Optimizing Novel Immunotherapy Combinations Targeting the Tumor Microenvironment in Canine Spontaneous Osteosarcoma

项目摘要 自发性犬骨肉瘤（OS）是一种定义明确的人类OS大型动物模型，表现出类似于骨肉瘤的特征。 临床表现和分子畸变。事实上，犬类操作系统在历史上一直被用来帮助开发 新的肢体备用技术，评估各种非特异性免疫治疗剂，如L-MTP-PE， 评估靶向治疗的有效性，以防止转移性疾病的发展。尽管尽了最大努力， 转移性疾病的预防和治疗的进展在过去30年中基本停滞; 30%的人和90%的狗仍然死于肿瘤扩散，主要是肺部。许多临床试验 在肉眼可见转移的人和在显微镜和肉眼可见转移的狗中进行 疾病，但所有人都未能证明改善的结果。这一点在以下方面尤其明显： 免疫检查点抑制剂不会诱导在其他疾病中通常观察到的显著疾病消退， 癌症如黑色素瘤和肺癌。一个特别艰巨的挑战是基于免疫疗法的 OS中的治疗涉及肿瘤微环境（TME）的容许性，用于诱导抗肿瘤治疗。 免疫反应。我们的数据表明，相对较低的突变负荷加上总体抑制， OS中的免疫应答可能导致观察到的对当前治疗方法缺乏应答。我们 提出靶向OS中的免疫抑制性TME对于产生有效和持久的抗- 肿瘤免疫为了实现这一点，可能需要同时调制器中的几个元件。 TME，包括TME、MDSC、M2巨噬细胞和过表达的抑制性检查点分子。支持 其中，我们已经产生了大量数据，证明了多种治疗剂的免疫活性，包括 具有良好安全性记录的再利用药物（氯沙坦、奥拉替尼）、具有已确定安全性的小分子抑制剂 犬中的PK/PD（toceranib、RV 1001、reparixin、JHU-292）和检查点分子特异性抗体（抗- PD1）。然而，对转移性OS最有效的确切组合尚未确定。 这一点已经确定，这也是本提案的一个主要目标。因此，我们假设适应性先导试验设计 可用于在患有以下疾病的犬中快速筛选靶向TME的免疫治疗药物组合 肉眼可见的化疗耐药转移性OS，并且可以细化该信息来评估 在随后的辅助试验中，最有效的方法对显微镜下转移的活性。这 将通过测试四种TME修饰免疫疗法组合来实现抗肿瘤和免疫治疗。 在具有肉眼OS转移的犬中的调节活性，询问与 对治疗的反应，然后使用这些信息进行辅助免疫治疗试验， 在具有显微镜下转移性OS的狗中的组合。从该提议生成的数据将创建一个 通过消除被认为无效的方法，为OS患者的未来免疫治疗研究制定蓝图 以及产生一组临床生物标志物以指导治疗。

Project Abstract Spontaneous canine osteosarcoma (OS) is a well-defined large animal model of human OS, exhibiting similar clinical presentation and molecular aberrations. Indeed, canine OS has historically been used to help develop novel limb spare techniques, evaluate a variety of non-specific immunotherapeutics such as L-MTP-PE, and assess the efficacy of targeted therapeutics to prevent the outgrowth of metastatic disease. Despite best efforts, progress in the prevention and treatment of metastatic disease has essentially stalled for the past 3 decades; 30% of people and 90% of dogs still die of tumor spread, primarily to the lungs. Numerous clinical trials have been undertaken in people with macroscopic metastases and in dogs with both microscopic and macroscopic disease, yet all have failed to demonstrate improved outcomes. This is particularly evident with respect to immune checkpoint inhibitors that do not induce the dramatic disease regressions typically observed in other cancers such as melanoma and lung cancer. One particularly daunting challenge for immunotherapy-based therapeutics in OS relates to the permissiveness of the tumor microenvironment (TME) for inducing anti-tumor immune responses. Our data suggests that a relatively low mutational load combined with a dampened overall immune response in OS may contribute to the observed lack of response to current treatment approaches. We propose that targeting the immune suppressive TME in OS is essential to generating potent and durable anti- tumor immunity. To accomplish this, it may be necessary to simultaneously modulate several elements in the TME, including Tregs, MDSCs, M2 macrophages and overexpressed inhibitory checkpoint molecules. In support of this, we have generated a body of data demonstrating immunological activity of multiple therapeutics, including repurposed drugs with good safety records (losartan, oclacitinib), small molecule inhibitors with established PK/PD in dogs (toceranib, RV1001, reparixin, JHU-292) and antibodies specific for checkpoint molecules (anti- PD1). However, the exact combinations that are most effective against metastatic OS have not yet been identified, and this is a major goal of this proposal. As such, we hypothesize that an adaptive pilot trial design can be used to rapidly screen TME-targeting immunotherapy drug combinations in dogs with macroscopic chemotherapy-resistant metastatic OS and that this information can be refined to assess activity of the most active approach against microscopic metastases in a subsequent adjuvant trial. This will be accomplished by testing four TME modifying immunotherapy combinations for anti-tumor and immune modulatory activity in dogs with macroscopic OS metastases, interrogating relevant biomarkers associated with responses to therapy, then using this information to conduct an adjuvant immunotherapy trial with the most active combination in dogs with microscopic metastatic OS. The data generated from this proposal will create a blueprint for future immunotherapy studies in people with OS by eliminating approaches deemed inactive and generating a set of clinical biomarkers to guide treatment.