Leveraging doxorubicin immune-modulation, blood-brain barrier opening, and personalized medicine for effective immunotherapy in glioblastoma. A mechanistic approach and pharmacokinetic trial.

摘要 尽管在部分患者中存在临床前的希望和偶尔的长期(ER)肿瘤生长控制，但抗PD1 检查点阻断(APD1)未能改善胶质母细胞瘤(GBM)的预后。未能证明 抗PD1抗体(APD1)的益处可能归因于1)免疫抑制微环境 免疫原性肿瘤细胞；2)aPD1对血脑屏障(BBB)的穿透不足，无法 达到瘤周肿瘤细胞的浸润性；3)基底膜的分子异质性。在这里我们 系统地应对这些挑战中的每一个。我们的目标是诱导Balstilimab产生强大的抗肿瘤反应 (Agenus Bio)，一种通过小剂量阿霉素调节免疫反应的新型aPD1抗体 之前已经展示过了。为了允许足够的药物组织渗透，我们将暂时扰乱血液-大脑 颅骨植入超声仪(SonoCloud-9)与静脉微泡相关的屏障 (美制/MB)。在我们正在进行的研究和临床试验中，我们已经证明了这种方法的可行性，包括 对强化和非强化组织进行靶向活检，并测量药物组织分布。最后，我们的目标是 识别分子特征，从而能够预测基于以下因素的PD1免疫疗法的益处 我们之前的工作是将MAPK激活(PERK染色)确定为假定的生物标记物。我们将首先 在临床前模型中完善DOX和aPD1的给药顺序。第二，用于核查和 优化我们将在我们的试验的引入阶段治疗一些试点患者。第三，优化的方案将是 对将接受DOX和aPD1 Balstilimab治疗的复发GBM患者进行的多队列研究 (DOX APD1)。主要终点是切除标本和/或周围的肿瘤免疫反应 免疫反应，增强和非增强脑组织中的药物浓度(在 切除时间)和安全性。临床结果和生物标记物是次要终点。四组患者 将在不同时间点开始DOX/aPD1治疗的地方进行检查：诱导(新佐剂，在 切除)；或术中切除，每一项都有或没有US/MB。一种非干预性标准 护理队列将作为对照。我们的建议有三个具体目标：SA1：表征和优化 DOX-aPD1对大鼠肾小球系膜细胞抗肿瘤免疫的影响SA2：确定US/MB对浓度的影响 人脑中的DOX aPD1和GBM的抗肿瘤免疫反应SA3：调查肿瘤是否 PERK/MAPK激活可预测GBM对DOX aPD1的反应。成功完成将决定i) DOX和aPD1的免疫调节价值；II)诱导(切除前)治疗和体内治疗的价值 抗肿瘤免疫反应的评估；iii)血脑屏障开放对aPD1疗效的价值(或不存在)； 以及iv)PERK是否可以预测反应并确定将从治疗中受益的患者。

ABSTRACT Despite preclinical promise and occasional long(er) term tumor growth control in subsets of patients, anti-PD1 checkpoint blockade (aPD1) has failed to improve outcome in glioblastoma (GBM). The failure to demonstrate a benefit to an anti-PD1 antibody (aPD1) may be due to 1) an immunosuppressive microenvironment with few immunogenic tumor cells; 2) insufficient aPD1 penetration across the blood-brain barrier (BBB), which fail to reach the infiltrating tumor cells in the peritumoral brain; and 3) molecular heterogeneity of GBM. Here we systematically address each of these challenges. We aim to elicit robust anti-tumoral response to Balstilimab (Agenus Bio), a novel aPD1 antibody by modulating the immune response by low doses of doxorubicin as has been shown previously. To allow for adequate drug tissue penetration, we will transiently disrupt the blood-brain barrier by a skull implantable ultrasound device (SonoCloud-9) in association with intravenous microbubbles (US/MB). In our ongoing research and clinical trials we have shown the feasibility of this approach including targeted biopsies of enhancing and non-enhancing tissue and measure drug tissue distribution. Lastly, we aim at identifying molecular characteristics that will allow to predict a benefit from aPD1 immunotherapy based on our prior work where we have identified MAPK activation (pERK staining) as a putative biomarker. We will firstly refine the sequence of DOX & aPD1 administration in preclinical models. Second, for verification and optimization we will treat a few pilot patients in the lead-in phase of our trial. Third, the optimized regimen will be tested in a multi-cohort study in patients with recurrent GBM who will be treated by DOX and the aPD1 Balstilimab (DOX+aPD1). Primary endpoints are tumor immune response in the resection specimen and/or peripheral immune response, drug concentrations in enhancing and non-enhancing brain tissue (targeted biopsies at the time of resection) and safety. Clinical outcome and biomarkers are secondary endpoints. Four cohorts of patient will be examined where DOX/aPD1 treatment starts at different time points: Induction (neoadjuvant, prior to resection); or intraoperatively upon resection, each with and without US/MB. A non-interventional standard of care cohort will serve as control. Our proposal has 3 specific aims: SA1: Characterize & optimize the effect of DOX + aPD1 on anti-tumoral immunity in GBM. SA2: Determine the effect of US/MB on the concentration of DOX + aPD1 in the human brain and anti-tumoral immune response in GBM. SA3: Investigate whether tumor pERK/MAPK activation predicts GBM response to DOX + aPD1. Successful completion will determine the i) value of immune modulation by DOX and aPD1; ii) the value of induction (pre-resection) treatment and in vivo evaluation of anti-tumor immune response; iii) the value (or absence thereof) of BBB-opening for aPD1 efficacy; and iv) whether pERK predicts response and identifies patients that will benefit from treatment.