ERAP1

不知不觉，肿瘤免疫治疗进入市场已经有十几年光景，虽然不至于“飞入寻常百姓家”，但也不再是“已恨碧山相阻隔，碧山还被暮云遮”。此前小编发布过CAR-T细胞疗法的10年随访数据，表明血液瘤患者在CAR-T细胞治疗后可以得到长期缓解。那么在肿瘤免疫治疗领域，除了细胞免疫治疗，还有免疫检查点治疗。免疫检查点抑制剂（ICIs）的临床成功改善了癌症治疗，但仅在一部分患者中实现了长期持久的缓解。2023年6月，美国俄亥俄州克利夫兰癌症中心发表于Nature的临床评论文章，从肿瘤抗原呈递机制（APM）出发，解释ICI临床结果差异的原因，从而指导更精确的免疫疗法，也为新免疫疗法指明新方向。   01  ICIs的临床成功改善了癌症治疗目前上市的ICI主要是CTLA-4抑制剂和PD-1/PD-L1抑制剂。2010年，BMS的抗CTLA4单克隆抗体Ipilimumab的疗效在黑色素瘤患者中首次得到证实，并于次年获得FDA批准。几种靶向PD-1/PD-L1的抗体，如Merck的Pembrolizumab（2014），Roche的Atezolizumab（2016），AstraZeneca的Durvalumab（2017），随后也陆陆续续被获批用于临床应用。ICI适应症广泛，包括黑色素瘤、肺癌、肾细胞癌、头颈癌、膀胱癌、食管癌和某些类型的乳腺癌。表1：全球上市的免疫检查点抑制剂药物基本情况ICI最初用于转移性癌症患者，现在已在辅助和维持治疗环境中显示出临床实用性。2019年FDA批准抗PD-1抗体用于高肿瘤突变负荷（TMB）的实体瘤患者，因为有不少研究指出，具有高TMB的肿瘤对ICIs更敏感。值得关注的是，2022年，抗PD-1抗体Dostarlimab的单药治疗在具有缺陷错配修复（dMMR）的直肠癌患者的Ⅱ期试验中产生了100%的完全缓解率。  02  肿瘤细胞的抗原处理和呈递机制MHC I和MHC II是两个主要的MHC，由人类HLA基因编码，在脊椎动物进化上是保守的，但有几个高度多态的区域，如肽结合槽。所以HLA位点是人类基因组中最多态性区域之一。每个个体中有6个HLA-I等位基因，每个HLA-I分子的独特抗原偏好以及HLA-I同种异型的组合，塑造了每个患者肽选择和呈现的巨大多样性（图1）。 图1：HLA-I 种系变异肿瘤细胞抗原处理从蛋白酶体介导内源性蛋白质降解开始(图2):第一步，获得成熟的抗原肽。细胞因子（如IFNγ）诱导蛋白酶体的表达，组成免疫蛋白酶体，降解蛋白得到抗原肽。抗原肽通过与抗原加工（TAP）复合物相关的转运蛋白转运到内质网腔中，经过内质网氨基肽酶1（ERAP1）和ERAP2修剪。第二步，获得成熟的MHC I复合物。MHC I类（MHC I），β2-微球蛋白（B2M），Tapasin，ERp57以及钙网蛋白（Calreticulin）一起形成肽负载复合物（PLC），促进MHC I折叠，获得由MHC I和B2M组成的MHC I复合物。第三步，形成肽-MHC I复合物。随后抗原肽加载到MHC I复合物的肽结合槽中。然后，稳定的肽-MHC I复合物从PLC中解离，通过高尔基体运输到细胞表面。一旦呈现在肿瘤细胞表面，结合的肽就可以被CD8 T细胞的T细胞受体（TCR）识别，产生免疫反应。 图2：肿瘤细胞中抗原处理和呈递机制。（图中标⭐是肿瘤细胞在ICIs治疗中改变的部分）  03  抗原呈递和ICI的不良临床反应息息相关个体对ICI的治疗反应是高度可变的，并且ICI仅在一小部分患者中实现了长久的疾病控制。此外，ICI可引起急性和慢性免疫相关不良事件，包括多器官损伤，甚至某些患者死亡。因此准确预测ICI临床反应的生物标志物，有助于探明耐药机制，调整患者的精准治疗。3.1 B2M功能丧失使肿瘤细胞能够逃避免疫监视，导致对ICI的耐药性B2M的功能丧失是抑制MHC I抗原呈递的有效方法。一项研究将黑色素瘤患者经Pembrolizumab治疗后复发的肿瘤组织与治疗前进行基因组分析：一名患者的B2M存在耐药特异性截断突变，另外两名患者存在JAK1或JAK2功能丧失突变。与基线肿瘤样本相比，纯和移码B2M缺失导致复发肿瘤中MHC I重链的外膜定位丢失。一项类似的涉及14个ICI耐药肺癌样本的研究发现，一个样本中存在纯合子B2M丢失，另外两个样本中B2M表达下调。3.2 HLA进化多样性（HED）预测ICI临床反应在接受单药ICI治疗的170例NSCLC患者中，HLA-I位点的纯和性与更差的OS和PFS结局相关，这种影响在65岁、ECOG状态高或者PD-L1肿瘤比例评分≥50%的患者中更为突出。从机制上讲高HED可能会增加病毒、自身和新抗原肽的多样性（图3）。HED在ICI反应中的临床意义已得到独立验证，HED与TMB联合使用可提高任一特征的预测能力。 图3：MHC介导的抗原呈递塑造肿瘤免疫肽3.3 HLA-I和HLA-II基因的差异表达改变肿瘤免疫原性基于免疫表达特征，大多数具有免疫原性活性的肿瘤中HLA-I基因上调；而获得最佳临床结果的炎症免疫亚型肿瘤中出现HLA-II基因的过表达。从治疗角度看，有43%的黑色素瘤患者，肿瘤细胞上缺少MHC I表达，导致患者对抗CTLA4抗体耐药，这与HLA-I基因或B2M的潜在转录抑制有关。MHC II在1%的黑色素瘤患者的肿瘤细胞中检测到表达，与抗PD-1的临床反应有关。以上观察结果可能反映了MHC I和MHC II对ICI的反应涉及不同的信号通路。另一项涉及黑色素瘤患者的研究表明，那些对抗PD-1抗体作为单一疗法有持久反应的患者肿瘤组织都表达完整的MHC I复合物；而MHC I表达不完整的肿瘤，则呈现T细胞浸润减少的微环境。肿瘤细胞MHC II表达可以预测有利的临床结果，比如改善黑色素瘤患者和接受抗PD-1和抗PD-L1抗体的经典霍奇金淋巴瘤患者的反应率、PFS和OS。  04  抗原呈递和抗原靶向工程——开发新治疗方案抗原加工和呈递的改变对于ICI治疗后的治疗反应和患者结局至关重要，鉴于患者之间的肿瘤异质性，文章已探索了一系列预测性生物标志物对各类癌症患者ICI临床反应的影响，用机器学习和/或深度学习增强这些预测工具的临床效用。根据预测的治疗反应对癌症患者进行适当的分层，指导精准免疫疗法的开发，提供最大的临床疗效，同时最大程度降低不良事件的风险。 图4：癌症特异性变异在抗原呈递中的临床应用所以除了抗CTLA4和抗PD-1或抗PD-L1抗体之外，抗原加工和呈递机制可以为开发创新的治疗方案，提供新的见解（图4）。4.1 合理的组合策略4.1.1 多个ICI的联合与单独使用Nivolumab相比，将其与Relatlimab（一种靶向淋巴细胞活化基因3（LAG3）的单克隆抗体）联用，已被证明可以延长初治晚期黑色素瘤患者的PFS持续时间，所以FDA在2022年批准了这种联合疗法。而且这种组合下，有3-4级治疗相关不良事件的患者为18.9%，远低于在同一情况下使用Ipilimumab+Nivolumab的比例（59%），反映了这种联合用药有更好的安全性。4.1.2 靶向治疗和ICI的组合通过逆转免疫抑制的分子机制来提供协同活性。例如，靶向Wee1样蛋白激酶（WEE1）的抑制剂，激活人类内源性逆转录病毒（HERV）表达和双链RNA病毒防御途径，上调免疫信号传导和抗原呈递，从而提高临床前模型对ICI的敏感性。