Tyrosinemias

引言胞嘧啶碱基编辑器(CBEs)是引入C-T碱基转换的有效工具，但其临床应用受到脱靶效应和旁观者效应的限制。2024年3月29日，华东师范大学李大力、王立人及上海交通大学曾凡一共同通讯在Nature Chemical Biology 在线发表题为“Engineering APOBEC3A deaminase for highly accurate and efficient base editing”的研究论文，该研究开发了一种工程APOBEC3A脱氨酶，用于高精度和高效的碱基编辑。通过人类APOBEC3A (A3A)脱氨酶的结构引导工程，该研究开发了高度精确的A3A-CBE (haA3A-CBE)变体，该变体有效地产生C-to-T转换，具有狭窄的编辑窗口和接近背景水平的DNA和RNA脱靶活性，而不考虑甲基化状态和序列背景。工程脱氨酶结构域与PAM松弛的SpCas9-NG变体兼容，通过单导RNAs的灵活定位，能够精确校正同聚胞嘧啶位点的致病突变。双腺相关病毒将一种haA3A-CBE变体递送到酪氨酸血症小鼠模型中，在肝组织中诱导高达58.1%的编辑，并伴有最少的旁观者编辑，通过单剂量的脂质纳米颗粒信使RNA递送haA3A-CBE进一步降低了这一水平。这些结果凸显了haA3A-CBEs在精确基因组编辑治疗人类疾病方面的巨大前景。碱基编辑是一项革命性的技术，它能够在分裂和非分裂细胞中有效地将一个碱基对转化为另一个碱基对，而不需要双链DNA断裂或供体模板。有两种主要类型的碱基编辑器：腺嘌呤碱基编辑器(ABEs)和胞嘧啶碱基编辑器(CBEs)，它们分别诱导高效率的A-to-G和C-to-T转换。ABEs通常催化碱基转化，产物纯度非常高(>99.9%)，而CBEs通过胞嘧啶脱胺作用产生尿嘧啶，从而刺激尿嘧啶DNA糖基化酶产生基位，激活细胞碱基切除修复途径，将胞嘧啶转化为胸腺嘧啶和其他核苷酸。为了提高CBEs的产品纯度，使用尿嘧啶糖基化酶抑制剂(UGI)与nCas9和各种胞苷脱氨酶结构域融合，开发出具有高C•G-to-T•A产品纯度的CBEs。此外，一些研究小组还开发了C-to-G碱基编辑器，利用尿嘧啶DNA糖基化酶替代CBE中的UGI，或仅在CBE结构中使用进化的胞苷脱氨酶变体，有效地生成C•G-to-G•C转换。这些碱基编辑器已广泛应用于动物基因工程、植物基因工程，并在基因治疗中显示出良好的潜力。然而，一些研究报道了CBEs的脱氨酶结构域诱导Cas9非依赖性DNA和RNA脱靶突变，这可能会阻碍CBEs在精确编辑方面的广泛应用，特别是在临床环境中。此外，由目标位点上不希望的碱基转换引起的旁观者效应也可能对精确编辑构成挑战。已经实施了几种策略来提高碱基编辑器的准确性，包括缩小编辑窗口或募集具有定义序列上下文的脱氨酶变体。截断脱氨酶CDA1或缩短nCas9与脱氨酶结构域之间的连接可以适度缩小编辑窗口。此外，一些在特定序列背景下优先脱氨胞嘧啶的脱氨酶的工程设计导致了eA3A-CBE和A3G-CBE的发展，它们分别催化TC和CC基序中的C-to-T转化。特别是对于eA3A-CBE，由于限制基序偏好，旁观者编辑量大大减少，效率高，脱靶效应最小。rAPOBEC1脱氨酶的蛋白质工程已经产生了CBE变体，如YE1，FE1和R33A，这些变体显示出狭窄的编辑窗口和显著减少脱靶效应。变形式碱基编辑器具有最小的脱氨酶诱导的脱靶效应，但该系统应用复杂，旁观者编辑效果仍未得到改善。A3A的进一步工程开发haA3A-CBE（Credit: Nature Chemical Biology）该研究在细胞系和人类疾病动物模型中证明了haA3A-CBEs在纠正各种序列背景下的致病性 SNVs方面的显著效率和精确性。使用PAM松弛的SpCas9-NG结合灵活的sgRNA设计进一步提高了haA3A-CBEs校正人类致病性 SNVs的准确性。值得注意的是，大量与疾病相关的T-to-C突变存在于CpG二核苷酸中，CpG二核苷酸通常被甲基化，或者存在于GC基序中。haa3a -CBE特别适合于纠正这些类型的突变，使它们成为治疗人类疾病的有希望的候选者，并将CBE工具箱扩展到各种应用中。华东师范大学生命科学学院博士后杨磊，博士研究生霍雅楠，硕士研究生王嫚（现为东南大学博士研究生）以及博士后张丹为该论文的共同第一作者，华东师范大学为第一单位，华东师范大学李大力研究员，王立人副研究员和上海交通大学基础医学院曾凡一为本文通讯作者。华东师范大学生命科学学院刘明耀教授，宋高洁研究员、程义云教授、吕佳研究员、关玉婷研究员、北京大学伊成器教授及香港中文大学冯波教授等对本项研究提供了重要支持。原文链接https://www.nature.com/articles/s41589-024-01595-4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

PKU GOLIKE® is a commercial ultra-rare disease medical formula complementary to Eton's existing metabolic franchise and specialty call pointTransaction is expected to be accretive to 2024 earningsEstimated peak sales of more than $10 million annuallyU.S. phenylketonuria ("PKU") medical formula market estimated to be $100 million annually DEER PARK, Ill., March 22, 2024 (GLOBE NEWSWIRE) -- Eton Pharmaceuticals, Inc (“Eton” or the “Company”) (Nasdaq: ETON), an innovative pharmaceutical company focused on developing and commercializing treatments for rare diseases, today announced that it has acquired U.S. rights to PKU GOLIKE® from RELIEF THERAPEUTICS Holding SA (“Relief”) (SIX: RLF, OTCQB: RLFTF, RLFTY). “We are excited to be partnering with Relief on PKU GOLIKE in the United States. After extensive discussions with metabolic geneticists, dieticians, and PKU patients, we believe PKU GOLIKE is the best product in the estimated $100 million U.S. PKU medical formula market. With our sales force and existing relationships in the metabolic community, we believe we can significantly increase the awareness, education, and adoption of this important product,” said Sean Brynjelsen, CEO of Eton Pharmaceuticals. “We are very pleased to gain this partnership with Eton for PKU GOLIKE patients in the US as it is aligned with RELIEF’s strategy to enhance patient access to our innovative products,” said Michelle Lock, interim CEO of Relief. “Eton brings valuable know-how in the metabolic space as well as commercialization expertise for products in rare diseases.” PKU is a rare inherited disorder caused by a defect in the enzyme needed to break down phenylalanine, leading to a toxic buildup of phenylalanine when eating foods that contain proteins. Treatment of PKU requires patients to follow a strict diet that severely limits phenylalanine content and typically requires low protein foods supplemented by phenylalanine-free medical formulas. Excessive levels of phenylalanine