Avidity Biosciences (RNA) has upcoming FDA regulatory milestones for Delpacibart Braxlosiran and del-desiran. The table below outlines estimated target dates and event types for these pending regulatory actions.
This section highlights FDA-related milestones and regulatory updates for drugs developed by Avidity Biosciences (RNA).
Over the past two years, Avidity Biosciences has reported clinical trial outcomes, regulatory submissions, approvals, and other FDA events for drugs and therapies such as
del-desiran, del-zota, EXPLORE44, Delpacibart, AOC, AOC, and AOC. For definitions of regulatory abbreviations such as NDA, BLA, or PDUFA, see the event status legend.
Select a button below to view the list of FDA events for that drug.
Del-desiran FDA Regulatory Timeline and Events
Del-desiran is a drug developed by Avidity Biosciences for the following indication: for Treatment of Myotonic Dystrophy Type 1.
This drug is under review by the U.S. Food and Drug Administration (FDA).
Below is a timeline of key regulatory milestones for this therapy.
- Drug:
- del-desiran
- Announced Date:
- February 18, 2026
- Indication:
- for Treatment of Myotonic Dystrophy Type 1
Announcement
Avidity Biosciences, Inc. announced that the final results from the completed Phase 1/2 MARINA® trial of delpacibart etedesiran (del-desiran) in people living with myotonic dystrophy type 1 (DM1) will be published in the February 19 issue of The New England Journal of Medicine (NEJM). The manuscript is titled "An Antibody Oligonucleotide Conjugate for Myotonic Dystrophy Type 1."
AI Summary
Avidity Biosciences announced that final results from the completed Phase 1/2 MARINA trial of delpacibart etedesiran (del‑desiran) in people with myotonic dystrophy type 1 (DM1) will be published in the February 19 issue of The New England Journal of Medicine. The manuscript is titled "An Antibody Oligonucleotide Conjugate for Myotonic Dystrophy Type 1."
The published MARINA data show del‑desiran effectively delivered siRNA to skeletal muscle, producing about a 40% mean reduction in DMPK mRNA and improving disease‑related RNA missplicing. Clinically, participants experienced benefits across multiple measures, including reduced myotonia, better muscle function and strength, improved mobility, and favorable patient‑reported outcomes. Safety was acceptable, with most adverse events mild or moderate. These findings support continued development of del‑desiran for DM1.
Del‑desiran (4 mg/kg) is being evaluated in the global Phase 3 HARBOR study in people 16 and older, with an open‑label extension (HARBOR‑OLE) for MARINA completers. HARBOR completed enrollment in July 2025, and a 54‑week topline readout is expected in the second half of 2026.
Read Announcement- Drug:
- del-desiran
- Announced Date:
- July 28, 2025
- Target Action Date:
- Q4 2025
- Estimated Target Date Range:
- October 1, 2025 - December 31, 2025
- Indication:
- for Treatment of Myotonic Dystrophy Type 1
Announcement
Avidity Biosciences, Inc. announced that On track to share updates from ongoing MARINA-OLE™ trial of del-desiran including long-term 4 mg/kg efficacy and safety data in Q4 2025 -
AI Summary
Avidity Biosciences today said it finished enrolling patients in its global Phase 3 HARBOR study of del-desiran for myotonic dystrophy type 1 (DM1). Topline results from this trial are expected in the second quarter of 2026. The company plans to submit marketing applications in the U.S., EU and Japan in the second half of 2026, aiming to deliver the first approved therapy for DM1.
In addition to HARBOR, Avidity is running the ongoing MARINA-OLE™ trial of del-desiran. It is on track to share long-term efficacy and safety data from the 4 mg/kg dose in the fourth quarter of 2025. These updates will provide more insight into the drug’s ability to slow or reverse disease progression.
If approved, del-desiran could be the first treatment that addresses the genetic cause of DM1. Researchers remain optimistic about its potential to improve muscle function and daily living activities for patients.
