LEXINGTON, MA - (March 11, 2003) - Indevus Pharmaceuticals, Inc. (NASDAQ: IDEV) today announced that it has signed an exclusive agreement with Shire Laboratories Inc., a subsidiary of Shire Pharmaceuticals Group plc (LSE: SHP, NASDAQ: SHPGY, TSX: SHQ), under which Shire will develop extended release formulations of trospium, a product currently under development for overactive bladder. The agreement includes milestone payments from Indevus to Shire, as well as royalties based on future sales of extended release trospium. Indevus will be responsible for all development costs and the commercialization of the extended release formulations of trospium under this agreement.

   "We are pleased to bring the advanced drug delivery technology of Shire to bear upon the development of an extended release formulation of trospium suitable for once-a-day dosing," said Glenn L. Cooper, M.D., chairman, president and chief executive officer of Indevus. "Our decision to partner with Shire follows an evaluation of multiple competing technologies. By applying the proprietary formulation and drug delivery expertise and capabilities of Shire, we expect to improve the already highly competitive attributes of the existing formulation of trospium. Our shared objective is to introduce once-a-day trospium at the appropriate time in the life cycle of the twice-a-day product."

   Indevus plans to submit a New Drug Application (NDA) for trospium (twice-a-day) in the second quarter of calendar 2003, contingent upon the finalization of discussions with the U.S. Food and Drug Administration (FDA). Full results of the Company's recently completed Phase III trial with trospium will be presented during the American Urological Association meeting, April 26 - May 1, 2003.

   "We are excited about the opportunity of working with Indevus and adding value to the development of this unique product," said Jack Khattar, president and chief executive officer of Shire Laboratories. "Our advanced drug delivery expertise and leadership in oral controlled release and bioavailability enhancement provide Indevus with access to multiple technologies that will be considered in the development of the once-a-day trospium product."

   Currently marketed in Europe and under development in the U.S., trospium belongs to a class of anticholinergic compounds known as muscarinic receptor antagonists. These compounds relax smooth muscle tissue found in the bladder, thus decreasing bladder contractions. Overactive or unstable detrusor muscle function is believed to be the cause of overactive bladder.

   Shire Laboratories Inc. is the advanced drug delivery subsidiary of Shire Pharmaceuticals Group plc. Shire Laboratories markets its Predictive Lead Selection Technology (ProScreen™) and Predictive Formulation Optimization Technology (OptiScreen®) to the pharmaceutical industry along with its proven and patented oral controlled release formulation technologies, Microtrol®, Solutrol® and EnSoTrol®.

   Indevus Pharmaceuticals is engaged in the development and commercialization of a portfolio of products and product candidates, including multiple compounds in late-stage clinical development. The Company's core products under development include trospium for overactive bladder, pagoclone for panic/anxiety disorders, citicoline for ischemic stroke, IP 751 for pain and inflammation, and PRO 2000 for the prevention of infection by HIV and other sexually transmitted pathogens.

Except for the descriptions of historical facts contained herein, this press release contains forward-looking statements that involve risks and uncertainties that could cause the Company's actual results and financial condition to differ materially from those anticipated by the forward-looking statements. These risks and uncertainties are set forth in the Company's filings under the Securities Act of 1933 and the Securities Exchange Act of 1934 under "Risk Factors" and elsewhere, and include, but are not limited to: uncertainties relating to clinical trials, regulatory approval and commercialization of our products, particularly trospium; the early stage of products under development; need for additional funds and corporate partners, including for the commercialization of trospium and the development of pagoclone and citicoline; history of operating losses and expectation of future losses; product liability and insurance uncertainties; risks relating to the Redux-related litigation; dependence on third parties for manufacturing and marketing; competition; risks associated with contractual arrangements; limited patent and proprietary rights; and other risks.

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