CollaGenex Reports Encouraging Findings From Metastat Clinical Study.

Business Editors/Medical Writers

NEWTOWN, Pa.--(BUSINESS WIRE)--April 4, 2000

CollaGenex Pharmaceuticals, Inc. (Nasdaq: CGPI), today released initial findings from a clinical study carried out by the AIDS Malignancy Consortium that was sponsored by the National Cancer Institute (NCI) under a Cooperative Research and Development Agreement between the NCI and CollaGenex on its lead anti-angiogenesis compound for the treatment of cancer, Metastat(R).

The results will be presented at the 2000 International AIDS Malignancy Conference in May. The study was chaired by Bruce Dezube, M.D., Principal Investigator, Beth Israel Deaconess Medical Center/Harvard Medical School.

The AIDS Malignancy Consortium abstract discusses preliminary findings from a dose escalating Phase 1 study in patients with HIV-associated Kaposi's sarcoma, many of whom had received prior therapy. Metastat was found to be well tolerated at the lowest dose level tested. Anti-tumor activity was observed at all dose levels.

Metastat has previously been shown in a wide variety of preclinical tumor models to inhibit invasion, metastasis and angiogenesis. These properties of Metastat are believed, at least in part, to be mediated by the compound's ability to inhibit matrix metalloproteinases (MMPs).

CollaGenex Pharmaceuticals' first product, Periostat(R), which was approved by FDA in 1998 for the adjunctive treatment of adult periodontitis, is the first MMP inhibitor approved for sale anywhere in the world.

"It is encouraging that, following oral administration, Metastat achieved a clinical response in a number of subjects in this group of patients with HIV-associated Kaposi's sarcoma," noted Brian M. Gallagher, PhD, president and chief executive officer of CollaGenex. "The identification of a dose at which the clinical response was apparent without significant side effects encourages us to pursue Phase 2 development in this disease."

CollaGenex Pharmaceuticals, Inc. is a specialty pharmaceutical company focused on providing innovative medical therapies to the dental market. The company's lead product, Periostat, was approved by the FDA in September 1998 and is the first and only pharmaceutical to treat periodontal disease by inhibiting the enzymes that destroy periodontal support tissues.

Periostat is marketed to the dental community in the United States by CollaGenex through a professional pharmaceutical sales force composed of approximately 135 sales representatives and managers. Currently, the company's dental sales force is also marketing Vioxx(R), a Merck & Co. drug that the Company promotes for the treatment of acute dental pain, and Denavir(R), a SmithKline Beecham Consumer Healthcare prescription drug for the treatment of cold sores.

Research has shown that the enzyme-suppression technology underlying Periostat may also be applicable to other diseases involving destruction of the body's connective tissues including cancer metastasis and a broad range of inflammatory diseases. CollaGenex is developing a series of novel, proprietary compounds known as IMPACS(TM) (Inhibitors of Multiple Proteases And CytokineS) to address these applications. The Company intends to pursue further research and development of this technology primarily through partnerships with third parties.

For additional information on CollaGenex, please visit the Company's web site at www.collagenex.com, which is not a part of this press release.

This news 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, 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) and IMPACS(TM) are trademarks of CollaGenex Pharmaceuticals, Inc.