Read Announcement- Drug:
- del-desiran
- Announced Date:
- July 28, 2025
- Target Action Date:
- Q2 2026
- Estimated Target Date Range:
- April 1, 2026 - June 30, 2026
- Indication:
- for Treatment of Myotonic Dystrophy Type 1
Announcement
Avidity Biosciences, Inc. announced that Topline data from HARBOR, the first global Phase 3 clinical trial in DM1, are anticipated in the second quarter of 2026.
AI Summary
Avidity Biosciences, Inc. has finished enrolling participants in its global Phase 3 HARBOR trial of del-desiran for people living with myotonic dystrophy type 1 (DM1). The company expects to report topline results from HARBOR in the second quarter of 2026. Following that readout, Avidity plans to submit marketing applications for del-desiran in the United States, European Union and Japan during the second half of 2026. The firm also aims to share long-term efficacy and safety data from its ongoing MARINA-OLE trial in the fourth quarter of 2025.
The randomized, placebo-controlled, double-blind HARBOR study is testing del-desiran in about 150 adults with DM1 at roughly 40 sites worldwide. The primary endpoint is video hand opening time (vHOT) to measure myotonia, while key secondary endpoints include hand grip strength, total muscle strength and activities of daily living scores.
Del-desiran uses Avidity’s Antibody Oligonucleotide Conjugate (AOC™) platform to target the underlying genetic cause of DM1 by reducing toxic DMPK mRNA. If approved, it could become the first global therapy for this rare, progressive neuromuscular disease that currently has no approved treatments.
Read Announcement- Drug:
- del-desiran
- Announced Date:
- July 28, 2025
- Indication:
- for Treatment of Myotonic Dystrophy Type 1
Announcement
Avidity Biosciences, Inc. announced the completion of enrollment in the ongoing global Phase 3 HARBOR™ clinical trial of delpacibart etedesiran (del-desiran) for people living with myotonic dystrophy type 1 (DM1)
AI Summary
Avidity Biosciences announced on July 28, 2025 that it has finished enrolling about 150 participants in its global Phase 3 HARBOR trial of delpacibart etedesiran (del-desiran) for myotonic dystrophy type 1 (DM1). This randomized, placebo-controlled study tests the therapy every eight weeks. It measures improvements in myotonia through video hand opening time (vHOT) and also tracks muscle strength and daily living activities as key endpoints.
Topline results are expected in the second quarter of 2026. If positive, Avidity plans to submit marketing applications in the U.S., European Union and Japan in the second half of 2026—potentially making del-desiran the first approved treatment for DM1. The company also expects to share long-term safety and efficacy data from its ongoing MARINA-OLE extension study in late 2025. These milestones represent significant progress toward a new therapeutic option for people living with this rare, progressive neuromuscular disease.
Read Announcement- Drug:
- del-desiran
- Announced Date:
- April 8, 2025
- Indication:
- for Treatment of Myotonic Dystrophy Type 1
Announcement
Avidity Biosciences, Inc. announced that the Japan Ministry of Health, Labour and Welfare (MHLW) has granted Orphan Drug designation (ODD) to delpacibart etedesiran (del-desiran) for the treatment of myotonic dystrophy type 1 (DM1), an investigational treatment designed to address the root cause of DM1, an underrecognized, progressive and often fatal neuromuscular disease with no approved therapies.
AI Summary
Avidity Biosciences announced that Japan’s Ministry of Health, Labour and Welfare (MHLW) has granted Orphan Drug designation to its investigational treatment, delpacibart etedesiran (del-desiran), for myotonic dystrophy type 1 (DM1). DM1 is a rare, progressive neuromuscular disease with no approved therapies, and del-desiran is designed to tackle the root cause by reducing harmful DMPK mRNA levels in patients.
This designation, the first for a DM1 treatment in Japan, highlights the urgent need for effective therapies. It also supports Avidity’s global development plans, which include a Phase 3 trial known as HARBOR. The decision reinforces the potential of del-desiran to improve outcomes for people living with DM1, while providing benefits like prioritized regulatory consultations and fee reductions to help speed up its clinical development and eventual approval.
