Dyne Therapeutics Receives Orphan Drug Designation in Japan for DYNE-251 in Duchenne Muscular Dystrophy
Dyne Therapeutics (Nasdaq: DYN) has received Orphan Drug designation in Japan from the Ministry of Health, Labour and Welfare for DYNE-251, its treatment for Duchenne muscular dystrophy (DMD) patients with mutations amenable to exon 51 skipping.
The ongoing DELIVER Phase 1/2 clinical trial has shown sustained functional improvement through 18 months, with significant dystrophin expression. Results from the Registrational Expansion Cohort are expected in late 2025. The Japanese designation joins existing designations in the U.S. (Breakthrough Therapy, Fast Track, Rare Pediatric Disease, and Orphan Drug) and Europe (Orphan Drug).
The Japanese Orphan Drug status provides benefits including development cost subsidies and potential 10-year market exclusivity upon approval, applying to diseases affecting fewer than 50,000 patients in Japan.
Dyne Therapeutics (Nasdaq: DYN) ha ottenuto lo status di Farmaco Orfano in Giappone dalla Ministry of Health, Labour and Welfare per DYNE-251, suo trattamento per la distrofia muscolare di Duchenne (DMD) nei pazienti con mutazioni idonee all’eson skipping dell’esone 51. Il trial in corso DELIVER Phase 1/2 ha mostrato un miglioramento funzionale sostenuto per 18 mesi, con significativa espressione di distrofina. I risultati della Registrational Expansion Cohort sono attesi entro la fine del 2025. La designazione giapponese si aggiunge alle designazioni esistenti negli Stati Uniti (Breakthrough Therapy, Fast Track, Rare Pediatric Disease e Orphan Drug) e in Europa (Orphan Drug). Il status Orphan Drug in Giappone prevede benefici tra cui sussidi per i costi di sviluppo e una possibile esclusività di mercato di 10 anni al momento dell’approvazione, applicabile a malattie che interessano meno di 50.000 pazienti in Giappone.
Dyne Therapeutics (Nasdaq: DYN) ha recibido designación de fármaco huérfano en Japón por parte del Ministerio de Salud, Trabajo y Bienestar para DYNE-251, su tratamiento para la distrofia muscular de Duchenne (DMD) en pacientes con mutaciones susceptibles de skipping del exón 51. El ensayo DELIVER Phase 1/2 en curso ha mostrado mejora funcional sostenida durante 18 meses, con una expresión significativa de distrofina. Se esperan los resultados de la Cohorte de Expansión Registracional para finales de 2025. La designación japonesa se suma a las designaciones existentes en EE. UU. (Breakthrough Therapy, Fast Track, Rare Pediatric Disease y Orphan Drug) y en Europa (Orphan Drug). El estatus de Fármaco Huérfano en Japón ofrece beneficios como subvenciones para costos de desarrollo y una posible exclusividad de mercado de 10 años tras la aprobación, aplicable a enfermedades que afectan a menos de 50.000 pacientes en Japón.
Dyne Therapeutics (Nasdaq: DYN)은 DYNE-251에 대해 일본 보건복지성으로부터 외래 약물(Orphan Drug) designation을 받았으며, 이는 Exon 51 건너뛰기에 적합한 변이가 있는 Duchenne 근이영양증(DMD) 환자에 대한 치료제입니다. 진행 중인 DELIVER 1/2상 임상은 18개월 동안 지속된 기능 개선과 유의미한 디스트로핀 발현을 보여주었습니다. Registrational Expansion Cohort의 결과는 2025년 말에 기대됩니다. 이 일본의 designation은 미국의 (Breakthrough Therapy, Fast Track, Rare Pediatric Disease, Orphan Drug) 및 유럽의 (Orphan Drug) 기존 designation과 함께합니다. 일본의 Orphan Drug 지위는 개발 비용 보조 등 혜택과 승인이 되면 10년 간의 시장 독점권이 가능하며, 이는 일본에서 환자 수가 5만 명 미만인 질환에 적용됩니다.
