– PBGENE-DMD restored dystrophin protein expression and significantly improved muscle function over time while demonstrating long-term durability in an in vivo DMD disease model

PBGENE-DMD dystrophin gene correction observed in muscle satellite stem cells suggesting potential for permanent functional benefit

DURHAM, NC, USA I March 19, 2025 I Precision BioSciences, Inc. (Nasdaq: DTIL), a clinical stage gene editing company utilizing its novel proprietary ARCUS® platform to develop in vivo gene editing therapies, including novel gene excision programs for high unmet need genetic diseases, today announced the presentation of preclinical data for its PBGENE-DMD development program for the treatment of Duchenne muscular dystrophy (DMD) during an oral presentation at the 2025 Muscular Dystrophy Association (MDA) Clinical & Scientific Conference being held March 16-19, 2025 in Dallas, TX.

“While there has been much-needed progress in the DMD field recently, patients still lack treatments that offer significant durable functional improvement. These PBGENE-DMD preclinical data compellingly demonstrate the potential for gene correction in the body to natively produce near full length dystrophin and restore muscle function while offering durability through the editing of muscle satellite stem cells,” said Dr. Cassie Gorsuch PhD, Chief Scientific Officer. “By precisely and directly excising the genetic root cause for DMD patients with defects between exon 45 and 55, our approach could provide more durable outcomes for these patients compared to microdystrophin gene therapies. Furthermore, this therapeutic approach is applicable for up to 60% of DMD patients, far more than exon skipping approaches currently approved or in development. The results presented today demonstrate the therapeutic potential of PBGENE-DMD to improve the lives of patients with DMD and support future clinical development of the first widely applicable gene editing approach.”

Presentation Details:

Title: ARCUS-Mediated Excision of Exons 45-55 Leads to Functional Del45-55 Dystrophin and Restoration of Skeletal Muscle-Function for the Treatment of DMD
Oral Presentation Date and Time: Wednesday, March 19, 2025, 8:00 AM CT
Poster Number: O159

In preclinical data to be presented today, PBGENE-DMD demonstrated significant functional improvement in a humanized DMD mouse model by employing two complementary ARCUS nucleases delivered in a single AAV to excise exons 45-55 of the dystrophin gene. This approach aims to restore the body’s native production of a functional dystrophin protein that more closely resembles normal dystrophin than synthetic microdystrophins. This dystrophin gene correction approach which involves editing muscle satellite stem cells potentially enhances durability and functional outcomes compared to synthetic approaches. Since up to 60% of DMD cases are caused by defects between exons 45 and 55, this approach is more broadly applicable for the majority of DMD patients than exon skippers.

Key findings from the study include:

  • Functional dystrophin protein production: PBGENE-DMD restored the body’s ability to produce a functional dystrophin protein across multiple muscles, including heart, diaphragm, and skeletal muscles at levels expected to provide therapeutic benefit.
  • Enhanced Muscle Resilience: Treated mice exhibited a 66% improvement in resistance to eccentric injury, an indicator of enhanced muscle resilience, compared to untreated diseased counterparts.
  • Long-Term Functional Improvement: In mice treated with PBGENE-DMD the maximum force output (MFO), a critical functional metric, reached up to 93% of the MFO in healthy control mice with improvement observed in PBGENE-DMD-treated mice between 3 and 6 months.
  • Durable Outcomes: PBGENE-DMD-edited dystrophin mRNA transcript was detected in PAX7+ cells, a marker for muscle satellite stem cells, suggesting potential for durable therapeutic effects compared to standard gene therapy approaches.

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. Key capabilities and differentiating characteristics may enable ARCUS nucleases to drive more intended, defined therapeutic outcomes. Using ARCUS, the Company’s pipeline is comprised of 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 insertion (inserting DNA into gene to cause expression/add function), elimination (removing a genome e.g. viral DNA or mutant mitochondrial DNA), and excision (removing a large portion of a defective gene by delivering two ARCUS nucleases in a single AAV like in the DMD program).

About Duchenne Muscular Dystrophy (DMD)

DMD is a genetic disease caused by mutations in the dystrophin gene that prevent production of the dystrophin protein. Dystrophin stabilizes the cell membrane during muscle contraction to prevent damage, and the absence of intact dystrophin protein leads to inflammation, fibrosis, and progressive loss of muscle function and mass. Over time, children with DMD will develop problems walking and breathing, eventually leading to death in their second or third decade of life due to progressive cardiomyopathy and respiratory insufficiency. DMD occurs in 1 in 3,500 to 5,000 male births with an estimated prevalence of 15,000 patients and incidence of 550 patients/year in the United States alone. Unmet need for DMD patients remains high as there are no approved therapies with curative intent that can drive durable and significant functional improvements.

SOURCE: Precision BioSciences