Read Announcement
Del-zota FDA Regulatory Timeline and Events
Del-zota is a drug developed by Avidity Biosciences for the following indication: for people living with Duchenne Muscular Dystrophy amenable to exon 44 skipping (DMD44).
This drug is under review by the U.S. Food and Drug Administration (FDA).
Below is a timeline of key regulatory milestones for this therapy.
- Drug:
- del-zota
- Announced Date:
- October 13, 2025
- Indication:
- for people living with Duchenne Muscular Dystrophy amenable to exon 44 skipping (DMD44).
Announcement
Avidity Biosciences, Inc. announced that the Company completed a positive pre-BLA meeting with the U.S. Food and Drug Administration (FDA) regarding its upcoming BLA submission of delpacibart zotadirsen (del-zota).
AI Summary
Avidity Biosciences, Inc. announced it completed a positive pre-BLA meeting with the FDA about its upcoming Biologics License Application for delpacibart zotadirsen (del-zota). Del-zota, which has Breakthrough Therapy designation, is an investigational treatment for Duchenne muscular dystrophy in patients with mutations suitable for exon 44 skipping (DMD44).
The company updated its BLA submission timing to Q1 2026 from year-end 2025. This change ensures the FDA receives extra data supporting the drug’s chemistry, manufacturing, and controls (CMC) package. Avidity said the FDA meeting was highly collaborative and provided clear CMC guidance. The company believes this alignment will help streamline the accelerated approval pathway.
Avidity remains confident in del-zota’s potential. It plans to file its first of three BLA submissions in Q1 2026 and is preparing a confirmatory study to support full global approval.
Read Announcement- Drug:
- del-zota
- Announced Date:
- September 10, 2025
- Indication:
- for people living with Duchenne Muscular Dystrophy amenable to exon 44 skipping (DMD44).
Announcement
Avidity Biosciences, Inc. announced positive new data from participants treated continuously with del-zota for one year in the EXPLORE44® and EXPLORE44-OLE™ trials.
AI Summary
Avidity Biosciences announced one-year results from the EXPLORE44 and EXPLORE44-OLE trials in people with Duchenne muscular dystrophy amenable to exon 44 skipping. Seventeen participants treated continuously with del-zota showed functional gains versus natural history declines: 4-Stair Climb improved by 2.1 seconds (vs. a 2.7-second decline), 10-Meter Walk/Run by 0.7 seconds (vs. a 1.5-second decline), Time to Rise from Floor by 3.2 seconds (vs. a 1.6-second decline), and Performance of Upper Limb by 1.5 points (vs. a 0.7-point decline). Blood creatine kinase dropped over 80%, staying near normal for up to 16 months, with 50% of participants reaching normal levels at one year. Dystrophin production rose by 25% of normal, reaching as high as 58%. Del-zota was well tolerated with mostly mild side effects.
Avidity remains on track to submit a Biologics License Application by year-end 2025 to seek accelerated approval.
Read Announcement- Drug:
- del-zota
- Announced Date:
- July 23, 2025
- Target Action Date:
- LATE 2025
- Estimated Target Date Range:
- October 1, 2025 - December 31, 2025
- Indication:
- for people living with Duchenne Muscular Dystrophy amenable to exon 44 skipping (DMD44).
Announcement
Avidity Biosciences, Inc. announced that its On track for planned BLA submission for del-zota at year end 2025
AI Summary
Avidity Biosciences, Inc., a biopharmaceutical company focused on Antibody Oligonucleotide Conjugates (AOCs™), announced that the FDA has granted Breakthrough Therapy designation to delpacibart zotadirsen (del-zota). Del-zota is designed to treat Duchenne muscular dystrophy with mutations amenable to exon 44 skipping (DMD44). It has shown substantial increases in dystrophin protein, significant exon skipping, and a consistent safety profile in the completed Phase 1/2 EXPLORE44 trial and in the ongoing Phase 2 EXPLORE44-OLE study.
Steve Hughes, M.D., Chief Medical Officer at Avidity, emphasized the urgent need for new DMD treatments and the encouraging biomarker results seen so far. The company remains on track for its planned BLA submission for del-zota at year end 2025. Topline and functional data from the EXPLORE44-OLE trial are expected in Q4 2025. Commercial preparations for a potential U.S. launch are already underway, laying the groundwork for future neuromuscular therapy launches.