in the blood accumulate in the brain and inhibit proper brain development. It is estimated that 8,000 PKU patients in the U.S. utilize medical formulas to manage their diet. PKU GOLIKE® is a next generation medical formula product engineered with the patent protected, pharmaceutical grade Physiomimic™ technology for the dietary management of PKU under medical supervision. PKU GOLIKE’s taste-masked, odor-free coating technology is designed to provide a better taste and a superior experience compared to alternative PKU medical formulas. In addition, PKU GOLIKE’s delayed amino acid release formulation is designed to keep patients full for a longer period of time. Relief launched PKU GOLIKE Granules in the United States in the fourth quarter of 2022 and the PKU GOLIKE Tropical Bar in the second quarter of 2023. Only a few months into the product’s launch, PKU GOLIKE’s fourth quarter net sales in the U.S. were at an annual run rate of more than $1 million. Relief, through its subsidiary APR, has commercialized PKU GOLIKE in Europe since 2019 and seen strong adoption. Eton plans to promote PKU GOLIKE with its existing metabolic sales force, which currently promotes Eton’s Carglumic Acid, Betaine, and Nitisinone products. PKU patients’ care is typically overseen by metabolic geneticists and their support staff of nurse practitioners and registered dieticians. Medical formulas for PKU are frequently covered by insurance and are regulated by the FDA as medical food products. PKU GOLIKE is exclusively distributed in the United States by Pentec Health. Patients and healthcare professionals seeking additional information on the product can visit www.PKUGOLIKE.com. The transaction is expected to be accretive to Eton’s 2024 earnings and the company expects peak sales of more than $10 million annually. As part of the transaction, Eton also received U.S. rights to Relief’s GOLIKE medical formulas line extensions under development for the management of the metabolic conditions tyrosinemia and homocystinuria, which are expected to launch in 2025 and 2026, respectively. Eton has also been granted a right of first negotiation for Relief’s RLF-OD032 development candidate. RLF-OD032 is an innovative drug product candidate under development for the treatment of PKU and is expected to be filed with the FDA in the second half of 2025 as a 505(b)(2) New Drug Application. Relief will continue to own PKU GOLIKE rights outside the United States. About Eton Pharmaceuticals Eton is an innovative pharmaceutical company focused on developing and commercializing treatments for rare diseases. The Company currently has five commercial rare disease products: ALKINDI SPRINKLE®, PKU GOLIKE®, Carglumic Acid, Betaine Anhydrous, and Nitisinone. The Company has three additional product candidates in late-stage development: ET-400, ET-600, and ZENEO® hydrocortisone autoinjector. For more information, please visit our website at www.etonpharma.com. About RELIEF THERAPEUTICS Holding SA Relief is a commercial-stage biopharmaceutical company committed to advancing treatment paradigms and delivering improvements in efficacy, safety, and convenience to benefit the lives of patients living with select specialty and rare diseases. Relief’s portfolio offers a balanced mix of marketed, revenue-generating products, proprietary, globally patented Physiomimic™ and TEHCLO™ platform technologies and a targeted clinical development pipeline consisting of risk-mitigated assets focused in three core therapeutic areas: rare metabolic disorders, rare skin diseases and rare respiratory diseases. In addition, Relief is commercializing several legacy products via licensing and distribution partners. Relief’s mission is to provide therapeutic relief to those suffering from rare diseases and is being advanced by an international team of well-established, experienced biopharma industry leaders with extensive research, development and rare disease expertise. Relief is headquartered in Geneva, with additional offices in Balerna, Switzerland, Offenbach