物标记物，以及4) 完成一项支持IND的GLP药物毒性研究。 R-5780的成功商业化将大大推进癌症的免疫疗法治疗。

Project Summary The goal of this project is to develop a novel oral drug, R-5780, which engages microbiome-associated Pattern Recognition Receptors (PRRs) to enhance the activity of immune checkpoint inhibitor (ICI) therapy for the treatment of cancer. R-5780 is based on a unique enzyme known as secreted antigen A (SagA) identified from Enterococcus faecium which our research team showed can engage microbiome-associated immunological pathways of the gut and potentiate the effects of PD-1 and CTLA4 pathway targeting agents [19, 29, 30]. Gut microbiota are associated with remarkable effects on host health and disease, and discrete species of commensal bacteria have been correlated with improved patient responses to cancer immunotherapy [7-14]. The molecular mechanisms underlying these beneficial bacterial effects remain poorly understood. In particular, specific strains of Enterococci have been linked with improved response to anti-PD-1/PD-L1 treatment in patients with metastatic melanoma, lung, and kidney cancers, but their mechanism of action has not been elucidated nor employed to improve cancer immunotherapy. Recent work from our laboratory demonstrated that these beneficial strains of Enterococci express the SagA peptidoglycan remodeling enzyme which, when delivered recombinantly via a probiotic that does not endogenously express SagA, can potentiate the anti- tumor effects of PD-1 checkpoint therapy in murine tumor model studies. The peptidoglycan metabolites generated by SagA directly engage host PRRs activating key host immune signaling pathways [19]. While defined microbiome commensal strains may offer an interesting alternative to prevent and treat cancer in combination with ICI therapy, many strains are not suitable for human use (including certain SagA positive Enterococci), and the mechanism of action is difficult to characterize making drug development challenging. However, recent studies suggest that improved probiotics engineered to carry specific recombinant biological targeting agents to the gut can be an effective approach to target intestinal microbiome pathways. Indeed, our recent results demonstrate that engineering or ‘reprogramming’ of probiotics to recombinantly express and deliver SagA to the intestinal tract can impact immune responsiveness of cancer and greatly enhances the effects of ICI therapy. These anti-tumor effects occur via intestinal PRR engagement. Our goal is to develop a novel probiotic strain to deliver SagA (referred to as R-5780) as an orally administered drug that synergizes with ICI agents to enhance effectiveness of immunotherapy. The key objectives of are to: 1) finalize R-5780 validation by determining activity in a second tumor model, and demonstrating preliminary manufacturability, 2) perform necessary scale up process development to prepare for GMP manufacturing, 3) assess R-5780 activity in dose escalation studies and identify novel biomarkers that could be use in clinical trials, and 4) complete an IND-enabling GLP pharm tox study. Successful commercialization of R-5780 will profoundly advance immunotherapy treatment of cancer.