Read Announcement- Drug:
- del-zota
- Announced Date:
- July 23, 2025
- Indication:
- for people living with Duchenne Muscular Dystrophy amenable to exon 44 skipping (DMD44).
Announcement
Avidity Biosciences, Inc. announced that the U.S. Food and Drug Administration (FDA) has granted Breakthrough Therapy designation to delpacibart zotadirsen (del-zota) for the treatment of Duchenne muscular dystrophy (DMD) in people living with mutations amenable to exon 44 skipping (DMD44).
AI Summary
Avidity Biosciences, Inc. announced that the U.S. Food and Drug Administration (FDA) has granted Breakthrough Therapy designation to delpacibart zotadirsen (del-zota) for treating Duchenne muscular dystrophy in patients with mutations amenable to exon 44 skipping (DMD44). This status recognizes the potential of del-zota to address the underlying cause of DMD44 and speed its development and review.
Del-zota uses a targeted antibody-oligonucleotide approach to deliver molecules that skip exon 44 of the dystrophin gene, helping cells produce near-full-length dystrophin protein. In the completed Phase 1/2 EXPLORE44 trial, patients showed significant increases in dystrophin, enhanced exon skipping and sustained reductions in creatine kinase, all with a favorable safety profile. The ongoing Phase 2 EXPLORE44 Open-Label Extension study is fully enrolled and will provide additional data by late 2025.
Avidity remains on track to submit a Biologics License Application (BLA) for del-zota at year-end 2025, aiming to bring this innovative therapy to people living with DMD44 as quickly as possible.
Read Announcement- Drug:
- del-zota
- Announced Date:
- March 17, 2025
- Indication:
- for people living with Duchenne Muscular Dystrophy amenable to exon 44 skipping (DMD44).
Announcement
Avidity Biosciences, Inc. announced positive del-zota topline data from the Phase 1/2 EXPLORE44® trial in people living with Duchenne muscular dystrophy amenable to exon 44 skipping (DMD44) demonstrating consistent, statistically significant improvements in dystrophin, exon skipping and creatine kinase as well as favorable safety and tolerability across the dose cohorts.
AI Summary
Avidity Biosciences recently announced positive topline results from the Phase 1/2 EXPLORE44® trial testing del-zota in patients with Duchenne muscular dystrophy (DMD) who are amenable to exon 44 skipping (DMD44). The data showed consistent and statistically significant improvements in key biomarkers, including increases in dystrophin production and exon skipping, along with a notable reduction in creatine kinase levels, a marker of muscle damage. In addition, del-zota demonstrated favorable safety and tolerability across different dose groups. These promising results suggest that del-zota effectively delivers the treatment components to skeletal and cardiac muscles, offering new hope for patients and families affected by DMD. The positive outcomes underscore the potential of this innovative therapy as it advances toward a planned Biologics License Application submission later this year, marking a significant milestone in the development of new RNA-based treatments for rare neuromuscular diseases.
Read Announcement- Drug:
- del-zota
- Announced Date:
- March 12, 2025
- Indication:
- for people living with Duchenne Muscular Dystrophy amenable to exon 44 skipping (DMD44).
Announcement
Avidity Biosciences, Inc. announced that the company will be presenting one oral and two poster presentations at the 2025 MDA Clinical & Scientific Conference (MDA) in Dallas, Texas, being held March 16-19, 2025 and will host an investor and analyst webcast event on March 17, 2025.
AI Summary
Avidity Biosciences, Inc. announced that it will present one oral and two poster presentations at the 2025 MDA Clinical & Scientific Conference in Dallas, Texas, from March 16-19, 2025. The oral presentation, scheduled for March 19, 2025, will feature topline data from the EXPLORE44 trial, which evaluates del-zota treatment in patients with Duchenne Muscular Dystrophy amenable to exon 44 skipping. Additionally, the company will showcase two poster presentations during the conference. Avidity will also host an investor and analyst webcast event on March 17, 2025, at 8:00 a.m. ET, where management will discuss the latest topline data from the EXPLORE44 trial. These presentations and webcast aim to highlight advances in RNA therapeutics and provide insight into how Avidity’s Antibody Oligonucleotide Conjugates (AOCs™) are being developed to address rare neuromuscular diseases.
