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FDA Acceptance of Casimersen

Sarepta Therapeutics Announces FDA Acceptance of Casimersen (SRP-4045) New Drug Application for Patients with Duchenne Muscular Dystrophy Amenable to Skipping Exon 45

Original press release, CAMBRIDGE, Mass., Aug. 25, 2020 (GLOBE NEWSWIRE)

Quickly

  • FDA grants Priority Review Status and sets regulatory action date for February 25, 2021
  • FDA has indicated it does not currently plan to hold an advisory committee meeting to discuss the application
  • Received FDA’s conditional approval of AMONDYS 45™ as a brand name for casimersen
  • Casimersen has been studied for the treatment of exon 45 amenable patients, approximately eight percent of patients with Duchenne

About the FDA Acceptance of Casimersen

Sarepta Therapeutics, Inc. announced the U.S. Food and Drug Administration (FDA) has accepted the Company’s New Drug Application (NDA) seeking accelerated approval for casimersen (SRP-4045) and provided a regulatory action date of February 25, 2021. The FDA has indicated it does not currently plan to hold an advisory committee to discuss the application. In addition, the Company has received conditional approval of AMONDYS 45 as the brand name for casimersen. Casimersen, a phosphorodiamidate morpholino oligomer (PMO), is engineered to treat patients with Duchenne muscular dystrophy (DMD) who have genetic mutations that are amenable to skipping exon 45 of the dystrophin gene.

The Company submitted its NDA filing in June 2020 and requested priority review, which the FDA granted. The NDA included data from the casimersen arm of the ESSENCE study (also known as Study 4045-301), a global, randomized, double-blind, placebo-controlled Phase 3 study evaluating the efficacy and safety of casimersen in patients amenable to skipping exons 45. An interim analysis from ESSENCE demonstrated a statistically significant increase in dystrophin production as measured by western blot in patients who received casimersen compared to baseline and placebo. The study is ongoing and remains blinded to collect additional efficacy and safety data.

Doug Ingram, president and chief executive officer, Sarepta Therapeutics – “The FDA’s acceptance of our NDA for casimersen is an important step toward our goal of rapidly bringing therapies to patients living with Duchenne muscular dystrophy. If it is approved, casimersen, our third exon-skipping medicine in our PMO RNA-based platform, will offer treatment to the 8% of Duchenne patients who are amenable to exon 45 skipping.”

About Casimersen

Casimersen uses Sarepta’s proprietary phosphorodiamidate morpholino oligomer (PMO) chemistry and exon-skipping technology to skip exon 45 of the Duchenne gene. Casimersen is designed to bind to exon 45 of dystrophin pre-mRNA, resulting in exclusion, or “skipping,” of this exon during mRNA processing in patients with genetic mutations that are amenable to exon 45 skipping. Exon skipping is intended to allow for the production of an internally truncated dystrophin protein. Read more here.

About the ESSENCE Study

The ESSENCE study is a double-blind, placebo-controlled, multi-center Phase 3 study evaluating the efficacy and safety of casimersen (SRP-4045) and golodirsen (SRP-4053, approved as VYONDYS 53™). Eligible patients with out-of-frame deletion mutations amenable to exon 45 or 53 skippings are randomized to receive once-weekly intravenous (IV) infusions of 30 mg/kg of SRP-4045 or 30 mg/kg of SRP-4053, respectively (combined-active group) or placebo for up to 96 weeks. This is followed by an open-label extension period in which all patients will receive open-label active treatment for 48 weeks, up to week 144 of the study.

Clinical efficacy is being assessed at regularly scheduled study visits, including functional tests such as the six-minute walk test (6MWT). All patients undergo a muscle biopsy at baseline and will undergo a second muscle biopsy either at week 48 or week 96.

Safety is being assessed through the collection of adverse events, laboratory tests, electrocardiograms (ECGs), echocardiograms (ECHOs), vital signs, and physical examinations throughout the study.

About Sarepta Therapeutics

The Company has built an impressive position in Duchenne muscular dystrophy (DMD) and in gene therapies for limb-girdle muscular dystrophies (LGMDs), mucopolysaccharidosis type IIIA, Charcot-Marie-Tooth (CMT), and other CNS-related disorders, with more than 40 programs in various stages of development. The Company’s programs and research focus span several therapeutic modalities, including RNA, gene therapy and gene editing. For more information, please visit www.sarepta.com or follow them on TwitterLinkedInInstagram and Facebook.

More about DMD

DMD is caused by genetic mutations that prevent dystrophin production. Patients with DMD experience progressive and irreversible muscle loss with symptoms appearing as early as two years of age. 

