Delpacibart zotadirsen
An investigational treatment for Duchenne Muscular Dystrophy.
Drug facts
The same compound appears under different names depending on the context. Here is how to identify Delpacibart zotadirsen wherever you encounter it, plus the key facts at a glance.
- Generic name
- Delpacibart zotadirsen
- Development codes
- AOC 1044, del-zota, KPE179
- Drug class
- Antibody oligonucleotide conjugate (exon skipping therapy)
- Manufacturer
- Avidity Biosciences, a Novartis company
- How it's taken
- IV infusion, in trials and under FDA review
An investigational IV infusion for Duchenne muscular dystrophy in people whose dystrophin gene change can be treated by skipping exon 44, a group Avidity calls DMD44[1].
- Novartis said on September 8, 2026 that the FDA had accepted its Biologics License Application for priority review under the accelerated approval pathway, and no FDA decision date has been made public[1][2].
- In the EXPLORE44 trial, dystrophin rose by about 25% of normal on del-zota, against no rise on placebo[7].
- No exon skipping therapy is FDA approved for people amenable to exon 44 skipping[7].
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Where Delpacibart zotadirsen fits
Del-zota is an investigational exon 44 skipping treatment under FDA review for Duchenne muscular dystrophy in people whose gene change is amenable to exon 44 skipping[1].
- Standard Duchenne care centers on corticosteroids along with heart, lung and physical therapy care.
- The 4 FDA-approved exon skipping drugs target other exons: Exondys 51 skips exon 51, Vyondys 53 and Viltepso skip exon 53, and Amondys 45 skips exon 45, so none of them is approved for people amenable to exon 44 skipping.
- Del-zota has not been compared head to head with any other Duchenne treatment, and its functional results so far compare treated participants with untreated natural history records rather than a placebo group[5].
- A family can ask a neuromuscular specialist whether genetic testing confirms a variant amenable to exon 44 skipping and whether the managed access program could fit.
How Delpacibart zotadirsen works
Duchenne happens when a change in the dystrophin gene stops muscle from making dystrophin, a protein that protects muscle fibers as they contract. In some people, skipping 1 piece of the gene's message, called exon 44, lets the cell read past the error and make a shorter dystrophin that still partly works. Del-zota carries a short man-made strand of genetic material, a phosphorodiamidate morpholino oligomer (PMO), that tells the cell to skip exon 44[8].
PMOs given on their own reach muscle poorly, so del-zota joins the PMO to an antibody that latches onto transferrin receptor 1, a doorway muscle cells use to take in iron, which carries the PMO into skeletal and heart muscle[8][5].
Clinical trial results
EXPLORE44 (NCT05670730) was a Phase 1/2 trial. Its Part B randomized 26 males with DMD44 aged 7 to 27, at 10 US sites, 3 to 1 to del-zota (9 at 5mg/kg, 10 at 10mg/kg) or placebo (7); its main measure was safety. At month 4 or 5, exon 44 skipping rose by an average of 36.6% at 5mg/kg and 43.4% at 10mg/kg against 1.6% on placebo, and dystrophin rose by 25.0% and 25.6% of normal against a change of minus 0.7% on placebo.
The results were published in Lancet Neurology in November 2026[9][7]. In the open-label extension, EXPLORE44-OLE (NCT06244082)[10], Avidity reported on September 10, 2025 that creatine kinase, a blood marker of muscle damage, fell rapidly by more than 80% from baseline and stayed near normal for up to 16 months. Avidity also reported that participants did better than a matched group of untreated boys from natural history records on timed tests such as rising from the floor and climbing 4 stairs; that comparison was not with a placebo group[5].
The confirmatory Phase 3 trial, SAFARI44 (NCT07587242), began in September 2026 and is recruiting about 70 boys aged 7 to 16 who can walk and take steady corticosteroids, comparing del-zota with placebo for 54 weeks; its main measure is the speed of rising from the floor, and its sites are outside the US[11][1]. A US managed access program (NCT07250737) lists del-zota as available for eligible people aged 2 and older[12].
Main registered trial: NCT05670730 on ClinicalTrials.gov. Check it for the current status, sites and contacts before asking about enrollment.
Side effects and safety
Del-zota has no FDA label yet, so the full list of side effects and warnings is not set. In the placebo-controlled part of EXPLORE44, 16 of 19 participants on del-zota (84%) and 6 of 7 on placebo (86%) had at least 1 side effect, most of them mild or moderate. In the 5mg/kg group, 2 participants stopped because of reactions to the infusion: 1 anaphylactic reaction and 1 infusion-related reaction[7].
