By Frances Bishopp

Advanced Tissue Sciences Inc. received FDA approval for Dermagraft-TC for use as a temporary wound covering for severe thermal burns in patients who require autograft placement.

The La Jolla, Calif., company develops and manufactures human tissue replacement products for tissue repair and transplantation. Dermagraft-TC, a human fibroblast-derived temporary skin substitute, is the first product of its kind to be approved by the FDA.

Gail Naughton, president and CEO of Advanced Tissue Sciences, said severe thermal burns — also called full-thickness and deep partial-thickness or third-degree thermal burns -- are those in which both the epidermis and the dermis are destroyed and the underlying tissue is damaged.

Naughton, a co-inventor of Dermagraft-TC, was enroute Wednesday to a meeting at the American Burn Association in New York to launch the newly approved product today.

She told BioWorld Today Advanced Tissue Sciences' sales force of five will market the product at the approximately 80 burn centers throughout the U.S.

"The market for the first indication, severe thermal burns, is approximately $30 million," Naughton added.

Advanced Tissue Sciences' stock (NASDAQ:ATIS) closed Wednesday unchanged at $12.75.

Data for a second indication for Dermagraft-TC, Naughton said, demonstrates the product is efficacious for partial-thickness burns such as scald burns, where the market opportunity worldwide is approximately $300 million. The company plans to file for an expanded label with the FDA for a second indication in the near future.

"With the partial-thickness burns, you put it on and the patient's skin grows under it," Naughton explained. "As it grows under it, you can lift the product off and you have beautiful skin underneath. There are tremendous patient benefits such as relief of pain, quicker healing and better cosmesis."

Dermagraft-TC is a product of tissue engineering, combining a bioengineered human dermal layer and a synthetic epidermal layer.

The bioengineered human dermal layer is produced through the culturing of fibroblasts onto a commercially available biosynthetic material bonded to a nylon mesh which acts as a three-dimensional scaffold. Fibroblasts proliferate on the nylon mesh and secrete extracellular matrix proteins and growth factors.

After the growth period, Dermagraft-TC is frozen to minus 70 degrees Celsius and stored until shipment. Each cassette contains two 5 by 7.5 inch Dermagraft-TC sheets. The product remains sterile until the surgeon thaws and opens it for use. Dermagraft-TC is stapled onto the burn, where it remains until a patient is ready to receive an autograft.

The approval of Dermagraft-TC was based on data from a pivotal clinical trial which demonstrated that after two weeks, the mean autograft take (the primary endpoint in the trial) of wounds treated with Dermagraft-TC was statistically equivalent to that of wounds treated with cadaver skin or allograft (94.7 percent for Dermagraft-TC vs. 93.1 percent for allograft).

In addition, Dermagraft-TC performed significantly better than control with respect to important secondary endpoints such as ease of removal, amount of excision required, amount of bleeding upon excision and overall satisfaction ratings among investigators as a temporary covering.

Last month, Advanced Tissue Sciences filed a premarket approval application with the FDA for Dermagraft, a diabetic foot ulcer product, which is currently under expedited review.

The company, Naughton said, plans to launch the product with its joint venture partner, London-based Smith & Nephew plc, during the second half of this year in Europe and in the U.S. following FDA approval.

Advanced Tissue Sciences and Smith & Nephew also are collaborating on worldwide commercialization of human tissue-engineered cartilage for orthopedic applications. Human cartilage is grown to repair and replace damaged cartilage in knee joints, Naughton said. "Like dermis," she explained, "cartilage does not get rejected for several reasons. Cartilage is avascular and the cells themselves are surrounded by a dense cartilaginous matrix which protects them from being seen as foreign."

Advanced Tissue Sciences has submitted an investigational device exemption for FDA approval to begin pilot clinical trials with the cartilage product.

As of Dec. 31, 1996, the company had $40 million in cash as well as access to a $50 million equity line of credit with an undisclosed private investor. Advanced Tissue Sciences reported a net loss of $22.4 million for last year. *