Ultragenyx Pharmaceutical Inc, a biopharmaceutical company focused on the development and commercialization of novel products for rare and ultra-rare genetic diseases, today announced that the U.S. Food and Drug Administration has granted Orphan Drug Designation to UX701 for the treatment of Wilson disease, a larger rare metabolic disease that affects more than 50,000 people in the developed world.

“FDA Orphan Drug Designation is an important milestone in the development of UX701, a gene therapy for the treatment of Wilson Disease, and highlights the significant unmet medical need for people with this genetic disorder,” stated Eric Crombez, M.D., Chief Medical Officer of the Ultragenyx Gene Therapy development unit. “Current treatment options involve the often complicated and lifetime use of medications that block the absorption of copper from the diet or remove copper by chelation. UX701 is designed to directly address the underlying cause of disease by restoring normal copper metabolism in the liver. By correcting copper trafficking and removal, this one-time treatment has the potential to better address the many serious effects of this disease and improve the lives of patients.”

UX701 is currently in late preclinical development, and an investigational new drug (IND) application is expected to be filed with the US FDA by the end of the year.

The US FDA Orphan Drug Designation program provides orphan status to drugs and biologics that are intended for the safe and effective treatment, diagnosis, or prevention of rare diseases that affect fewer than 200,000 people in the U.S. Among the benefits of orphan designation in the U.S. are seven years of market exclusivity following FDA approval, waiver or partial payment of application fees, and tax credits for clinical testing expenses conducted after the orphan designation is received.

Wilson disease is a rare inherited disorder caused by mutations in the ATP7B gene, which results in deficient production of ATP7B, a protein that transports copper. Loss of function of this copper-binding protein results in the accumulation of copper in the liver and other tissues, most notably the central nervous system. Patients with Wilson disease experience hepatic, neurologic and/or psychiatric problems. Those with liver disease can experience such symptoms as fatigue, lack of appetite, abdominal pain and jaundice, and can progress to fibrosis, cirrhosis, life-threatening liver failure and death. Wilson disease can be treated by reducing copper absorption or removing excess copper from the body using life-long chelation therapy, but unmet needs exist because some treated patients experience clinical deterioration and severe side effects. Wilson disease affects more than 50,000 individuals in the developed world.

UX701 is an investigational AAV type 9 gene therapy designed to deliver a stable expression of the ATP7B copper transporter following a single intravenous infusion. It has been shown in preclinical studies to normalize copper trafficking and excretion from the body. UX701 was granted Orphan Drug Designation in the United States.