BioTime, Inc. announced the issuance of United States patent number 7,981,871 titled “Modified Macromolecules and Associated Methods of Synthesis and Use,” covering aspects of the composition of Glycosan hydrogels. The patent and related patent family members, assigned to the University of Utah, are licensed to BioTime's subsidiary OrthoCyte Corporation for the manufacture of research products and for therapeutic uses when combined with human cells by BioTime or its subsidiaries.

The patent is of strategic value to the BioTime family of companies, as it provides protection for the formulation of a number of adult and embryonic stem cell-based cellular therapies that may be developed using Glycosan hydrogels, as well as for a stand-alone medical device, HyStem-Rx, that is currently under development by BioTime.

The new patent protects compositions related to the products HyStem and Extracel, both of which are cross-linked scaffolds of two molecules crucial to connective tissues, collagen and hyaluronic acid. Together with the previously issued United States patent 7,928,069, which protects the composition of certain chemical modifications of the extracellular matrix proteins and gelatin, this patent covers the complete composition of HyStem-Rx products. The allowed claims include 3-D cell culture, as well as pharmaceutical compositions that combine the products with human cells of all types.

“This patent represents the second US patent issued that covers Glycosan hydrogels, and its claims cover, among other things, HyStem-Rx, a product slated for near-term development as a medical device for the delivery of cells,” said Michael D West, PhD, president and chief executive officer of BioTime. “Our subsidiary OrthoCyte Corporation is already utilizing HyStem hydrogels in the development of stem cell-based products for the treatment of osteoarthritis.”

HyStem-Rx is a biocompatible hydrogel that mimics the extracellular matrix in which cells reside. As an injectable product, HyStem-Rx may address an immediate need in cosmetic and reconstructive surgery and other procedures by improving the process of transplanting adipose (fat) cells or other adult stem cells. Adult stem cell types such as adipose stem cells obtained from a patient through liposuction can be transplanted back into the same patient at another location in the body, without the risk of rejection associated with the transplant of donor tissues. However, the transplantation of cells without the molecular matrix in which cells normally reside often leads to widespread cell death or the failure of the transplanted cells to remain at the transplant site.

The transfer of cells in HyStem-Rx may resolve these issues by localizing the transplanted cells at the intended location and by providing a three-dimensional form upon which cells can rebuild normal tissue. HyStem-Rx may support other emerging cell and tissue transplant therapies such as those derived from human embryonic stem and induced pluripotent stem cells, in addition to its potential application in the treatment of a number of conditions such as osteoarthritis, brain tumours, stroke, bone fracture, and wounds.

The use of HyStem-Rx as an implantable cell delivery matrix in humans will require approval by the United States Food and Drug Administration and comparable regulatory agencies in foreign countries, which has not yet been obtained. Related patent applications are pending outside of the United States in the European Union, Canada, Japan, and Australia. Due to delays in prosecution of this patent at the US Patent and Trademark Office, a patent term extension has been awarded, extending the expiration date to August of 2027.

BioTime, headquartered in Alameda, California, is a biotechnology company focused on regenerative medicine and blood plasma volume expanders.