CollaGenex Pharmaceuticals Reports Positive Outcome of Phase 3 Clinical Study Evaluating Periostat as a Treatment for Rosacea.

Business Editors

NEWTOWN, Pa.--(BUSINESS WIRE)--Feb. 17, 2004

Detailed study results to be presented at the Skin Disease Education Foundation's Phoenix Dermatology Open Seminar on March 21, 2004

CollaGenex Pharmaceuticals, Inc. (Nasdaq:CGPI) today announced the positive outcome of a Phase 3 double-blinded, placebo-controlled clinical study designed to evaluate the safety and efficacy of Periostat(R) (doxycycline hyclate tablets, 20 mg BID), for the treatment of rosacea. The study enrolled 134 patients and is the largest clinical trial ever conducted to evaluate a systemic therapy for rosacea.

Preliminary data analysis indicates that patients treated with Periostat showed a continuous improvement during the 16-week course of the study compared to patients on placebo. In the study, patients on Periostat had a significantly greater reduction in the number of inflammatory lesions (papules and pustules) compared to patients on placebo. This improvement was both clinically and statistically highly significant (P = 0.009).

Overall clinical disease severity based on the Clinician's Global Severity Assessment Scale declined significantly in the group of patients treated with Periostat compared to placebo, with a greater number of patients on Periostat showing a complete clearing of the disease at 16 weeks compared to those patients on placebo (P = 0.014). The erythema in patients in the Periostat group showed a trend towards greater improvement compared to patients in the placebo group (P = 0.08).

Colin Stewart, president and chief executive officer of CollaGenex, stated, "The results from this clinical study confirm that Periostat offers significant benefits for rosacea patients. There are currently no FDA-approved systemic therapies for this disease. As part of our plan to extend the indications for Periostat, we will meet with FDA to review all of the data supporting the approvability of Periostat for the treatment of rosacea and determine the appropriate regulatory path."

The detailed results of the study will be presented by Diane M. Thiboutot, M.D., Professor of Dermatology, Pennsylvania State College of Medicine and a principal investigator in the study, at the Skin Disease Education Foundation's Phoenix Dermatology Open Seminar on March 21, 2004.

"The results of this study show that a non-antimicrobial dose of doxycycline clearly produces improvement in rosacea," noted James Leyden, M.D., Professor Emeritus, University of Pennsylvania, and an investigator in the study. "These results complement the recently published similar findings in acne and demonstrate that this very low dose has anti-inflammatory effects. Sub-antimicrobial dose doxycycline has the additional benefit of not disturbing the microbial ecology of the body. Antibiotic resistance is not an issue with this dosage." Dr. Leyden is a consultant for CollaGenex but has no equity position in the Company.

Rosacea is an increasingly common diagnosis affecting more than 14 million people in the United States. The disease is characterized by the appearance of erythema, a persistent redness of the skin, and inflammatory lesions that usually affect the nose, cheeks and forehead. As rosacea becomes more severe, itching and pain can occur. The prescription rosacea category is one of the fastest growing segments of the dermatology market and is estimated to be $500 million annually.

CollaGenex Pharmaceuticals, Inc. is a specialty pharmaceutical company focused on providing innovative medical therapies to the dental and dermatology markets. Currently, the Company's 115-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 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 Atridox(R), Atrisorb(R) FreeFlow(TM) and Atrisorb-D FreeFlow, Atrix Laboratories Inc.'s products for the treatment of adult periodontitis, to the dental market and Pandel(R), a prescription topical corticosteriod licensed form Altana, Inc., to the dermatology market.

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) compounds, 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 Web site 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) and other products that the Company markets, the outcome and consequences of the patent litigation against Mutual and the outcome of litigation initiated by Mutual, risks that the FDA will approve generic products, such as Mutual's products, that will compete with and limit the market for Periostat, 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), IMPACS(R) and Metastat(R) are registered trademarks, and Restoraderm(TM) is a trademark, of CollaGenex Pharmaceuticals, Inc.

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.

Pandel(R) is a trademark of Taisho Pharmaceuticals.

Atridox(R), Atrisorb(R) and Atrisorb-D(R) are trademarks of Atrix Laboratories, Inc.