By Randall Osborne

West Coast Editor

OraPharma Inc. said the FDA has agreed to sink its teeth into the company's new drug application (NDA) for an antibiotic-based periodontal disease therapy.

The agency has accepted for review OraPharma's NDA for the Minocycline Periodontal Therapeutic System (MPTS), which delivers as dry powder into periodontal pockets the broad-spectrum antibiotic minocycline, encapsulated in bioresorbable microspheres.

Mike Kishbauch, president and CEO of Westminster, Pa.-based OraPharma, said MPTS would be used as an adjunct with the scaling and planing procedure, which is the standard of care - and with another periodontal disease drug, Periostat, developed by CollaGenex Pharmaceuticals Inc., of Newton, Pa.

"We don't see this as a race with CollaGenex," Kishbauch said. "The drugs fill different needs."

MPTS is locally delivered and can be administered "one, two, three times a year," whereas Periostat, an oral form of doxycycline hyclate, is given as a systemic, maintenance therapy. Earlier this month, CollaGenex filed an NDA for a new 20 mg dosage of Periostat in tablet form. (See BioWorld Today, April 3, 2000, p. 1.)

OraPharma filed the NDA for MPTS Feb. 17, "right smack in the middle of our road show" related to the company's initial public offering, which last month raised $72 million, so the firm was restricted from talking about the filing by the Securities and Exchange Commission's "quiet period" rule, Kishbauch said.

"We weren't in a position to do any hooting and hollering," he said.

Kishbauch said many experts in the field believe the ideal approach would be to use MPTS with Periostat, as adjuncts to scaling and planing.

"The market is potentially huge," he said. About 50 million people in the U.S. are affected by periodontal disease, which is the most common, chronic infectious disease in the world, Kishbauch said. Of those affected, 8 million to 10 million are undergoing treatment, he said.

Two products already on the market for the condition include a locally delivered doxycycline gel that must be refrigerated and mixed before use in two syringes - "squished back and forth as many as 100 times," Kishbauch said. This treatment was studied as a replacement for scaling and planing, he added, although it may be used as an adjunct.

That product, Atridox, was developed by Atrix Laboratories Inc., of Fort Collins, Colo., and was approved by the FDA in September 1998. It's regarded as the more significant competitor to MPTS. (See BioWorld Today, Dec. 14, 1998, p. 1.)

The other treatment is a collagen-based, antimicrobial chip that is "jimmied into the [periodontal] pocket," as an adjunct to scaling and planing, Kishbauch said. It also must be refrigerated, and scientists have been "historically concerned" about potential toxicity of the antimicrobial approach to periodontal disease, he said.

In any case, both existing treatments are "far less streamlined" than MPTS, which is administered directly off the shelf to affected pockets in the patient's gums, he said.

Periodontal disease especially afflicts older people and smokers. OraPharma's "landmark" Phase III trials, which last fall finished evaluating more than 900 patients at 23 centers, were "two or more times greater than anything else done in this space," Kishbauch said, and found particular efficacy in a subset of smokers over 50.

Because the amount of minocycline - a tetracycline derivative originally formulated for the systemic treatment of acne - used in MPTS is very low, it bypasses problems such as creating antibiotic resistance, causing side effects or interacting harmfully with other drugs, Kishbauch said.

At the same time, the polymer microspheres ensure that minocycline is released effectively for at least 14 days, he said. Studies "suggest rather provocatively" an even longer period, he added.

Kishbauch declined to guess when the FDA might complete its review, but said OraPharma is gearing up to begin marketing next year.

"We'll be ready to go by the second quarter," he said.

OraPharma's stock (NASDAQ:OPHM) closed Wednesday at $10.375, up 2.625, or about 34 percent.

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