Precision BioSciences Doses First Patient in Phase 1/2 FUNCTION-DMD Trial of PBGENE-DMD for Duchenne Muscular Dystrophy
Precision BioSciences, Inc., a clinical-stage gene editing company developing in vivo therapies for diseases with significant unmet medical needs, has announced that the first patient has been dosed in August in the Phase 1/2 FUNCTION-DMD clinical trial evaluating PBGENE-DMD for the treatment of Duchenne muscular dystrophy (DMD).
The first patient dosing marks an important milestone for Precision BioSciences as the company advances its proprietary ARCUS® gene editing platform from preclinical research into clinical development for Duchenne muscular dystrophy. PBGENE-DMD is a wholly owned in vivo gene editing program designed to make a durable modification to the dystrophin gene with the goal of improving muscle function in patients affected by DMD.
Duchenne muscular dystrophy is a severe, progressive genetic disorder that primarily affects boys and is caused by mutations in the DMD gene, which provides instructions for producing dystrophin. Dystrophin is an essential protein that helps maintain the structural integrity of muscle fibers. When dystrophin is absent or severely reduced, muscles become progressively damaged, leading to loss of strength and mobility and, over time, potentially serious cardiac and respiratory complications.
Precision BioSciences is developing PBGENE-DMD with the objective of addressing the genetic cause of the disease rather than simply providing temporary or symptom-focused treatment. The company’s approach is designed to permanently edit the patient’s own dystrophin gene so that muscle cells can produce a near full-length functional dystrophin protein.
Aiming to Restore Near Full-Length Dystrophin
PBGENE-DMD is designed around a novel gene editing strategy intended to restore a form of dystrophin that more closely resembles the naturally occurring protein.
The program uses two complementary ARCUS nucleases delivered together in a single adeno-associated virus (AAV). These nucleases are designed to excise exons 45 through 55 of the dystrophin gene. The resulting genetic modification is intended to allow the patient’s cells to produce a near full-length dystrophin protein.
The targeted exon region is particularly important because mutations involving exons 45-55 account for a substantial proportion of DMD cases. Precision BioSciences estimates that the approach could potentially apply to up to 60% of boys living with Duchenne muscular dystrophy, although clinical evaluation will be necessary to determine the safety, effectiveness and durability of the treatment.
The strategy differs from approaches that rely on delivering a synthetic, truncated microdystrophin protein. Microdystrophin therapies are designed to provide a shortened version of dystrophin that can retain certain functional elements of the naturally occurring protein. PBGENE-DMD, by contrast, seeks to modify the patient’s endogenous dystrophin gene so that the body can produce a near full-length protein.
Precision believes this distinction could potentially provide advantages by generating dystrophin that more closely resembles the protein produced naturally in healthy muscle.
FUNCTION-DMD Clinical Trial Begins
The Phase 1/2 FUNCTION-DMD study is designed to evaluate PBGENE-DMD in ambulatory boys with Duchenne muscular dystrophy. The trial is currently enrolling patients between the ages of 2 and 7 who have mutations located between exons 45 and 55.
Patients are being recruited across multiple clinical trial sites in the United States, with the study focusing on specialized Duchenne care centers experienced in treating children with neuromuscular diseases.
The first patient was dosed at Arkansas Children’s Hospital, where the clinical team is participating in the study. The initiation of dosing represents the transition of PBGENE-DMD from laboratory and preclinical development into human clinical testing.
As an early-stage Phase 1/2 trial, the study is expected to focus substantially on assessing the safety and tolerability of the gene editing therapy while also generating preliminary evidence regarding its biological and functional effects. Precision BioSciences expects to report initial safety data by the end of 2026.
The company’s clinical development team views the study as an important opportunity to determine whether its ARCUS-based approach can safely make the intended genetic modification in patients with DMD.
Potential to Address an Underlying Cause of Duchenne
Sam Collins, M.D., Senior Vice President of DMD Clinical Development at Precision BioSciences, described the first patient dosing as an important milestone for both the company and the broader Duchenne community.