Dyne Therapeutics (Nasdaq: DYN) a reçu la désignation de médicament orphelin au Japon de la part du Ministère de la Santé, du Travail et du Bien-être pour DYNE-251, son traitement pour la dystrophie musculaire de Duchenne (DMD) chez les patients présentant des mutations éligibles au skipping de l’exon 51. Le essai DELIVER Phase 1/2 en cours a démontré une amélioration fonctionnelle soutenue sur 18 mois, avec une expression significative de la dystrophine. Les résultats de la Cohorte d’Expansion Registrational sont attendus fin 2025. Cette designation japonaise s’ajoute aux désignations existantes aux États‑Unis (Thérapie Breakthrough, Fast Track, Rare Pediatric Disease et Orphan Drug) et en Europe (Orphan Drug). Le statut d’Orphan Drug au Japon offre des avantages tels que des subventions pour les coûts de développement et une éventuelle exclusivité de marché de 10 ans après l’approbation, applicable aux maladies affectant moins de 50 000 patients au Japon.
Dyne Therapeutics (Nasdaq: DYN) hat vom japanischen Gesundheitsministerium für Gesundheit, Arbeit und Wohlfahrt die Orphan-Drug-Deklaration für DYNE-251 erhalten, seine Behandlung der Duchenne-Muskeldystrophie (DMD) bei Patienten mit Mutationen, die für das Exon-Skipping von Exon 51 geeignet sind. Die laufende DELIVER-Phase-1/2-Studie zeigte eine anhaltende funktionelle Verbesserung über 18 Monate hinweg, mit signifikanter Dystrophin-Expression. Ergebnisse der Registrational Expansion Cohort werden für Ende 2025 erwartet. Die japanische Kennzeichnung ergänzt die bestehenden Kennzeichnungen in den USA (Breakthrough Therapy, Fast Track, Rare Pediatric Disease und Orphan Drug) und Europa (Orphan Drug). Der japanische Orphan-Drug-Status bietet Vorteile wie Subventionen für Entwicklungskosten und eine potenzielle 10-jährige Marktexklusivität nach der Zulassung, die für Krankheiten gilt, die weniger als 50.000 Patienten in Japan betreffen.
Dyne Therapeutics (ناسداك: DYN) قد حصلت على وضع الدواء اليتيم في اليابان من وزارة الصحة والعمل والخير للدواء DYNE-251، وهو علاج للضمور العضلي X-DMD Duchenne لدى المرضى الذين لديهم طفرات قابلة لتخطي الإكسون 51. أظهرت تجربة DELIVER من المرحلة 1/2 الجارية تحسنًا وظيفيًا مستمرًا حتى 18 شهرًا، مع تعبير ملحوظ للدستروفين. من المتوقع صدور نتائج cohort Expansion السجلي في أواخر عام 2025. يختم هذا الوضع الياباني مع وضعيات الولايات المتحدة (علاج اختراقي، المسار السريع، مرض نادر لدى الأطفال، دواء يتيم) وأوروبا (دواء يتيم). يوفر وضع الدواء اليتيم في اليابان مزايا مثل subsidies لتكاليف التطوير وإمكانية حقوق حصرية للسوق لمدة 10 سنوات بعد الموافقة، وتطبق على الأمراض التي تؤثر على أقل من 50,000 مريض في اليابان.