Read Announcement
EXPLORE44 FDA Regulatory Events
EXPLORE44 is a drug developed by Avidity Biosciences for the following indication: in People Living with DMD44.
This drug is under review by the U.S. Food and Drug Administration (FDA).
Below is a timeline of key regulatory milestones for this therapy.
- Drug:
- EXPLORE44
- Announced Date:
- October 6, 2025
- Indication:
- in People Living with DMD44
Announcement
Avidity Biosciences, Inc. announced that it will deliver late-breaking oral and poster presentations at the 30th Annual International Congress of the World Muscle Society (WMS), to be held October 7-11, 2025, in Vienna, Austria.
AI Summary
Avidity Biosciences, a San Diego–based biopharma company developing Antibody Oligonucleotide Conjugates (AOCs™), announced that it will deliver late-breaking oral and poster presentations at the 30th Annual International Congress of the World Muscle Society (WMS). The event will take place October 7–11, 2025, in Vienna, Austria.
At WMS, Avidity will share data supporting its positive September 2025 findings from the Phase 1/2 EXPLORE44® and Phase 2 EXPLORE44-OLE™ trials of delpacibart zotadirsen (del-zota) in Duchenne muscular dystrophy patients with mutations amenable to exon 44 skipping (DMD44). One year of continuous treatment with del-zota showed reversal of disease progression, strong functional gains, higher dystrophin levels, and improved muscle health markers in patients, whether they could walk or not.
Dr. Kevin M. Flanigan will present an oral talk on October 11, and Dr. Aravindhan Veerapandiyan will present poster 674P on October 8. Both presentations will be posted on Avidity’s website after the congress.
Read Announcement- Drug:
- EXPLORE44
- Announced Date:
- September 10, 2025
- Indication:
- in People Living with DMD44
Announcement
Avidity Biosciences, Inc. announced positive new data from participants treated continuously with del-zota for one year in the EXPLORE44® and EXPLORE44-OLE™ trials.
AI Summary
Avidity Biosciences announced positive new data from participants treated continuously with del-zota for one year in the EXPLORE44® and EXPLORE44-OLE™ trials. The data showed a reversal of disease progression and significant improvements in key muscle function tests compared to natural history.
Participants achieved a 25 percent increase in dystrophin production (up to 58 percent of normal) and an over 80 percent drop in creatine kinase (CK) levels, maintained through 16 months. Functional gains included a 2.1 second improvement in 4-Stair Climb (versus a 2.7 second decline in natural history), a 0.7 second faster 10-Meter Walk/Run (versus 1.5 second decline), a 3.2 second faster Time to Rise from Floor (versus 1.6 second decline), and a 1.5-point gain in Performance of Upper Limb (versus a 0.7-point drop). North Star Ambulatory Assessment scores remained stable, while natural history patients lost 2.4 points.
All participants transitioned to a 5 mg/kg dose every six weeks, and del-zota showed a favorable long-term safety profile. Avidity remains on track to submit a Biologics License Application to FDA by the end of 2025 for accelerated approval.
Read Announcement
Delpacibart Braxlosiran FDA Regulatory Timeline and Events
Delpacibart Braxlosiran is a drug developed by Avidity Biosciences for the following indication: In People Living with Facioscapulohumeral Muscular Dystrophy.
This drug is under review by the U.S. Food and Drug Administration (FDA).
Below is a timeline of key regulatory milestones for this therapy.
- Drug:
- Delpacibart Braxlosiran
- Announced Date:
- June 11, 2025
- Indication:
- In People Living with Facioscapulohumeral Muscular Dystrophy
Announcement
Avidity Biosciences, Inc. announced that the company will be presenting two oral and one poster presentations at the 32nd Annual FSHD Society International Research Congress, being held June 12-13, 2025, in Amsterdam, the Netherlands.
