CollaGenex Pharmaceuticals Announces Publication of Significant New Clinical Data on Periostat.

Business Editors/Health & Medical Writers

Periostat(R) is the Only Approved Evidence-Based Systemic Therapy for

Periodontitis Demonstrating Clinical Benefit in People with Severe,

Generalized, Chronic Periodontitis, Including Smokers

CollaGenex Pharmaceuticals, Inc. (Nasdaq:CGPI) announced today that new and important evidence from a Phase IV clinical trial of the adjunctive use of Periostat (doxycycline hyclate 20mg tablets) will be published in the July 2002 issue of the Journal of Periodontology, the official journal of the American Academy of Periodontology.

The study was conducted by M. John Novak, BDS, LDS, MS, PhD, of the University of Kentucky, College of Dentistry.

This single-center, placebo-controlled, double-blinded study evaluated the adjunctive benefits of Periostat during a period of nine months in a population of 30 patients with severe, generalized, chronic periodontitis. Patients received dental cleanings above and below the gum line as part of a typical course of treatment used in clinical practice.

70 percent of patients who completed the study and were eligible for analysis were either current or prior smokers. Smoking is a known risk factor for the development of all forms of periodontitis, typically leading to more severe disease and making treatment significantly more challenging.

The results of this study produced solid evidence demonstrating Periostat's significant clinical benefits compared to a placebo (sugar pill).

In teeth exhibiting clinical symptoms of severe periodontitis, defined as tooth pockets of 7mm or more, the adjunctive administration of Periostat, along with a deep cleaning, resulted in average pocket reductions of 3mm or more, compared with around 1.5mm in patients receiving placebo combined with the same standard therapy.

"The data from this study clearly show the clinical benefit of the adjunctive use of Periostat in a group of periodontitis patients who are at a significantly greater risk for rapid disease progression, and respond less well to traditional periodontal therapy," said Dr. Novak, who is Professor of Periodontics and Associate Director of the Center for Oral Health Research at the University of Kentucky. "Average reductions in pocket depth of 3mm or more as a result of adjunctive systemic therapy with Periostat mean that patients and their dentists will now have many more treatment options available. It is clear that the evidence from this study should serve as the basis for recommending this approach as part of routine therapy for patients with severe forms of periodontitis or in those whose periodontal status is compromised due to smoking."

"Periostat, the only evidence-based long-term systemic therapy for periodontitis, has an outstanding efficacy and safety record. Over 2,500,000 prescriptions have been written by U.S. dental professionals and filled by patients since 1998. Systemic therapy with Periostat, which is designed to control the body's ability to destroy its own tissue, is used routinely by many dental professionals along with traditional antibacterial therapy," said Brian M. Gallagher, PhD, chairman, president and chief executive officer of CollaGenex. "The new evidence from this clinical study is noteworthy because the patients were predominately smokers, representative of more than 50 percent of all periodontitis sufferers. Periodontitis is an extremely common and potentially debilitating disorder, and the Novak study confirms the positive findings from other large-scale clinical studies and every day clinical experience that Periostat can have a beneficial adjunctive effect to traditional therapy for this disease."

Whereas traditional periodontal therapy and newer, locally applied antimicrobial therapies address the bacterial component of the disease process, Periostat has a significant effect on the parameters of the host response. It is the only evidence-based systemic therapy for periodontitis approved for marketing by the FDA.

"Only two months ago the American Academy of Periodontology Committee on Research, Science and Therapy recommended continued research to evaluate the role of host response modulation, as accomplished by Periostat, in specific patient types such as smokers, diabetics and those patients with a genetic susceptibility to the disease," noted Dr. Novak. "Our study represents the first of this type, and confirms the value of host response modulation with Periostat in the treatment of patients with risk factors for disease progression. Hopefully other patient populations with diverse risk factors such as diabetes and osteoporosis will be subjected to similar studies; I am confident that the outcomes will also prove to be clinically valuable."

CollaGenex Pharmaceuticals, Inc. is a specialty pharmaceutical company focused on providing innovative medical therapies to the dental and dermatology markets.

The Company's 120-person professional pharmaceutical sales force markets Periostat(R), the first and only pharmaceutical to treat periodontal disease by inhibiting the enzymes that destroy periodontal support tissues, Vioxx(R), a Merck & Co. drug that CollaGenex co-promotes for the treatment of acute dental pain, Atridox(R), Atrisorb(R) and Atrisorb-D(R), Atrix Laboratories Inc.'s products for the treatment of adult periodontitis, and Pandel(R), a mid-potent topical steroid for the treatment of inflammatory skin disorders, licensed from Savage Laboratories.

Research has shown that the enzyme suppression technology underlying Periostat may also be applicable to other diseases involving inflammation and/or destruction of the body's connective tissues, including acne, rosacea, blepharitis and cancer metastases, among others.

CollaGenex is further developing Periostat as well as a series of novel, proprietary compounds known as IMPACS(TM) (Inhibitors of Multiple Proteases and Cytokines) to address 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 is not 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 and 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), IMPACS(TM) and Restoraderm(TM) are United States trademarks of CollaGenex Pharmaceuticals, Inc. Periostat(R) is a European Community trademark of CollaGenex Pharmaceuticals, Inc.

Periostat(R), IMPACS(R) and Restoraderm(R) are United Kingdom trademarks of the Company's wholly owned subsidiary, CollaGenex International Limited. CollaGenex(R) is a European Community and United Kingdom trademark of CollaGenex International Limited.

Pandel(R) is a trademark of Taisho Pharmaceuticals.

VIOXX(R)is a trademark of Merck & Co., Inc.

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