EP4

J Hematol Oncol.(一) 类花生酸(Eicosanoid)信号通路：二十烷基硫酸酯信号通路在生理过程和病理过程中都起着关键作用，通过类花生酸将炎症与癌症联系起来。二十碳多不饱和脂肪酸(PUFAs)是由20碳多不饱和脂肪酸(PUFAs)氧化而成的具有高度生物活性的衍生物，可通过环氧合酶(COX)、脂氧合酶(LOX)和细胞色素P450途径产生。COX途径产生前列腺素(PGs)和血栓素A(TXs)，而LOX途径则产生白三烯(LTs)和脂氧素(LXs)。COX信号通路COX家族中，COX-2的表达会受到早期炎症(proinflammatory)的上调，并被发现和调控多种肿瘤的进展相关。在炎症反应的早期阶段，COX-2衍生的PG被认为具有促炎功能。前列腺素D2、前列腺素E2、前列腺素F2α、前列腺素I2和血栓素A2是通过COX通路衍生的五种关键 PG。COX/PEG2COX-2/CSK3β信号还和上皮-间充质转化有关，通过抑制GSK3β来促进E-钙粘蛋白、β-连环蛋白和p120连环蛋白的蛋白质稳定性。抑制COX-2可以下调E-钙黏蛋白导致细胞死亡。PGE2通过其两种E-前列腺素受体EP2和EP4提供信号传导来塑造DC功能。EP4调节CD80、CD86、CD83、MHC II等激活标志物上调以及IL-10和IL-23的产生，引导cDC2成熟，促进T细胞扩增，形成抑制性而非促炎性T细胞群富集。PGE2还可能通过E2调节NK细胞合成IFN-γ来诱导免疫抑制，从而促进肿瘤的发生。肿瘤来源的前列腺素E2(PGE2)介导MDSC分化和获得促肿瘤特征。在PGE2暴露期间，EP2/4联合阻断M-MDSCs可防止这些抑制特征的发生。双重 EP2/EP4 PGE2受体拮抗剂增加了肿瘤微环境淋巴细胞浸润，并显着降低了多种肿瘤模型中的疾病负担。前列腺素D2则是COX-2的另一种代谢物，可能在慢性炎症和癌症中发挥双重作用。PGD2与其受体PTGDR2之间的相互作用抑制了胃癌细胞的自我更新，并减弱了胃癌的生长和转移。脂氧合酶(LOX)信号通路LOX通路负责将花生四烯酸代谢为白三烯，包括白三烯A4(LTA4)、LTB4和LTD4等。炎症细胞(包括白细胞、巨噬细胞和肥大细胞)是白三烯的主要来源。抑制LTB4受体可抑制炎症相关肿瘤的进展，LTD4则在肝细胞癌和慢性乙型肝炎患者的循环中上调。LOX途径主要包括5-LOX、12-LOX和15-LOX。5-LOX在上皮性癌和淋巴瘤中高度表达，具有促血管生成和促肿瘤活性。12-LOX通过激活整合素连接的激酶/NF-κB途径来促进肿瘤的生长。而15-LOX的代谢产物被发现能增强肿瘤相关炎症，既有促肿瘤作用又有抗肿瘤作用。另一种由LOX衍生的类花生酸脂毒素(lipoxins， LXs)则具有抗肿瘤作用。在前列腺癌中，LXA4通过抑制METTL3和或FPR2/IRF4途径，以促进巨噬细胞M2样极化。LXA4对炎性巨噬细胞极化的抑制作用与p-NF-κB p65和IRF5活性的下调有关，从而降低了LPS诱导的M1巨噬细胞通过FPR2/IRF5信号通路的表型和功能极化。 J Hematol Oncol.(二)JAK/STAT信号通路STAT3在炎症反应和肿瘤进展中发挥着广泛的作用。多种生长因子和细胞因子参与典型的STAT3通路，调节细胞分化、血管生成和肿瘤形成。IL-6和STAT3是启动肿瘤的肠上皮细胞生存和增殖所必需的。此外，在设计肠道的肿瘤如前列腺癌中，肠道生物失调增加了肠道通透性，肿瘤内的内毒素通过NF-κB/IL 6/STAT3轴促进了肿瘤的进展。Int Immunopharmacol.影响JAK/STAT通路的药物种类复杂，包括植物化学物质、合成药物和生物分子等等。Int Immunopharmacol.(三)金属代谢铁和ROS氧化还原铁代谢失调是肿瘤细胞的一个重要标志，在肿瘤细胞中，恶性肿瘤细胞需要大量的铁来生存和增殖。细胞色素P450酶、一氧化氮合酶、NADPH氧化酶和脂氧合酶等铁依赖性酶参与ROS的产生。同时，谷胱甘肽过氧化物酶GPX4是一种铁死亡的中枢抑制剂，GPX4利用还原性谷胱甘肽将活性的PUFA-PL-OOH还原为非活性和非致死性的PUFA-PL-OH。抑制Gpx4可通过诱导铁性死亡而增强治疗的抗肿瘤效应。十年铁死亡：双向调控与药物开发锌和NF-κB通路锌与许多炎症性细胞因子的产生和信号传递有关。当对应激刺激做出急性反应时，血浆锌浓度迅速下降。人体的锌代谢与ZIP8等锌转运蛋白的活性密切相关。在感染过程中，激活的NF-κB增加ZIP8的表达，ZIP8定位于细胞膜并调节锌的摄取。锌抑制了IKKβ的活性，从而减弱了炎症反应。参考文献：1.Wang M, Chen S, He X, Yuan Y, Wei X. Targeting inflammation as cancer therapy. J Hematol Oncol. 2024 Mar 22;17(1):13. doi: 10.1186/s13045-024-01528-7.2.Balamurugan K,et al.Stabilization of E-cadherin adhesions by COX-2/GSK3β signaling is a targetable pathway in metastatic breast cancer. JCI Insight. 2023 Mar 22;8(6):e156057. doi: 10.1172/jci.insight.156057.3.Cuenca-Escalona J,et al.PGE2-EP4 signaling steers cDC2 maturation toward the induction of suppressive T-cell responses. Eur J Immunol. 2024 Mar;54(3):e2350770. doi: 10.1002/eji.202350770.4.Francica BJ,et al.Dual Blockade of EP2 and EP4 Signaling is Required for Optimal Immune Activation and Antitumor Activity Against Prostaglandin-Expressing Tumors. Cancer Res Commun. 2023 Aug 8;3(8):1486-1500. doi: 10.1158/2767-9764.CRC-23-0249.5.Yuan J, et al. Lipoxin A4 regulates M1/M2 macrophage polarization via FPR2-IRF pathway. Inflammopharmacology. 2022 Apr;30(2):487-498. doi: 10.1007/s10787-022-00942-y.6.Wang Y,et al. Deciphering JAK/STAT signaling pathway: A multifaceted approach to tumorigenesis, progression and therapeutic interventions. Int Immunopharmacol. 2024 Mar 22;131:111846. doi: 10.1016/j.intimp.2024.111846.·····

