US Stem Cell Patent

Stem Cell Sciences plc
15 August 2007


Press Release
15 August 2007

         US PATENT & TRADEMARK OFFICE GRANTS STEM CELL SELECTION PATENT


Stem Cell Sciences plc (SCS, AIM:STEM, ASX:STC), the global biotechnology
company focused on the commercialisation of stem cells and stem cell
technologies, is pleased to announce that the US Patent & Trademark Office
(USPTO) has granted a broad patent covering SCS' Stem Cell Selection technology
(US Patent 7,256,041). Claims granted to SCS by the USPTO cover all methods of
purifying any type of mammalian stem cell via any introduced gene and all stem
cells purified by the method. All adult human stem cells and all human embryonic
stem cells are covered by the claims which further extend the protection already
secured by SCS for Stem Cell Selection using cell surface antigens and
fluorescent markers (US Patent 6,878,542), as well as antibiotic resistance (US
Patent 6,146,888).

Stem cell purification is an essential step in preparing stem cells for use in
almost all drug discovery and cell therapy applications. Without this step, the
other (non-stem) cells in the population contaminate the stem cell sample,
rendering it unsuitable for use. With the ever increasing importance of stem
cells in the US biopharmaceutical industry, the extension of SCS' patent
position reinforces a key income stream and productivity advantage held by the
company.

Dr Peter Mountford, Chief Executive Officer of SCS said, "As pioneers in the
stem cell industry, SCS has been able to secure very broad claims for this
fundamental and important technology. We expect further growth in licensing
revenues and are pleased to have secured a further competitive advantage for
both our exclusive and non-exclusive licensees of the technology."

"The value of such fundamental, proprietary technology cannot be underestimated,
particularly in such a competitive and rapidly growing industry. Stem Cell
Sciences has always placed great emphasis on using patent law to maximise
revenue opportunity. This technology has been successfully defended in Europe's
largest ever patent office hearing and now the full breadth of claims has been
recognised and granted in the USA as well. We look forward to building on
further licensing opportunities in this substantial industry" he added.


                                    - Ends -

For further information, please contact:

Stem Cell Sciences plc (United Kingdom)
Hugh Ilyine, Vice President and Chief Operating Officer         [phone]

Weber Shandwick Financial
Louise Robson or James White                                    [phone]

Stem Cell Sciences (Australia) pty ltd
Peter Mountford, President and CEO                               [phone]

Talk Biotech
Fay Weston                                                       [phone]

Stem Cell Sciences llc (USA)
George Murphy, Vice President Business Development               [phone]


Notes to Editors

Stem Cell Selection explained
Stem cells are usually isolated or grown as a mixture of different cell types,
however, the preferred format for the great majority of drug discovery and
clinical uses is pure preparations of stem cells.

Stem cells have historically been purified by making use of proteins
(antibodies) that bind specifically to other proteins that are only found on the
surface of stem cells. That is, stem cells have unique natural markers on their
surface and antibodies can bind to these and enable scientists to pull them out
of the mixture - typically one stem cell at a time.

Unfortunately, many stem cells do not have appropriate markers on their surface
and/or the number of stem cells that can be purified using this approach is too
small for industrial scale use.

The SCS technology works by placing a selectable marker into any stem cell
specific gene. The stem cell specific gene provides the machinery to make the
introduced selectable marker protein. The selectable marker protein can be any
one of a number of different types including fluorescent proteins or proteins
that make cells resistant to certain chemicals that would otherwise normally
kill them.

Once the selectable marker has been introduced into the cells, only the stem
cells in the mixture of cells glow green and these can be purified by selecting
the green cells. Alternatively, only stem cells in the mixture are resistant to
a certain antibiotic and so on adding the drug to the mixture of cells, all
cells except the stem cells die. The use of antibiotic selection is particularly
powerful as commercial scale purification of stem cells can be achieved simply
by adding a drug to the culture.


Stem Cell Sciences plc (SCS, AIM: STEM, ASX: STC) is a global biotechnology
company providing the biological infrastructure of cells and cell culture media
to the burgeoning stem cell research market.

Stem Cell Sciences' core objective is to develop safe and effective cell-based
therapies for currently incurable diseases. SCS retains all rights to its
technology for therapeutic use and is targeting cell-based therapies for
neurodegenerative disease and injury.

Revenues from Stem Cell Sciences' research business are delivered via an
integrated network of business teams and regional offices in Edinburgh and
Cambridge (UK), Kobe (Japan), Melbourne (Australia) and San Francisco (USA).
This global reach provides the Company with the direct access to markets through
experienced personnel and local business networks needed to drive SCS's business
growth in each region.

The key challenge for the successful application of stem cells in both research
and clinical applications is the reproducible supply of pure, fully
characterized stem cells and stem cell-derived specialised cells such as nerves
and muscle. This represents a significant technological challenge that will
require access to multiple technologies and a globally integrated stem cell
initiative.

To access cutting edge technologies on a rapid and on-going basis, Stem Cell
Sciences has built an exceptional network of highly interactive collaborations
with academic centres of excellence in the stem cell field. These collaborations
have been the source of our founding technologies and continue to provide an
expanding pipeline of products and intellectual property that are central to the
Company's strategy and success.

To facilitate research and technology transfer with its major collaborating
academic institutions, Stem Cell Sciences' business and scientific teams are
usually co-located on site or adjacent to the centre of excellence in
independent company facilities. The Company's key collaborating institutes
include the Wellcome Trust Centre for Stem Cell Research (University of
Cambridge), the Institute of Stem Cell Research (University of Edinburgh), RIKEN
Centre for Developmental Biology (Kobe) and the Australian Stem Cell Centre
(Melbourne).

Academic and commercial use of stem cells in basic research and drug discovery
provides the Company with immediate and growing revenue streams and offsets the
cost of technology development for full scale cell production of SCS cell-based
therapeutics.

For further information on the company please visit:
www.stemcellsciences.com




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