Neoadjuvant immunotherapy approaches to early stage melanoma

项目概要-项目3 改善高风险II期黑色素瘤患者的生存率的需求尚未得到满足。目前 II期黑色素瘤的治疗是监测，尽管复发率和死亡率高得令人无法接受 仅通过手术观察。前哨淋巴结（SLN）是原发性肿瘤引流的第一个淋巴结 并且不仅是转移癌细胞的靶标，而且是肿瘤抗原的免疫传感器 由原发性皮肤黑色素瘤释放我们在引流淋巴结（LN）转移模型中的初步数据 显示了在黑色素瘤转移到LN之前和期间髓样细胞群的显著增加。我们 我认为LN的这些变化可能会损害其（i）作为预防黑色素瘤的看门人的能力 （ii）作为抗原特异性T细胞免疫的指导者，能够控制局部免疫， 疾病和干预血源性传播。因此，我们的总体假设是， SLN防止局部和远处黑色素瘤扩散取决于其免疫健康， 它是柔韧的，并由淋巴结驻留骨髓的免疫刺激能力决定。 细胞在目标1中，Karakousis博士（临床共同项目负责人（PL））和Schuchter博士（共同研究者（I））将进行 在临床IIB/C期黑色素瘤中进行的新辅助pembrolizumab的促发剂启动的II期临床试验。 使用来自该临床试验和分期匹配的历史队列的原发性肿瘤和前哨淋巴结（SLN）， 我们将确定免疫治疗对肿瘤免疫表型和抗转移能力的影响。 SLN。我们将使用由Wherry博士（co-I）开创的无偏见的全球分析策略， 假设驱动的方法，我们的发现指导巨噬细胞在准备转移性肿瘤中的作用， niche（Beatty，Applied co-PL）来确定SLN阳性和阴性患者中的治疗相关变化。 同基因模型的研究将告知髓系细胞亚群在指导LN生物学变化中的作用 由黑色素瘤的发展及其对抗PD 1治疗的影响引发。目标2将检验以下假设： 淋巴结树突状细胞的免疫刺激能力决定了对抗PD 1抗体应答的可能性 疗法在共同PL博士的领导下，Herlyn和Beatty，我们将使用基于组织和细胞的多重 分析从我们的II期试验和阶段匹配的历史对照中收集的样本， 确定T细胞与骨髓细胞（包括树突状细胞）的相互作用及其对治疗反应的影响 临床结果。此外，我们将确定临床上可用的TLR激动剂是否可以增强 免疫刺激能力的引流LN，并在这样做，提高抗PD-1治疗的疗效，使用 用患者来源的异种移植物攻击的人源化小鼠，其以高保真度模拟早期黑素瘤。 影响：我们预计新辅助免疫治疗将在未来大幅降低SLN阳性率 旨在改变临床实践的随机研究。我们希望将SLN确定为重要的 黑色素瘤发病机制和免疫治疗的临床结果的决定因素。

Project Summary – Project 3 There is an unmet need to improve the survival of patients with high-risk Stage II melanoma. Currently, the treatment for Stage II melanoma is surveillance despite unacceptably high recurrence and mortality rates observed with surgery alone. The sentinel lymph node (SLN) is the first lymph node drained by a primary tumor and is not only a target for metastasizing cancer cells but also an immunological sensor of tumor antigens released by primary cutaneous melanoma. Our preliminary data in a draining lymph node (LN) metastasis model shows striking increases in myeloid cell populations prior to and during melanoma metastasis to the LN. We propose that these changes in the LN may compromise its ability to act (i) as a gatekeeper to prevent melanoma spread via the lymphatics and (ii) as an instructor of antigen-specific T cell immunity capable of controlling local disease and intervening on hematogenous spread. Thus, our overall hypothesis is that the capacity of the SLN to protect against locoregional and distant melanoma spread is dependent on its immune health, which is pliable and determined by the immunostimulatory capacity of lymph node-resident myeloid cells. In Aim 1, Drs. Karakousis (Clinical co-Project Leader (PL)) and Schuchter (co-Investigator (I)) will conduct an investigator-initiated Phase II clinical trial of neoadjuvant pembrolizumab in clinical Stage IIB/C melanoma. Using primary tumors and sentinel LNs (SLN) from both this clinical trial and stage-matched historical cohorts, we will determine the effects of immunotherapy on the immunophenotype and anti-metastatic capacity of the SLN. We will use a combination of unbiased global profiling strategies pioneered by Dr. Wherry (co-I) and hypothesis-driven approaches guided by our discoveries into the role of macrophages in preparing the metastatic niche (Beatty, Applied co-PL) to determine therapy-associated changes in SLN-positive and -negative patients. Studies in syngeneic models will then inform the role of myeloid cell subsets in directing changes in LN biology triggered by melanoma development and their impact on anti-PD1 therapy. Aim 2 will test the hypothesis that the immunostimulatory capacity of lymph node dendritic cells determines the likelihood of response to anti-PD1 therapy. Under the leadership of co-PLs Drs. Herlyn and Beatty , we will use multiplex tissue- and cell-based assays to analyze samples collected from our Phase II trial and stage-matched historical controls with the goal to define T cell interactions with myeloid cells, including dendritic cells, and their impact on treatment response and clinical outcomes. In addition, we will determine if clinically-available TLR agonists can enhance the immunostimulatory capacity of the draining LN and in doing so, improve the efficacy of anti-PD-1 therapy using humanized mice challenged with patient-derived xenografts which model early stage melanoma with high fidelity. Impact: We anticipate neoadjuvant immunotherapy will substantially reduce SLN positivity rates warranting future randomized studies designed to change clinical practice. We expect to identify the SLN as an important determinant of melanoma pathogenesis and clinical outcomes to immunotherapy.