Duchenne muscular dystrophy occurs primarily in males. Early signs of DMD may include delayed ability to sit, stand or walk. There is a progressive loss of mobility, and by adolescence, patients with DMD may require the use of a wheelchair. Cardiac and respiratory muscle problems begin in the teenage years and lead to serious, life-threatening complications. Read more here.

World Duchenne Awareness Day

September 7 is World Duchenne Awareness Day. On this day, we raise awareness for Duchenne and Becker muscular dystrophy (DMD and BMD) around the globe.

An initiative coordinated by the World Duchenne Organization

Together, we are stronger.

The current Corona pandemic is profoundly impacting our daily lives. It changes the way we spend time altering our habits. Although it is changing our everyday life, it cannot overrule our projects and voices.

As the Duchenne community, we are very aware of how strongly this affects us in terms of isolation, facing emergencies and adaptation. We are familiar with words as fear, pain and distance. However, World Duchenne Organization is trying to turn fear into hope, pain into resilience, and distance into closeness.

This World Duchenne Awareness Day 2020, we share a message that many people have experienced and are still experiencing: Together, we are stronger. Even after the emergency will finish, our cause will always be there, our engagement is still there, and we need every single person to be involved.

 

Duchenne and the brain

September 7 is World Duchenne Awareness Day. On this day, we raise awareness for Duchenne and Becker muscular dystrophy (DMD and BMD) around the globe. As every year, we have a special theme that deserves more attention: this year, that will be Duchenne and the brain. The seventh day of the ninth month represents the 79 exons in the dystrophin gene.

The same protein that is missing in the muscle, causing muscle breakdown, is also missing in the brain. This can cause problems like learning difficulties and behavioural issues such as ADD, ADHD, OCD and autism. For many families, these issues result in more stress and worries in daily life than physical problems.

This crucial neurological aspect of DMD/BMD was already recognized in 1861 when Duchenne de Boulogne first described this neuromuscular condition. In the last decades, however, most of the efforts have focused on improving outcomes related to muscle weakness. Brain involvement received less attention.

What we plea for is early screening, appropriate testing, more research and better care on this aspect of the disease. This is needed to have everyone reach their full potential.

 

Video from World Duchenne Organization

 

About DMD/BMD

Duchenne and Becker muscular dystrophy (DMD and BMD) are two muscle-wasting conditions. Mutations in the dystrophin gene cause both. A certain part of the DNA is missing, duplicated, or changed, so the code cannot be read correctly by the body. This leads to the absence of the dystrophin protein, which plays an essential role in the muscle and brain. Without dystrophin, muscle cells easily get damaged, leading to a loss of these cells and, thereby, muscle function.

This can also happen in the brain, where dystrophin is missing as well. Where Duchenne individuals have a complete lack of dystrophin, people affected with Becker muscular dystrophy have lower levels or a shorter version of this protein.

 

Key facts

  • Duchenne and Becker muscular dystrophy are rare genetic diseases defined by muscle weakness
  • The dystrophin protein cannot be made due to an error on the X chromosome
  • Currently, there is no cure available for this fatal disease
  • Each year, 1 in 5.000 newborn boys receive the diagnosis DMD
  • Lack of awareness contributes to an average delay of diagnosis of 2,5 years

 

Useful links

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Viltolarsen, exon 53 skipping therapy, approved

N.S. Pharma’s VILTEPSO™ (viltolarsen) injection now FDA-Approved in the U.S. for the treatment of Duchenne muscular dystrophy in patients amenable to exon 53 skipping therapy.

 

  • Patients taking VILTEPSO showed an increase in dystrophin expression to an average of 5.9% of normal after 20-24 weeks of treatment.
  • Overall, in a pivotal study of VILTEPSO, 100% of patients showed an increase in dystrophin levels after treatment, and 88% of patients showed dystrophin levels of 3% of average or higher.

Press release > PARAMUS, NJ: August 12, 2020 – N.S. Pharma, Inc.

 

N.S. Pharma announced that the U.S. Food & Drug Administration (FDA) has approved VILTEPSO™ (viltolarsen) injection for patients with Duchenne muscular dystrophy (DMD) who are amenable to exon 53 skipping therapy. VILTEPSO received an Accelerated Approval by the FDA based on an increase in dystrophin, an essential protein for supporting muscle health. Since a lack of dystrophin is the underlying cause of DMD, increasing dystrophin as much and as early as possible is a key goal in the treatment of DMD. VILTEPSO is the first and only exon 53 skipping therapy to demonstrate an increase in dystrophin in children as young as four years old. The continued approval of VILTEPSO may be contingent on confirmation of a clinical benefit in the Phase 3 confirmatory trial.