Dyne Therapeutics（纳斯达克股票代码：DYN）已获日本厚生劳动省对 DYNE-251 的外来药物（Orphan Drug）认证，用于对因外显子 51 跳跃而可治疗的 Duchenne 肌营养不良病（DMD）患者。正在进行的 DELIVER 阶段1/2 临床显示出在18个月内的持续功能改善，以及显著的肌萎缩蛋白（dystrophin）表达。注册扩展队列的结果预计于 2025 年底公布。日本的外来药物认证与美国（突破性治疗、快速通道、罕见儿童疾病、外来药物）及欧洲（外来药物）的现有认证共同存在。日本的外来药物地位提供的好处包括开发成本补贴，以及获批后可能的 10 年市场独占期，适用于在日本患者少于 5 万的疾病。
- Sustained functional improvement through 18 months in DELIVER trial
- Significant dystrophin expression observed in clinical trials
- Multiple regulatory designations across major markets (US, Europe, Japan)
- Potential 10-year market exclusivity in Japan if approved
- Development cost subsidies available through Japanese designation
- Results from Registrational Expansion Cohort still pending
- Limited to specific DMD patients with exon 51 skipping mutations
Insights
Japan's Orphan Drug designation for DYNE-251 enhances global regulatory momentum and market potential for Dyne's promising DMD therapy.
The Japanese MHLW's Orphan Drug designation for DYNE-251 represents a significant regulatory milestone for Dyne Therapeutics, complementing existing designations in the US (Breakthrough Therapy, Fast Track, Rare Pediatric Disease) and Europe. This designation provides tangible benefits including development subsidies and potential 10-year market exclusivity in Japan, strengthening the global commercial positioning of this therapy.
What's particularly compelling is the clinical data context behind this regulatory progress. The ongoing DELIVER trial has demonstrated "unprecedented and sustained functional improvement through 18 months," driven by significant dystrophin expression. For DMD—a devastating progressive muscle-wasting disease—functional improvement (rather than merely slowing decline) represents a potentially transformative clinical outcome.
The regulatory strategy appears comprehensive and well-executed. By securing orphan designations across major markets, Dyne is positioning DYNE-251 for accelerated development and review pathways globally. The exon 51 skipping approach targets one of the most prevalent DMD mutation subtypes, addressing approximately 13% of DMD patients.
The announcement's timing is strategically significant with the Registrational Expansion Cohort results expected in late 2025. This suggests Dyne is preparing for potential regulatory submissions across multiple jurisdictions, with this Japanese designation laying important groundwork for that market. The regulatory momentum across three major markets significantly enhances the therapy's commercial potential if approved.
DYNE-251 shows unprecedented functional improvement in DMD patients, with strategic global regulatory designations enhancing its development potential.
The clinical implications of DYNE-251's data are potentially groundbreaking for Duchenne muscular dystrophy treatment. DMD is a devastating X-linked recessive disorder characterized by progressive muscle degeneration, with patients typically losing ambulation by early adolescence and facing severely shortened lifespans. Current approved exon-skipping therapies have shown modest dystrophin production but limited functional benefits.
What distinguishes DYNE-251 is the reported "sustained functional improvement through 18 months" in the DELIVER trial. This represents a significant departure from the natural disease course, where function steadily declines. Functional improvement suggests DYNE-251 may not merely slow progression but potentially reverse some disease effects—an outcome rarely seen in DMD interventions.
The mechanism targeting exon 51 skipping addresses approximately 13% of DMD patients, representing one of the largest actionable mutation subgroups. While several exon 51 skipping therapies exist, including eteplirsen, golodirsen, and casimersen, their clinical benefit has been questioned due to modest dystrophin production and limited functional improvement.
Japan's Orphan Drug designation is particularly notable as the Japanese regulatory authority has historically been stringent in evaluating rare disease treatments. This designation, alongside the U.S. Breakthrough Therapy designation, suggests regulatory bodies recognize DYNE-251's potentially differentiated clinical profile.
The therapeutic landscape for DMD is evolving rapidly, and DYNE-251's apparent ability to deliver meaningful functional improvement could position it as a potential new standard of care for eligible patients if late-stage data confirms early results.
