Advanced Tissue Sciences, Inc., Begins Pivotal Periodontal Trial

July 8, 2002
Patient enrollment to begin this summer.

Advanced Tissue Sciences, Inc. (NASDAQ: ATIS) today announced that it has received FDA approval to begin a pivotal clinical trial investigating the use of its core technology, a human fibroblast-derived dermal substitute, as a substitute for a soft tissue graft during periodontal surgery. This technology has already been approved for the treatment of diabetic foot ulcers under the name Dermagraft(R).

Corrective periodontal surgery with a soft tissue graft is
frequently required in patients whose gums recede and expose the tooth root. During this procedure, a donor graft (autograft) is harvested from the patient's own palatal tissue. This graft is placed over the exposed root and covered by a flap of gingival tissue, thereby preventing further recession and maintaining the health of the tooth.

According to the American Dental Association, approximately 500,000 periodontal soft tissue grafts are performed annually in the U.S. This controlled, randomized trial will investigate whether the use of Advanced Tissue Sciences' human fibroblast-derived dermal substitute is equivalent to an autograft for treating patients requiring root coverage. The trial is a within-patient paired design, meaning that each patient will undergo treatment of two defects. One defect will be treated with Advanced Tissue Sciences' product, while the other is treated with palatal tissue. Up to 50 patients are expected to participate in the trial.

The average improvement in gingival recession with Advanced Tissue Sciences' product will be compared to the improvement achieved with the patient's own tissue. If equivalence is demonstrated, the fibroblast-derived dermal substitute could eliminate the need for a second surgical procedure to obtain the autograft, therefore reducing patient pain and morbidity. In addition, it may allow periodontists to treat several exposed roots in a single patient without the need for repeat surgeries.

"It is our hope that the outcome of this trial will be another
indication for our core technology, and a new treatment option for
periodontists and their patients," said Arthur J. Benvenuto, Advanced Tissue Sciences' chairman, president and CEO. "In addition, the start of this trial underscores our commitment to commercializing short- and medium-term products derived from our existing fibroblast technology."

Patient enrollment will begin this summer. Each patient is
expected to be followed for a minimum of six months, after which the data will be compiled and submitted for regulatory review.