In the extension study, Avidity reported that 1 more participant stopped after a hypersensitivity reaction, and that the most common side effects were upper respiratory symptoms, diarrhea, falls, back pain and headache[5].
This is not a complete list of side effects. Talk to your doctor or pharmacist about what to expect and when to seek medical attention.
Taking Delpacibart zotadirsen
Given as an IV infusion. In EXPLORE44, participants received 3 doses of either 5mg/kg every 6 weeks or 10mg/kg every 8 weeks[7], and everyone moved to 5mg/kg every 6 weeks in the extension study[5]. The Phase 3 SAFARI44 trial also gives it every 6 weeks[11]. The dose and schedule for any approved use would be set by the FDA label.
Development history
EXPLORE44 began in late 2022 and its extension in January 2024[9][10]. The FDA granted del-zota Breakthrough Therapy designation, which Avidity announced on July 23, 2025, and it also holds Orphan Drug, Rare Pediatric Disease and Fast Track designations[6][5]. Novartis completed its acquisition of Avidity Biosciences on February 27, 2026[3]. Avidity told the Duchenne community on June 25, 2026 that it had submitted the application to the FDA[4], and Novartis said on September 8, 2026 that the FDA had accepted it for priority review under accelerated approval[1].
Novartis's third quarter report on October 27, 2026 lists the priority review without a decision date[2]. The FDA had not announced a decision as of November 7, 2026.
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Common questions about Delpacibart zotadirsen
▸What is Delpacibart zotadirsen?
An investigational IV infusion for Duchenne muscular dystrophy in people whose dystrophin gene change can be treated by skipping exon 44, a group Avidity calls DMD44[1]. Novartis said on September 8, 2026 that the FDA had accepted its Biologics License Application for priority review under the accelerated approval pathway, and no FDA decision date has been made public[1][2]. In the EXPLORE44 trial, dystrophin rose by about 25% of normal on del-zota, against no rise on placebo[7]. No exon skipping therapy is FDA approved for people amenable to exon 44 skipping[7].
▸How does Delpacibart zotadirsen work?
Duchenne happens when a change in the dystrophin gene stops muscle from making dystrophin, a protein that protects muscle fibers as they contract. In some people, skipping 1 piece of the gene's message, called exon 44, lets the cell read past the error and make a shorter dystrophin that still partly works. Del-zota carries a short man-made strand of genetic material, a phosphorodiamidate morpholino oligomer (PMO), that tells the cell to skip exon 44[8]. PMOs given on their own reach muscle poorly, so del-zota joins the PMO to an antibody that latches onto transferrin receptor 1, a doorway muscle cells use to take in iron, which carries the PMO into skeletal and heart muscle[8][5].
▸What are the side effects of Delpacibart zotadirsen?
Del-zota has no FDA label yet, so the full list of side effects and warnings is not set. In the placebo-controlled part of EXPLORE44, 16 of 19 participants on del-zota (84%) and 6 of 7 on placebo (86%) had at least 1 side effect, most of them mild or moderate. In the 5mg/kg group, 2 participants stopped because of reactions to the infusion: 1 anaphylactic reaction and 1 infusion-related reaction[7]. In the extension study, Avidity reported that 1 more participant stopped after a hypersensitivity reaction, and that the most common side effects were upper respiratory symptoms, diarrhea, falls, back pain and headache[5].
▸How is Delpacibart zotadirsen taken?
Given as an IV infusion. In EXPLORE44, participants received 3 doses of either 5mg/kg every 6 weeks or 10mg/kg every 8 weeks[7], and everyone moved to 5mg/kg every 6 weeks in the extension study[5]. The Phase 3 SAFARI44 trial also gives it every 6 weeks[11]. The dose and schedule for any approved use would be set by the FDA label.
▸Is Delpacibart zotadirsen FDA approved?
Not yet. Delpacibart zotadirsen is under FDA review for Duchenne Muscular Dystrophy; Novartis has filed an application and a decision is pending. The FDA calendar page tracks the outcome.
▸Is del-zota FDA approved?
No. Del-zota is under FDA review and has no approval yet.
Status: Novartis said on September 8, 2026 that the FDA accepted the application for priority review under the accelerated approval pathway.
Decision date: Novartis has not disclosed a target action date.
Source: Novartis community letter, September 8, 2026; Novartis Q3 2026 release
▸What did the EXPLORE44 trial show for del-zota?
