Medicines Co. ( MDCO) yanked a proposed stock offering, saying it believes action may be imminent on a regulatory application.

The Parsippany, N.J., drug company said it learned late Tuesday that "it is possible that some administrative activity may occur in the near term with respect to the Company's application for term extension for the principal patent covering the Company's product Angiomax (bivalirudin). The Company does not know whether any definitive action will be taken or, if taken, whether such action will be favorable or unfavorable."

As a result Medicines Co. withdrew a 6 million-share offering it had filed a week ago.