AI Summary
Avidity Biosciences, Inc. announced it will showcase its latest research at the 32nd Annual FSHD Society International Research Congress in Amsterdam on June 12-13, 2025. The company will deliver two oral presentations and one poster presentation, highlighting important advancements in therapies for facioscapulohumeral muscular dystrophy (FSHD).
Dr. Jeffrey M. Statland will present topline data from the dose escalation cohorts of the Phase 1/2 FORTITUDE trial investigating delpacibart braxlosiran (del-brax). Meanwhile, Dr. Stephen Tapscott will share findings on a novel DUX4-regulated circulating biomarker, offering new insights into FSHD diagnostics. These presentations reflect Avidity’s ongoing commitment to advancing RNA therapeutics through its innovative Antibody Oligonucleotide Conjugates (AOCs). For more details, the research sessions will be available on the company’s website.
Read Announcement- Drug:
- Delpacibart Braxlosiran
- Announced Date:
- June 9, 2025
- Target Action Date:
- H2 2026
- Estimated Target Date Range:
- July 1, 2026 - December 31, 2026
- Indication:
- In People Living with Facioscapulohumeral Muscular Dystrophy
Announcement
Avidity Biosciences, Inc. announced that Planning accelerated approval BLA submission in H2 2026
AI Summary
Avidity Biosciences recently announced its plan to submit a Biologics License Application (BLA) for accelerated approval in the second half of 2026. The company is advancing its investigational therapy, delpacibart braxlosiran (del‐brax), designed to target the disease-causing DUX4 gene in patients with facioscapulohumeral muscular dystrophy (FSHD). This therapy aims to treat the root cause of FSHD, which leads to progressive muscle weakness and loss of function.
The decision to pursue an accelerated approval pathway follows promising early clinical data from the FORTITUDE study, where del‐brax showed consistent improvements in muscle strength, mobility, and patient-reported outcomes compared to placebo. Avidity hopes that building on these encouraging results will support the accelerated BLA submission and provide an effective treatment option for patients battling FSHD.
Read Announcement- Drug:
- Delpacibart Braxlosiran
- Announced Date:
- June 9, 2025
- Target Action Date:
- Q2 2026
- Estimated Target Date Range:
- April 1, 2026 - June 30, 2026
- Indication:
- In People Living with Facioscapulohumeral Muscular Dystrophy
Announcement
Avidity Biosciences, Inc announced that topline data from FORTITUDE™ biomarker cohort in Q2 2026 .
AI Summary
Avidity Biosciences, Inc. has announced promising progress in its Phase 1/2 FORTITUDE program for del-brax, a novel treatment for Facioscapulohumeral Muscular Dystrophy (FSHD). The topline data from the dose escalation cohorts have shown significant improvements in muscle strength, functional mobility, and patient-reported outcomes while also demonstrating rapid and meaningful biomarker reductions. Building on these findings, the company plans to submit a Biologics License Application (BLA) for accelerated approval in the second half of 2026. Crucially, topline data from the FORTITUDE biomarker cohort, with its primary endpoint focused on lowering KHDC1L—a novel DUX4-regulated circulating biomarker—are expected in Q2 2026. These results underscore del-brax’s potential to directly target the underlying cause of FSHD, offering hope for improved quality of life to patients with this progressive and currently untreatable condition.
Read Announcement- Drug:
- Delpacibart Braxlosiran
- Announced Date:
- June 9, 2025
- Indication:
- In People Living with Facioscapulohumeral Muscular Dystrophy
Announcement
Avidity Biosciences, Inc. announced the accelerated approval regulatory pathway in the United States is open for delpacibart braxlosiran (del-brax) in the treatment of facioscapulohumeral muscular dystrophy (FSHD).