在APM失调的肿瘤中，第一代ICI的临床疗效可能有限，联合这种新靶点或许能提高临床成功几率。4.2第二代ICI除了靶向LAG3的药物外，目前针对其他新型抑制性免疫检查点疗法的临床试验正在进行，例如TIM3（NCT02817633）、NKG2A（NCT04752215）等。4.3 开发蛋白质降解剂图5：PROTAC蛋白降解剂ARV-471（NCT05654623）调节抗原加工和呈递的另一种策略是开发蛋白水解靶向嵌合体，也称为蛋白质降解剂。这是一类异型双功能小分子，可将内源性E3泛素连接酶与靶蛋白紧密接近，并诱导随后反诉介导的蛋白质降解。这些降解剂可以增强MHC I上靶蛋白衍生肽的呈递，将T细胞招募到肿瘤细胞，可以协同ICI治疗。部分降解剂已进入早期临床试验（例如，NCT05654623和NCT04886622）。4.4 开发特异性靶向肽-MHC复合物的TCR样抗体 图6：T细胞受体(TCR)和TCR样抗体示意图与传统的基于抗体的疗法（通常仅限于细胞表面的蛋白质靶标）相比，TCR样抗体可识别源自特定MHC分子呈递的细胞内蛋白质的肽。在生化水平上，工程化的TCR样抗体对特定MHC复合物的亲和力水平比野生型高约1000倍，表明了其巨大的治疗潜力。4.5 制造工程T细胞 图7：基于T细胞的scFv生成系统产生具有卓越抗肿瘤功能的CAR-T细胞TCR样抗体可用于制造工程T细胞，靶向肿瘤细胞上过表达或包含肿瘤特异性突变的独特肽抗原。设计用于表达2D2 scFV的第二代CAR-T细胞能够在三阴性乳腺癌和黑色素瘤小鼠模型中识别和消除表达NY-ESO-1的肿瘤。4.6 双特异性抗体 图8：双特异性抗体结构示意图TCR样抗体可用于产生双特异性抗体，比如靶向RAS。双特异性分子既能募集T细胞，又能促进针对缺乏MHC I介导的抗原呈递肿瘤的免疫应答。许多此类药物正在进行临床试验，例如NCT04082364、NCT03321981和NCT05577182。  总结免疫系统能够通过识别非自身抗原来检测和根除恶性细胞。肿瘤细胞的抗原加工和呈递对于T细胞的活化和对ICI的持久临床反应至关重要。研究揭示了肿瘤抗原呈递机制（APM）的成分和肿瘤细胞中基因畸变对免疫疗法的反应有决定性作用。但仍然存在一些挑战，我们尚未了解APM成分的多种变化如何结合影响免疫原性，癌细胞如何调节各种AMP成分的表达，以及如何将这些信息用作治疗的生物标志物。路漫漫其修远兮，还需要大量的研究工作，全面动态地把握抗原呈递的机制，以便在癌症患者中更精确地使用免疫疗法。参考资料：[1] Yang, K., Halima, A. & Chan, T.A. Antigen presentation in cancer — mechanisms and clinical implications for immunotherapy. Nat Rev Clin Oncol 20, 604–623 (2023).[2] Ochi, T., Maruta, M., Tanimoto, K. et al. A single-chain antibody generation system yielding CAR-T cells with superior antitumor function. Commun Biol 4, 273 (2021).为促进抗体行业的交流与创新，2023年10月14-15日第六届金秋十月抗体产业发展大会如约而至。会议旨在为研究人员提供一个互动交流的平台，有助于推动抗体产业的进一步发展。会议内容时间：2023年10月14-15日地点：苏州（酒店定向通知）规模：600-800人主办单位：生物制品圈、抗体圈指导单位：康维讯生物、夏尔巴生物会议费用：免费FREE!（仅收取50元报名定金，含参会学习、茶歇、会议手册，定金概不退还），9月15日报名定金提高到100元，先到先得，报完即止，超过9月20日预登记将收取会议费！报名方式：扫描下方二维码或点击文章最底部“阅读原文”→ 填写表格 → 报名成功（报名志愿者，承担一定工作，请慎重考虑，免交定金）！组委会获得报名信息后，根据报名信息进行初筛，并进一步与报名者沟通确认，实现精准邀请。最终有机会进入大会微信群（严格审核通过）。日程安排更多嘉宾仍在邀请中。。。。。。识别微信二维码，添加生物制品圈小编，符合条件者即可加入生物制品微信群！请注明：姓名+研究方向！版权声明本公众号所有转载文章系出于传递更多信息之目的，且明确注明来源和作者，不希望被转载的媒体或个人可与我们联系(cbplib@163.com)，我们将立即进行删除处理。所有文章仅代表作者观点，不代表本站立场。

New Data Demonstrate Ability of ERAP1 Inhibition to Generate and Upregulate Cancer Antigens to be Targeted by MHC Class I Directed T Cell Receptor Bispecific Therapies First-in-Class ERAP1 Inhibitor Drives Improved Potency and Magnitude of Anti-Tumour Activity of an Immunocore TCR Bispecific ImmTAC® Therapy OXFORD, England, April 17, 2023 /PRNewswire/ -- Grey Wolf Therapeutics, a biotechnology company focused on generating entirely novel anti-tumour immune responses through targeted cancer neoantigen creation, today announced the presentation of new preclinical data on the company's potential first-in-class inhibitors of ERAP1 at the American Association of Cancer Research (AACR) Annual Meeting 2023. Presented data highlighted the ability of the company's ERAP1 inhibitors to generate and upregulate cancer antigens, creating novel therapeutic targets for combination with MHC Class I directed therapies, including an investigational T cell receptor (TCR) bispecific therapy. The study results were featured in an oral presentation (#3467) entitled, "First-in-class inhibitors of ERAP1: