By Lisa Seachrist

Washington Editor

CollaGenex Pharmaceuticals Inc. filed a new drug application for a tablet form of its periodontitis treatment, Periostat.

The new dosage form is a small, film-coated tablet containing 20 mg doxycycline hyclate, the same active ingredient in the company's approved capsule formulation of Periostat.

"Because we already have an approval for Periostat as an adjunct to standard therapy, we've submitted data showing the new formulation has bioequivalence to the capsule form," said Nancy Broadbent, chief financial officer for CollaGenex. "This is really a nice milestone for the company."

CollaGenex, of Newton, Pa., had $15 million in revenue from sales of Periostat last year. The capsule formulation was approved in September 1998.

Broadbent noted the tablet form of Periostat is cheaper to produce, which likely will increase the company's gross margins. Tablets also are less difficult to swallow for a number of patients and can be provided in blister packs, giving CollaGenex flexibility in packaging. Because the tablets are simply compounded in a different way, the approval process may be shorter than the statutory 12-month review time.

In periodontal disease, which affects up to 67 million Americans, bacteria around teeth cause inflammation, triggering the release of collagenase and separation of the gums from the teeth. Standard treatment involves the mechanical removal of bacterial deposits from below the gumline in a procedure called scaling and planing.

Periostat is a sub-antibiotic dose of the common antibiotic doxycycline. At these low levels, Periostat inhibits the production of collagenase without generating bacterial resistance.

The same enzyme suppression technology underlying Periostat also may be applicable to other diseases involving the 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 called inhibitors of multiple proteases and cytokines (IMPACS) to address these applications. That technology will be developed primarily through partnerships.

The company's stock (NASDAQ:CGPI) closed Friday at $16, up $2, or 14 percent.