AI Summary
Avidity Biosciences recently announced that the accelerated approval regulatory pathway in the United States is now open for its investigational therapy, delpacibart braxlosiran (del-brax), for treating facioscapulohumeral muscular dystrophy (FSHD). Del-brax is designed to target the underlying cause of FSHD by directly inhibiting the DUX4 gene, which is linked to the progressive loss of muscle strength and function. Early clinical data from the FORTITUDE study showed promising signs of improved muscle function and strength for participants receiving del-brax compared to those on placebo.
Based on these positive results, Avidity is pursuing a faster review process for del-brax, with plans to submit a Biologics License Application (BLA) in the second half of 2026. This regulatory pathway could potentially speed up the availability of the first approved treatment for FSHD, offering new hope to thousands affected by this rare, debilitating condition.
Read Announcement- Drug:
- Delpacibart Braxlosiran
- Announced Date:
- June 9, 2025
- Indication:
- In People Living with Facioscapulohumeral Muscular Dystrophy
Announcement
Avidity Biosciences, Inc. announced that it has initiated its global, confirmatory, Phase 3 FORWARD™ study intended to support a subsequent full approval package for del-brax for people living with FSHD in the U.S. and additional countries around the world.
AI Summary
Avidity Biosciences, Inc. has launched its global, confirmatory Phase 3 FORWARD™ study for del-brax, an investigational therapy designed to treat facioscapulohumeral muscular dystrophy (FSHD). The study aims to support a full regulatory approval package for del-brax in the United States and other countries around the world. Del-brax targets the gene DUX4, which is responsible for the progression of FSHD, a debilitating neuromuscular disease that leads to significant muscle weakness and loss of function. With promising early data indicating improvements in muscle strength, mobility, and quality of life, this Phase 3 trial marks a crucial step forward in confirming the drug’s clinical benefits. Avidity’s strategy focuses on providing new treatment options for people living with FSHD, addressing unmet medical needs and potentially changing the treatment landscape for this rare disorder.
Read Announcement- Drug:
- Delpacibart Braxlosiran
- Announced Date:
- March 31, 2025
- Indication:
- In People Living with Facioscapulohumeral Muscular Dystrophy
Announcement
Avidity Biosciences, Inc. announced the completion of enrollment in the biomarker cohort in the Phase 1/2 FORTITUDE™ clinical trial of delpacibart braxlosiran (del-brax) in people living with facioscapulohumeral muscular dystrophy (FSHD).
AI Summary
Avidity Biosciences, Inc. recently reached a key milestone by completing enrollment in the biomarker cohort of its Phase 1/2 FORTITUDE™ clinical trial. This phase is studying delpacibart braxlosiran (del-brax) in 51 participants with facioscapulohumeral muscular dystrophy (FSHD), a rare disease that causes progressive muscle weakness. The biomarker cohort is designed to support a potential accelerated approval pathway in the U.S., focusing on changes in DUX4 gene expression, which is linked to the muscle degeneration seen in FSHD.
Early data have shown promising results, including significant reductions in DUX4-regulated gene activity and trends toward improved muscle function. Avidity Biosciences plans to share additional data and key regulatory updates in the near future, moving closer to bringing the first approved therapy for FSHD to patients who currently have no treatment options.
Read Announcement
AOC 1001 FDA Regulatory Events
AOC 1001 is a drug developed by Avidity Biosciences for the following indication: Myotonic Dystrophy type 1 (DM1).
This drug is under review by the U.S. Food and Drug Administration (FDA).
Below is a timeline of key regulatory milestones for this therapy.
- Drug:
- AOC 1001
- Announced Date:
- October 3, 2024
- Indication:
- Myotonic Dystrophy type 1 (DM1)
Announcement
Avidity Biosciences, Inc. announced that the U.S. Food and Drug Administration (FDA) has removed the partial clinical hold on delpacibart etedesiran (del-desiran/AOC 1001), an investigational treatment designed to address the root cause of myotonic dystrophy type 1 (DM1).
AI Summary
The U.S. Food and Drug Administration (FDA) has removed the partial clinical hold on Avidity Biosciences’ investigational treatment, delpacibart etedesiran (del-desiran/AOC 1001). This treatment targets the root cause of myotonic dystrophy type 1 (DM1) by lowering the levels of DMPK mRNA, a key factor in the disease’s progression. Del-desiran uses a novel approach combining a monoclonal antibody that binds to the transferrin receptor with a siRNA that specifically targets the problematic mRNA.
