Immunotherapy for Malignant Mesothelioma, Lung Cancer and Thymic Malignancies

我们项目的总体目标是为胸部癌症患者开发更有效的治疗方法。这项工作主要分为两大类：1。利用间皮素治疗间皮瘤。2. 免疫疗法和其他治疗肺癌和胸腺癌的方法。1. 我们目前的研究重点是针对肿瘤分化抗原间皮素（mesothelin）的免疫治疗，该抗原在胸膜、心包和腹膜的正常间皮细胞上表达，但在几种人类肿瘤中，尤其是间皮瘤、卵巢癌、肺癌和胰腺腺癌中高度表达。这种间皮素的差异表达使其成为肿瘤特异性治疗的有吸引力的候选者。我们现在的工作重点是利用不同的方法将其用于间皮瘤的治疗。这些药物包括抗间皮素免疫毒素（LMB-100）、抗间皮素药物偶联物（BAY 94-9343）和间皮素疫苗（CRS-207）。LMB-100是一种由抗间皮素Fv组成的免疫毒素，它与强效细菌毒素假单胞菌外毒素a的截断形式相连，假单胞菌外毒素a已被去免疫以降低其抗原性。我们最近完成了LMB-100的I期试验，并确定了其安全性和最大耐受剂量。目前，我们正在间皮瘤患者联合免疫检查点抑制剂Pembrolizumab进行一项II期研究。我们最近完成了一项I期临床试验，以确定抗间皮素抗体药物偶联物BAY 94-9343的安全性和MTD，该偶联物包括一种人源抗间皮素单克隆抗体，与美坦素类DM4相连接，以及该偶联物联合化疗的I期研究。我们还进行了一项I期临床试验，将表达活的减毒单核细胞增生李斯特菌（CRS207）的间皮素与化疗结合使用，发现恶性胸膜间皮瘤患者的OS得到改善。目前，我的实验室正在研究DNA修复基因的种系突变，这种突变可能易患间皮瘤并影响临床结果。我们已经证明，DNA修复基因的种系突变增加了对铂治疗的敏感性，并提高了胸膜间皮瘤患者的总生存率。在实验室，我们专注于开发人类间皮瘤的体外和体内模型。我们从患者的腹水和胸水中建立了几个早期传代肿瘤细胞系。我们已经评估了这些细胞系的形态和遗传特征，并正在使用它们来研究体外药物敏感性。目前，我们正在评估这些患者来源的间皮瘤细胞系对PARP抑制剂（奥拉帕尼和塔拉唑帕尼）和DNA烷基化剂替莫唑胺的遗传背景的敏感性。此外，我们已经建立了一个人源性间皮瘤异种移植肿瘤模型，该模型使用来自患者的肿瘤细胞和来自健康供体的人pbmc进行体内研究。由于pmc人源化小鼠模型中移植物抗宿主病（GVHD）的发展限制了抗肿瘤疗效持续时间的评估，我们开发了一种同源免疫能力小鼠模型。由于免疫毒素LMB-100能特异性靶向人间皮素，我们利用编码hMSLN膜结合片段的hMSLN表达载体转染PD-L1阳性小鼠肺腺癌细胞系，建立了表达人间皮素免疫活性的同基因小鼠肿瘤模型。这些细胞系被用来发展肿瘤。我们研究了LMB-100联合抗pd1抗体在两种模型中的作用，并观察到肿瘤消退。这些模型对于评估间皮瘤的新型治疗药物和抗肿瘤疗效的机制研究至关重要。其他正在进行的实验室研究主要集中在了解间皮瘤肿瘤免疫微环境和抗间皮瘤靶向药物治疗后的变化。2. 免疫疗法治疗胸腺癌和肺癌。胸腺癌：胸腺瘤是一种罕见的肿瘤，其特征是淋巴细胞的浸润，使它们特别适合免疫检查点抑制。胸腺瘤患者目前正在接受抗pd - l1单克隆抗体MSB0010718C的I期临床试验治疗。我们已经在这些患者中看到了显著的抗肿瘤活性，并且伴随着胸腺瘤患者特有的副作用。此外，我们正在进行舒尼替尼治疗胸腺癌的II期研究。肺癌：我们目前正在对先前治疗失败的肺腺癌患者进行抗pd - l1单克隆抗体MSB0010718C的临床试验。我们的实验室最近发现约25%的转移性肺腺癌患者高表达间皮素。这些肿瘤中的间皮素表达与KRAS突变和野生型EGFR状态高度相关，并且独立地与不良预后相关。我们的假设是，K-RAS突变肺癌患者可以从间皮素定向治疗中获益。间皮素导向疗法治疗肺癌的临床试验即将开启。我们的实验室也在研究免疫检查点在恶性间皮瘤中的作用，以便针对这一途径的药物可以用于治疗间皮瘤。

The overall goal of our program is to develop more effective therapies for patients with thoracic cancers. This work falls under two main categories: 1. Exploiting mesothelin for cancer therapy in mesothelioma. 2. Immunotherapy and other approaches to treat lung cancer and thymic cancers. 1. Exploiting mesothelin for mesothelioma therapy and related translational research Our current studies are focused on using immunotherapy directed against the tumor differentiation antigen mesothelin, which is expressed on normal mesothelial cells lining the pleura, pericardium and peritoneum but is highly expressed in several human tumors especially mesothelioma, ovarian cancer, lung cancer and pancreatic adenocarcinomas. This differential expression of mesothelin makes it an attractive candidate for tumor specific therapy. Our efforts are now focused on exploiting it for mesothelioma therapy using different approaches. These include anti mesothelin immunotoxins (LMB-100), an anti-mesothelin drug conjugate (BAY 94-9343) and a mesothelin vaccine (CRS-207). LMB-100 is an immunotoxin consisting of the anti-mesothelin Fv linked to a truncated form of the potent bacterial toxin, Pseudomonas exotoxin A, which has been de-immunized to decrease its antigenicity. We have recently completed the phase I trial of LMB-100 and established its safety and maximum tolerated dose. Currently we are conducting a phase II study in patients with mesothelioma in combination with immune checkpoint inhibitor Pembrolizumab. We have recently completed a phase I clinical trial to determine the safety and MTD of the anti-mesothelin antibody drug conjugate BAY 94-9343, which consists of a humanized anti-mesothelin monoclonal antibody linked to the maytansinoid DM4 and a phase I study of the same in combination with chemotherapy. We have also conducted a Phase I clinical trial with mesothelin expressing