Epigenetic priming enhances anti-tumor immunity in resistant ovarian cancer [methylation array]

Here we describe the clinical and biological activity of guadecitabine, a second generation HMA, given in a low dose as a priming strategy before pembrolizumab, a humanized anti-PD1 antibody in a clinical trial for patients with recurrent, platinum resistant ovarian cancer. The methylomic and transcriptomic effects of the combination demonstrate readily activation of the anti-tumor immunity. High dimensional immune profiling of periferal mononuclear cells (PBMCs) and tumor biopsies obtained before and after treatment show distinct immune profiles and tissue architectural features associated with clinical benefit. Our study provides an in-depth view of the immune milieu of platinum resistant ovarian cancer and of the effects of the combination of HMAs and pembrolizumab on the interactions between immune cell populations and tumor cells. This was a non-randomized open-label two stage phase II trial testing guadecitabine and pembrolizumab in recurrent platinum-resistant OC. Patients all had epithelial ovarian, fallopian tube or primary peritoneal cancer that had recurred or progressed <6 months after their last dose of platinum-based chemotherapy. Guadecitabine (G) 30 mg/m2 was administered by subcutaneous (sc) injection on days 1 - 4 of a 21-day cycle. On day 5 pembrolizumab 200 mg was administered intravenously (iv). Each cycle was 21 days. The drug combination was given until progression of disease or unacceptable toxicity. Imaging-guided tumor biopsies, ascites, or blood for determining cytokine response and collection of PBMCs were obtained from consenting patients at specific timepoints. Three 18-gauge tumor cores were obtained on C1D1 (day 1 of cycle 1) and C2D8 (day 8 of cycle 2) and the material was immediately snap frozen (~25-50mg/specimen). C1D1 and C2D8 tumor samples were obtained from 11 patients (total of 22 samples). When available, ascites or pleural fluid was centrifuged and fluid and cell pellets were separated prior to cryo-preservation.

本研究旨在描述吉他西滨（guadecitabine）——第二代低甲基化剂（Hypomethylating Agent, HMA）——作为预治疗策略，以低剂量在帕博利珠单抗（pembrolizumab，人源化抗PD1抗体）给药前使用的临床与生物学活性，该临床试验针对复发性铂耐药卵巢癌患者开展。该联合疗法的甲基组学与转录组学效应显示，其可快速激活抗肿瘤免疫应答。对治疗前后采集的外周血单个核细胞（peripheral mononuclear cells, PBMCs）与肿瘤活检样本开展高维免疫表征分析，结果显示与临床获益相关的独特免疫特征与组织架构特征。本研究深入解析了铂耐药卵巢癌的免疫微环境，以及HMAs与帕博利珠单抗联合疗法对免疫细胞群与肿瘤细胞间相互作用的调控效应。本试验为一项非随机、开放标签的两阶段II期临床试验，旨在评估吉他西滨与帕博利珠单抗联合疗法在复发性铂耐药卵巢癌（Ovarian Cancer, OC）患者中的疗效。所有入组患者均为上皮性卵巢癌、输卵管癌或原发性腹膜癌患者，且在末次含铂化疗后6个月内出现肿瘤复发或进展。每21天为一个治疗周期，吉他西滨（G）以30 mg/m²的剂量在周期第1-4天经皮下（subcutaneous, sc）注射给药；第5天给予帕博利珠单抗200 mg静脉（intravenous, iv）输注，每个周期时长为21天。该联合疗法持续给药直至疾病进展或出现不可耐受的毒性反应。在特定时间点从签署知情同意书的患者处采集影像学引导下的肿瘤活检样本、腹水或血液样本，以检测细胞因子应答并收集PBMCs。在周期1第1天（C1D1）与周期2第8天（C2D8）采集3枚18G穿刺肿瘤组织芯，采集后立即置于液氮中快速冷冻（每份样本约25-50mg）。共从11例患者处获取C1D1与C2D8肿瘤样本，总计22份。若可获取腹水或胸腔积液，则先进行离心分离，将上清液与细胞沉淀分开后再进行低温保存。