Exploring biomarkers of clinical benefit to VEGFR inhibitor combined with PD-L1 inhibitor in recurrent/metastatic Adenoid Cystic Carcinoma

腺样囊性癌（ACC）是第二常见的唾液腺肿瘤，化疗难治， 复发/转移性（R/M）疾病患者没有标准的护理治疗，突出了一个主要的 未满足的临床需求。血管内皮生长因子受体（VEGFR）抑制剂经常用于治疗 ACC，但主要使疾病稳定。ACC对单药免疫检查点抑制剂也有耐药性 (ICI)，与其低肿瘤突变负荷（TMB）和总体无炎症肿瘤免疫一致。 微环境（TIME）检测抗VEGFR治疗的免疫调节作用是否可增强ICI疗效 并克服对VEGFR抑制剂单药治疗的耐药性，我们正在进行一项化疗启动的II期 一项试验，其中进展性R/M ACC患者接受阿西替尼（一种VEGFR酪氨酸激酶抑制剂）和avelumab （抗PD-L1抗体）。最近完成了研究招募，28例患者可用于疗效分析。 中期结果显示，根据RECIST 1.1，总体缓解率为18%（5/28），优于VEGFR，上级 或ICI单药治疗，以及临床获益率，定义为客观缓解或疾病稳定> 6个月， 百分之五十最近，我们对54个ACC进行了全面的蛋白质组学分析，发现了两个 不同的亚型ACC-I和ACC-II。ACC-I富含NOTCH 1激活突变和MYC ACC-II表现出TP 63和受体的上调， 酪氨酸激酶和更长的患者生存期。到目前为止，28例中有22例可进行P63/MYC的IHC肿瘤染色。 试验患者; 12例为ACC-I，10例为ACC-II，证明ACC分子 亚型我们发表的54例ACC队列的RNA-seq数据的计算分析表明， ACC-I亚型与CD 8 T细胞的增加有明显的时间关系，沿着免疫抑制因子的上调。 标记。基于我们有趣的数据，我们假设：1）基因组异质性与 在R/M ACC中对阿西替尼/avelumab的不同应答，和2）不同的ACC免疫景观和T细胞 属性与接受阿西替尼/avelumab治疗的患者的临床结局相关。我们将测试这些 利用来自我们试验的独特肿瘤组织和血液的假设，有两个目的：1）鉴定遗传学上的基因， 使用基线肿瘤（n=28），我们将 进行全外显子组测序（seq）和RNA-seq，并评估是否有任何特定的基因改变、TMB或基因 表达谱与益处相关。2)评估临床获益的基质和免疫学决定因素 我们将使用成像质谱细胞术检查ACC TIME组成， 确定TIME的组成是否与临床益处相关。我们还将评估肿瘤相关性 通过基线肿瘤TCR-seq的T细胞属性和通过配对血液的TCR-seq的循环T细胞属性 （基线和治疗中），并与临床获益相关。总的来说，这个项目可能会导致生物标志物 发现和分层可从ICI+抗血管生成治疗中获益的R/M ACC患者。

Adenoid Cystic Carcinoma (ACC), the 2nd most common salivary gland tumor, is chemotherapy-refractory and there is no standard of care treatment for patients with recurrent/metastatic (R/M) disease, highlighting a major clinical unmet need. Vascular endothelial growth factor receptor (VEGFR) inhibitors are frequently used to treat ACC, but render mostly disease stabilization. ACC is also resistant to single agent immune checkpoint inhibitors (ICI), consistent with its low tumor mutational burden (TMB) and overall uninflamed tumor immune microenvironment (TIME). To test if the immunomodulatory role of anti-VEGFR therapy can enhance ICI efficacy and overcome resistance to VEGFR inhibitor monotherapy, we are conducting an investigator-initiated phase II trial, where progressing R/M ACC patients receive axitinib (a VEGFR tyrosine kinase inhibitor) and avelumab (anti-PD-L1 antibody). Study accrual has recently completed with 28 patients evaluable for the efficacy analysis. Interim results revealed an overall response rate of 18% (5/28) per RECIST 1.1, which is superior over VEGFR or ICI monotherapy, and a clinical benefit rate, defined as objective response or disease stability > 6 months, of 50%. Recently, we have conducted a comprehensive proteogenomic analysis of 54 ACC which revealed two distinct subtypes ACC-I and ACC-II. ACC-I is enriched with NOTCH1 activating mutations and MYC overexpression and is associated with poor prognosis while ACC-II exhibited upregulation of TP63 and receptor tyrosine kinases and longer patient survival. Thus far, IHC tumor staining for P63/MYC is available for 22 of 28 trial patients; 12 are ACC-I and 10 are ACC-II demonstrating significant representation of both ACC molecular subtypes. Computational analysis of RNA-seq data of our published cohort with 54 ACC suggested that the ACC-I subtype has a distinct TIME with increased CD8 T cells, along with upregulation of immune suppressive markers. On the basis of our intriguing data, we hypothesize 1) genomic heterogeneity is associated with differential responses to axitinib/avelumab in R/M ACC, and 2) distinct ACC immune landscape and T cell attributes are associated with the clinical outcomes of patients treated with axitinib/avelumab. We will test these hypotheses leveraging the unique tumor tissue and blood from our trial with two aims: 1) Identify genetic determinants of clinical benefit to axitinib and avelumab in ACC. Using the baseline tumors (n=28), we will conduct whole exome sequencing (seq) and RNA-seq and assess if any specific gene alterations, TMB or gene expression profile are associated with benefit. 2) Assess stroma and immunologic determinants of clinical benefit to axitinib and avelumab in ACC. We will examine ACC TIME composition using imaging mass cytometry and determine if the composition of the TIME correlates with clinical benefit. We will also assess tumor-associated T-cell attributes via baseline tumors TCR-seq and circulated T-cell attributes via TCR-seq of paired blood (baseline and on-treatment) and correlate with clinical benefit. Collectively, this project may lead to biomarker discovery and stratification of R/M ACC patients who can benefit from ICI+ anti-angiogenic therapy.