According to Collins, PBGENE-DMD is intended to take a fundamentally different approach from therapies designed around delivery of highly truncated synthetic dystrophin. Instead, the program aims to permanently modify the patient’s own dystrophin gene, enabling endogenous production of a near full-length functional protein.
This strategy reflects a broader trend in genetic medicine toward therapies that seek to address the underlying molecular cause of inherited disorders. Rather than repeatedly administering a replacement protein or relying on temporary genetic expression, gene editing approaches aim to make a lasting change to the DNA.
However, the potential durability of gene editing also makes careful clinical evaluation particularly important. Researchers will need to assess not only whether the intended edit occurs but also the safety of the editing process, the consistency of the genetic modification, the distribution of the therapy and the persistence of any resulting dystrophin production.
The FUNCTION-DMD trial will provide the first opportunity to evaluate these questions in patients receiving PBGENE-DMD.
Clinical Community Welcomes the Program
Aravindhan Veerapandiyan, M.D., Director of the Comprehensive Neuromuscular Program at Arkansas Children’s Hospital, said his institution was proud to have administered the first dose in the FUNCTION-DMD study.
Veerapandiyan emphasized the significance of developing a therapy that is designed to address the genetic cause of Duchenne muscular dystrophy. He also highlighted the potential importance of restoring near full-length functional dystrophin and said the clinical team looks forward to evaluating the safety and potential functional benefits of the treatment.
For families affected by DMD, new therapeutic approaches are particularly important because the disease is progressive and can lead to substantial physical limitations over time. Although advances in diagnosis, supportive care and disease-directed treatments have improved the management of Duchenne, significant unmet needs remain.
The entry of PBGENE-DMD into clinical development therefore provides another potential avenue for research into treatments that could produce longer-lasting effects.
Importance for the Duchenne Community
Patient advocacy organizations have also welcomed the clinical advancement of PBGENE-DMD.
Pat Furlong, President of Parent Project Muscular Dystrophy (PPMD), described the transition from research into clinical testing as an important development for the Duchenne community. She noted that families continue to seek new treatment options capable of addressing limitations associated with existing approaches.
The involvement of patient organizations and Duchenne families can play an important role in clinical development. Their participation can help researchers better understand the priorities of patients, improve trial design and support awareness about opportunities for eligible individuals to participate in clinical studies.
As FUNCTION-DMD progresses, data from the trial will help determine whether the scientific rationale behind PBGENE-DMD translates into meaningful clinical outcomes.
ARCUS Platform Supports Precision’s Gene Editing Strategy
PBGENE-DMD is being developed using Precision BioSciences’ proprietary ARCUS platform, a gene editing technology designed to enable targeted DNA modifications.
The company is applying its in vivo gene editing capabilities to diseases in which a precise genetic intervention could potentially provide a durable therapeutic effect. In the case of DMD, the ARCUS system is being used to target a specific region of the dystrophin gene and remove exons 45-55.
The use of two complementary nucleases in a single AAV is a key component of the PBGENE-DMD design. The intended result is an edited dystrophin gene capable of producing a protein with substantially greater length and structural similarity to naturally occurring dystrophin than certain truncated microdystrophin approaches.
The company believes this strategy could potentially address a broad segment of the DMD population because mutations in the targeted region represent a significant proportion of Duchenne cases.
Next Steps for Clinical Development
The immediate priority for Precision BioSciences will be continued enrollment and dosing in the FUNCTION-DMD study. The trial is actively recruiting ambulatory boys between 2 and 7 years of age who have eligible mutations between exons 45 and 55.
As patients receive PBGENE-DMD, investigators will monitor safety and assess biological and functional measures to determine how the therapy behaves in the clinical setting. Early data will be particularly important in determining the appropriate direction and scope of further development.
Precision expects to provide initial safety information by the end of 2026. Additional clinical data over time will be necessary to determine whether the gene editing approach can produce sustained dystrophin expression and translate that biological effect into meaningful improvements in muscle function.
The development of a potentially durable gene editing therapy also raises important questions around long-term monitoring. Because gene editing is designed to create a lasting genetic change, clinical studies will need to follow treated patients over extended periods to better understand durability and long-term safety.
