Biogen Inc. said its board of directors authorized a program to buy back up to $5 billion of its common stock.

The share repurchase program does not have an expiration date. All share repurchases under the program will be retired.

The current program is in addition to the buyback program authorized by the Cambridge, Mass.-based drugmaker's board in March.

Biogen develops and manufactures therapies for neurological and neurodegenerative diseases.