- DT-9045 is a game-changer in immuno-oncology with competitive pharmacological properties and unique therapeutic potential to unlock new cancer treatment possibilities - Preclinical studies highlight the efficacy of DT-9045 in overcoming resistance to EGFR-targeting therapies and immunotherapy in cancer models - IND-enabling studies are currently ongoing STRASBOURG, France & MONTREAL & BOSTON--(BUSINESS WIRE)-- Domain Therapeutics (“Domain” or “the Company”), a global clinical-stage biopharmaceutical company developing innovative drug candidates in immuno-oncology targeting G Protein-Coupled Receptors (GPCRs), today announces that latest preclinical data on DT-9045, a novel protease-activated receptor 2 (PAR2) Negative Allosteric Modulator candidate, will be presented at the American Association for Cancer Research (AACR) Annual Meeting 2024 in San Diego, California. Date/Time: 7 April 2024 1:30 PM - 5:00 PM PST – Section 27 Abstract number: 684 / 30 Poster session: PO.ET09.05 - Novel Antitumor Agents 2 Title: DT-9045, a novel PAR2 inhibitor with best-in-class properties that reduces resistance to both EGFR-targeting therapies and immunotherapy in oncology models The abstract will be made available in the online Proceedings of the AACR. PAR2 is one of the genes most significantly linked to resistance against immune checkpoint blockage (ICB) and T cells dysfunction in cancer patients. Its upregulation across a variety of cancer types and expression on diverse cells within the tumor microenvironment underscore PAR2’s critical role in cancer development. Leveraging its integrated precision research approach, backed by over 20 years of solid GPCR expertise, Domain has developed a novel highly potent and selective PAR2 inhibitor, DT-9045. This first-in-class Negative Allosteric Modulator has shown unparalleled potential in oncology and immuno-oncology. Remarkably, when compared to its most advanced competitors positioned in other therapeutic areas, this candidate has demonstrated clear differentiated features. Moreover, several proof-of-concept studies have shown strong potency in models resistant to EGFR-targeting therapies and immunotherapy opening solid perspectives of strategic clinical positioning and revenues generation in tumor types that constitute a high medical unmet need. DT-9045 is a small molecule, orally available, insurmountable, biased, and active in tumor-like conditions (high concentration of activating proteases and acidic pH). IND-enabling studies are currently ongoing to advance the candidate toward the clinic. Stephan Schann, Chief Scientific Officer of Domain Therapeutics, commented: “We are excited to present our newest findings on DT-9045 at AACR. The results not only confirm the immense potential of our PAR2 inhibitor to change the way we treat cancer, but also emphasize its high potency and efficacy against several drug resistance, offering cancer patients a clear therapeutic perspectives in immuno-oncology. More broadly, they reflect our deep commitment to precision research, pioneering innovative new GPCR targets in immunosuppression, designing clear competitive properties to deliver game-changing candidates. We eagerly anticipate advancing this groundbreaking research, with a focus on addressing a substantial unmet medical need for cancer patients.” This progress, follows the announcement in June 2023 when DT-9045 was nominated as a first-in-class clinical PAR2 antagonist. It has shown great therapeutic potential in enhancing the efficacy to immunotherapy aiming to substantially improve treatment outcomes for non-responding cancer patients. About Domain Therapeutics Domain Therapeutics, a global clinical-stage biopharmaceutical company, is developing innovative immunotherapies targeting