May 14, 2026 —
Precision BioSciences presented new preclinical data at the ASGCT 2026 Annual Meeting supporting the potential of PBGENE-DMD, its investigational in vivo gene editing program for Duchenne muscular dystrophy (DMD). The data showed that treatment in early-juvenile mice resulted in substantially greater dystrophin restoration across key skeletal and respiratory muscles compared with treatment in late-juvenile mice, reinforcing the rationale for evaluating PBGENE-DMD in younger DMD patients.
PBGENE-DMD is designed to address the underlying genetic cause of DMD by using Precision’s proprietary ARCUS® gene editing platform. The approach employs two complementary ARCUS nucleases delivered by a single AAV vector to excise exons 45–55 of the dystrophin gene. This strategy is intended to restore expression of a near full-length dystrophin protein, which more closely resembles natural dystrophin than synthetic microdystrophin approaches. Precision estimates that this exon 45–55 excision strategy could be applicable to approximately 60% of patients with DMD.
In the new preclinical data, PBGENE-DMD treatment in early-juvenile mice achieved up to 3-fold higher dystrophin protein restoration in skeletal muscle and up to 12-fold higher restoration in respiratory muscle compared with late-juvenile mice at equivalent dose levels. Respiratory muscle findings were particularly notable, with dystrophin restoration reaching up to 12% in the diaphragm and up to 30% in intercostal muscles, tissues that are critical for long-term respiratory function in DMD.
The study also showed high levels of dystrophin-positive fibers in early-juvenile mice, reaching up to 70% dystrophin-positive fibers and exceeding levels observed in late-juvenile mice by approximately 2- to 3-fold in skeletal and respiratory tissues. Similar therapeutic efficacy was observed in cardiac muscle in both early- and late-juvenile mice.
These findings support the design of Precision’s ongoing Phase 1/2 FUNCTION-DMD trial, which is evaluating PBGENE-DMD in ambulatory boys aged 2 to 7 years. The company highlighted that earlier intervention may be especially important because treating younger patients could allow gene editing to occur before more extensive muscle degeneration and disease progression.
Precision also positioned PBGENE-DMD as differentiated from AAV microdystrophin gene therapy approaches. Because PBGENE-DMD is designed to edit the native dystrophin gene rather than deliver a synthetic transgene, the company believes its therapeutic effect may be less vulnerable to the AAV dilution effect associated with muscle growth and turnover in young patients. This could be particularly relevant in very young children, where ongoing muscle growth may reduce the durability of episomal AAV-delivered transgenes.
The new data build on prior preclinical findings showing reductions in serum creatine kinase, improvements in muscle pathology, sustained dystrophin restoration, dystrophin-positive myofibers, and durable muscle function in treated DMD models. PBGENE-DMD has received FDA Orphan Drug Designation and Fast Track designation, and the program is eligible for a Rare Pediatric Disease Priority Review Voucher. While clinical safety, editing efficiency, and functional benefit remain to be established in patients, the ASGCT data strengthen the preclinical rationale for early intervention with AAV-delivered gene editing in DMD.
