Precision BioSciences advances PBGENE-DMD in its Phase 1/2 DMD trial after the DSMB reports no safety concerns in the first patient’s eight-week review.
Written By: Creola Gonsalves, MS Biotech
Reviewed By: Pharmacally Editorial Team
Precision BioSciences has received a positive safety assessment for PBGENE-DMD, its investigational gene-editing therapy for Duchenne muscular dystrophy (DMD), after an independent Data Safety Monitoring Board (DSMB) reviewed safety data from the first treated patient in the Phase 1/2 FUNCTION-DMD trial (NCT07429240).
No serious adverse events (SAEs) or adverse events of special interest (AESIs) were reported through the patient’s initial eight-week observation period. Following its review, the DSMB identified no safety concerns and endorsed proceeding with dosing additional patients, supporting completion of enrollment in Part 1 of the study.
The decision represents an early clinical development milestone for Precision as it advances an approach designed to modify the patient’s native dystrophin gene rather than introduce a shortened version of the dystrophin protein.
Initial Safety Assessment Supports Further Clinical Development
According to Precision, the initial eight-week observation period is particularly important for monitoring potential early safety events associated with adeno-associated virus (AAV)-based therapies.
Dr. Sam Collins, Senior Vice President of DMD Clinical Development at Precision BioSciences, described the successful completion of the initial safety assessment and the DSMB’s authorization to proceed with additional patient dosing as an important milestone for FUNCTION-DMD.
The company stated that safety monitoring will remain a priority as the trial progresses. It also expects to provide further safety and efficacy updates from the study throughout 2027.
Although the absence of reported SAEs and AESIs in the first patient is encouraging, these findings represent an initial safety observation rather than evidence of an established safety profile. The effects of treatment on dystrophin expression, muscle function and longer-term clinical outcomes remain to be evaluated.
PBGENE-DMD Uses ARCUS Gene Editing to Target the Native Dystrophin Gene
PBGENE-DMD is designed to address the underlying genetic cause of DMD through a muscle-targeted gene-excision strategy using Precision’s proprietary ARCUS genome-editing platform.
The investigational therapy employs two complementary ARCUS nucleases delivered through a single AAV vector to excise exons 45–55 of the dystrophin gene. This region represents a frequently mutated hotspot associated with a substantial proportion of DMD cases.
By removing the targeted exon region, the approach aims to restore production of a near full-length, functional dystrophin protein from the patient’s native gene.
This strategy differs from microdystrophin gene therapies, which introduce shortened versions of the dystrophin protein because of the limited packaging capacity of AAV vectors. Rather than supplying an engineered, truncated protein, PBGENE-DMD is designed to modify the existing genetic sequence to enable production of near full-length dystrophin.
However, whether this approach can achieve sufficient dystrophin expression and translate into meaningful functional improvements in patients remains an important question for clinical development.
FUNCTION-DMD Targets a Genetically Defined DMD Population
The Phase 1/2 FUNCTION-DMD study is enrolling ambulatory patients aged 2–7 years with DMD mutations between exons 45 and 55. According to the company, this mutation region represents up to 60% of boys with DMD.
The study is designed to evaluate the safety, tolerability and efficacy of PBGENE-DMD, including dystrophin protein expression and functional outcomes.
The clinical programme also incorporates an immunomodulation regimen and a dedicated safety-monitoring programme, with treatment administered at specialized DMD clinical sites.
The selection of a genetically defined patient population is central to this strategy because the intended exon-excision approach is relevant to patients whose mutations can be addressed through removal of exons 45–55.
FDA Designations Support PBGENE-DMD Development
PBGENE-DMD has received several FDA regulatory designations supporting its development for DMD:
- Orphan Drug Designation: Granted in July 2025.
- Fast Track Designation: Granted in February 2026.
- Rare Pediatric Disease Designation: Granted for the treatment of DMD.
The Rare Pediatric Disease Designation may make the programme eligible for a Priority Review Voucher, subject to applicable regulatory requirements.
Clinical Evidence Will Determine the Potential of PBGENE-DMD
The positive DSMB review provides Precision with an opportunity to advance enrollment in Part 1 of FUNCTION-DMD. However, the clinical significance of PBGENE-DMD will ultimately depend on whether its gene-editing strategy can produce meaningful dystrophin restoration, improve muscle function and maintain an acceptable safety profile over time.
The programme’s differentiation lies in its attempt to restore near full-length dystrophin through editing of the patient’s native gene. The forthcoming clinical data will be important in determining whether this molecular approach can translate into meaningful benefits for patients with DMD.
Precision expects to provide further safety and efficacy updates from FUNCTION-DMD throughout 2027.
Reference
Precision BioSciences Announces Positive DSMB Safety Review Supporting Additional PBGENE-DMD Dosing in Phase 1/2 FUNCTION-DMD Study, Precision Bioscience, 05 November 2026
PBGENE-DMD Phase 1/2a Safety and Preliminary Efficacy Study in Duchenne Muscular Dystrophy (FUNCTION-DMD), ClinicalTrials.gov ID NCT07429240
About the Writer
Creola Gonsalves (Linkedin) is an M.S. Biotechnology postgraduate with a strong interest in clinical research, evidence interpretation, and healthcare writing, with a focus on translating life-science knowledge into meaningful real-world insights.
She is trained in Good Clinical Practice (GCP), clinical research principles, and critical interpretation of randomized clinical trials, with certifications from NIH and Stanford University.
Her research background in biotechnological applications and microbial research strengthens her ability to understand scientific evidence and develop clear, accurate, and research-driven healthcare content.