Geron Reports Advances in Its Human Embryonic Stem Cell Programs
MENLO PARK, Calif.--(BUSINESS WIRE)--April 3, 2003--
Presentations Demonstrate Engraftment of Dopaminergic
Neurons in a Model of Parkinson's Disease as Well as
Characterization and Long-Term Stability Data
Geron Corporation (Nasdaq:GERN) reported on multiple advances in
its human embryonic stem cell (hESC) programs at the 2003 Keystone
Symposium entitled "From Stem Cells to Therapy" held in Steamboat
Springs, Colorado. Geron scientists presented data showing engraftment
of hESC-derived dopaminergic neurons transplanted into the brains of a
rat model of Parkinson's disease and the production of pure
populations of hESC-derived cardiomyocytes. Also, in four separate
presentations, Geron scientists described studies that defined the
properties and biological stability of hESCs over long-term culture.
Neurons for Parkinson's Disease
Geron scientists demonstrated that hESCs can be differentiated
into dopaminergic neurons, the therapeutic cell type for the potential
treatment of Parkinson's disease. Using protocols developed at Geron,
hESCs were differentiated first into neural progenitors and then into
neurons expressing thyrosine hydroxylase - the rate-limiting enzyme
for the production of dopamine. The differentiated cells formed
robust, viable dopaminergic neural grafts after transplantation into
the brains of an established rat model of Parkinson's disease.
"These results demonstrate that hESCs can be differentiated into
target cells which have been difficult to scalably produce by other
means," said Jane S. Lebkowski, Ph.D., Geron's vice president of
regenerative medicine. "The survival of the human dopaminergic neurons
in the brains of the rat model of Parkinson's disease shows that these
cells can engraft in the adult brain micro-environment."
Cardiomyocytes for Heart Disease
Geron scientists presented new data showing that cardiomyocytes
(heart muscle cells) can be derived from hESCs and enriched by a
serum-free culture formulation that prevents the growth of unwanted
cell populations. These hESC-derived cardiomyocytes displayed
appropriate cardiomyocyte molecular markers and responded normally to
cardiac drugs used clinically to treat heart disease. These results
are important because they predict integration of the hESC-derived
cardiomyocytes into damaged heart tissue when transplanted.
Furthermore, the results predict that such newly regenerated heart
muscle tissue will respond normally to cardioactive drugs.
hESC Stability
Recent Geron data demonstrate that the unique properties of
undifferentiated hESCs are fully retained even after long-term
continuous culture. Three different hESC lines were cultured long-term
using feeder-free conditions (developed by Geron) and monitored for
eight cell surface markers. All eight markers were continually
expressed for over 70 culture passages (more than one year in
continuous culture). This remarkable cellular stability was also
reflected by the constant expression during the culture period of
telomerase activity and multiple specific transcription factors known
to regulate gene expression. Microarray analysis further demonstrated
this stability: only 23 of 2,798 tested genes exhibited more than a
three-fold change in expression after hESCs were cultured for 12 to 27
weeks. Approximately 80% of individual hESCs cultures maintained their
normal complement of chromosomes, and those that developed karyotypic
abnormalities could be identified, discarded and replenished from
frozen hESC banks. Most importantly, the hESCs remained pluripotent --
capable of differentiating into cells of all major lineages of the
body -- even after nearly one and one half years in continuous
culture.
"These data show that hESCs have very stable properties when
scalably propagated in feeder-free culture," stated Thomas B. Okarma,
Ph.D., M.D., Geron's president and chief executive officer. "This
important and unique feature of hESCs validates our product model for
commercialization of hESC-based therapies. The therapeutic cells can
be manufactured in large, multi-dose lots, shipped and stored frozen
for 'off the shelf' use by healthcare providers."
hESC Qualification
Finally, Geron presented data on the qualification and culture of
hESCs for human therapeutic use. Qualification of hESCs establishes
safety and consistency criteria necessary for use in human testing.
Four hESC lines, originally derived at the University of
Wisconsin-Madison, were tested for sterility and various human
pathogens including HIV 1 & 2, human T-cell leukemia viruses 1 & 2,
human cytomegalovirus, and hepatitis B & C viruses. All four hESC
lines showed no evidence of infection with any of these human
pathogens. In addition, the H1 cell line was extensively tested for
infection by pathogens that could have contaminated the reagents used
to derive or culture that particular hESC line. No evidence was found
for H1 line infection by viruses of human, porcine, murine, or bovine
origin. Other results presented by Geron at the meeting demonstrated
that defined and highly purified reagents can be used to culture
hESCs, enabling the development of manufacturing specifications for
hESC-based products that will meet the high standards required for
human therapeutic use.
Geron is a biopharmaceutical company focused on developing and
commercializing therapeutic and diagnostic products for applications
in oncology and regenerative medicine, and research tools for drug
discovery. Geron's product development programs are based upon three
patented core technologies: telomerase, human embryonic stem cells and
nuclear transfer.
This news release may contain forward-looking statements made
pursuant to the "safe harbor" provisions of the Private Securities
Litigation Reform Act of 1995. Investors are cautioned that such
forward-looking statements in this press release regarding future
applications of Geron Corporation's technology constitute
forward-looking statements involving risks and uncertainties,
including, without limitation, risks inherent in the development and
commercialization of potential products, need for additional capital,
need for regulatory approvals or clearances, and the maintenance of
our intellectual property rights. Actual results may differ materially
from the results anticipated in these forward-looking statements.
Additional information on potential factors that could affect our
results and other risks and uncertainties are detailed from time to
time in Geron's periodic reports, including the annual report on Form
10-K for the year ended on December 31, 2002.
--30--GM/sf*
CONTACT: Geron Corporation
David L. Greenwood, 650/473-7765
KEYWORD: COLORADO CALIFORNIA
INDUSTRY KEYWORD: PHARMACEUTICAL BIOTECHNOLOGY
SOURCE: Geron Corporation |
