UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

WASHINGTON, D.C. 20549

FORM 8-K

CURRENT REPORT

Pursuant to Section 13 or 15(d) of the

Securities Exchange Act of 1934

Date of report (Date of earliest event reported) December 11, 2009

Cephalon, Inc.

(Exact Name of Registrant as Specified in Charter)

Delaware	0-19119	23-2484489
(State or Other Jurisdiction	(Commission	(IRS Employer
of Incorporation)	File Number)	Identification No.)

41 Moores Road
Frazer, Pennsylvania		19355
(Address of Principal Executive Offices)		(Zip Code)

Registrant’s telephone number, including area code (610) 344-0200

Not Applicable

(Former Name or Former Address, if Changed Since Last Report)

Check the appropriate box below if the Form 8-K filing is intended to simultaneously satisfy the filing obligation of the registrant under any of the following provisions:

¨ Written communications pursuant to Rule 425 under the Securities Act (17 CFR 230.425)

¨ Soliciting material pursuant to Rule 14a-12 under the Exchange Act (17 CFR 240.14a-12)

¨ Pre-commencement communications pursuant to Rule 14d-2(b) under the Exchange Act (17 CFR 240.14d-2(b))

¨ Pre-commencement communications pursuant to Rule 13e-4(c) under the Exchange Act (17 CFR 240.13e-4(c))

Item 8.01 Other Events.

On December 11, 2009, Cephalon, Inc. (“Cephalon”) filed a lawsuit in U.S. District Court in Delaware against Mylan Pharmaceuticals, Inc., Mylan Inc., Matrix Laboratories Limited and Matrix Laboratories Inc. (collectively, “Mylan”) for infringement of U.S. Patent Nos. 7,132,570 and RE37,516 for the Cephalon product NUVIGIL® (armodafinil) Tablets [C-IV]. The lawsuit is based upon an Abbreviated New Drug Application (“ANDA”) filed by Mylan seeking approval from the U.S. Food and Drug Administration (“FDA”) for a generic equivalent of armodafinil to be sold in the United States. Mylan alleges that the above NUVIGIL patents are invalid, unenforceable and/or will not be infringed by Mylan’s manufacture, use or sale of the product described in its ANDA.

The filing of this lawsuit is provided for by the Hatch-Waxman Act, a federal statute governing certain aspects of generic drug approvals. Under that statute, the filing of the lawsuit stays any FDA approval of the Mylan ANDA until the earlier of entry of a district court judgment in favor of Mylan or 30 months from Cephalon’s November 2009 receipt of a Paragraph IV certification letter from Mylan.

SIGNATURES

Pursuant to the requirements of the Securities Exchange Act of 1934, the registrant has duly caused this report to be signed on its behalf by the undersigned hereunto duly authorized.

	CEPHALON, INC.


Date: December 15, 2009	By:	/s/ Gerald J. Pappert
		Gerald J. Pappert
		Executive Vice President, General Counsel