Generating antigens as novel targets for MHC1-directed therapies," at the AACR annual meeting, being held April 14-19, 2023, in Orlando, Florida. Grey Wolf Therapeutics' unique therapeutic strategy is centered on generating entirely novel immune responses against tumours thereby overcoming key resistance mechanisms to current immuno-oncology therapy such as poor tumour recognition by T cells and T cell exhaustion. This is achieved through targeted inhibition of the endoplasmic reticulum aminopeptidases (ERAP1 or ERAP2), which drives the generation and presentation of novel and potent cancer antigens to the surface of tumour cells, in turn eliciting a de novo T cell response against tumours. The presented findings included results from a preclinical research collaboration between Grey Wolf Therapeutics and Immunocore (Nasdaq: IMCR) which evaluated the combination of ERAP1 inhibition, a potential first-in-class mechanism, and an investigational MHC Class I directed TCR bispecific therapy (ImmTAC®). Data showed that ERAP1 inhibition upregulated, across multiple cancer types, the surface presentation of the ACTL8 cancer peptide that is targeted by the ImmTAC therapy. This drove an improvement in the potency and magnitude of cancer cell line killing of the ACTL8-targeted ImmTAC in translationally relevant primary human co-culture assay systems. This preclinical research lays the foundation for broadening the potential of ERAP inhibition, demonstrating that upregulated and new cancer antigens created with ERAP1 inhibition can generate novel targets for MHC Class I directed therapies. "Grey Wolf continues to generate compelling preclinical data that support the therapeutic potential of ERAP1 inhibition in the treatment of cancer. These latest research findings reported at AACR are notable as they offer a promising glimpse into the potential of our clinical stage ERAP1 inhibitor, GRWD5769, to significantly enhance the therapeutic activity of MHC Class I directed therapies such as TCR bispecifics like Immunocore's ImmTAC therapy used in the research collaboration. This is just the latest anti-tumour therapeutic modality, joining immune checkpoint inhibitors, that we have shown the ability to enhance with our novel approach to immuno-oncology," said Peter Joyce, Ph.D., chief executive officer of Grey Wolf Therapeutics. "Our growing data collection, which consistently spotlights the impact of ERAP1 inhibition on neoantigen generation, differentiated T cell response and tumour growth inhibition, provides us with great optimism for our recently initiated first-in-human clinical trial of GRWD5769. Furthermore, we are leveraging these latest preclinical findings to drive further research into the ability of our ERAP1 inhibition platform to identify entirely novel therapeutic cancer antigens, which has the potential to support new internal and collaborative drug discovery and development efforts." About Grey Wolf Therapeutics Grey Wolf Therapeutics is a UK- and Australian-based drug discovery and development biotechnology company