Neuren Pharmaceuticals Ltd. said the U.S. Food and Drug Administration classified its therapy NNZ-2591 as an orphan drug for treating three genetic conditions.
NNZ-2591 is being developed to treat Angelman syndrome, Phelan-McDermid syndrome and Pitt Hopkins syndrome.
In patients with Angelman syndrome, the ubiquitin protein ligase E3A gene on chromosome 15 is either missing or mutated. The complex genetic disorder, which mainly affects the nervous system, causes development delays and learning disabilities.
Phelan-McDermid syndrome is caused by a deletion or other change in the 22q13 region of chromosome 22 and is characterized by intellectual disability, speech impairment, low muscle tone and epilepsy, among other things.
Patients with Pitt Hopkins syndrome lack a copy of or have a mutated TCF4 gene on chromosome 18. They experience breathing problems, recurrent seizures, gastrointestinal problems and sleep disturbance.
There are no approved therapies for the three genetic conditions, the Australian drugmaker said.
Medicines classified by the FDA as orphan are those intended to treat rare conditions that affect fewer than 200,000 people in the U.S. They receive various development incentives from the regulator, including tax credits and an extended period of exclusivity.