By Randall Osborne

Well over a year after submitting the new drug application (NDA) forits pill to fight gum disease, CollaGenex Pharmaceuticals Inc. is preparingto answer the FDA's second request for more information.

Newtown, Pa.-based CollaGenex filed its NDA for Periostat, its drugagainst periodontitis, in September 1996. Last fall, the FDA asked foradditional facts related to the statistical methods the company used toevaluate trial results. (See BioWorld Today, Sept. 5, 1996, p. 1,and BioWorld Today, Sept. 3, 1997, p. 1.)

In periodontal disease, bacteria around the teeth cause inflammation,which triggers the release of collagenase, an enzyme that breaks down connectivetissue and allows the gums to recede from the teeth.

Current treatments are administered locally and target the bacteria,killing them with antibiotics around the teeth or scraping the bacteriaaway.

Periostat, a systemic therapy, contains a low dose of the antibioticdoxycycline, which at Periostat's levels inhibits the production of collagenasewithout stimulating antimicrobial activity.

The drug's sub-antibiotic dosage allows patients to use Periostat overa long period of time, without concern for generating bacterial resistance.

CollaGenex was notified in a letter from the FDA that Periostat is stillnot approved. The company has spoken with the agency by phone and is workingto resolve the remaining issues.

The company has completed three Phase III studies of Periostat, andin each trial the drug demonstrated statistical significance in reducingand reversing periodontitis.

CollaGenex's core technology is focused on inhibiting enzymes that destroyconnective tissues of the body. Other applications being researched includecancer metastasis, wound healing, osteoarthritis, osteoporosis, rheumatoidarthritis and diabetic nephropathy. Founded in 1992, the company went publicin 1996 with an initial public offering of 2 million shares.

The company's stock (NASDAQ:CGPI) closed Thursday at $8.375, down $0.25.*