FDA grants orphan drug designation to PRX-OTC for rare liver disease

The FDA granted PhaseRx Inc. orphan drug designation for PRX-OTC for the treatment of the rare liver disease ornithine transcarbamylase deficiency in children, according to the company.

PRX-OTC (PhaseRx Inc.) is an intracellular enzyme replacement therapy designed to replace missing or defective enzyme in children with ornithine transcarbamylase deficiency (OTCD) — a rare liver disorder caused by an inherited single-gene deficiency. It is usually diagnosed in patients between birth and age 12 years, and can lead to elevated ammonia in the blood; this may then lead to irreversible neurological impairment, coma and death. The only cure is to undergo liver transplant, according to a press release.

“PRX-OTC is the first of three drugs in development using our Hybrid mRNA Technology, and we believe it has the potential to correct the disease in children, a population that could particularly benefit from treatment for this rare disease,” Robert W. Overell, PhD, president and chief executive officer, said in the release. “Our team at PhaseRx is driving hard to advance these drugs to help the lives of families affected by this devastating liver disease that causes irreversible brain damage and potentially fatal ammonia toxicity.”

In a preclinical model of OTCD, PRX-OTC lowered blood ammonia in 100% of treated mice, according to the release. PhaseRx Inc. said the company plans to file an investigational new drug application in late 2017.

Disclosure: Overell is employed by PhaseRx Inc.