MyD88 fusion protein with antigen specific T Cell therapy for enhanced response in solid tumors

摘要 尽管癌症治疗取得了最新进展，但胰腺癌患者仍然没有有效的选择 只有不到10%的人能存活五年以上。基于T细胞受体（TCR）的疗法具有 在晚期实体瘤患者的一个子集中获得了阳性反应，代表了一种有希望的 胰腺癌的治疗方法然而，低水平的抗原表达和免疫抑制肿瘤 微环境损害抗原识别并限制T细胞的持久性和功能，阻碍一致性 成功对抗实体瘤。为了克服这些挑战，我们设计了一种改善抗肿瘤治疗的策略。 在一个基于T细胞的平台上。间皮素（MSLN）在80-85%的胰腺肿瘤中表达， 它是治疗胰腺癌的有吸引力的TCR靶点。我们已经验证了T的细胞溶解活性 用针对表达MSLN的胰腺肿瘤的人HLA-A2限制性MSLN特异性TCR工程化的细胞 体外细胞我们小组先前的工作是在胰腺癌小鼠模型中使用鼠Msln特异性TCR， 癌症进一步证明了工程化T细胞在体内降低了肿瘤负荷，但缺乏持久性。我们因此 寻求开发一种新的免疫疗法，将我们的MSLN特异性TCR与独特有效的共 合成的CD 8 α：MyD 88融合蛋白的刺激特性。在转基因小鼠中，肿瘤反应性T细胞 表达CD 8 α：MyD 88融合蛋白证明了细胞因子产生的抗原特异性增加， 增殖和细胞毒性，与对照相比引起持久的肿瘤消退。为了评估这种方法， 作为胰腺癌的临床相关免疫治疗平台，我们将利用一种新的非病毒遗传学， 在原代人中共表达MSLN特异性TCR与CD 8 α：MyD 88融合蛋白的工程方法 T细胞。将通过评价稳定的TCR和CD 8 α：MyD 88融合表面优化载体构型 表达以及T细胞表型、功能和体外对胰腺癌细胞的细胞毒性。 优化的载体配置将在临床前动物模型中进行试验，以评估安全性 支持后续IND使能研究的有效性。如果成功，我们的努力将导致一个创新的新 免疫策略，以克服阻碍胰腺癌有意义改善的挑战， 癌症患者的结果。

Abstract Despite recent advances in cancer treatment, patients with pancreatic cancer still do not have effective options for treatment and fewer than 10% survive more than five years. T cell receptor (TCR) based therapies have achieved positive responses in a subset of patients with advanced solid tumors, representing a promising approach for pancreatic cancer. However, low level antigen expression and the immunosuppressive tumor microenvironment impair antigen recognition and limit T cell persistence and function, impeding consistent success against solid tumors. To surmount these challenges, we have devised a strategy to improve anti-tumoral responses in a T cel- based platform. Mesothelin (MSLN) is expressed by 80-85% of pancreatic tumors, making it an attractive TCR target for the treatment of pancreatic cancer. We have validated the cytolytic activity of T cells engineered with human HLA-A2 restricted MSLN specific TCRs against MSLN expressing pancreatic tumor cells in vitro. Previous work from our group with murine Msln specific TCRs in a mouse model of pancreatic cancer further demonstrated engineered T cells reduced tumor burden in vivo but lacked persistence. We thus seek to develop a novel immunotherapy that combines our MSLN specific TCRs with the uniquely potent co- stimulatory properties of a synthetic CD8α:MyD88 fusion protein. In transgenic mice, tumor reactive T cells expressing the CD8α:MyD88 fusion protein demonstrate antigen specific increases in cytokine production, proliferation, and cytotoxicity, eliciting durable tumor regression compared to controls. To evaluate this approach as a clinically relevant immunotherapy platform for pancreatic cancer we will utilize a novel non-viral genetic engineering approach to co-express MSLN specific TCRs with the CD8α:MyD88 fusion protein in primary human T cells. Vector configuration will be optimized by evaluating stable TCR and CD8α:MyD88 fusion surface expression, as well as T cell phenotype, function, and cytotoxicity against pancreatic cancer cells in vitro. Optimized vector configurations will be carried forward and tested in preclinical animal models to evaluate safety and efficacy in support of follow-on IND enabling studies. If successful, our efforts will lead to an innovative new immunotherapeutic strategy to overcome challenges that have prevented meaningful improvement in pancreatic cancer patient outcomes.