FOR IMMEDIATE RELEASE

BioStratum Receives patent on Type IV Collagen-Derived Anti-Angiogenesis Agent
-- In vivo results show efficacy against three tumor types --

Research Triangle Park, N.C., April 21, 1999 -
BioStratum Incorporated announced today the
issuance of US Patent No. 5,856,184 to the University
of Kansas Medical Center on type IV collagen-derived
anti-angiogenesis agents. The patent's claims cover
domain structures of type IV collagen, including the
non-collagenous (NC1) domain, as agents to inhibit
tumor growth by restricting a tumor's blood supply.
This patent is the fourth in a series of patents exclusively licensed to BioStratum that cover the use of type IV collagen domains to interrupt cell-basal lamina interactions that are fundamental to tissue growth and development.

BioStratum has used the NC1 domain of type IV collagen to develop an anti-tumor agent called Angiocol. In four separate model systems, Angiocol significantly inhibited angiogenesis, the growth of new capillaries from existing blood vessels. Additionally, in three tumor types, Angiocol inhibited tumor growth by as much as 70%.

“Angiocol looks very promising as a non-cytotoxic agent for use in conjunction with a number of cytotoxic anti-cancer drugs”, said Dr. Archie Prestayko, President and CEO
of BioStratum. “Our recombinant method of production produces a soluble, robust molecule that exhibits consistent lot-to-lot anti-angiogenesis and anti-tumor activity when administered intravenously in our in vivo angiogenesis model systems.”

The company is currently scaling up the recombinant production of Angiocol for the initiation of human clinical studies anticipated to begin early next year.

Type IV collagen, from which Angiocol is derived, is a principal component of the basal lamina, also known as the basement membrane. The basal lamina is a specialized form of the extracellular matrix that directs cell growth and tissue development through specific binding interactions between neighboring cell receptors and specific domain structures within basal lamina components.

“As we studied the assembly and organization of type IV collagen molecules to form a functional basal lamina, we discovered that the introduction of specific domain structures of type IV collagen disrupted the process”,
said Dr. Billy Hudson, Professor and Chairman of the Department of Biochemistry and Molecular Biology at
the University of Kansas Medical Center, and cofounder
of BioStratum. “Realizing the requirement for a functional basal lamina in the angiogenesis process, we examined the anti-angiogenesis activity of these domain structures and further characterized their interactions with specific matrix metalloproteinases and cell receptors. What
has emerged are potent type IV collagen-derived
anti-angiogenesis agents with well-defined mechanisms
of action.”

BioStratum is a privately held company developing proprietary therapeutics based on recent scientific advances in basal lamina and related technologies. The company's drug candidates are directed against novel
basal lamina extracellular targets involved in degenerative and invasive disease processes fundamental to kidney disease, diabetes and cancer. The company has also developed methods for the production of recombinant
basal lamina proteins for use in wound repair and
advanced tissue regeneration protocols.

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