DURHAM, N.C. — Precision BioSciences, Inc. (Nasdaq: DTIL), a clinical stage gene editing company utilizing its novel proprietary ARCUS® platform to develop in vivo gene editing therapies for high unmet need diseases, today announced new preclinical data from its PBGENE-DMD program in an oral presentation at the American Society of Gene & Cell Therapy (ASGCT) 2026 Annual Meeting in Boston, Massachusetts. The new data show that treatment with PBGENE-DMD in early-juvenile mice resulted in significantly higher efficacy across key skeletal and respiratory muscles than treatment in late-juvenile mice over a comparable timeframe. This new data further supports evaluating PBGENE-DMD in younger DMD patient populations, including the 2- to 3-year-old patients, who are a key demographic of the ongoing Phase 1/2 FUNCTION-DMD trial evaluating PBGENE-DMD in boys ages 2 to 7.
The greater efficacy observed in early-juvenile mice is also expected to be an important point of differentiation for PBGENE-DMD versus microdystrophin approaches. With microdystrophin approaches the AAV dilution effect driven by muscle growth and turnover would be expected to be even more pronounced in younger DMD patients.
“These new data give us a clear preclinical rationale for treating DMD as early as possible. By directly comparing early- and late-juvenile mice, we showed that intervening earlier translated into substantially greater dystrophin restoration in the skeletal and respiratory muscles that matter most for long-term outcomes. This is important because the FUNCTION-DMD trial is designed to treat children between the ages of two and seven years,” said Cassie Gorsuch, Ph.D., Chief Scientific Officer of Precision BioSciences. “These results also reinforce a meaningful point of differentiation for PBGENE-DMD. Because we are correcting the gene rather than delivering a synthetic transgene, the durability of effect would not be expected to be subject to the AAV dilution that affects microdystrophin approaches as young patients grow, a limitation that becomes more pronounced the younger the patient.”
New preclinical data: strong efficacy in early-juvenile mice (age 2 weeks, equivalent to a patient population aged 2–3 years)
- PBGENE-DMD in early-juvenile mice achieved up to 3x higher dystrophin protein restoration in skeletal muscle, and up to 12x higher dystrophin protein restoration in respiratory muscle, compared with late-juvenile mice at equivalent dose levels.
- Strong efficacy which exceeded the expected dystrophin protein restoration therapeutic threshold of 5% was observed in respiratory muscle tissues, with mice achieving up to 12% dystrophin restoration in the diaphragm and up to 30% in the intercostals, muscles whose function is critical to preventing respiratory failure in patients with DMD.
- PBGENE-DMD drove high levels of dystrophin-positive fibers in early-juvenile mice, with levels 2–3x higher in skeletal and respiratory muscle tissues than in late-juvenile mice after three months, reaching up to 70% dystrophin-positive fibers.
- Similar therapeutic efficacy was achieved in cardiac muscle in both early- and late-juvenile mice.
Building on a growing body of preclinical evidence
These new data extend Precision’s previously reported preclinical findings supporting the safety, efficacy, and durability profile of PBGENE-DMD:
- A toxicology study in a humanized DMD mouse model showed that PBGENE-DMD treatment led to greater than 45% reduction in serum creatine kinase across multiple dose levels, alongside improvements in muscle pathology relative to vehicle-treated controls, supporting the safety profile of the program.
- Beyond safety, PBGENE-DMD has demonstrated sustained efficacy over time through dystrophin protein restoration and dystrophin-positive myofibers, translating into durable muscle function. Treated mice maintained up to 92% of the maximum force output of non-diseased animals, while untreated, diseased mice showed progressively declining force output.
Presentation details
Abstract title: PBGENE-DMD gene editing drives safe, efficacious, and durable functional improvement in a humanized Duchenne muscular dystrophy mouse model
Session: Emerging molecular therapeutic strategies for muscular dystrophies
Presenter: Adam Mischler, Ph.D., DMD Research Lead, Precision BioSciences
Date and time: Thursday, May 14, 2026, 8:45 A.M. ET
About PBGENE-DMD, A Muscle-Targeted Excision Program
PBGENE-DMD is Precision’s development program for the treatment of Duchenne Muscular Dystrophy (DMD), a devastating genetic disease caused by mutations in the dystrophin gene that prevents production of the dystrophin protein, which is essential for maintaining muscle structural integrity and function. DMD affects approximately 15,000 patients in the U.S. alone, and there are currently no approved therapies capable of driving significant, durable functional improvements over time.
PBGENE-DMD is designed to durably improve function for approximately 60% of patients with DMD by employing two complementary ARCUS nucleases, delivered using a single AAV, to excise exons 45-55 of the dystrophin gene, restoring expression of a near full-length dystrophin protein. Compared with DMD, deletion of exons 45-55 is often associated with a more mild prognosis for patients. This protein more closely resembles normal dystrophin than synthetic, truncated microdystrophin approaches, which currently offer minimal proven functional benefit. Precision’s Phase 1/2 FUNCTION-DMD study is expected to enroll ambulatory DMD patients with mutations between exons 45 and 55, which impact approximately 60% of boys with DMD. The clinical trial will employ an appropriate immune modulation regimen and safety monitoring program to treat 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 Priority Review Voucher (PRV) 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.
Further details on the trial can be found on Precision’s website and clinicaltrials.gov identifier NCT07429240.
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), and 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).
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