SHIRES' OPTION FOR RIGHTS TO EMITASOL EXPIRES.

Questcor Pharmaceuticals, Inc. (AMEX: QSC), Union City, Calif., has announced that the option held by Shire Pharmaceuticals Group plc to acquire the exclusive rights to market Emitasol(R) (intranasal metaclopramide) in North America has expired.

Emitasol(R) is being developed to treat delayed-onset emesis (nausea and vomiting) related to chemotherapy.

According to the American Cancer Society (ACS), approximately 75% of the 1.3 million new cancer patients diagnosed every year require some type of chemotherapy treatment. The ACS estimates about 60% of chemotherapy treated patients experience delayed-onset emesis. There is currently no FDA approved product for treating delayed-onset emesis.

"We have always been excited about the potential of Emitasol(R) and are very pleased to have the North American rights," said Charles J. Casamento, chairman, president and CEO of Questcor. "We believe Questcor is in an excellent position to maximize this product opportunity."

Emitasol(R) is approved and marketed in Italy under the trade name Pramidin(R). Questcor recently announced that Pramidin(R) has been approved for marketing in Poland and the Czech Republic where it will be marketed by CSC Pharmaceuticals. The product has also been submitted for marketing approval in Russia, Hungary and Slovak Republic. Questcor's partner in Korea, Ahn-Gook Pharmaceuticals is preparing to submit a registration document seeking approval to market Pramidin(R) in that country. Laboratorios Silesia S.A., another of Questcor's collaboration partners is preparing registration documents to market the product in Chile.

"Emitasol(R) is a very important late stage clinical project for Questcor" said Kenneth R. Greathouse, vice president of Commercial Operations. "Patients who experience cancer chemotherapy induced delayed onset emesis have few therapeutic alternatives. Patients at home cannot take injectable therapy and oral tablets are of little use in treating a patient who is experiencing emesis and or vomiting."

In an agreement signed in July 1998, Questcor granted Roberts Pharmaceuticals (which subsequently was acquired by Shire Pharmaceuticals Group plc) an option to acquire an exclusive license to market Emitasol(R) in North America. The exclusive option agreement expired in July 2001. As previously disclosed, the company and Shire had been in discussions about the extent and nature of a future collaboration on Emitasol. The companies are no longer in discussions.

About Questcor Pharmaceuticals

Questcor Pharmaceuticals, Inc. is a fully integrated specialty pharmaceutical company that serves the needs of the acute care and critical care hospital market with its proprietary products including Glofil(TM)-125 and Inulin for measuring renal GFR, Ethamolin(R)for sclerotherapy, HP Acthar(R)Gel to treat a seizure complex, referred to as West syndrome or infantile spasm, and Pramidin(R)for various gastrointestinal disorders. Questcor's late stage pipeline products are being developed to treat delayed onset emesis (nausea and vomiting), congenital lactic acidosis (CLA), and various central nervous system disorders. As part of a strategy to develop its products globally, Questcor has entered into over 20 contractual relationships with public and private companies including: Ahn-Gook Pharmaceuticals, of Korea; Aventis Pharmaceuticals, Inc. of Bridgewater, NJ; CSC Pharmaceuticals Handels GmbH of Vienna, Austria; Crinos Group of Como, Italy; Dainippon Pharmaceutical Co., Ltd., of Osaka, Japan; Rigel, Inc. of South San Francisco, CA; Sigma-Tau Finanziaria S.p.A. in Rome, Italy; and Tularik, Inc. of South San Francisco, CA.

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