am Main, Germany and Monza, Italy. Relief is listed on the SIX Swiss Exchange under the symbol RLF and quoted in the U.S. on OTCQB under the symbols RLFTF and RLFTY. For more information, visit www.relieftherapeutics.com. About Phenylketonuria (PKU) Phenylketonuria (PKU) is caused by a defect of the enzyme needed to break down phenylalanine (Phe), leading to a toxic buildup of Phe from the consumption of foods containing protein or aspartame. Untreated PKU can result in global developmental delay or severe irreversible intellectual disability, as well as growth failure, hypopigmentation, motor deficits, ataxia and seizures. Living with PKU requires a limited diet and very careful management. If left unmanaged, PKU can lead to devastating consequences, such as brain damage. People living with PKU do not have the ability to metabolize Phe, which is found in many foods, and they require supplementation of amino acid-based phenylalanine-free medical formulas as part of an effort to prevent protein deficiency and optimize metabolic control. Medical formulas used in PKU are challenged to provide a range of amino acids slowly and without a medicinal aftertaste. About PKU GOLIKE PKU GOLIKE® products are foods for special medical purposes (FSMPs) for the dietary management of PKU in both children and adults for use under medical supervision. Developed with Relief’s proprietary, patent-protected Physiomimic Technology™ drug delivery platform, PKU GOLIKE® products are the first prolonged-release amino acid FSMPs, characterized by a special coating that ensures physiological absorption of the amino acids mirroring that of natural proteins. The special coating also masks the unpleasant taste, odor and aftertaste of the amino acids. PKU GOLIKE® granules are flavorless and can be mixed with many foods. PKU GOLIKE® products contain all 19 amino acids that people with PKU need to maintain neurological and muscular health and is fortified with 27 essential vitamins and minerals, including ones normally found in protein-rich foods like iron, calcium and vitamin B12. The PKU GOLIKE® line of products are available in convenient packets (PKU GOLIKE Plus® 3-16 and 16+) and medical formula bars (PKU GOLIKE BAR®). PKU GOLIKE® products have been commercially available in the U.S. since October 2022. For more information, visit www.pkugolike.com (Please note this site is intended for U.S. audiences only). Forward-Looking Statements Statements contained in this press release regarding matters that are not historical facts are “forward-looking statements” within the meaning of the Private Securities Litigation Reform Act of 1995, including statements associated with the expected ability of Eton to undertake certain activities and accomplish certain goals and objectives. These statements include but are not limited to statements regarding Eton’s business strategy, Eton’s plans to develop and commercialize its product candidates, the safety and efficacy of Eton’s product candidates, Eton’s plans and expected timing with respect to regulatory filings and approvals, and the size and growth potential of the markets for Eton’s product candidates. Because such statements are subject to risks and uncertainties, actual results may differ materially from those expressed or implied by such forward-looking statements. Words such as “believes,” “anticipates,” “plans,” “expects,” “intends,” “will,” “goal,” “potential” and similar expressions are intended to identify forward-looking statements. These forward-looking statements are based upon Eton’s current expectations and involve assumptions that may never materialize or may prove to be incorrect. Actual results and the timing of events could differ materially from those anticipated in such forward-looking statements as a result of various risks and uncertainties, which include, without limitation, risks associated with the process of discovering, developing and commercializing drugs that are safe and effective for use as human therapeutics, and in the endeavor of building a business around such drugs. These and other risks concerning Eton’s development programs and financial position are described in additional detail in Eton’s filings with the Securities and Exchange Commission. All forward-looking statements contained in this press release speak only as of the date on which they were made. Eton undertakes no obligation to update such statements to reflect events that occur or circumstances that exist after the date on which they were made. Investor Relations:Lisa M. Wilson, In-Site Communications, Inc.T: 212-452-2793E: lwilson@insitecony.com

