Preclinical development of WP1066, an effective inhibitor of STAT3 activation for

描述(申请人提供)：缺乏治疗中枢神经系统恶性肿瘤的有效疗法导致我们对脑癌的长期科学兴趣，以及我们之前的发现和临床前开发的另外两种明显不同类别的小分子(拓扑异构酶II抑制剂-WP744和肿瘤细胞代谢抑制因子-WP1122)，专门用于治疗中枢神经系统恶性肿瘤。目前，在一项非常成功的第一阶段研究之后，WP744正在进行第二阶段的临床试验。随后，我们将我们的兴趣集中在独特的分子靶标信号转导和转录激活因子3(STAT3)上，并通过第一阶段SBIR拨款获得了资金。我们非常有希望的结果，在我们众多出版物的支持下，导致选择WP1066进行进一步的临床前和临床开发，从而提交了这项第二阶段SBIR赠款提案。STAT3是一个分子枢纽，控制着一系列对肿瘤细胞的生存和增殖至关重要的基因的转录。P-STAT3是多种实体瘤中最常被激活的致癌蛋白之一，已被证明在大多数人类肿瘤中持续激活。更具体地说，大量数据表明，在许多恶性肿瘤中，典型的静止的p-STAT3通路的激活对肿瘤的发生至关重要，并且是预后不良的预测因子，包括胃、肾、乳腺、卵巢、鳞状细胞癌、间变性大细胞淋巴瘤、黑色素瘤和胶质瘤。除了调节生长和增殖，STATs还密切参与免疫功能的调节。我们已经确定了许多深刻的免疫抑制因素，包括Tregs、免疫抑制细胞因子和小胶质细胞，它们可以在癌细胞的微环境中诱导T细胞无能。这一发现表明，即使对抗原靶点产生了强有力的系统免疫反应，当遇到肿瘤微环境时，这些反应也会在功能上变得惰性。目前可用的免疫激活剂不足以克服这种免疫耐受和免疫抑制。然而，一种新的信号转导和转录激活因子3(STAT3)小分子抑制物在体内显示出显著的免疫激活特性，并可用于癌症患者的免疫治疗。我们的新型STAT3激活途径小分子抑制剂WP1066具有药物样特性，可口服生物利用，跨越血脑屏障，并在各种临床前肿瘤模型中显示包括免疫激活在内的体内活性。鉴于这种高度的疗效，我们建议进行研究，重点放在IND指导的临床前开发这种新的、治疗中枢神经系统恶性肿瘤的一流药物。该建议的具体目标集中在完成WP1066的临床前测试，以便迅速启动第一个人体临床试验，并包括：1)生产原料药的放大合成和工艺开发，2)进一步确定WP1066的作用机制、选择性和可能的耐药机制，3)确定WP1066的口服安全性和吸收，4)合成和筛选WP1066的假定代谢物，用于安全性和有效性，5)开发和验证定量分析方法，6)确定ADME，7)确定剂量安排并进行安全药理学、毒理学和毒代动力学研究，8)编写WP1066作为治疗中枢神经系统恶性肿瘤的IND申请。 公共卫生相关性：尽管在过去30年中采用了多种治疗策略，但多形性胶质母细胞瘤的总体生存时间仍不到14个月。由于这些肿瘤的侵袭性及其与关键脑结构的关联，完全手术消融是不可能的，辅助治疗，如化疗和放射治疗，虽然需要，但对疾病的影响仍然很小。我们的SBIR I期研究结果表明，STAT3激活的抑制剂(如WP1066)很有可能成为中枢神经系统肿瘤局部环境中癌细胞死亡的有效诱导者和免疫激活的正向调节器。

DESCRIPTION (provided by applicant): Lack of effective therapeutics for CNS malignancies led to our long term scientific interest in brain cancers and to our previous discoveries and preclinical development of two other small molecules of distinctly different classes (a topoisomerase II inhibitor-WP744 and an inhibitor of tumor cell metabolism-WP1122) specifically directed at the treatment of CNS malignancies. Currently, WP744 is in Phase II clinical trials following a very successful Phase I study. We have subsequently focused our interest on the unique molecular target Signal Transducer and Activator of Transcription 3 (STAT3) and obtained funding through a Phase I SBIR grant. Our very promising results, supported by our numerous publications, led to the selection of WP1066 for further preclinical and clinical development leading to submission of this Phase II SBIR grant proposal. STAT3 is a molecular hub controlling the transcription of a wide array of genes important to the survival and proliferation of tumor cells. P-STAT3 is among the most frequently activated oncogenic proteins in multiple solid tumor types and has been shown to be persistently activated in most human cancers. More specifically, a large body of data has demonstrated activation of the typically quiescent p-STAT3 pathway is crucial to tumorigenesis and a predictor of poor prognosis in many malignancies including gastric, renal, breast ovarian, squamous, hepatocellular carcinoma, anaplastic large cell lymphoma, melanoma and gliomas. In addition to regulating growth and proliferation, STATs are intimately involved in the regulation of immune function. We have identified a number of profound immunological suppressive factors including Tregs, immunosuppressive cytokines, and microglia that induce T cell anergy in the microenvironment of cancer cells. This finding suggests that even if a vigorous systemic immune response were generated to an antigen target, upon encountering the tumor microenvironment these responses would be rendered functionally inert. Currently available immune activators are insufficient to overcome this immune tolerance and immunosuppression. However, a novel small molecular inhibitor of the signal transducer and activator of transcription 3 (STAT3) has demonstrated marked immune activation properties in this setting in vivo, and could be employed to potently synergize with immunotherapies for patients with cancer. Our novel small molecule inhibitor of the STAT3 activation pathway, WP1066, possesses drug- like characteristics, is orally bioavailable, crosses the blood-brain barrier, and demonstrates in vivo activity, including immune activation, in a variety of preclinical tumor models. Given this high degree of efficacy we propose studies focused on IND-directed preclinical development of this novel, first in class drug to treat CNS malignancies. The specific aims of this proposal are focused on completion of preclinical testing of WP1066 in order to rapidly start the first in man clinical trials and include: 1) scale-up synthesis and process development for the production of API, 2) further determination of the mechanism of action, selectivity, possible resistance mechanisms of WP1066, 3) determination of the oral safety profile and absorption of WP1066, 4) synthesize and screen putative metabolites of WP1066 for safety and efficacy, 5) development and validation of a quantitative analytical methodology, 6) defining the ADME, 7) determination of dose-scheduling and performing safety pharmacology, toxicology, and toxicokinetic studies, and 8) writing the IND application for WP1066 as a treatment for CNS malignancies. PUBLIC HEALTH RELEVANCE: Despite multimodality therapeutic strategies employed over the past three decades, the overall survival time for glioblastoma multiforme is still less than 14 months. Due to the invasiveness of these tumors and their association with critical brain structures, complete surgical ablation is not possible and adjuvant therapy, such as chemotherapy and radiation therapy, while required still has minimal impact on the disease. Results from our SBIR Phase I studies indicated the strong likelihood that an inhibitor of STAT3 activation (such as WP1066) would be an effective inducer of cancer cell death and positive modulator of immune activation in the local environment of CNS tumors.