By Randall Osborne

Advanced Tissue Sciences Inc. bounced back from the FDA's nonapprovable letter two months ago for Dermagraft, its bioengineered skin implant for diabetic foot ulcers, by completing plans for another clinical trial that could lead to marketing the product.

"It's taken us this long to work out the protocol with the FDA," said Jack Strube, director of finance for La Jolla, Calif.-based Advanced Tissue. "The plan is finally in place."

Dermagraft is a living, metabolically active implant derived from discarded foreskin tissue. In June, the FDA set aside an advisory panel's recommendation and turned down the company's premarket approval application (PMA), saying a retrospective analysis of a clinical trial was not enough to support it. (See BioWorld Today, June 15, 1998, p. 1.)

Enrollment will begin soon, Strube said, and an interim analysis is slated after 180 patients are enrolled. If that analysis proves encouraging, Advanced Tissue could submit another PMA within about a year of the trial's start.

"The design of the plan, in our minds at least, makes the extra time worth it," Strube told BioWorld Today. "We feel pretty good about what we were able to work out with the [FDA]."

Unlike the earlier trial, which lasted 32 weeks, the new study will last 12 weeks, at up to 30 centers.

"We would expect, since [the FDA has] worked closely with us, that we would receive a timely response to our submission," Strube said.

Still, the delay sets Dermagraft's launch back about two years.

"We'd be looking at a potential launch in early 2000," Strube said. "We had originally hoped to launch in the second quarter of 1998."

Advanced Tissue is also preparing an investigational device exemption (IDE) application for Dermagraft, which would let physicians use it on a patient-by-patient basis, prior to formal FDA approval.

"It's a fairly new program," Strube said, adding the company expects the IDE to win the agency's blessing, followed by the PMA.

"We have a considerable amount of trial experience with the FDA on the product, since we've conducted three previous trials," he said. "We're confident about the outcome."

Advanced Tissue also said it has expanded its joint venture with London-based Smith & Nephew plc to include marketing Dermagraft-TC for burns in the U.S., effective in October. The original deal, signed in 1996 and valued at $70 million, allowed Smith & Nephew to market the product for all wound-care applications outside the U.S. and for all wound applications except burns in the U.S. (See BioWorld Today, April 30, 1996, p. 1.)

Under the expanded joint venture with Advanced Tissue, Smith & Nephew will market and sell Dermagraft-TC in the U.S. for full- and partial-thickness burns.

Dermagraft-TC is designed to act as an artificial epidermis layer. "TC" stands for "transitional covering." The product will be renamed TransCyte to differentiate it from Dermagraft and to indicate its ability to allow migration of keratinocytes (the primary cells in the upper layer of skin) in partial-thickness wounds.

Advanced Tissue's stock (NASDAQ:ATIS) closed Thursday at $3.343, up $0.062. *