CollaGenex Pharmaceuticals Initiates Phase 2 Clinical Trial to Evaluate Incyclinide (COL-3) for the Treatment of Acne.

NEWTOWN, Pa. -- CollaGenex Pharmaceuticals, Inc. (Nasdaq:CGPI) today announced that it has initiated a Phase 2, double-blinded, placebo-controlled, dose-finding clinical trial to evaluate the safety and efficacy of its novel compound, incyclinide (formerly known as COL-3), for the treatment of acne.

This study will enroll 300 patients with moderate to severe acne at 20 investigational centers throughout the United States. The study design will evaluate three dosage strengths of incyclinide and a placebo over a 12-week period with the objective of determining an optimal dose for Phase 3 testing. The Company anticipates that the results of the study will be available in the fourth quarter of 2006.

In a recent 14-patient, Phase 2 study evaluating the potential of incyclinide to treat rosacea, patients treated with incyclinide showed a clinically and statistically significant improvement in the reduction of inflammatory lesions. In this study, the incyclinide patients experienced nearly a 70% reduction in inflammatory lesions after 28 days of treatment compared to a slight increase in inflammatory lesions experienced by the patients on placebo (p=0.014). The Company believes that incyclinide could have a similar effect on the inflammatory lesions associated with acne.

"Based on our understanding of incyclinide's biological properties and the success that it demonstrated in the study for patients with rosacea earlier this year, we believe there is a strong potential that it will treat acne safely and effectively," said Klaus Theobald, M.D., Ph.D., Senior Vice President and Chief Medical Officer of CollaGenex. "If our clinical development program for incyclinide proves successful, this could lead to the approval of the first new compound to treat acne since Accutane(R) (isotretinoin) was approved in 1984."

CollaGenex Pharmaceuticals, Inc. is a specialty pharmaceutical company that has built its reputation on providing innovative medical therapies to the dermatology and dental markets. CollaGenex's professional dermatology sales force markets Pandel(R), a prescription topical corticosteroid licensed from Altana, Inc., Alcortin(TM) (1% iodoquinol and 2% hydrocortisone), a prescription topical antifungal steroid combination, and Novacort(TM) (2% hydrocortisone acetate and 1% pramoxine HCl). Alcortin and Novacort are marketed by the Company under a co-promotion agreement with Primus Pharmaceuticals Inc. CollaGenex also currently sells Periostat, which the Company developed as the first pharmaceutical to treat periodontal disease by inhibiting the enzymes that destroy periodontal support tissues and by enhancing bone protein synthesis, and Atridox(R), Atrisorb FreeFlow(R) and Atrisorb-D FreeFlow(R), which are products of QTL, Inc., the successor to Atrix Laboratories, Inc., for the treatment of adult periodontitis.

Research has shown that certain tetracyclines can be chemically modified to retain non-antibiotic properties that may make them effective in treating diseases involving inflammation and/or destruction of the body's connective tissues. CollaGenex is evaluating various chemically modified tetracyclines (so called "IMPACS" compounds because they are Inhibitors of Multiple Proteases And CytokineS") to assess whether they are safe and effective in these applications. The Company has a pipeline of innovative product candidates with possible applications in dermatology and other disease states. In addition, CollaGenex has acquired the Restoraderm technology, a unique, proprietary dermal drug delivery system, and plans 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.

Forward-Looking Statements

Statements in this press release regarding management's future expectations, beliefs, intentions, goals, strategies, plans or prospects, including statements relating to the Company's revenue and expenses, future cash position, including the second quarter and for the remainder of 2005, and its future development efforts, including clinical and development programs and the dermatology franchise, may constitute forward-looking statements within the meaning of the Private Securities Litigation Reform Act of 1995. CollaGenex' actual results could differ materially from those stated or implied in forward-looking statements due to a number of factors, including those factors contained in CollaGenex' Quarterly Report on Form 10-Q for the quarter ended March 31, 2005 under the section "Additional Factors That May Affect Future Results" as well as other documents that may be filed by CollaGenex from time to time with the Securities and Exchange Commission. Forward-looking statements include statements regarding CollaGenex' expectations, beliefs, intentions, goals strategies, plans or prospects regarding the future and can be identified by forward-looking words such as "anticipate", "believe", "could", "estimate", "expect", "intend", "may", "should", "will", and "would" or similar words. CollaGenex assumes no obligations to update the information included in this press release.

Periostat(R) and Restoraderm(R) are registered trademarks and IMPACS(TM) and Oracea(TM) are trademarks 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.

Novacort(TM) and Alcortin(TM) are trademarks of Primus Pharmaceuticals, Inc.

Pandel(R) is a trademark of Taisho Pharmaceuticals.

Atridox(R), Atrisorb(R) and Atrisorb-D(R) are registered trademarks of QLT USA, Inc.