G Protein-Coupled Receptors (GPCRs), one of the most important drug target classes, to unlock new possibilities in cancer. As the leading GPCR immuno-oncology company, Domain aims to beat resistance to immune modulation within the tumor microenvironment by unveiling therapeutic potential of GPCRs to defeat cancer. Two decades of solid GPCR expertise, validated through multiple pharma partnerships across various therapeutic areas and associated to a world-class drug discovery platform, enable the Company to deepen the understanding of cancer biology and deliver the next-generation of immunotherapies to patients. Domain’s proprietary programs include DT-7012, a Treg-depleting CCR8 antibody, DT-9045, a first-in-class PAR2 negative allosteric modulator, and DT-9081, an EP4 receptor antagonist alongside the M1069, an A2aR/A2b receptor antagonist identified in partnership with Merck KGaA. The company has also an optimized pipeline of best-in-class and first-in-class GPCR targets selected through Domain’s proprietary cross-validation drug discovery and development platform. Since 2022, the Company raised €51m ($55m) in series A to progress preclinical and clinical development of its high-value drug candidates to address GPCR-mediated immunosuppression. Domain is supported by leading international venture capital firms from Europe (3B Future Health Fund, Seventure, Schroders, Omnes, Turenne, Theodorus), Asia (Panacea and Viva) and North America (CTI Life Science, adMare). For more information, please visit:

HTL0033744 has been designed by Sosei Heptares to promote mucosal healing and resolve inflammation in people with IBD Tokyo, Japan and Cambridge, UK, 21 March 2024 – Sosei Group Corporation (“Sosei Heptares” or “the Company”; TSE: 4565) announces it has dosed the first subject in a Phase 1 trial evaluating its novel EP4 receptor agonist, HTL0033744 (HTL’744) for the treatment of Inflammatory Bowel Disease (IBD), a therapeutic area where there remains significant unmet need for millions of people worldwide. HTL’744 is a potent, selective and gut-restricted prostaglandin EP4 receptor agonist that has been uniquely designed to bring clinical benefit by accelerating the healing of damaged epithelial mucosa and suppressing exaggerated gut inflammation, with minimal systemic exposure to avoid adverse events. This approach is widely recognized to promote deeper remission and offer better long-term clinical outcomes1,2. HTL’744 aims to address the significant unmet need of people with IBD that do not achieve satisfactory disease control. Current treatments for IBD typically achieve remission rates of less than 25%, and the safety profile of these drugs mean that they require careful monitoring. The Phase 1 trial is a first-in-human randomized, double-blind study to assess the safety, pharmacokinetics and effects on pharmacodynamic biomarkers of single and multiple ascending doses of HTL’744 in adult healthy volunteers and people with Crohn’s disease to generate proof of mechanism. The trial will be conducted in the UK and initial data read-outs are anticipated from 2025. Matt Barnes, President of Heptares Therapeutics and Head of UK R&D, said: “It’s great to see the progression of HTL’744, another of our wholly owned assets, into the clinic. EP4 agonists are a recognized and exciting class of drugs with a dual mechanism of action that can resolve inflammation and promote mucosal healing. We’ve utilized our StaR®/SBDD