Preclinical drug development in pancreatic cancer

我的实验室旨在通过开发新的癌症药物来解决未满足的医疗需求，为胰腺和其他实体器官癌症患者提供更有效的治疗。过去一年所进行的药物开发项目的科学成果包括：1. metarrestin的临床安全剂量水平的鉴定，metarrestin是一类靶向转移性癌细胞基因组组织的小分子。Metarrestin是一种新型的，一流的小分子抑制剂，对癌细胞的转移表型具有选择性活性。目前，Metarrestin以递增剂量给予晚期恶性肿瘤患者，以确定药物的安全性和耐受性。前6个接受metarrestin治疗的患者队列的PK数据确定了负荷剂量后维持剂量的方案是安全的，其达到了人体等效治疗水平，超过了既往临床前血浆有效性研究的有效水平，并且没有药物蓄积风险。迄今为止，在接受美他瑞司汀治疗的患者中未发生临床剂量限制性毒性。然而，在EKG监测期间观察到2例患者的QTc间期延长，目前将其作为可能与美他瑞汀相关的疑似非预期严重不良反应（SUSAR）进行随访。最近的临床前研究表明，metarrestin通过破坏核仁中的液相-相分离（LPPS）来抑制聚合酶I的转录。LPPS受生物分子缩合物（BMC）调节，其指导rRNA合成、rRNA加工和SSU加工体组装所必需的核仁的独特超微结构。富含嘧啶的非编码转录物（PNCTR）长非编码RNA（lnRNA）的表达水平降低，其是PNC的必需支架并且由聚合酶I转录，导致PNC的解体和PNC组分易位到核质中。PNCTR转录水平、21号染色体上PNCTR基因座的基因组改变、PNC患病率以及参与LPPS调节的核仁蛋白质的固有无序区（IDR）突变目前被评估为预测对metarrestin的反应的生物标志物。认识到metarrestin的成功临床转化对于药物开发的基本过程的教育价值，从最初的高含量筛选测试化合物到拆解PNC，药物化学活动，临床前工作，IND使能研究，到临床测试，NIH FAES课程总结了metarrestin开发转化过程中的关键里程碑，现已进入第三年。2.靶向肿瘤相关巨噬细胞（TAM）上CD 206的基于小分子的先天检查点调节剂的临床前开发和临床转化。我们先前的工作表明，M2样TAM上的甘露糖受体CD 206起免疫检查点的作用。CD 206活化将TAM从促肿瘤、免疫抑制重编程为抗肿瘤、炎性表型，并且CD 206连接能够通过直接癌细胞吞噬作用重振先天性抗肿瘤应答。由于其有限的表达，CD 206是免疫学上的“冷”癌症中的新型癌症免疫疗法的有吸引力的靶标，这些癌症目前通过免疫检查点抑制对T细胞活化没有反应。我们的小组通过对大型化学文库的计算机筛选鉴定了基于苯基-咪唑偶氮[2，3]吡嗪的小分子候选药物NCGC 72，其最近被NCATS的治疗开发分支（TDB）选择用于IND使能研究和临床翻译。NCGC 72在鼠和人临床前癌症模型中诱导肿瘤消退。NCGC 72具有有限的脱靶活性，并在临床前安全性和毒性研究中显示出较大的治疗窗口。NCGC 72目前正在一项专门的I/II期研究中评估其在荷肉瘤犬中的安全性、耐受性和疗效。在TDB、NCATS接受NCGC 72作为临床候选药物后，已开始生产用于GLP安全性和毒代动力学研究的GMP原料药以及用于人体I期试验的临床级产品，预计将于2025年提交IND申请，并于2026年开始临床试验。另外的临床前工作集中于NCGC 72的双重作用机制：（1）M2样巨噬细胞杀伤和（2）通过诱导I型干扰素应答将交替活化的M2样TAM重编程为促炎表型。目前的作用机制研究已经表明，阻断NCGC 72介导的M2样细胞杀伤招募TAM用于增强重编程、癌细胞吞噬和肿瘤控制，并且由NCGC 72触发的I型干扰素应答（其对于M2至M1样转换是必需的）诱导选择数量的表观遗传变化，从而释放对交替激活的启动子和增强子的闭合染色质的抑制，类似M2的TAM。目前的工作扩展了这些发现，正在研究（1）免疫肿瘤学药物与NCGC 72的药物组合设计原理，以及（2）选择最可能对NCGC 72有反应的肿瘤的分子标记物。最近有报道称，CD 206阳性巨噬细胞介导非恶性疾病（如眼病或II型糖尿病）的致病过程，我们之前在增殖性糖尿病视网膜病变的临床前模型中评估了NCGC 72。NCGC 72实质上减少视网膜下纤维化和硫酸中毒，这是糖尿病视网膜病变中的致盲原因。为了进一步扩展NCI专有的CD 206小分子技术NCGC 72用于治疗非恶性疾病的可能适应症，我们目前正在非酒精性脂肪性肝病（NAFLD）和肝纤维化的临床前模型中评估NCGC 72。

My laboratory aims to address the unmet medical need for more effective treatments for patients afflicted by pancreas and other solid organ cancers by developing new cancer drugs. Scientific achievements with regard to the pursued drug development projects in the last year include: 1. Identification of a clinically safe dose level of metarrestin, a first-in-class small molecule targeting genome organization in metastatic cancer cells. Metarrestin is a novel, first-in-class small molecule inhibitor with selective activity against the metastatic phenotype of cancer cells. Metarrestin is currently administered to patients with advanced malignancies in escalating doses to determine safety and tolerability of the drug. PK data from the first six cohorts of patients treated with metarrestin identified a regimen of a loading dose followed by a maintenance dose as safe, which achieves human-equivalent therapeutic levels exceeding efficacious levels of prior preclinical efficacy studies in plasma and do not carry risk(s) of drug accumulation. No clinical dose-limiting toxicities have occurred so far in patients treated with metarrestin. However, two patients had prolongations of their QTc intervals observed during EKG monitoring which are currently followed as possible metarrestin-related suspected unexpected serious adverse reaction (SUSAR). Recent preclinical work has shown that metarrestin inhibits polymerase I transcription via disruption of liquid phase-phase separation (LPPS) in the nucleolus. LPPS is regulated by biomolecular condensates (BMCs) which direct the unique ultrastructure of the nucleolus necessary for rRNA synthesis, rRNA processing, and the assembly of the SSU processome. Reduced expression levels of the pyrimidine-rich non-coding transcript (PNCTR) long non-coding RNA (lnRNA), which is an essential scaffold of the PNC and which is transcribed by polymerase I, leads to disassembly of the PNC and translocation of PNC components into the nucleoplasm. PNCTR