FDA Issues Approvable Letter for VIVITROL(TM) (Formerly VIVITREX(R)), for the Treatment of Alcohol Dependence; Alkermes and Cephalon Continue to Anticipate Product Launch in Second Quarter 2006

Alkermes, Inc. (Nasdaq: ALKS) and Cephalon, Inc.(Nasdaq: CEPH) today announced that the U.S. Food and DrugAdministration (FDA) issued an approvable letter for VIVITROL(TM)(naltrexone for extended-release injectable suspension), which isunder review for the treatment of alcohol dependence in combinationwith a treatment program that includes psychosocial support. The NewDrug Application (NDA) for VIVITROL, formerly known as VIVITREX(R),was submitted on March 31, 2005. Alkermes and Cephalon continue toprepare for the launch of VIVITROL during the second quarter of 2006.

FDA approval of VIVITROL is contingent upon finalizing the productlabel and satisfying a request by the FDA for preclinicalpharmacokinetic data to support reference to existing oral naltrexonepreclinical data. VIVITROL was filed as a 505(b)(2) NDA application,permitting Alkermes to reference results of studies that werepreviously submitted to the FDA in support of the original oralnaltrexone NDA.

"This approvable letter is a positive step toward the approval ofVIVITROL," stated Richard Pops, CEO of Alkermes. "We look forward toworking diligently with the FDA to gain final approval and bringforward VIVITROL as an important new medication for the treatment ofalcohol dependence."

"Our plans for the launch of VIVITROL in the second quarter of2006 are on track," said Frank Baldino, Jr., Ph.D., Chairman and CEOof Cephalon. "We are hiring sales representatives and designingeducation and training programs to ensure that physicians andcounselors can identify patients who could benefit the most from theinclusion of this medication in their treatment plan."

About Alkermes, Inc.

Alkermes, Inc. is a pharmaceutical company that develops productsbased on sophisticated drug delivery technologies to enhancetherapeutic outcomes in major diseases. The Company's lead commercialproduct, RISPERDAL(R) CONSTA(R) ((risperidone) long-acting injection),is the first and only long-acting atypical antipsychotic medicationapproved for use in schizophrenia, and is marketed worldwide byJanssen-Cilag (Janssen), a wholly owned division of Johnson & Johnson.The Company's lead proprietary product candidate, VIVITROL(TM)(naltrexone for extended-release injectable suspension), is beingdeveloped as a once-monthly injection for the treatment of alcoholdependence. The Company has a pipeline of extended-release injectableproducts and pulmonary drug products based on its proprietarytechnology and expertise. Alkermes' product development strategy istwofold: the Company partners its proprietary technology systems anddrug delivery expertise with several of the world's finestpharmaceutical companies and it also develops novel, proprietary drugcandidates for its own account. The Company's headquarters are inCambridge, Massachusetts, and it operates research and manufacturingfacilities in Massachusetts and Ohio.

About Cephalon, Inc.

Founded in 1987, Cephalon, Inc. is an internationalbiopharmaceutical company dedicated to the discovery, development andmarketing of innovative products to treat sleep and neurologicaldisorders, cancer and pain. Cephalon currently employs approximately2,600 people in the United States and Europe. U.S. sites include thecompany's headquarters in Frazer, Pennsylvania, and offices,laboratories or manufacturing facilities in West Chester,Pennsylvania, Salt Lake City, Utah, and suburban Minneapolis,Minnesota.

The company currently markets four proprietary products in theUnited States: PROVIGIL(R) (modafinil) (C-IV), GABITRIL(R) (tiagabinehydrochloride), ACTIQ(R) (oral transmucosal fentanyl citrate) (C-II)and TRISENOX(R) (arsenic trioxide) injection, and more than 20products internationally. Full prescribing information for all U.S.products is available at www.cephalon.com or by calling1-800-896-5855.

Certain statements set forth above may constitute forward-lookingstatements within the meaning of the Private Securities LitigationReform Act of 1995, including, but not limited to, statements relatedto attaining final regulatory approval of VIVITROL, which will includelabeling discussions with FDA and satisfying a request for preclinicaldata, the status of launch plans, the timing of the VIVITROL launch,and the ultimate commercial success of VIVITROL. Although bothCephalon and Alkermes believe that such statements are based onreasonable assumptions within the bounds of their respectiveknowledge, the forward-looking statements are neither promises norguarantees, and both the Alkermes and Cephalon businesses are subjectto significant risk and uncertainties. As such, there can be noassurance that either or both of Cephalon's or Alkermes' actualresults will not differ materially from their respective expectations.Such expectations are subject to risks, including, among otherswhether Alkermes can successfully scale up and manufacture VIVITROL ata commercial scale; whether VIVITROL will ultimately receive marketingapproval from FDA in a timely fashion or at all, and, if approved,whether it will be launched and commercialized successfully byAlkermes and Cephalon; the outcome of clinical and preclinical workAlkermes and its partners are pursuing, including the results ofpreclinical pharmacokinetic data; decisions by the FDA regardingVIVITROL, which may be based on interpretations of data that differfrom Alkermes' interpretations; and whether VIVITROL in commercialuse, may have unintended side effects, adverse reactions or incidentsof misuse that could cause the FDA or other health authorities torequire post approval studies or require removal of the product fromthe market. For further information with respect to specific risks,uncertainties and factors that could cause actual results to differfrom expectations, reference is made to the reports on Forms 8-K, 10-Qand 10-K that Cephalon and Alkermes each filed with the Securities andExchange Commission under the Securities Exchange Act of 1934, asamended. The forward-looking statements made in this release are madeonly as of the date hereof and both Cephalon and Alkermes disclaim anyintention or responsibility for updating such statements, except asmay be required by law.