LEAPER RNA Editing for Duchenne Muscular Dystrophy – First-in-Human Clinical Study

China-developed LEAPER RNA editing technology has achieved the world's first clinical application in Duchenne muscular dystrophy (DMD), with three patients showing sustained motor function improvement and no serious adverse events at one-year follow-up.

Introduction

Duchenne muscular dystrophy (DMD) is an X-linked recessive neuromuscular disorder affecting approximately 1 in 3,500–5,000 male births worldwide. Caused by mutations in the DMD gene — the largest known human gene, spanning 2.4 million base pairs — the disease leads to the absence of functional dystrophin protein, resulting in progressive muscle degeneration, loss of ambulation, and ultimately death from respiratory or cardiac failure in early adulthood.[reference:0]

The enormous size of the DMD gene and the diversity of mutations — over 7,000 distinct pathogenic variants have been identified — have made DMD one of the most challenging targets for gene therapy.[reference:1]

On June 10, 2026, a collaborative team from Peking University/Changping Laboratory (Professor Wei Wensheng), Shanghai Children's Medical Center (Dr. Wang Jiwen), Kunming University of Science and Technology (Professor Chen Yongchang and Academician Ji Weizhi), and Beijing Lipu Biotechnology published the first-in-human clinical results of LEAPER-based RNA editing therapy for DMD in the journal Cell.[reference:2][reference:3]

The LEAPER Technology Platform

LEAPER (Leveraging Endogenous ADAR for Programmable Editing of RNA) is a proprietary RNA editing platform developed by Professor Wei Wensheng's team at Peking University/Changping Laboratory. First reported in 2019, LEAPER has now evolved to version 3.0.[reference:4]

Unlike DNA-editing technologies such as CRISPR-Cas9, LEAPER does not permanently alter the genome. Instead, it recruits endogenous ADAR (adenosine deaminase acting on RNA) enzymes — naturally present in human cells — to perform targeted RNA editing. The therapy uses a circular ADAR-recruiting RNA (circ-arRNA) that guides the endogenous ADAR enzyme to skip specific exons during RNA processing, restoring the dystrophin reading frame and enabling the production of functional dystrophin protein.[reference:5][reference:6]

This approach offers several advantages:

• No exogenous proteins — eliminates immunogenicity risks associated with bacterial or viral-derived editing enzymes[reference:7]
• Reduced delivery complexity — the circ-arRNA is smaller and simpler to deliver than full gene constructs[reference:8]
• Broader applicability — can address a wider range of mutations than single-base correction strategies[reference:9]
• Reversible editing — RNA editing is transient, reducing off-target risks

The candidate drug, LE051, is the first LEAPER-based RNA editing therapeutic to enter clinical development.[reference:10]

Clinical Study Design

The clinical study was led by Shanghai Children's Medical Center, which served as the primary clinical site responsible for patient screening, drug administration, functional assessment, safety monitoring, and long-term follow-up.[reference:11]

Study Highlights:

Parameter	Details
Lead Institution	Shanghai Children's Medical Center
Principal Investigator	Dr. Wang Jiwen
Drug Candidate	LE051 (circ-arRNA-based RNA editing therapy)
Number of Patients	3 DMD patients
Dosing	Single administration
Follow-up Duration	12 months

Clinical Results: One-Year Follow-Up

The one-year follow-up data from the three treated patients demonstrated compelling efficacy and safety outcomes:[reference:12][reference:13]

Efficacy

• Exon skipping — significant levels of exon skipping were detected in patient samples, confirming successful RNA editing
• Dystrophin restoration — functional dystrophin protein expression was restored[reference:14]
• Motor function — sustained improvement across multiple motor function assessment parameters[reference:15]
• Respiratory function — respiratory muscle function showed improvement, a critical finding as respiratory failure is the leading cause of mortality in DMD[reference:16]

Safety

• No treatment-related serious adverse events reported[reference:17]
• No significant immunotoxicity or organ damage observed[reference:18]
• No apparent immune toxicity — consistent with the LEAPER platform's use of endogenous enzymes[reference:19]

As the research team noted, the study represents the world's first clinical application of RNA editing technology for DMD treatment and the first time a China-developed RNA editing technology has entered clinical research with positive results.[reference:20]

Mechanism of Action: A Closer Look

The LEAPER-based RNA editing approach operates through a sophisticated mechanism:

1. Delivery — the circular ADAR-recruiting RNA (circ-arRNA) is delivered to muscle cells
2. ADAR recruitment — the circ-arRNA structure recruits endogenous ADAR enzymes to the target RNA sequence
3. A-to-I editing — ADAR converts adenosine (A) to inosine (I) at the target site, which is read as guanosine (G) during translation
4. Exon skipping — the editing event promotes skipping of the mutated exon, restoring the reading frame
5. Dystrophin production — the restored reading frame enables production of functional dystrophin protein[reference:21]

Preclinical studies in non-human primates demonstrated that a single administration achieved over one year of sustained protein restoration and motor function improvement, establishing the "one-dose, long-term benefit" profile of the therapy.[reference:22]

Significance and Future Directions

This breakthrough has profound implications:

• First validation of RNA editing in DMD — establishes a new therapeutic modality for this devastating disease
• Platform technology — the LEAPER platform can potentially be adapted to other genetic disorders[reference:23]
• China-origin innovation — demonstrates China's capability to develop first-in-class genetic medicines[reference:24]
• Expanding applications — the technology could be extended to other neuromuscular and genetic diseases[reference:25]

The research team emphasized that while the current results are highly encouraging, the limited sample size warrants larger-scale clinical trials and longer follow-up to fully validate the therapy's long-term value.[reference:26]

Shanghai Children's Medical Center has built a comprehensive rare neurological disease care system spanning precision diagnosis, clinical treatment, research translation, and long-term follow-up. The institution is also advancing gene therapy programs for spinal muscular atrophy (SMA), aromatic L-amino acid decarboxylase deficiency, and other conditions, alongside exploring brain-computer interfaces and cell therapy.[reference:27]