GENEVA, SWITZERLAND / ACCESSWIRE / March 22, 2024 / RELIEF THERAPEUTICS Holding SA (SIX:RLF)(OTCQB:RLFTF)(OTCQB:RLFTY ) (Relief, or the Company), a biopharmaceutical company committed to delivering innovative treatment options for select specialty, unmet and rare diseases, today announced it has granted an exclusive license to Eton Pharmaceuticals, Inc. (Nasdaq: ETON) (Eton) for the commercialization of GOLIKE ® family of products in the United States. "This transition is fully aligned with Relief's strategy of moving the GOLIKE products into partnership models in the U.S. and Europe. We are very pleased to be establishing this partnership with Eton for GOLIKE patients in the U.S. given their valuable experience in the metabolic area," said Michelle Lock, interim CEO of Relief. "We are excited to be partnering with Relief on PKU GOLIKE in the United States. After extensive discussions with metabolic geneticists, dieticians, and PKU patients, we believe PKU GOLIKE is the best product in the estimated $100 million U.S. PKU medical formula market. With our sales force and existing relationships in the metabolic community, we believe we can significantly increase the awareness, education, and adoption of this important product," said Sean Brynjelsen, CEO of Eton Pharmaceuticals. Under the terms of the agreement, Relief will receive an upfront payment of $2.2 million and is eligible to receive an additional $2.0 million in sales milestones payments as well as mid-teens royalties on net sales. In the fourth quarter of 2023, PKU GOLIKE's annualized net sales exceeded $1 million in the U.S., continuing its growth trajectory since its launch in late 2022. As part of the agreement, Eton also received U.S. rights to Relief's GOLIKE Medical Food line extensions under development for the management of other inherited rare metabolic diseases such as tyrosinemia and homocystinuria, which are both expected to launch in 2025 and 2026 under the same trademark. Relief is also in discussions with Eton related to additional development assets, including RLF-OD032. RLF‑OD032 is an innovative drug product candidate under development for the treatment of PKU expected to be filed for approval before the FDA in H2/2025 as 505(b)(2) application. Relief will continue to fully own GOLIKE rights outside the United States. About Relief Relief is a commercial-stage biopharmaceutical company committed to advancing treatment paradigms and delivering improvements in efficacy, safety, and convenience to benefit the lives of patients living with select specialty and rare diseases. Relief's portfolio offers a balanced mix of marketed, revenue-generating products, our proprietary, globally patented Physiomimic™ and TEHCLO™ platform technologies and a targeted clinical development pipeline consisting of risk-mitigated assets focused in three core therapeutic areas: rare metabolic disorders, rare skin diseases and rare respiratory diseases. In addition, Relief is commercializing several legacy products via licensing and distribution partners. Relief's mission is to provide therapeutic relief to those suffering from rare diseases and is being advanced by an international team of well-established, experienced biopharma industry leaders with extensive research, development and rare disease expertise. Relief is headquartered in Geneva, with additional offices in Balerna, Switzerland, Offenbach am Main, Germany and Monza, Italy. Relief is