Porphyrias, Hepatic

引言通过小分子激活Nrf2是治疗绝经后骨质疏松症的一种很有前途的策略。然而，目前还没有批准用于治疗慢性疾病的Nrf2激活剂，Nrf2调控破骨细胞分化的下游机制尚不清楚。2024年4月2日，华中科技大学李锋及宋科翰共同通讯在Cell Metabolism 在线发表题为“A clinical-stage Nrf2 activator suppresses osteoclast differentiation via the iron-ornithine axis”的研究论文，该研究表明bitopertin，一种临床阶段的甘氨酸摄取抑制剂，通过激活Nrf2抑制破骨细胞分化并改善卵巢切除术诱导的骨质流失。从机制上讲，bitopertin与Keap1 Kelch结构域相互作用，减少Keap1-Nrf2结合，导致Nrf2泛素化和降解减少。在小鼠和人类受试者中，与临床批准的Nrf2激活剂相比，Bitopertin与更少的不良事件相关。此外，Nrf2转录激活铁转运蛋白编码基因Slc40a1，以降低破骨细胞内的铁水平。Nrf2缺失或补铁上调鸟氨酸代谢酶Odc1，从而降低鸟氨酸水平，从而促进破骨细胞分化。总之，该研究确定了一种新的临床阶段Nrf2激活剂，并提出了破骨细胞中一种新的Nrf2-铁-鸟氨酸代谢轴。绝经后骨质疏松症是在缺乏雌激素的情况下由破骨细胞过度活化引起的代谢紊乱。骨密度(BMD)的降低使患者髋部或椎体脆性骨折的风险增加，在全球范围内造成严重的残疾和社会经济负担破骨细胞在巨噬细胞集落刺激因子(M-CSF)和核因子kB配体受体激活剂(RANKL)的刺激下向骨髓源性巨噬细胞(bmdm)分化。用双膦酸盐化合物靶向破骨细胞是治疗骨质疏松症的主流策略。然而，严重的不良反应和较差的依从性是许多患者标准化双膦酸盐治疗的障碍，导致骨质疏松症治疗不足需要发现新的治疗靶点，以确保对这些患者提供更好的护理。核因子E2相关因子2 (Nrf2)是一种氧化还原相关的转录因子，其激活可通过抑制破骨细胞分化来改善绝经后骨质疏松症。在非胁迫条件下，Nrf2被Keap1隔离在细胞质中，并被Cul3泛素连接酶泛素化，用于蛋白酶体降解在氧化应激过程中，Nrf2与Keap1分离并易位到细胞核，激活多种参与细胞抗氧化反应的细胞保护基因。这些基因的Nrf2结合位点被称为抗氧化反应元件(AREs)由于具有细胞保护作用，已经发现了许多Nrf2激活因子。然而，它们中的大多数是亲电性和间接Nrf2激活剂，共价靶向KEAP1中的半胱氨酸151，其中只有两种被批准用于临床使用，即延胡索酸二甲酯(DMF)用于治疗复发型多发性硬化症和omaveloxolone (OMA)用于治疗弗里德赖希共济失调。除Keap1外，这些亲电Nrf2激活因子还与其他关键酶或蛋白质的半胱氨酸残基相互作用并影响其功能，导致“脱靶”和毒性作用。在人类中，在临床试验中，间接Nrf2激活剂与高不良事件发生率相关另一种策略是找到Keap1-Nrf2相互作用的直接抑制剂来选择性激活Nrf2。然而，直接Nrf2激活剂通常分子大小较大，这降低了其进入中枢神经系统治疗相关疾病的能力，目前尚无临床批准的直接Nrf2激活剂。因此，开发更安全、更有效的Nrf2激活剂用于临床仍然是一个挑战。模式图（Credit: Cell Metabolism）Bitopertin是一种口服、临床甘氨酸转运蛋白1 (Glyt1)抑制剂，最初用于治疗精神分裂症。最近，bitopertin被FDA授予孤儿药资格，用于治疗红细胞生成性卟啉原症(EPP)，这是一种罕见的、使人衰弱的、潜在威胁生命的血液疾病。bitopertin治疗EPP的疗效正在两项正在进行的2期临床试验AURORA (NCT05308472)和BEACON (ACTRN12622000799752)中进行评估bitopertin的潜在临床应用是基于其限制甘氨酸摄取的作用。有趣的是，骨质疏松症患者的血清甘氨酸水平明显高于骨密度正常的患者。另一项研究显示，甘氨酸支持谷胱甘肽的形成，并有助于脂多糖刺激后BMDMs中白细胞介素(IL)-1β的产生，表明甘氨酸具有促炎作用。然而，目前尚不清楚甘氨酸水平升高是否与骨质疏松症有因果关系，以及甘氨酸是否影响BMDMs向破骨细胞的分化。该研究发现bitopertin，而不是甘氨酸补充剂，通过Nrf2激活改善卵巢切除术(OVX)诱导的骨质疏松症。在机制上，bitopertin与Kelch结构域相互作用，减少Keap1-Nrf2相互作用，减少Nrf2降解。与现有的临床Nrf2激活剂相比，Bitoeprtin在人类受试者中更安全，与更少的不良事件相关。更重要的是，该研究发现了一个新的Nrf2 -铁-鸟氨酸代谢轴在破骨细胞分化。该研究结果表明，bitopertin在治疗骨质疏松症中具有先前未被认识到的治疗作用，并有助于阐明Nrf2对破骨细胞作用的分子机制。原文链接https://www.cell.com/cell-metabolism/abstract/S1550-4131(24)00084-6责编|探索君排版|探索君文章来源|“iNature”End往期精选围观一文读透细胞死亡(Cell Death) | 24年Cell重磅综述（长文收藏版）热文Nature | 破除传统：为何我们需要重新思考肿瘤的命名方式热文Nature | 2024年值得关注的七项技术热文Nature | 自身免疫性疾病能被治愈吗？科学家们终于看到了希望热文CRISPR技术进化史 | 24年Cell综述

Met primary endpoint, demonstrating dose-dependent, statistically significant reductions in protoporphyrin IX (PPIX) compared to placebo in both 20 mg and 60 mg dose groupsImproved measures of light tolerance, including the key secondary endpoint, in both 20 mg and 60 mg dose groups, but did not meet statistical significance compared to placeboDose-dependent reductions in the rate of phototoxic reactions with pain, with statistical significance at the 60 mg dose group compared to placeboDose-dependent improvements in the Patient Global Impression of Change (PGIC), with statistical significance at the 60 mg dose group compared to placeboInvestor webcast at 8:30 am ET to discuss top-line data WATERTOWN, Mass., April 01, 2024 (GLOBE NEWSWIRE) -- Disc Medicine, Inc. (NASDAQ:IRON), a clinical-stage biopharmaceutical company focused on the discovery, development, and commercialization of novel treatments for patients suffering from serious hematologic diseases, today presented topline data from AURORA, a phase 2 study of bitopertin in patients with EPP. Treatment with bitopertin resulted in statistically significant reductions in PPIX, the primary endpoint, and significant improvements in the rate of phototoxic reactions with pain and the Patient Global Impression of Change (PGIC). On the key secondary endpoint of cumulative time in sunlight on days without pain, bitopertin patients had a positive response consistent with BEACON results, but the endpoint did not meet statistical significance due to strong placebo performance. “This study has confirmed that bitopertin significantly reduces the toxic metabolite, PPIX, in patients with EPP, and we have shown that bitopertin-treated patients experience improvements in the clinically meaningful outcomes of Patient Global Impression of Change and the number and rate of phototoxic reactions with pain, with the 60 mg dose reaching statistical significance compared to placebo. Despite the strong performance of bitopertin on the key secondary endpoint of cumulative time in