Canada's largest publicly listed pharmaceutical company Biovail Corp. acquired U.S. privately held Prestwick Pharmaceuticals Inc. for $100 million, a move that would allow the Canadian drug maker to change its focus to central nervous system medication.

Prestwick holds the Canadian and U.S. rights to Xenazine, a drug used to treat chorea, an illness related to Huntington's disease, a rare genetic disorder that could lead to memory loss, uncontrolled movements and death. The drug is approved by the Food and Drugs Administration.

With the merger, Biovail will take over Prestwick's contract with Ovation Pharmaceuticals Inc. to market and distribute Xenazine in the U.S.

Biovail will also be given access to Prestwick's drugs for the medication of Parkinson's disease and schizophrenia.

Biovail, which makes the antidepressant Wellbutrin XL, said the acquisition will add to profits next year. The company seeks to recover from an underperforming second quarter.