MeiraGTx (MGTX) Study Update summary

Study background and patient population

• Eleven children aged 1–4 with AIPL1-associated Leber Congenital Amaurosis (LCA4), all legally blind at birth, were treated with AAV-AIPL1 gene therapy under a UK MHRA 'Specials' license.

• The first cohort of 4 received unilateral treatment; the second cohort of 7 received bilateral sequential therapy.

• Patients were recruited globally, including from the UK, US, Turkey, Tunisia, New Zealand, Australia, and Thailand.

• All children had biallelic AIPL1 mutations and profound visual impairment with developmental delays.

• The initial four-patient cohort's data were published in The Lancet.

Study design and treatment approach

• rAAV8.hRKp.AIPL1 gene therapy delivers wild-type human AIPL1 under a photoreceptor-specific promoter, administered subretinally.

• Open-label, first-in-human interventional study design.

• Designed as a one-time administration to restore vision in children with LCA4.

Efficacy and safety outcomes

• All 11 children showed unequivocal, durable improvements in visual function, visual acuity, and visual behavior, with previously blind children now able to see.

• No safety concerns or serious adverse effects were reported in either treatment group.

• Unilateral group showed sustained efficacy up to 4 years post-treatment; bilateral group followed for a mean of 5 months, both with improved visual acuity and EEG/visual cortex activity.

• Retinal structure was better preserved in treated eyes compared to untreated eyes, as shown by OCT imaging.

• Pre-treatment, most had only light perception or hand motion; post-treatment, measurable visual acuity was achieved, with best acuity reaching LogMAR 0.6.