Dystrophin rose by about 25% of normal on del-zota, against no rise on placebo.
Exon skipping: Exon 44 skipping rose by 36.6% at 5mg/kg and 43.4% at 10mg/kg, against 1.6% on placebo.
Trial: 26 males aged 7 to 27 with DMD44, randomized 3 to 1 to del-zota or placebo.
Function: Avidity's 1-year functional comparison was with untreated natural history records, not a placebo group.
▸Can someone get del-zota before FDA approval?
Possibly, through a US managed access program that lists del-zota as available.
Who: US residents aged 2 and older with a dystrophin variant amenable to exon 44 skipping.
How: A neuromuscular specialist can ask about eligibility.
Source: ClinicalTrials.gov NCT07250737
Sources and references
Every factual claim on this page is drawn from the public sources listed below. Click any reference to open the original document.
- Avidity Biosciences, a Novartis company (hosted by Parent Project Muscular Dystrophy) · 2026-09-08. Community Update: FDA Accepts Delpacibart Zotadirsen (del-zota) Biologics License Application for Priority Review in DMD44. https://www.parentprojectmd.org/wp-content/uploads/2026/09/FA-11774961_AOC-1044_Avidity-BLA-Acceptance-PAG-Community-Letter_2026.pdf
- Novartis · 2026-10-27. Novartis delivered sales growth and core margin expansion in Q3; raised FY core operating income guidance. https://www.novartis.com/news/media-releases/novartis-delivered-sales-growth-and-core-margin-expansion-q3-raised-fy-core-operating-income-guidance
- Novartis · 2026-02-27. Novartis successfully completes acquisition of Avidity Biosciences. https://www.novartis.com/news/media-releases/novartis-successfully-completes-acquisition-avidity-biosciences-strengthening-late-stage-neuroscience-pipeline-and-advancing-xrna-strategy
- Avidity Biosciences, a Novartis company (hosted by CureDuchenne) · 2026-06-25. Avidity Community Letter, BLA Submission, June 2026. https://cureduchenne.org/wp-content/uploads/2026/06/Avidity-Community-Letter_BLA-Submission_June-2026.pdf
- Avidity Biosciences via PR Newswire (BioSpace copy) · 2025-09-10. Avidity Biosciences' Del-zota Demonstrated Reversal of Disease Progression Across Key Functional Endpoints in EXPLORE44® and EXPLORE44-OLE™ Phase 1/2 Trial in People Living with DMD44. https://www.biospace.com/press-releases/avidity-biosciences-del-zota-demonstrated-reversal-of-disease-progression-across-key-functional-endpoints-in-explore44-and-explore44-ole-phase-1-2-trial-in-people-living-with-dmd44
- Parent Project Muscular Dystrophy · 2025-07-23. FDA Grants Breakthrough Therapy Designation to Avidity's del-zota. https://www.parentprojectmd.org/fda-grants-breakthrough-therapy-designation-to-aviditys-del-zota/
- The Lancet Neurology · 2026-11. Safety and efficacy of delpacibart zotadirsen in Duchenne muscular dystrophy mutations amenable to exon 44 skipping in the USA (EXPLORE44): a randomised, placebo-controlled, double-blind, phase 1/2 trial. https://pubmed.ncbi.nlm.nih.gov/42874619/
- Nucleic Acids Research · 2025. AOC 1044 induces exon 44 skipping and restores dystrophin protein in preclinical models of Duchenne muscular dystrophy. https://pubmed.ncbi.nlm.nih.gov/40183632/
- ClinicalTrials.gov. Study of AOC 1044 in Healthy Adult Volunteers and Participants With Duchenne Muscular Dystrophy (DMD) Mutations Amenable to Exon 44 Skipping. https://clinicaltrials.gov/study/NCT05670730
- ClinicalTrials.gov. Ph2 Open-label Study of AOC 1044 in Duchenne Muscular Dystrophy Participants With Mutations Amenable to Exon44 Skipping. https://clinicaltrials.gov/study/NCT06244082
- ClinicalTrials.gov. A Phase 3 Study to Evaluate the Safety and Efficacy of AOC 1044 (Also Referred to as Delpacibart Zotadirsen) in Participants With DMD With Gene Mutations Amenable to Exon 44 Skipping. https://clinicaltrials.gov/study/NCT07587242
- ClinicalTrials.gov. Managed Access Program for Del-zota in Participants With DMD Mutations Amenable to Exon 44 Skipping. https://clinicaltrials.gov/study/NCT07250737