The drugmaker The Medicines Co. said Friday it filed a federal lawsuit against several government agencies over the denial of an extension for the principal U.S. patent covering the anti-clotting drug Angiomax.

The Parsippany, N.J., company said it filed a complaint in the U.S. District Court for the Eastern District of Virginia against the Patent and Trademark Office, the Food and Drug Administration and the Department of Health and Human Services.

The company said the same court had set aside a prior denial of the company's application and sent the case back to the patent office for reconsideration. But the office issued a new denial about three days later.

The Medicines Co. wants the court to set aside the office's latest decision and order it to extend the patent.

Company spokeswoman Mary Kathryn Covert said the patent is slated to expire in November.

The company markets Angiomax in the United States and other countries for use in patients undergoing coronary angioplasty. Angiomax had worldwide sales of $400 million last year.

Shares of The Medicines Co. fell 6 cents to $7.78 in late morning trading Friday.