CollaGenex Pharmaceuticals Announces US Patent for New IMPACS Compound.

Business Editors/Health/Medical Writers

NEWTOWN, Pa.--(BUSINESS WIRE)--March 6, 2003

First Chemical Compound Patent from Proprietary Research Effort is

Granted; Patents for Other Compounds Pending

CollaGenex Pharmaceuticals, Inc. (Nasdaq:CGPI) today announced that the United States Patent and Trademark Office has granted U.S. Patent 6,506,740 covering the first of its new IMPACS(R) (Inhibitors of Multiple Proteases and Cytokines) compounds.

The patent, entitled "4-dedimethylaminotetracycline derivatives," issued January 14, 2003, is owned by CollaGenex Pharmaceuticals, Inc. The patent claims a specific chemical structure and its use for a wide variety of diseases involving, among other things, the destruction of the body's connective tissues.

CollaGenex is employing multiple strategies to exploit its IMPACS technology, initially focusing on the development of products that use known antimicrobial and non-antimicrobial tetracyclines in new and proprietary ways.

For example, the well-known antibiotic doxycycline, administered at a unique, proprietary, sub-antimicrobial dose, is the active ingredient in Periostat(R), CollaGenex's flagship product for the adjunctive treatment of adult periodontitis.

Similarly, COL-3, a non-anti-microbial tetracycline compound which is the active ingredient in Metastat(R), is the subject of an extensive portfolio of patents describing its use in the treatment of cancer and other diseases.

However, U.S. Patent 6,506,740 is the Company's first issued patent that claims a completely new chemical compound, representing a significant breakthrough in the development of the next generation of IMPACS-based products.

"One of the Company's stated objectives has been to build a portfolio of proprietary IMPACS compounds with the potential for optimal therapeutic benefits and extended patent life," said Robert A. Ashley, senior vice president of commercial development at CollaGenex. "The particular compound disclosed in this patent is a substituted, non-antimicrobial derivative of minocycline, which may have characteristics particularly suitable for the treatment of inflammatory dermatological disorders such as rosacea."

"Patents for numerous other compounds with a variety of novel properties are pending," continued Mr. Ashley. "The Company is now engaged in characterizing the proprietary compounds that offer the most promise for a given indication with a view to carrying out clinical development, either ourselves or in partnership with others."

CollaGenex Pharmaceuticals, Inc. is a specialty pharmaceutical company currently focused on providing innovative medical therapies to the dental and dermatology markets. Currently, the Company's 120-person professional dental pharmaceutical sales force markets Periostat(R), which is indicated as an adjunct to scaling and root planing for the treatment of adult periodontitis.

Periostat(R) is the first and only pharmaceutical to treat periodontal disease by inhibiting the enzymes that destroy periodontal support tissues, and by enhancing bone protein synthesis.

The sales force also promotes Vioxx(R), a Merck & Co. drug that CollaGenex co-promotes for the treatment of acute dental pain, Denavir(R), a Novartis Group prescription anti-viral medication for the treatment of cold sores, and Atridox(R), Atrisorb(R) and Atrisorb-D(R), Atrix Laboratories Inc.'s products for the treatment of adult periodontitis.

Research has shown that certain unique properties of the tetracyclines discovered during the development of Periostat may be applicable to other diseases involving inflammation and/or destruction of the body's connective tissues, including acne, rosacea, meibomianitis and cancer metastasis, among others.

CollaGenex is further evaluating Periostat, as well as the new IMPACS(R), to assess whether they are safe and effective in these applications. In addition, CollaGenex has licensed the Restoraderm(TM) technology, a unique, proprietary dermal drug delivery system, in order to develop a range of topical dermatological products with enhanced pharmacologic and cosmetic properties.

To receive additional information on the Company, please visit our website at www.collagenex.com, which does not form part of this press release.

This press release contains forward-looking statements within the meaning of Section 21E of the Securities and Exchange Act of 1934, as amended. Investors are cautioned that forward-looking statements involve risks and uncertainties, which may affect the Company's business and prospects.

The Company's business of selling, marketing and developing pharmaceutical products is subject to a number of significant risks, including risks relating to the implementation of the Company's sales and marketing plans for Periostat(R), the outcome and consequences of the patent litigation against West-ward, other products that the Company markets, risks inherent in research and development activities, risks associated with conducting business in a highly regulated environment and uncertainty relating to clinical trials of products under development, all as discussed in the Company's periodic filings with the U.S. Securities and Exchange Commission.

Periostat(R), Metastat(R), Dermostat(R), Nephrostat(R), Osteostat(R), Arthrostat(R), Rheumastat(R), Corneostat(R), Gingistat(R), IMPACS(R), PS20(TM), The Whole Mouth Treatment(R), Restoraderm(TM) and Dentaplex(R) are United States trademarks of CollaGenex Pharmaceuticals, Inc.

Periostat(R), Nephrostat(R), Optistat(R), Xerostat(R) and IMPACS(TM) are European Community trademarks of CollaGenex Pharmaceuticals, Inc. Periostat(R), Nephrostat(R), Optistat(R), Xerostat(R), IMPACS(R), Dentaplex(R), Restoraderm(R), Dermastat(R), Periocycline(R), Periostatus(R) and Periostan(R) are United Kingdom trademarks of our wholly owned subsidiary, CollaGenex International Limited.

CollaGenex(R), PS20(R), "C" Logo(R) and The Whole Mouth Treatment(R) are European Community and United Kingdom trademarks of CollaGenex International Limited. Periocycline(TM) and Periostan(TM) are European Community Trademarks of CollaGenex International Limited.

All other trade names, trademarks or service marks are the property of their respective owners and are not the property of CollaGenex Pharmaceuticals, Inc. or any of our subsidiaries.