Protein Polymer Technologies Receives Important Notice Of Allowance From
U.S. Patent Office; Second Patent Issued In 1997
SAN DIEGO, Nov. 6, 1997 -- Protein Polymer Technologies,
Inc. (Nasdaq: PPTI) announced today that it received a notice of allowance
from the US Patent and Trademark Office (USPTO) for broad composition of
matter claims based on its core protein engineering technology. The
U.S. patent is expected to issue within the next 6 months. PPTI currently
has six issued U.S. patents, two of which issued this year, two USPTO notices
of allowance, and fifteen other patent applications pending. Corresponding
patent applications have been filed in major international markets. Many
of the issued patents and pending applications relate to inventions that
build upon, or which are components of, the broad proprietary position established
by these newly allowed claims.
"Composition of Matter" Patent. The allowed
claims cover recombinantly produced proteins that consist of relatively
short sequences of amino acids found to be repeated in natural proteins.
These "repeat units" are used by PPTI scientists as building blocks
for creating "protein polymers" that have unique materials properties
due to the repetition of these sequences throughout the polymer molecules.
Silk and collagen are but two of the many natural proteins whose valuable
properties result from such repeat units.
The protein polymers PPTI creates, however, are not found
in nature. Rather, these "designer" proteins isolate, amplify
and combine properties found in natural proteins. The value of PPTI's proprietary
technology platform is based on its capability to create new proteins with
new performance properties for use in products designed to improve medical
and surgical outcomes.
Protein polymers are made using recombinant DNA technology
to create synthetic genes which direct host cells, typically bacteria, to
produce the protein designed by PPTI's scientists. By using a genetic template
to direct the production process, high molecular weight polymers are created
with an exquisite degree of control over their composition and properties.
Such control is required in the natural production of proteins which sustain
life, but has been unobtainable using traditional methods of polymer synthesis.
Genetic "Methods" Patent. The synthesis and
manipulation of DNA required to create synthetic genes encoding "protein
polymers" is covered under U.S. Patent No. 5, 641, 648, which was issued
to the Company in June 1997. In addition, related patent applications claiming
methods useful in preparing synthetic repetitive DNA are pending. Prior
to these inventions, scientists had not been successful in creating genes
that would express high molecular weight proteins of repetitive amino acid
sequences. Cells have built-in mechanisms to prevent multiple identical
sequences of DNA encoding proteins from being maintained. Instead proteins
are normally created with variation in their repeated amino acid segments
to maintain genetic stability of the corresponding DNA.
"Silk & Elastin" Protein Polymers.
One example of the usefulness of the technology was in the creation of a
family of protein polymers combining repeat units from silk and elastin,
another structural protein which provides elasticity to animal tissues including
skin, blood vessels and lungs. These unique biomaterial compositions are
covered in U.S. Patent
No. 5,606,019, which was issued to the Company in February 1997. The
Company's current product development efforts, based on this family of polymers,
have a wide range of applications in large markets, including medical device
coatings and soft tissue bulking agents, particularly for the treatment
of stress urinary incontinence.
Protein Polymers capable of Enzymatic cross-linking.
The technology also has been used in the development of polymers that are
capable of being cross- linked by enzymes normally found in the body. Enzymatic
cross-linking is, for example, the method used by the body to form blood
clots, and is the mechanism underlying fibrin sealants which are marketed
in Europe and Japan and under development for use in the United States.
Although capable of sealing tissues to prevent the loss of blood, these
blood-derived products set-up slowly and have low bond strength. PPTI has
created protein polymers that incorporate more of the sites for enzymatic
cross linking than are present in the natural protein substrate, fibrin.
These polymers set up more quickly, with much higher bond strength, than
fibrin sealant products.
PPTI has received a notice of allowance from the USPTO
for its patent application covering this enzymatic cross-linking technology.
The U.S. patent is expected to issue within the next few months. The allowed
claims are not limited to compositions for use in tissue adhesives or sealants,
and should be useful in a number of PPTI's targeted product applications,
particularly in enhancing the tissue regeneration process.
"Thus far, this has been an outstanding year for
PPTI's patent portfolio. This latest notice of allowance is for broad claims
that significantly extend the protection of our powerful technology platform
used to create unique protein polymers, and fortifies our pioneering position
in the field of biomaterials" said J. Thomas Parmeter, President and
Chief Executive Officer of Protein Polymer Technologies, Inc. "Our
strategic and layered approach to intellectual property protection covers
both protein and DNA compositions, the recombinant DNA methods used to create
the genes which express the proteins, methods for purifying the protein
compositions, and products which are based on the protein compositions.
We believe an exceptionally strong proprietary position has been established
that will protect our commercial interests well into the future."
Protein Polymer Technologies, a San Diego-based biotechnology
company, has developed a number of different classes of biocompatible polymers
that enable cell growth, promote the regeneration of tissue, bond to synthetic
surfaces and resorb into tissue at controlled rates. Targeted applications
include tissue adhesives and sealants, soft tissue augmentation, wound healing,
contact lens coatings, surgical adhesion barriers and drug delivery vehicles.
PPTI's lead products are being developed in collaboration with Ethicon,
a Johnson & Johnson company, for use as a new generation of surgical
adhesives and sealants to replace or augment the use of sutures and staples.
For more information on these and other issued patents, visit PPTI's
online Patents page.