- Data from ongoing DELIVER trial demonstrated sustained functional improvement through 18 months; results from Registrational Expansion Cohort expected late 2025 -
WALTHAM, Mass., Sept. 29, 2025 (GLOBE NEWSWIRE) -- Dyne Therapeutics, Inc. (Nasdaq: DYN), a clinical-stage company, today announced that the Ministry of Health, Labour and Welfare (MHLW) in Japan has granted Orphan Drug designation for DYNE-251 in individuals with Duchenne muscular dystrophy (DMD) who have mutations in the DMD gene that are amenable to exon 51 skipping. DYNE-251 is being evaluated in the ongoing Phase 1/2 DELIVER global clinical trial.
“In the DELIVER trial, we’ve seen unprecedented and sustained functional improvement, driven by significant dystrophin expression, underscoring the potential of DYNE-251 to transform the care of people living with Duchenne muscular dystrophy,” said Doug Kerr, M.D., Ph.D., chief medical officer of Dyne. “With orphan drug designation now granted in Japan, complementing existing designations in the U.S. and Europe, DYNE-251 continues to advance as a promising next-generation exon 51 skipping therapy. Individuals with mutations amenable to exon 51 skipping are among the most prevalent and functionally impacted in the DMD population. Potentially addressing this unmet need further fuels our commitment to develop a therapy that delivers functional improvement for the Duchenne community, and we look forward to collaborating with the Japanese regulators to determine the regulatory pathway for DYNE-251 in Japan.”
In Japan, Orphan Drug designation is granted to drugs intended for the treatment of rare diseases affecting fewer than 50,000 patients in the country and for which there is a high medical need. Benefits include subsidies for development costs and potential market exclusivity for up to 10 years if approved. DYNE-251 has also been granted Breakthrough Therapy designation, Fast Track and Rare Pediatric Disease designations from the U.S. Food and Drug Administration (FDA), and Orphan Drug designation from the FDA and European Medicines Agency (EMA) for the treatment of individuals with DMD, amenable to exon 51 skipping.
About the DELIVER Trial
DELIVER is a global, randomized, placebo-controlled, double-blind, Phase 1/2 clinical trial evaluating the safety, tolerability and efficacy (as measured by both biomarker and functional improvement) of DYNE-251 in individuals with Duchenne muscular dystrophy (DMD) who have mutations in the DMD gene that are amenable to exon 51 skipping. The multiple ascending dose (MAD) portion of the study resulted in the selection of a registrational dose and regimen of 20 mg/kg of DYNE-251 administered every four weeks. A registrational expansion cohort to support a potential regulatory submission for U.S. Accelerated Approval is fully enrolled. The primary endpoint for this cohort is the change from baseline in dystrophin protein levels as measured by Western blot at 6 months. For more information on the DELIVER trial, visit clinicaltrials.gov (NCT05524883) and euclinicaltrials.eu (2023-510351-31-00).
About DYNE-251
DYNE-251 is an investigational therapeutic being evaluated in the Phase 1/2 global DELIVER clinical trial for individuals with DMD who have mutations in the DMD gene that are amenable to exon 51 skipping. DYNE-251 consists of a phosphorodiamidate morpholino oligomer (PMO) conjugated to an antigen-binding fragment (Fab) that binds to the transferrin receptor 1 (TfR1). It is designed to enable the production of near full-length dystrophin in muscle and the central nervous system (CNS) to provide functional improvement. DYNE-251 has received Breakthrough Therapy designation, Fast Track and Rare Pediatric Disease designations from the U.S. Food and Drug Administration (FDA), as well as Orphan Drug designation from the FDA and European Medicines Agency (EMA) for the treatment of individuals with DMD, amenable to exon 51 skipping.
In addition to DYNE-251, Dyne is building a DMD franchise and has preclinical programs targeting other exons, including 53, 45 and 44.
