An FDA clearance opens the first trial for Mucolipidosis type IV

The US Food and Drug Administration has allowed an Investigational New Drug application to proceed for the first clinical trial of a gene therapy for Mucolipidosis type IV, the ML4 Foundation announced on 2 September 2026. MLIV is an ultra-rare paediatric neurodegenerative disease; the Foundation puts the number of known children worldwide at fewer than 100. The therapy uses an AAV9 vector to deliver a working copy of the MCOLN1 gene, and is administered directly into the brain by a neurosurgeon.

The route to the clearance is the unusual part. The ML4 Foundation is a family-founded nonprofit, and it funded and coordinated the whole chain itself: basic science, natural history studies, preclinical gene therapy development, manufacturing, toxicology and the regulatory work. The gene therapy effort began in 2017, building on earlier work at Massachusetts General Hospital led by Susan Slaugenhaupt and Yulia Grishchuk, and was developed with Miguel Sena-Esteves and Heather Gray-Edwards at the University of Massachusetts Gene Therapy Center. Randy Gold, the Foundation’s president, said there is now an investigational drug developed specifically for MLIV that the FDA has permitted to move into human testing.

An IND clearance permits a trial and says nothing about whether the therapy works. The Foundation hopes the first children will be treated in 2026. For a population of fewer than a hundred known patients the commercial case for a sponsor is thin, and a decade of foundation coordination is what stood in its place.