light, consistent with results seen in BEACON, statistical significance was not met due to an outsized placebo response,” said John Quisel, J.D., Ph.D., President and Chief Executive Officer. “Given that, we will need to conduct an analysis of our final data set and work with investigators, regulators, and patient advocacy groups to define the optimal registrational endpoints moving forward. While we do this additional work, we continue to be excited about the upcoming readouts from our other programs, including updated data from our DISC-0974 study in anemia of myelofibrosis in Q2.” The AURORA study is a randomized, double-blind, placebo-controlled phase 2 study that enrolled 75 adult subjects with EPP. Subjects were randomized 1:1:1 to receive 20 mg of bitopertin, 60 mg of bitopertin, or placebo once daily for 17 weeks. Summary of topline results Primary endpoint Bitopertin resulted in significant, dose-dependent, and sustained reductions in whole blood PPIX levels: -21.6% for 20 mg (p=0.003 vs placebo) and -40.7% for 60 mg (p<0.001 vs placebo); the placebo group had mean increases of +8.0% Secondary endpoints Cumulative total time in sunlight between 10 am and 6 pm on days without pain observed over the 4-month treatment period: bitopertin-treated patients recorded a mean of 175.1 hours at 20 mg and 153.1 hours at 60 mg, compared with 133.9 hours for placebo; results were not statistically significant compared to placebo The magnitude of the improvement in the bitopertin-treated patients was comparable to that observed in the BEACON study, but the benefit in the placebo arm in the AURORA trial was greater than expected Large improvements in light tolerance from baseline in 20 mg and 60 mg bitopertin treatment groups as measured by time to prodrome; results were not statistically significant relative to placebo.Substantial and dose-dependent reductions in phototoxic reactions with pain during the 4-month study period: 75% reduction in the incidence rate of new phototoxic reactions with pain at the 60 mg dose group compared to placebo (p=0.011); 60% reduction in the 20 mg dose group (p=0.109)Fewer bitopertin-treated patients reported a phototoxic event compared to placebo: 19% for 20 mg and 12% for 60 mg compared to 46% for placebo Dose-dependent improvements in PGIC, which were statistically significant for the 60 mg dose: 77% of completers at 20 mg and 86% at 60 mg (p=0.022 vs placebo) reported that their EPP was “much better” compared with 50% for placeboBitopertin was generally well tolerated in both dose groups with no serious adverse events and stable hemoglobin levels. Two patients discontinued treatment due to treatment-emergent AEs, both in the 60 mg dose group: one due to dizziness and one due to a skin rash. The most common AE reported with bitopertin treatment was dizziness: n=4 in the 20 mg dose group, n=11 in the 60 mg dose group compared with n=4 in the placebo group (median durations of 4.5, 5, and 2 days, respectively) Webcast Conference Call InformationManagement will host a call on Monday, April 1 at 8:30 am ET to review the data. Please register for management’s webcast on the Events and Presentations page of Disc’s website (https://ir.discmedicine.com/). About BitopertinBitopertin is an investigational, clinical-stage, orally-administered inhibitor of glycine transporter 1 (GlyT1) that is designed to modulate heme biosynthesis. GlyT1 is a membrane transporter expressed on developing red blood cells and is required to supply sufficient glycine for heme biosynthesis and support erythropoiesis. Disc is planning to develop bitopertin as a potential treatment for a range of hematologic diseases including erythropoietic porphyrias, where it has potential to be the first disease-modifying therapy. There are currently two ongoing phase 2 clinical trials of bitopertin in patients with EPP that have fully enrolled and have had key data readouts: the open-label trial called BEACON and a randomized, double-blind placebo-controlled trial called AURORA. Bitopertin is an investigational agent and is not approved for use as a therapy in any jurisdiction worldwide. Disc obtained global rights to bitopertin under a license agreement from Roche in May 2021. About Erythropoietic Protoporphyria (EPP) and X-linked Protoporphyria (XLP)Erythropoietic protoporphyria (EPP) and X-linked Protoporphyria (XLP) are rare, debilitating and potentially life-threatening diseases caused by mutations that affect heme biosynthesis, resulting in the accumulation of a toxic, photoactive intermediate called protoporphyrin IX (PPIX). This causes severe reactions when patients are exposed to sunlight, characterized by excruciating pain, edema, burning sensations and potential blistering and disfigurement. PPIX also accumulates in the hepatobiliary system and can result in complications including gallstones, cholestasis, and liver damage in 20-30% of patients and in extreme cases liver failure. Current standard of care involves extreme measures to avoid sunlight, including restricting outdoor activities to nighttime, use of protective clothing and opaque shields, and pain management. This has a significant impact on the psychosocial development, quality of life, and daily activities of patients, particularly in young children and families. There is currently no cure for EPP and only one FDA-approved therapy, a surgically implanted synthetic hormone designed to stimulate melanin production called Scenesse® (afamelanotide). About Disc MedicineDisc Medicine is a clinical-stage biopharmaceutical company committed to discovering, developing, and commercializing novel treatments for patients who suffer from serious hematologic diseases. We are building a portfolio of innovative, potentially first-in-class therapeutic candidates that aim to address a wide spectrum of hematologic diseases by targeting fundamental biological pathways of red blood cell biology, specifically heme biosynthesis and iron homeostasis. For more information, please visit www.discmedicine.com. Disc Medicine Cautionary Statement Regarding Forward-Looking Statements This press release contains “forward-looking statements” within the meaning of the Private Securities Litigation Reform Act of 1995, including, but not limited to, express or implied statements regarding Disc’s expectations with respect to its BEACON Phase 2 clinical studies of bitopertin and projected timelines for the initiation and completion of its clinical trials and other activities. The use of words such as, but not limited to, “believe,” “expect,” “estimate,” “project,” “intend,” “future,” “potential,” “continue,” “may,” “might,” “plan,” “will,” “should,” “seek,” “anticipate,” or “could” or the negative of these terms and other similar words or expressions that are intended to identify forward-looking statements. Forward-looking statements are neither historical facts nor assurances of future performance. Instead, they are based on Disc’s current beliefs, expectations and assumptions regarding the future of Disc’s business, future plans and strategies, clinical results and other future conditions. New risks and uncertainties may emerge from time to time, and it is not possible to predict all risks and uncertainties. No representations or warranties (expressed or implied) are made about the accuracy of any such forward-looking statements. Disc may not actually achieve the plans, intentions or expectations disclosed in these forward-looking statements, and investors should not place undue reliance on these forward-looking statements. Actual results or events could differ materially from the plans, intentions and expectations disclosed in the forward-looking statements as a result of a number of material risks and uncertainties including but not limited to: the adequacy of Disc’s capital to support its future operations and its ability to successfully initiate and complete clinical trials; the nature, strategy and focus of Disc; the difficulty in predicting the time and cost of development of Disc’s product candidates; Disc’s plans to research, develop and commercialize its current and future product candidates; the timing of initiation of Disc’s planned preclinical studies and clinical trials; the timing of the availability of data from Disc’s clinical trials; Disc’s ability to identify additional product candidates with significant commercial potential and to expand its pipeline in hematological diseases; the timing and anticipated results of Disc’s preclinical studies and clinical trials and the risk that the results of Disc’s preclinical studies and clinical trials may not be predictive of future results in connection with future studies or clinical trials and may