listed on the SIX Swiss Exchange under the symbol RLF and quoted in the U.S. on OTCQB under the symbols RLFTF and RLFTY. For more information, please visit our website or follow Relief on LinkedIn . About Eton Pharmaceuticals Eton is an innovative pharmaceutical company focused on developing and commercializing treatments for rare diseases. It currently has five commercial rare disease products: ALKINDI SPRINKLE ® , PKU GOLIKE ® , Carglumic Acid, Betaine Anhydrous, and Nitisinone. Eton has three additional product candidates in late-stage development: ET-400, ET-600, and ZENEO ® hydrocortisone autoinjector. For more information, visit . About Phenylketonuria (PKU) Phenylketonuria (PKU) is caused by a defect of the enzyme needed to break down phenylalanine (Phe), leading to a toxic buildup of Phe from the consumption of foods containing protein or aspartame. Untreated PKU can result in global developmental delay or severe irreversible intellectual disability, as well as growth failure, hypopigmentation, motor deficits, ataxia and seizures. Living with PKU requires a limited diet and very careful management. If left unmanaged, PKU can lead to devastating consequences, such as brain damage. People living with PKU do not have the ability to metabolize Phe, which is found in many foods, and they require supplementation of amino acid-based phenylalanine-free Medical Foods to prevent protein deficiency and optimize metabolic control. Currently available Medical Foods may lead to poor or suboptimal clinical outcomes and compliance because they are rapidly absorbed and are characterized by an unpleasant odor and aftertaste. Such factors contribute to barriers to social interaction for PKU patients, further limiting Medical Foods compliance and exposing patients to the risks of poor disease control. About PKU GOLIKE PKU GOLIKE ® products are Medical Foods for the dietary management of PKU in both children and adults. Developed with the Relief proprietary, patent-protected Physiomimic Technology™ drug delivery platform, PKU GOLIKE ® products are the first prolonged-release amino acid Medical Food, characterized by a special coating that ensures physiological absorption of the amino acids mirroring that of natural proteins. The special coating also masks the unpleasant taste, odor and aftertaste of the amino acids. PKU GOLIKE ® granules are flavorless and can be mixed with many foods. PKU GOLIKE ® granule products contain all 19 amino acids that people with PKU need to maintain neurological and muscular health and is fortified with vitamins and minerals, including ones normally found in protein-rich foods like iron, calcium, and vitamin B12. The PKU GOLIKE ® line of products is available in convenient packets (PKU GOLIKE Plus ® 3-16 and 16+) and medical food bars (PKU GOLIKE BAR ® ). PKU GOLIKE ® products have been commercially available in the U.S. since October 2022. For more information, visit (this site is intended for U.S. audiences only). CONTACT : RELIEF THERAPEUTICS Holding SA Avenue de Sécheron 15 1202 Geneva Switzerland contact@relieftherapeutics.com DISCLAIMER This press release contains forward-looking statements. Forward-looking statements involve known and unknown risks, uncertainties, including its ability to achieve its corporate, development and commercial goals, and other factors which could cause the actual results, financial condition, performance or achievements of Relief to be materially different from any future results, performance or achievements expressed or implied by such forward-looking statements. A number of factors, including those described in Relief's filings with the SIX Swiss Exchange and the U.S. Securities and Exchange Commission (SEC), could adversely affect Relief. Copies of Relief's filings with the SEC are available on the SEC EDGAR database at . Relief does not undertake any obligation to update the information contained herein, which speaks only as of this date. SOURCE: Relief Therapeutics Holdings AG View the original press release on accesswire.com