SLS-005 Granted FDA’s Rare Pediatric Disease Designation for Sanfilippo

The U.S. Food and Drug Administration (FDA) has granted rare pediatric disease designation to Seelos Therapeutics‘ SLS-005 (trehalose) to treat Sanfilippo syndrome, the company has announced.

The designation is granted to product applications for diseases that affect fewer than 200,000 children, 18 and younger, in the U.S. and provides certain incentives for therapy development.

SLS-005 was granted the FDA’s orphan drug designation earlier this month.

The treatment is a small sugar (trehalose) administered directly into the blood (intravenously). It is thought to promote autophagy — a naturally-ocurring process that allows cells to dispose of waste — in cells of the central nervous system (the brain and spinal cord).

Specifically, SLS-005 enhances the cells’ ability to eliminate sugar molecules called glycosaminoglycans, whose toxic accumulation is characteristic of Sanfilippo syndrome.

SLS-005 was previously shown to extend the lifespan, ease inflammation in the brain and retina, and lessen nerve cell degeneration in a mouse model of Sanfilippo type B. The treatment also resulted in less hyperactivity and anxiety-related behaviour at early stages of the disease.

These positive results prompted clinical studies, with the FDA approving Seelo’s request to launch a Phase 2b/3 trial to test SLS-005’s safety, tolerability, and efficacy in patients with Sanfilippo syndrome types A and B.

A separate expanded access study will include patients with Sanfilippo types C and D, and patients with types A or B who are not eligible for the Phase 2b/3 trial. The expanded study was possible due to a collaboration between Team Sanfilippo Foundation, a nonprofit founded by parents of children with Sanfilippo syndrome, and Seelos.

Seelos is also planning a European clinical study of SLS-005 in patients with Sanfilippo syndrome types A and B.

SLS-005 was found to be safe and well-tolerated in two Phase 2 trials in patients with oculopharyngeal muscular dystrophy (NCT02015481) and spinocerebellar ataxia type 3 (NCT02147886). Importantly, it was effective at boosting the cells’ recycling system and preventing the accumulation of toxic molecules.

The therapy was granted orphan drug designation by the FDA and European Medicines Agency for spinocerebellar ataxia type 3 and oculopharyngeal muscular dystrophy, and the FDA’s fast track designation for oculopharyngeal muscular dystrophy. Fast track is a designation that aims to accelerate a therapy’s development and expedite its approval by providing more frequent meetings with the FDA and discussions about its development plan.