About Duchenne Muscular Dystrophy (DMD)
Duchenne muscular dystrophy (DMD) is a rare X-linked progressive neuromuscular disorder caused by mutations in the DMD gene. These mutations result in a complete or near-complete absence of dystrophin, a protein critical for maintaining muscle structure and function. DMD is the most common form of childhood-onset muscular dystrophy, affecting approximately 12,000 individuals in the U.S. and 16,000 in the EU. Symptoms typically emerge between ages 3 and 5, beginning with muscle weakness in the upper arms, thighs and pelvic region, and progressively impacting the lower limbs, forearms, neck and trunk. In addition to physical decline, individuals may experience cognitive impairment and neuropsychiatric challenges such as intellectual disabilities, learning difficulties and behavioral disorders. Despite existing therapies, there remains a significant unmet need for new treatment options that deliver functional improvement.
About Dyne Therapeutics
Dyne Therapeutics is focused on delivering functional improvement for people living with genetically driven neuromuscular diseases. We are developing therapeutics that target muscle and the central nervous system (CNS) to address the root cause of disease. The company is advancing clinical programs for myotonic dystrophy type 1 (DM1) and Duchenne muscular dystrophy (DMD), and preclinical programs for facioscapulohumeral muscular dystrophy (FSHD) and Pompe disease. At Dyne, we are on a mission to deliver functional improvement for individuals, families and communities. Learn more at https://www.dyne-tx.com/ and follow us on X, LinkedIn and Facebook.
Forward-Looking Statements
This press release contains forward-looking statements that involve substantial risks and uncertainties. All statements, other than statements of historical facts, contained in this press release, including statements regarding: Dyne’s strategy, future operations, prospects and plans, objectives of management; the potential of DYNE-251; the anticipated timelines for reporting additional data from the DELIVER clinical trial, submitting applications for marketing approval and commercial launches; and expectations regarding the timing and outcome of interactions with regulatory authorities, including whether Dyne will realize the anticipated benefits of orphan drug designation for DYNE-251 in Japan, constitute forward-looking statements within the meaning of The Private Securities Litigation Reform Act of 1995. The words “anticipate,” “believe,” “continue,” “could,” “estimate,” “expect,” “intend,” “may,” “might,” “objective,” “ongoing,” “plan,” “predict,” “project,” “potential,” “should,” “will” or “would,” or the negative of these terms, or other comparable terminology are intended to identify forward-looking statements, although not all forward-looking statements contain these identifying words. Dyne may not actually achieve the plans, intentions or expectations disclosed in these forward-looking statements, and you 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 these forward-looking statements as a result of various important factors, including: uncertainties inherent in the identification and development of product candidates, including the initiation and completion of preclinical studies and clinical trials; uncertainties as to the availability and timing of results from preclinical studies and clinical trials; uncertainties as to the timing of and Dyne’s ability to enroll patients in clinical trials; whether results from preclinical studies and data from clinical trials will be predictive of the final results of the clinical trials or other trials; whether data from clinical trials will support submission for regulatory approvals; uncertainties as to the FDA’s and other regulatory authorities’ interpretation of the data from Dyne's clinical trials and acceptance of Dyne's clinical programs and as to the regulatory approval process for Dyne’s product candidates; whether Dyne’s cash resources will be sufficient to fund its foreseeable and unforeseeable operating expenses, debt service obligations and capital expenditure requirements; as well as the risks and uncertainties identified in Dyne’s filings with the Securities and Exchange Commission (SEC), including the company’s most recent Form 10-Q and in subsequent filings Dyne may make with the SEC. In addition, the forward-looking statements included in this press release represent Dyne’s views as of the date of this press release. Dyne anticipates that subsequent events and developments will cause its views to change. However, while Dyne may elect to update these forward-looking statements at some point in the future, it specifically disclaims any obligation to do so. These forward-looking statements should not be relied upon as representing Dyne’s views as of any date subsequent to the date of this press release.
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FAQ
What is the significance of DYNE-251 receiving Orphan Drug designation in Japan?
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