live, attenuated Listeria monocytogenes (CRS207) along with chemotherapy, and have seen improved OS in patients with malignant pleural mesothelioma. Currently my laboratory is studying germline mutations in DNA repair genes that could predispose to mesothelioma and influence clinical outcome. We have shown that germline mutations in DNA repair genes increases sensitivity to platinum therapy and improves overall survival in patients with pleural mesothelioma. In the laboratory, we have focused on developing in-vitro and in-vivo models of human mesothelioma. We have established several early passage tumor cell lines from ascites and pleural fluid of patients. We have evaluated the morphological and genetic characteristics of these cell lines and are using them to study in-vitro drug sensitivity. Currently we are evaluating the sensitivity of these patient derived mesothelioma cell lines to PARP inhibitors (Olaparib and Talazoparib) and a DNA alkylating agent, Temozolomide with respect to their genetic background. Additionally, we have established a humanized mesothelioma xenograft tumor model with patient derived tumor cells and human PBMCs from healthy donor for in-vivo studies. As the development of Graft Versus Host Disease (GVHD) in the PBMC-humanized mouse model limits assessment of duration of anti-tumor efficacy, we have developed a syngeneic immunocompetent mouse model. Because the immunotoxin LMB-100 can target human mesothelin specifically, we established a human mesothelin expressing immunocompetent syngeneic mouse tumor model by transfecting PD-L1 positive mouse lung adenocarcinoma cell line with a hMSLN expressing vector encoding the membrane bound fragment of hMSLN. These cell lines were used to develop tumor. We have studied the effect of LMB-100 in combination with anti-PD1 antibody in both the models and have seen tumor regression. These models are essential to evaluate novel therapeutic agents for mesothelioma and for the mechanistic studies of anti-tumor efficacy. Other ongoing laboratory studies are focused on understanding the mesothelioma tumor immune micro-environment and changes following treatment with anti-mesothelin targeted agents. 2. Immunotherapy to treat thymic cancer and lung cancers. Thymic Cancers: Thymoma is a rare tumor characterized by infiltration of lymphocytes making them uniquely suitable for immune-checkpoint inhibition. Thymoma patients are currently being treated on a phase I clinical trial of the anti-PD-L1 monoclonal antibody MSB0010718C. We have seen remarkable anti-tumor activity in these patients that has been accompanied by side-effect profile unique to thymoma patients. In addition, we are conducting a Phase II study of sunitinib in thymic carcinomas. Lung Cancer: We are currently conducting clinical trial of the anti-PD-L1 monoclonal antibody MSB0010718C in patients with lung adenocarcinoma who have failed prior therapies. Our laboratory has recently shown that about 25% of patients with metastatic lung adenocarcinoma highly express mesothelin. Mesothelin expression in these tumors is highly associated with KRAS mutations and wild type EGFR status and is, independently, associated with poor prognosis. Our hypothesis is that patients with K-RAS mutant lung cancer can benefit from mesothelin directed therapies. Clinical trials of mesothelin directed therapies for treating lung cancer are about to open. Our laboratory is also studying the role of immune checkpoints in malignant mesothelioma so that drugs targeting this pathway can be exploited for treating mesothelioma.