spearheading a new therapeutic approach in immuno-oncology. The company's first-of-its-kind immuno-oncology approach is centered on inhibiting the endoplasmic reticulum aminopeptidases (ERAP1 or ERAP2), which play a key role in the antigen presentation pathway. Inhibiting ERAP1 or ERAP2 generates novel cancer antigens and upregulates certain other neoantigens, resulting in the mobilisation of an entirely novel T cell response against the tumour that increases tumour visibility where current therapies are ineffective, and bypasses the challenge faced by current immunotherapy when once anti-tumourigenic T cells become irreversibly exhausted and hence ineffective. Based on this approach, the company is developing a portfolio of potentially first-in-class small molecules that inhibit ERAP1 or ERAP2. The company's clinical candidate, GRWD5769, is a potent and selective ERAP1 inhibitor that is currently being evaluated in a Phase 1/2 clinical trial. A second program, focused on ERAP2 inhibition, is advancing through the discovery process. The company is also leveraging its leadership in neoantigen creation to unlock entirely novel cancer antigens that can be targeted with MHC Class I directed therapies, such as soluble T cell receptor (TCR) and TCR mimic bispecifics. For more information, please visit: Contacts: Grey Wolf Therapeutics Peter Joyce Chief Executive Officer +44 (0) 01865 292 038 enquiries@gwt.bio Vida Strategic Partners (on behalf of Grey Wolf Therapeutics) Tim Brons (Media) 415-675-7402 tbrons@vidasp.com Company Codes: NASDAQ-NMS:IMCR

First-in-Class ERAP1 Inhibitor Enters Clinical Development Study to Evaluate GRWD5769 as Monotherapy, as well as in Combination with PD-1 Inhibitor Libtayo® (cemiplimab) OXFORD, UK and MELBOURNE, AUSTRALIA, March 28, 2023 /PRNewswire/ -- Grey Wolf Therapeutics, a biotechnology company focused on generating entirely novel anti-tumour immune responses through targeted cancer neoantigen creation, today announced dosing of the first patient in the initial monotherapy module of an adaptive Phase 1/2 clinical trial evaluating GRWD5769, the company's investigational first-in-class ERAP1 inhibitor. The trial, named EMITT-1 (ERAP Mediated Immunopeptide Targeting Trial – 1), is a modular multi-part, multi-arm open-label study designed to evaluate the safety, tolerability, preliminary efficacy and pharmacokinetics of GRWD5769 alone and in combination with Regeneron's PD-1 inhibitor Libtayo® (cemiplimab) in patients with advanced solid tumours. While the potential for ERAP1 inhibition is broad and the study will include patients across different solid tumours in both the GRWD5769 monotherapy and GRWD5769/Libtayo® combination modules of the trial, a particular focus will be on patients with virally associated solid tumours, such as head and neck squamous cell carcinoma, cervical cancer, and hepatocellular carcinoma, as Grey Wolf's analysis of publicly available patient data suggests these could be particularly sensitive to ERAP1 inhibition. Regeneron is providing Libtayo® for the trial