A New Chapter in Duchenne Treatment Research
The first patient dosing of PBGENE-DMD represents a significant step in Precision BioSciences’ Duchenne muscular dystrophy program and reflects the increasing application of gene editing technologies to inherited diseases.
By targeting exons 45-55 of the dystrophin gene, PBGENE-DMD is designed to address a genetic region relevant to a large proportion of boys with DMD. Its objective of restoring near full-length dystrophin distinguishes the program from approaches based on synthetic truncated proteins and illustrates Precision’s strategy of using gene editing to modify the underlying genetic defect.
The Phase 1/2 FUNCTION-DMD trial will now provide critical clinical evidence on whether this strategy can be safely and effectively translated into patients. The first dose is only the beginning of that process, and substantial research will be required before the potential benefits of PBGENE-DMD can be fully understood.
For Precision BioSciences, the milestone represents the advancement of its ARCUS platform into an important clinical application. For the Duchenne community, it introduces another investigational approach aimed at addressing the underlying genetic cause of the disease.
With recruitment underway at specialized U.S. Duchenne centers and initial safety data expected by the end of 2026, attention will now turn to the emerging clinical evidence. If the therapy demonstrates an acceptable safety profile and evidence of successful gene editing and dystrophin restoration, PBGENE-DMD could become an important area of further investigation in the search for durable treatment options for Duchenne muscular dystrophy.
About the FUNCTION-DMD Trial
The Phase 1/2 FUNCTION-DMD study is enrolling ambulatory DMD patients between the ages of 2 and 7 with mutations between exons 45 and 55 representing up to 60% of boys with DMD. The objective of the FUNCTION-DMD study is to evaluate safety, tolerability, and efficacy, including dystrophin protein expression and functional outcomes in patients living with DMD. For more information about this clinical trial and contact information, please visit www.clinicaltrials.gov and search for NCT07429240.
About PBGENE-DMD, A Muscle-Targeted Excision Program
PBGENE-DMD is Precision’s development program for the treatment of DMD. DMD is a genetic disease caused by mutations in the dystrophin gene that prevent production of the dystrophin protein and affects approximately 15,000 patients in the U.S. alone. There are currently no approved therapies that can drive durable and significant functional improvements over time. PBGENE-DMD is designed to improve function by employing two complementary ARCUS nucleases delivered in a single AAV to excise exons 45-55 of the dystrophin gene.
The aim of this approach is to restore a near full-length functional dystrophin protein within the body that more closely resembles normal dystrophin as opposed to synthetic, truncated microdystrophin approaches with potentially minimal functional benefit. The Phase 1/2 FUNCTION-DMD study is enrolling ambulatory DMD patients with mutations between exons 45 and 55 impacting up to 60% of boys with DMD. The clinical trial employs an appropriate immune modulation regimen and safety monitoring program to treat ambulatory patients at world-class specialized DMD clinical sites.
PBGENE-DMD was granted Orphan Drug Designation by the FDA in July 2025. The PBGENE-DMD program is eligible for a Priority Review Voucher (PRV) via the Rare Pediatric Disease program, which was signed into law on February 3, 2026, as part of the Consolidated Appropriations Act of 2026. PBGENE-DMD received Fast Track designation from the FDA in February 2026.
About Precision BioSciences, Inc.
Precision BioSciences, Inc. is a clinical stage gene editing company dedicated to improving life (DTIL) with its novel and proprietary ARCUS® genome editing platform that differs from other technologies in the way it cuts, its smaller size, and its simpler structure. These features are intended for ARCUS nucleases to drive more defined therapeutic outcomes. Using ARCUS, the Company’s pipeline is comprised of clinical stage in vivo gene editing candidates designed to deliver lasting cures for the broadest range of genetic and infectious diseases where no adequate treatments exist. For more information about Precision BioSciences, please visit www.precisionbiosciences.com.
The ARCUS® platform is being used to develop in vivo gene editing therapies for sophisticated gene edits, including gene elimination (removing a genome e.g. viral DNA such as in the Company’s PBGENE-HBV program), excision (removing a large portion of a defective gene by delivering two ARCUS nucleases in a single AAV such as in the Company’s PBGENE-DMD program), and gene insertion (inserting DNA into gene to cause expression/add function).