 

More about the study

The VILTEPSO New Drug Application (NDA) submission included results from a Phase 2, a two-period study in patients aged four to less than ten years of age conducted in North America (Study 1, N=16) and a multicenter, open-label study in boys five to less than 18 years of age conducted in Japan (Study 2, N=16).

In Study 1, of those patients who received the recommended dose of 80 mg/kg/wk (N=8), 100% of patients (8/8) showed an increase in dystrophin levels after treatment with VILTEPSO and 88% of patients (7/8) showed dystrophin levels of 3% or greater than normal. Overall, after 20-24 weeks of treatment, a mean increase in dystrophin expression to nearly 6% of normal was observed with VILTEPSO (80 mg/kg/wk) versus 0.6% at baseline. The most common side effects of VILTEPSO included upper respiratory tract infection, injection site reaction, cough and fever.

 

Vamshi Rao, MD, Ann & Robert H. Lurie Children’s Hospital of Chicago – “For decades, neurologists who treat DMD have hoped for the discovery of therapies capable of significantly improving dystrophin production, and the magnitude of dystrophin increases observed with VILTEPSO are impressive. The approval of VILTEPSO is an exciting development for DMD patients amenable to exon 53 skipping therapy and may rapidly become a foundational treatment for these patients.”

 

  • In clinical studies, no patients experienced kidney toxicity during treatment with VILTEPSO. However, kidney toxicity from drugs like VILTEPSO may be possible. Your doctor may monitor the health of your kidneys before starting and during treatment with VILTEPSO.
  • The most common side effects of VILTEPSO included upper respiratory tract infection, injection site reaction, cough and fever.
  • For additional safety information, please see the full Prescribing Information.

N.S. Pharma continues to study the safety and efficacy of VILTEPSO in the confirmatory Phase 3 RACER53 trial. This study was initiated in October 2019 and is currently enrolling. The purpose of this Phase 3 trial is to confirm the clinical findings that were submitted under the Accelerated Approval pathway.

 

About VILTEPSO™ (viltolarsen) injection

Before its approval in the U.S., VILTEPSO was granted Priority Review as well as Rare Pediatric Disease, Orphan Drug and Fast Track Designations. In March 2020, VILTEPSO was approved in Japan for the treatment of patients with DMD who are amenable to exon 53 skipping therapy. Before its approval in Japan, VILTEPSO was granted the SAKIGAKE designation, Orphan Drug designation, and designation of Conditional Early Approval System.

VILTEPSO is indicated for the treatment of Duchenne muscular dystrophy (DMD) in patients who have a confirmed mutation of the DMD gene that is amenable to exon 53 skipping. This indication is approved under Accelerated Approval based on an increase in dystrophin production in skeletal muscle observed in patients treated with VILTEPSO. Continued approval for this indication may be contingent upon verification and description of clinical benefit in a confirmatory trial. It is an infusion that doctors administer into the bloodstream.

 

How Viltolarsen works

Viltolarsen contains an artificial piece of mRNA that masks exon 53, causing cells to “skip” this exon when they are making mature mRNA. This skip restores the so-called “reading frame” of the mRNA molecule. In other words, it ensures that the remaining exons fit together again, allowing a cell’s protein-making machinery to synthesize a shorter but working dystrophin protein.

Because viltolarsen is specific to exon 53, the treatment is effective only in those DMD patients who have a mutation that is amenable to exon 53 skipping. Thanks to Muscular Dystrophy News Today for this description.

 

N.S. Pharma

NS Pharma, Inc. is a wholly-owned subsidiary of Nippon Shinyaku Co., Ltd. For more information, please visit www.nspharma.com. N.S. Pharma is a registered trademark of the Nippon Shinyaku group of companies.

N.S. Pharma will provide families, physicians and healthcare professionals dedicated and individualized resources every step of the way through the N.S. Support program. N.S. Pharma will be hosting a series of webinars on the comprehensive care coordination available through N.S. Support. Follow them on LinkedIn and Twitter for information and registration for upcoming webinars.

 

Tsugio Tanaka, President, NS Pharma, Inc. – “On behalf of NS Pharma and Nippon Shinyaku, I would like to express our deepest gratitude to the families and physicians who participated in our clinical trials and made today’s approval possible. We are proud to now offer an important new treatment option to help address the significant unmet needs caused by this devastating disease.”

 

More about DMD

DMD is caused by genetic mutations that prevent dystrophin production. Patients with DMD experience progressive and irreversible muscle loss with symptoms appearing as early as two years of age. 

Duchenne muscular dystrophy occurs primarily in males. Early signs of DMD may include delayed ability to sit, stand or walk. There is a progressive loss of mobility, and by adolescence, patients with DMD may require the use of a wheelchair. Cardiac and respiratory muscle problems begin in the teenage years and lead to serious, life-threatening complications. Read more here.