CHARLOTTE, N.C. — Chelsea Therapeutics has signed a license agreement with a Japanese pharmaceutical firm for rights to a drug that combats a symptom of Parkinson’s Disease.

The drug Droxidopa is approved for use in Japan to fight orthostatic hypotension (frozen gait or dizziness) which is associated with Parkinson’s. Chelsea signed the license deal with Dainippon Sumitomo Pharma.

Chelsea intends to file for orphan drug status for Droxidopa in the United States and plans to begin clinical development, using in part data already gathered about the drug. Droxidopa produces some $50 million a year in sales in Japan, according to Chelsea.

Some 100,000 Americans suffer from orthostatic hypotension, which is associated with Parkinson’s as well as Pure Autonomic Failure and Multiple System Atrophy.