June 25, 2025 GenAssist Ltd (GenAssist) announced that the United States (U.S.) Food and Drug Administration (FDA) has granted Rare Pediatric Disease Designation (RPDD) to GEN6050X, the global first in vivo base editing drug for the treatment of Duchenne Muscular Dystrophy (DMD).
Duchenne muscular dystrophy (DMD) is a serious or life-threatening disease that affects approximately 450,000 to 600,000 patients worldwide. The serious or life-threatening manifestations, include loss of ambulation, respiratory insufficiency and cardiomyopathy primarily affect individuals aged from birth to 18 years.
GEN6050X injection is a novel intravenous cytosine base editing drug using dual AAV9 vectors, designed for DMD patients amenable to exon 50 skipping. It utilizes a dual AAV9 vector system, consisting of ss.AAV9.oTAM and ss.AAV9.hE50-sgRNA. One vector encodes the oTAM base editor driven by a muscle-specific promoter, the other AAV9 vector carries 3 copies of single-guide RNA and the human ACTG1 gene. GEN6050X is based on GenAssist’s novel RNA editing-free Targeted AID-mediated Mutagenesis (TAM) cytosine base editor technology. By one-shot systemic administration, GEN6050X can permanently restore the expression of dystrophin protein.
The RPDD program is designed to encourage the development of new drugs and biologics for the treatment of rare diseases that primarily affect children. Under this designation, GenAssist is eligible to receive a priority review voucher (PRV) upon potential FDA approval of GEN6050X. This voucher can be used to expedite the review of another drug or sold to another company.