as part of a clinical supply agreement. "We are proud to announce our advancement of GRWD5769 into the clinic as this reflects a critical first step in our evaluation of this first-in-class ERAP1 inhibitor. We have strategically designed this initial clinical study with an adaptive, modular framework to assist in the generation of the most informative data set possible," said Peter Joyce, Ph.D., chief executive officer of Grey Wolf Therapeutics. Grey Wolf Therapeutics' unique therapeutic strategy is centered on generating entirely novel immune responses against tumours thereby overcoming key resistance mechanisms to current immuno-oncology therapy such as poor tumour recognition by T cells and T cell exhaustion. This is achieved through targeted inhibition of the endoplasmic reticulum aminopeptidases (ERAP1 or ERAP2), which drives the generation and presentation of novel and potent cancer antigens to the surface of tumour cells, in turn eliciting a de novo T cell response against tumours. About Grey Wolf Therapeutics Grey Wolf Therapeutics is a UK- and Australian-based drug discovery and development biotechnology company spearheading a new therapeutic approach in immuno-oncology. The company's first-of-its-kind immuno-oncology approach is centered on inhibiting the endoplasmic reticulum aminopeptidases (ERAP1 or ERAP2), which play a key role in the antigen presentation pathway. Inhibiting ERAP1 or ERAP2 generates novel cancer antigens and upregulates certain other neoantigens, resulting in the mobilisation of an entirely novel T cell response against the tumour that increases tumour visibility where current therapies are ineffective, and bypasses the challenge faced by current immunotherapy when once anti-tumourigenic T cells become irreversibly exhausted and hence ineffective. Based on this approach, the company is developing a portfolio of potentially first-in-class small molecules that inhibit ERAP1 or ERAP2. The company's clinical candidate, GRWD5769, is a potent and selective ERAP1 inhibitor that elicits a powerful and differentiated immune response against the tumour pre-clinically. Further information about the initial Phase 1/2 clinical trial of GRWD5769 can be found by searching trial registration number ACTRN12623000108617 on the Australian New Zealand Clinical Trial Registry (). A second program, focused on ERAP2 inhibition, is advancing through the discovery process. The company is also leveraging its leadership in neoantigen creation to unlock entirely novel cancer antigens that can be targeted with MHC Class I directed therapies, such as soluble T cell receptor (TCR) and TCR mimic bispecifics. For more information, please visit: Contacts: Grey Wolf Therapeutics Pty Ltd Bio101, Suite 201/697 Burke Road Camberwell, VIC 3124 +61 8 6186 1875 [email protected] Grey Wolf Therapeutics Limited Peter Joyce Chief Executive Officer +44 1235 644970 [email protected] Vida Strategic Partners (on behalf of Grey Wolf Therapeutics) Tim Brons (Media) +1 415 675 7402 [email protected] SOURCE Grey Wolf Therapeutics