not support further development and marketing approval; the other risks and uncertainties described in the “Risk Factors” section of our Annual Report on Form 10-K for the year ended December 31, 2023 and other documents filed by Disc from time to time with the Securities and Exchange Commission (SEC), as well as discussions of potential risks, uncertainties, and other important factors in Disc’s subsequent filings with the SEC. Any forward-looking statement speaks only as of the date on which it was made. None of Disc, nor its affiliates, advisors or representatives, undertake any obligation to publicly update or revise any forward-looking statement, whether as result of new information, future events or otherwise, except as required by law. Media Contact Peg RusconiVerge Scientific Communicationsprusconi@vergescientific.com Investor Relations Contact Christina TartagliaStern Investor Relationschristina.tartaglia@sternir.com

DÜSSELDORF, Germany, March 28, 2024 (GLOBE NEWSWIRE) -- Pioneering biopharmaceutical company CLINUVEL yesterday hosted a wide-ranging market briefing discussing its novel drug SCENESSE® (afamelanotide) and the future of photomedicine. Over 70 guests discussed the Company’s unique history and future growth potential at an invitation-only event in Düsseldorf. Managing Director and CEO, Dr Philippe Wolgen shared the Company’s success in establishing profitability over the past seven financial years, building a strong balance sheet, commercialising the innovative melanocortin drug SCENESSE®, and plans to bring melanocortin technology to wider audiences with unmet needs. CLINUVEL is now investing heavily in R&D with an ambitious clinical pipeline, including a phase III clinical trial for the pigment loss disorder vitiligo. A case study presented at the American Academy of Dermatology Meeting on 9 March highlighted the systemic repigmentation of the skin of a female patient from the combination of SCENESSE® and phototherapy (light treatment). An estimated 45m individuals live with vitiligo globally, with no effective treatments for widespread depigmentation. The Company’s aspirations stretch beyond the clinical, with Dr Wolgen expanding upon the goal of making CLINUVEL a household name with the introduction of its PhotoCosmetics lines, incorporating novel melanocortin peptides. The consumer skincare lines are translating the Company’s targeted science into innovative products for the wider population. The lines were introduced to key US investors and celebrities during an intimate event at the home of Lady Gaga and longtime shareholder Michael Polansky in Malibu last month, resulting in positive feedback, a new international audience and anticipation for launch. “The potential of CLINUVEL to translate its expertise in melanocortins to address unmet needs in a range of conditions and as PhotoCosmetics underlies the future potential of the Company,” Dr Wolgen said. “German investors have been pivotal in supporting our work thus far and we hope to share our success with the wider investment community.” About The CLINUVEL Group: CLINUVEL is a public biopharmaceutical company whose pioneering melanocortin technology has revolutionised the field of photomedicine. Over the last 25 years, CLINUVEL’s work has furthered scientific knowledge, delivered breakthroughs in medical technology and transformed patients’ lives. The Company has developed and commercialised SCENESSE® (afamelanotide), the only approved treatment in the world for the prevention of phototoxicity in adult patients with EPP. The treatment was approved for use by the US FDA in 2019 and is also approved for commercial distribution in Europe, Israel and Australia. CLINUVEL is conducting clinical trials to assess the efficacy and safety of its melanocortin technology in treating severe disorders including xeroderma pigmentosum (XP), vitiligo and arterial ischemic stroke. In 2023 it announced its expansion into skincare with the introduction of its first PhotoCosmetic product CYACÊLLE, a polychromatic solar screen. Contact: Tel: +61 3 9660 4900 Fax: +61 3 9660 4909 Email: mail@clinuvel.com Australia (Head Office), Level 22, 535 Bourke Street, Melbourne, Victoria, 3000, Australia For more information visit Instagram: @clinuvel_pharmaceuticals Twitter: @ClinuvelNews Facebook: @Clinuvel Media Contact: lachlan.hay@clinuvel.com