transcript levels, genomic alterations of the PNCTR locus on chromosomes 21, PNC prevalence as well as mutations in intrinsically disordered regions (IDRs) of nucleolar proteins which are involved in the regulation of LPPS are currently evaluated as biomarkers to predict response to metarrestin. Recognizing the educational value of the successful clinical translation of metarrestin for essential processes of drug development from the initial high-content screen testing chemical compounds to disassemble the PNC, the medicinal chemistry campaign, preclinical work, IND enabling studies, to clinical testing, a NIH FAES course summarizing key milestones in translational processes of metarrestin's development has been designed and is now in its third year. 2. Preclinical development and clinical translation of small molecule-based innate checkpoint modulators targeting CD206 on tumor associated macrophages (TAMs). Prior work of ours has shown that the mannose receptor CD206 on M2-like TAMs functions as an immune checkpoint. CD206 activation reprograms TAMs from a pro-tumor, immune suppressive to an anti-tumor, inflammatory phenotype and CD206 ligation is able to reinvigorate innate anti-tumor responses via direct cancer cell phagocytosis. Due to its restricted expression, CD206 is an attractive target for novel cancer immunotherapy in immunologically 'cold' cancers which currently do not respond to T cell activation via immune checkpoint inhibition. Our group has via in silico screening of large chemical libraries identified a phenyl-imidoazo[2,3] pyrazine-based small molecule drug candidate, NCGC72, which has recently been selected for IND enabling studies and clinical translation by the Therapeutic Development Branch (TDB), NCATS. NCGC72 induces tumor regressions in murine and human preclinical cancer models. NCGC72 has limited off-target activity and showed a large therapeutic window in preclinical safety and toxicity studies. NCGC72 is currently evaluated in a dedicated phase I/II study for safety, tolerability, and efficacy in sarcoma-bearing dogs. After acceptance of NCGC72 as a clinical candidate by the TDB, NCATS, manufacturing of GMP drug substance for both GLP safety and toxicokinetic studies and clinical grade product for human phase I testing has commenced with IND filing estimated in 2025 and start of clinical testing in 2026. Additional preclinical work has focused on NCGC72's dual mechanism of action of (1) M2-like macrophage killing and (2) the reprogramming of alternatively activated, M2-like TAMs into a proinflammatory phenotype via the induction of an interferon type I response. Current mechanism of action studies have shown that blockade of NCGC72-mediated M2-like cell killing recruits TAMs for enhanced reprogramming, cancer cell phagocytosis, and tumor control, and that the interferon type I response triggered by NCGC72, which is essential for M2-to-M1-like switching, induces a select number of epigenetic changes releasing repression of closed chromatin of promotors and enhancers in alternatively activated, M2-like TAMs. Current work expanding on these findings is studying (1) rationale designed drug combinations of immuno oncology agents with NCGC72, and (2) molecular markers to select tumors most likely to respond to NCGC72. Spurned by recent reports that CD206 positive macrophages mediate disease-causing processes in non-malignant conditions like eye disease or type II diabetes, we previously evaluated NCGC72 in a preclinical model of proliferative diabetic retinopathy. NCGC72 substantially reduced sub-retinal fibrosis and vitriol hemorrhages, causes of blindness in diabetic retinopathy. To extend possible indications of NCI's proprietary CD206 small molecule technology NCGC72 for the treatment of non-malignant diseases further, we are currently evaluating NCGC72 in a preclinical model of nonalcoholic fatty liver disease (NAFLD) and liver fibrosis.