platform to develop a potent, selective and gut-restricted molecule that has potential to change the lives of the millions of people with IBD worldwide who are not benefitting from the currently available treatments.” -ENDS- About Sosei HeptaresSosei Heptares is a fully integrated, technology enabled pharmaceutical company focused on bringing life-changing medicines based on world-class science to patients globally. Our vision is to become one of Japan’s global pharmaceutical champions. Our global business combines our world-leading GPCR-targeted StaR® technology, structure-based drug design and early development capabilities in the UK with a highly experienced clinical development capability and a commercial operation in Japan. We are leveraging these capabilities to generate and advance a broad and deep pipeline of novel medicines across multiple therapeutic areas, including neurology, immunology, gastroenterology and inflammatory diseases. We intend to develop these opportunities for patients in Japan and globally both internally and through our partnerships with global biopharmaceutical companies and emerging technology companies. Sosei Heptares operates from key locations in Tokyo and Osaka (Japan), London and Cambridge (UK), Basel (Switzerland) and Seoul (South Korea). “Sosei Heptares” is the corporate brand and trademark of Sosei Group Corporation, which is listed on the Tokyo Stock Exchange (ticker: 4565). Sosei, Heptares, the logo and StaR® are trademarks of Sosei Group companies. For more information, please visit https://soseiheptares.com/LinkedIn: @soseiheptaresco | X: @soseiheptaresco | YouTube: @soseiheptaresco Enquiries: Sosei Heptares – Media and Investor RelationsKentaro Tahara, VP Investor Relations and Corporate Strategy Shinichiro Nishishita, VP Investor Relations, Head of Regulatory DisclosuresMaya Bennison, Communications Manager+81 (0)3 5210 3399 | +44 (0)1223 949390 | IR@SoseiHeptares.com MEDiSTRAVA Consulting (for International Media)Mark Swallow, Frazer Hall, Erica Hollingsworth+44 (0)203 928 6900 | SoseiHeptares@medistrava.com Forward-looking statementsThis press release contains forward-looking statements, including statements about the discovery, development, and commercialization of products. Various risks may cause Sosei Group Corporation’s actual results to differ materially from those expressed or implied by the forward-looking statements, including: adverse results in clinical development programs; failure to obtain patent protection for inventions; commercial limitations imposed by patents owned or controlled by third parties; dependence upon strategic alliance partners to develop and commercialize products and services; difficulties or delays in obtaining regulatory approvals to market products and services resulting from development efforts; the requirement for substantial funding to conduct research and development and to expand commercialization activities; and product initiatives by competitors. As a result of these factors, prospective investors are cautioned not to rely on any forward-looking statements. We disclaim any intention or obligation to update or revise any forward-looking statements, whether as a result of new information, future events or otherwise. 1 Neurath, MF: Gut 61.11 (2012): S. 1619-1635. http://gut.bmj.com/content/61/11/1619 2 Rath T et al: Gastroenterology Volume 164, Issue 2, February 2023, Pages 241-255 https://doi.org/10.1053/j.gastro.2022.10.014