The FDA’s decision allows the ongoing Phase 3 HARBOR trial to continue evaluating the safety and effectiveness of del-desiran in DM1 patients. DM1 is a progressive neuromuscular disease that currently has no approved therapies, making this development a significant step toward finding a treatment for those affected by this challenging condition.
Read Announcement
AOC 1044 FDA Regulatory Events
AOC 1044 is a drug developed by Avidity Biosciences for the following indication: Designed to deliver phosphorodiamidate morpholino oligomers (PMOs).
This drug is under review by the U.S. Food and Drug Administration (FDA).
Below is a timeline of key regulatory milestones for this therapy.
- Drug:
- AOC 1044
- Announced Date:
- August 9, 2024
- Indication:
- Designed to deliver phosphorodiamidate morpholino oligomers (PMOs)
Announcement
Avidity Biosciences, Inc. announced positive AOC 1044 5 mg/kg data demonstrated unsurpassed delivery of phosphorodiamidate morpholino oligomers (PMO) concentrations to skeletal muscle, statistically significant increase of 25% of normal in dystrophin production and statistically significant increase of 37% in exon 44 skipping in people living with Duchenne muscular dystrophy mutations amenable to exon 44 skipping (DMD44) in the Phase 1/2 EXPLORE44™ clinical trial.
AI Summary
Avidity Biosciences, Inc. announced positive Phase 1/2 EXPLORE44™ trial results for delpacibart zotadirsen (AOC 1044) in patients with Duchenne muscular dystrophy mutations amenable to exon 44 skipping (DMD44). At a 5 mg/kg dose, the treatment delivered unsurpassed concentrations of phosphorodiamidate morpholino oligomers (PMO) to skeletal muscle. The trial data showed a statistically significant 37% increase in exon 44 skipping and a 25% boost in dystrophin production—reaching 25% of normal levels—with some patients achieving up to 54% of normal dystrophin. Additionally, creatine kinase levels were reduced by over 80% compared to baseline, indicating an improvement in muscle health. The data suggest that delpacibart zotadirsen may offer a transformative treatment approach for DMD44 by enhancing muscle function and slowing disease progression, with a favorable safety and tolerability profile supporting further development and regulatory review.
Read Announcement
AOC 1020 FDA Regulatory Events
AOC 1020 is a drug developed by Avidity Biosciences for the following indication: Facioscapulohumeral Muscular Dystrophy (FSHD).
This drug is under review by the U.S. Food and Drug Administration (FDA).
Below is a timeline of key regulatory milestones for this therapy.
- Drug:
- AOC 1020
- Announced Date:
- June 12, 2024
- Indication:
- Facioscapulohumeral Muscular Dystrophy (FSHD)
Announcement
Avidity Biosciences, Inc. announced positive initial AOC 1020 data from the Phase 1/2 FORTITUDE™ trial demonstrating unprecedented and consistent reductions of greater than 50% in DUX4 regulated genes, trends of functional improvement, and favorable safety and tolerability in people living with facioscapulohumeral muscular dystrophy (FSHD).
AI Summary
Avidity Biosciences announced encouraging initial results from the Phase 1/2 FORTITUDE™ trial for delpacibart braxlosiran (AOC 1020), an investigational therapy for facioscapulohumeral muscular dystrophy (FSHD). The data showed unprecedented and consistent reductions of over 50% in DUX4 regulated genes at a four‐month assessment in patients treated with a 2 mg/kg dose. These gene expression reductions indicate that the therapy directly targets the underlying cause of FSHD. In addition to the biomarker improvements, trends also pointed to functional benefits such as enhanced muscle strength and improved reachable workspace, along with positive patient and clinician reported outcomes. The treatment was well tolerated, with only mild to moderate adverse events observed. Based on these promising results, Avidity plans to speed up the initiation of registrational cohorts in its ongoing FORTITUDE™ trial.
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