CollaGenex Pharmaceuticals Submits Response to USPTO Regarding Patent Application Covering Oracea.

NEWTOWN, Pa. -- CollaGenex Pharmaceuticals, Inc. (NASDAQ: CGPI) today announced that it has submitted its response to the U.S. Patent and Trademark Office's non-final rejection of U.S. Patent Application, Serial No. 10/117,709. This application relates to the use of sub-antimicrobial and non-antimicrobial tetracyclines for the treatment of acne and acne rosacea, including Oracea(TM) and incyclinide.

The USPTO issued a Notice of Allowance of this patent application in August 2005, and a patent was scheduled to issue on May 23, 2006. On May 17, 2006, CollaGenex submitted additional information to the USPTO that could be relevant to the allowed patent application and requested a continuing examination. On July 20, 2006, CollaGenex announced that the USPTO had posted on its Website a non-final rejection of CGPI's patent application for Oracea. Today's submission is the company's response to this non-final rejection.

Colin Stewart, president and chief executive officer of CollaGenex, said "We believe that our submission to the USPTO addresses all of the issues raised by the examiner. However, we could receive one or more additional rejections by the examiner until all of the issues are resolved, which we believe will take another four to six months. We remain confident that a patent protecting Oracea and incyclinide will issue."

CollaGenex Pharmaceuticals, Inc. is a specialty pharmaceutical company currently focused on developing and marketing innovative proprietary medical therapies to the dermatology market. In July 2006, CollaGenex launched Oracea(TM), the first FDA-approved systemic product for the treatment of rosacea, and is conducting a 300-patient, Phase II dose-finding study to evaluate its second dermatology candidate, incyclinide, for the treatment of acne. CollaGenex is also developing COL-118, utilizing the technology acquired in the acquisition of SansRosa Pharmaceutical Development Inc., as a preclinical topical compound for the treatment of redness associated with rosacea and other skin disorders. CollaGenex's professional dermatology sales force also 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), a prescription topical steroid and anesthetic. Alcortin and Novacort are marketed by the Company under a Promotion and Cooperation agreement with Primus Pharmaceuticals, Inc.

CollaGenex also currently sells Periostat(R), 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 QLT Inc., the successor to Atrix Laboratories, Inc., for the treatment of adult periodontitis.

Research has shown that certain tetracyclines can be chemically modified to remove their antibiotic effects while retaining the 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(TM)" 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(R) 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 Website 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 concerning the Company's U.S. patent application relating to the use of sub-antimicrobial and non-antimicrobial tetracyclines for the treatment of acne and acne rosacea, including Oracea and incyclinide, the outcome of the USPTO's review of such patent application and whether such patent application will issue as a patent, 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 the most recent Form 10-Q for the quarter ended June 30, 2006 under the section "Risk Factors" 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 or revise any forward-looking statements, whether as a result of new information, future events or otherwise.

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 registered trademark of Taisho Pharmaceuticals.

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