Development of a novel small molecule RPN13 inhibitor and therapeutic for advanced ovarian cancer patients

上皮性卵巢癌（EOC）是最致命的妇科恶性肿瘤，尽管积极的手术， 毒性化疗迫切需要更有效和更安全的靶向药物来解决这一未满足的问题 医疗需求。与正常组织相比，EOC表现出异常的蛋白酶体功能， 高分子量聚泛素化和错误折叠的蛋白质聚集体的积累。因为如此 由于未解决的蛋白毒性应激，EOC细胞系对蛋白酶体抑制剂高度敏感。虽然高度 对多发性骨髓瘤等液体癌有效，不幸的是，已获许可的20 S蛋白酶体抑制剂， 如硼替佐米，已被证明对实体瘤，包括EOC无效。这反映了有限的组织 获得这些基于肽的药物和剂量限制性毒性，特别是周围神经病变， 血小板减少症和中性粒细胞减少症。Up 284是一种专利的上游（19 S）蛋白酶体抑制剂，具有新的 目标和机制，RPN 13抑制，以及旨在克服许可的限制的结构 Up 284阻断底物识别和19 S去泛素化， 而不仅仅是三种20 S催化活性中的一种），对实体瘤的活性差（Up 284具有 与基于肽的20 S抑制剂相比，具有改善的药物样性质的新型螺环结构，以及 促进肿瘤细胞的抗原表达）、周围神经病变的关键毒性（临床上未 在最初的鼠研究中，Up 284明显）和血小板减少症和中性粒细胞减少症（Up 284使 免疫蛋白酶体和缺乏这些副作用）。Up 284在体外显示出广泛的抗癌活性，包括 针对针对铂类耐药选择的EOC系，具有稳健的治疗指数和有希望的安全性特征， 以及在EOC的原位小鼠模型中控制异种移植肿瘤的能力。这一令人鼓舞的数据反映了我们 广泛的药物化学努力，以实现药物样的性质，并已在美国获得专利 （在其他国家待定），以涵盖新的骨架和先导化合物。小鼠数据表明Up 284具有 具有良好的药效学，并证实了新的体内作用机制。通过抑制蛋白酶体 泛素受体RPN 13的功能及其相关的去泛素化酶活性，Up 284产生更快的 比20 S抑制剂更大分子量的多聚泛素化蛋白聚集体的积累。这些有毒 错误折叠的蛋白聚集体产生未解决的ER应激，激活典型的未折叠蛋白 响应（UPR），因此Up 284比20 S抑制剂更快地触发p53非依赖性凋亡。支持 在向FDA提交IND申请时，我们提出：目的1：评估治疗小鼠的毒性和周围神经病变（PN） IP vs IV，Up 284 vs硼替佐米（第1-3个月）。目的2：小鼠临床试验：测试 Up 284对13个卵巢PDX模型的IP vs IV给药（3-7个月）;目的3：工艺开发，GLP Up 284的制造、制剂稳定性和GLP生物分析方法开发（第7-24个月）; 5：Up 284在大鼠和狗中的GLP毒理学和安全性研究（15-24个月）。

Epithelial ovarian cancer (EOC) is the most lethal gynecological malignancy despite aggressive surgery and toxic chemotherapies. More effective and safer targeted drugs are urgently needed to address this unmet medical need. Compared to normal tissues, EOC exhibits aberrant proteasome function that triggers accumulation of high molecular weight polyubiqutinated and misfolded protein aggregates. Because of this unresolved proteotoxic stress, EOC cell lines are highly susceptible to proteasome inhibitors. While highly effective against liquid cancers like multiple myeloma, unfortunately the licensed 20S proteasome inhibitors, such as bortezomib, have proven ineffective against solid tumors, including EOC. This reflects limited tissue access for these peptide-based drugs and dose-limiting toxicities, notably peripheral neuropathy, thrombocytopenia and neutropenia. Up284 is a proprietary upstream (19S) proteasome inhibitor with a novel target and mechanism, RPN13 inhibition, and a structure designed to overcome the limitations of the licensed drugs with respect to limited potency (Up284 blocks substrate recognition and deubiquitination by the 19S rather than just one of the three 20S catalytic activities), poor activity against solid tumors (Up284 has a novel spiro structure with improved drug-like properties compared to peptide-based 20S inhibitors, and promotes antigen-representation by tumor cells), key toxicities of peripheral neuropathy (Not clinically apparent with Up284 in initial murine studies) and thrombocytopenia and neutropenia (Up284 spares the immunoproteasome and lacks these side effects). Up284 shows broad anticancer activity in vitro, including against EOC lines selected for platinum resistance, with a robust therapeutic index and a promising safety profile, and the ability to control xenograft tumor in an orthotopic mouse model of EOC. This promising data reflects our extensive medicinal chemistry effort to achieve drug-like properties and a patent has been awarded in US (pending in other countries) to cover the novel backbone and lead compounds. Murine data indicate Up284 has favorable pharmacodynamics and confirm the novel mechanism of action in vivo. By inhibiting proteasome ubiquitin receptor RPN13 function and its associated deubiquitinase activity, Up284 produces more rapid accumulation of larger molecular weight polyubiquinated protein aggregates than the 20S inhibitors. These toxic misfolded protein aggregates produce an unresolved ER stress, activate the canonical Unfolded Protein Response (UPR) and thus Up284 more rapidly triggers p53-independent apoptosis than 20S inhibitor. To support an IND application to FDA, we propose: Aim 1: Assessing toxicity & Peripheral Neuropathy (PN) in mice treated IP vs IV with Up284 vs. bortezomib (months 1-3). Aim 2: Mouse clinical trial: Testing therapeutic efficacy of Up284 delivered IP vs IV against 13 ovarian PDX models (months 3-7); Aim 3: Process development, GLP manufacture, formulation stability & GLP bioanalytical method development of Up284 (months 7-24); Aims 4 & 5: GLP toxicology and safety studies of Up284 in rats & dogs (months 15-24).