Duchenne muscular dystrophy (DMD) is a devastating disease caused by mutation of DMD gene. GEN6050X is a one-dose, intravenously administered, base editor drug targeting DMD patients amenable for exon 50 skipping (4% of DMD population), for whom no effective therapy currently exists. An investigator-initiated trial (IIT, NCT06392724) has been conducted in Peking Union Medical School hospital since August 2024. To date, three ambulatory patients have been dosed (aged 6.5 to 10) at 5 × 10¹³ vg/kg, and two patients have completed 52 weeks of follow-up.
Safety data to date show that GEN6050X is well tolerated, with only transient and manageable serious adverse events; and all events resolved within the planned two-week inpatient period. No clinically significant symptoms or laboratory abnormalities have been observed during follow-up.
52 weeks follow-up data from the first two patients demonstrate encouraging cardiac and pulmonary improvements. Both patients showed durable enhancement in cardiac function, with an average 13.3% improvement in LVEF relative to baseline. Respiratory capacity also exhibited meaningful improvement, with average increases of 14.6% in FVC% and 26.8% in PEF, relative to baseline, reflecting meaningful pulmonary recovery.
For motor function, patient 1 (10 years old) demonstrated a 1-point NSAA gain(from 31 to 32) and a 3-point PUL 2.0 gain (from 39 to 42). Patient2 (6.5 years old) maintained a PUL 2.0 improvement (41→42), and in NSAA exhibited an initial rise at week 26 (25 to 28) followed by a moderate decline at week 52. Time-function tests (such as, 10-meter walk/run and 6MWT) showed small decreases but remained largely stable for both patients.
Overall, these interim IIT data indicate that GEN6050X is well tolerated and provide early clinical benefits, particularly in cardiac and pulmonary function—key determinants of long-term outcomes in DMD. These results support GEN6050X as a potentially transformative base-editing therapy for DMD.