Protein Polymer Technologies Announces Grant of Patents Covering Tissue Adhesive Applications and Core Technology
With Seven U.S. Patents Issued in 1998, PPTI Achieves Comprehensive Proprietary Position

    SAN DIEGO, Oct. 22, 1998 -- Protein Polymer Technologies,Inc. (PPTI), today announced the grant of patents by the United States Patent and Trademark Office further solidifying protection of the Company's core technology, and its use in tissue adhesives and sealants for tissue repair.  PPTI has been issued a total of seven U.S. Patents in 1998, and has received notice of an eighth U.S. Patent to be issued in November.  PPTI's broad, multi-layered proprietary position affords the Company far-reaching control over the field of protein engineering with respect to protein compositions based on repetitive units of amino acids, their synthesis, and methods for their use.
    "Recombinant protein engineering is at the forefront of biomaterials commercial development, and we are proud of having established ourselves as leaders in this field," said PPTI's President and Chief Executive Officer, J. Thomas Parmeter.  "These patents are a significant accomplishment and provide meaningful recognition of the pioneering achievements of our scientists while also providing the Company and its shareholders with invaluable assets as we move our products through clinical trials and out into the marketplace."
    PPTI is developing novel products for medical and surgical use based on its proprietary biomaterials technology platform. Tissue adhesives and sealants are one of the Company's targeted areas of development. On October 6, 1998, the U.S. Patent and Trademark Office issued Patent No. 5,817,303 entitled "Bonding Together Tissue with Adhesive Containing Polyfunctional Cross-linking Agent and Protein Polymer".  This patent covers methods to hold separated tissue together and to seal defects in viable tissue using a special class of protein polymers engineered by PPTI scientists in combination with a chemical cross-linking agent.  Selected compositions, based on the Company's patented silk-elastin polymers, have demonstrated biocompatibility, exceptional strength and flexibility, and the ability to be resorbed by the body over a specified amount of time.  The Company intends to develop products using these compositions for applications inside the body where sutures and staples do not provide for adequate tissue repair.  To date, no tissue adhesive has been approved for internal use in the United States.
    Although compositions using chemical cross-linking agents are the focus of PPTI's current tissue adhesive product development efforts, U.S. Patent No. 5,773,577, issued on July 30, 1998, entitled "Products Comprising Substrates Capable of Enzymatic Cross-Linking" covers technology the Company has developed using enzymatic cross-linking agents.  A separate class of recombinant proteins have been developed that are cross-linked with blood-clotting enzymes found in the body, such as Factor XIII used in the preparation of fibrin sealant products currently marketed by other companies.  PPTI's formulation stands apart from fibrin sealants in that the adhesive matrix is not blood derived, and has demonstrated both higher strength and a faster cure rate.
    The Company's core technology is at the center of its proprietary position.  On June 23, 1998, PPTI was granted U.S. Patent No. 5,770,697 entitled "Peptides Comprising Repetitive Units of Amino Acids and DNA
Sequences Encoding the Same".  This patent, combined with methods patents previously issued for preparing synthetic repetitive DNA, gives PPTI exclusive rights to a broad range of protein compositions incorporating amino acid sequences found to be repeated in natural proteins.  In addition, in a separate action, the Company has received notice that U.S. Patent No. 5,830,713 will be issued in early November.  This patent covers second generation methods developed by the Company for recombinantly producing proteins with repetitive amino acid sequences.  It's issuance will further extend PPTI's proprietary technology umbrella beyond the protein compositions already patented.
    "The proteins we have created are proving to have unique and useful properties and to be very biocompatible," said Dr. Joe Cappello, PPTI's Chief Technical Officer.  "We take a natural protein and extract from it a specific property that we want to reproduce -- like the sequence in silk that makes it strong and the sequence in elastin that makes it flexible -- and we replicate it, tailoring the design of our proteins, and subsequently the finished product, to desired specifications.  Holding these patents gives PPTI the right to exclude others from practicing the technology."
    The other patents issued since March represent broad applications for PPTI's technology.  U.S. Patents No. 5,723,588 and No. 5,808,012 cover traditional thermoplastics having biological and chemical functionality through the incorporation of thermally stable proteins.  U.S. Patent No. 5,760,004 protects chemistries developed to modify the solution properties of silk-like polymers for improved processibility, and U.S. Patent No. 5,773,249 protects a broad class of collagen-like polymers.
    To date, PPTI's U.S. Patent estate includes thirteen patents, with one more expected to issue in November, and nine patents pending.  Patents are also pending in important foreign countries.  More detailed information can be obtained through PPTI's website (http://www.ppti.com) which has been designed to provide interested parties with timely, comprehensive information.
    Protein Polymer Technologies, Inc., is a San Diego-based company focused on developing products to improve medical and surgical outcomes.  From its inception in 1988, PPTI has been a pioneer in protein design and synthesis, developing an extensive portfolio of proprietary biomaterials.  These genetically engineered biomaterials are high molecular weight proteins, processed into products with physical and biological characteristics tailored to specific clinical performance requirements.  Targeted products include urethral bulking agents for the treatment of stress urinary incontinence, dermal augmentation products for cosmetic and reconstructive surgery, tissue adhesives and sealants, scaffolds for wound healing and tissue engineering, and depots for local drug delivery.
    This press release contains forward-looking statements that are based on management's views and expectations.  Actual results could differ materially from those expressed here; further, the Company is not obligated to comment specifically on those differences.  Risks associated with the Company's activities include scientific and product development uncertainties, competitive products and approaches, continuing collaborative partnership interest and funding, regulatory testing and approvals, and manufacturing scale-up.  The reader is encouraged to refer to the Company's 1997 Annual Report and 10-KSB, and recent filings with the Securities and Exchange Commission, copies of which are available from the Company, to further ascertain the risks associated with the above statements.


For more information on these and other issued patents, visit PPTI's online Patents page.