Valentis
Issued Third U.S. Patent for
GeneSwitch® Technology
August 12, 1999 Burlingame, CA — Valentis, Inc. (Nasdaq:
VLTS)
(formerly Megabios Corp.) announced today
that the US Patent and Trademark Office
(PTO) has issued a third patent covering the
company's GeneSwitch® gene
regulation technology. US patent 5,935,934
titled, "Mutated Steroid Hormone
Receptors, Methods for Their Use and
Molecular Switch for Gene Therapy,"
issued August 10, 1999.
The
GeneSwitch® technology provides
precise control over the level and duration
of gene expression when introduced via gene
therapy. Using the GeneSwitch®,
therapeutic genes may be turned on
(expressed) by administration of an orally
bioavailable drug in a dose-dependent
manner. Levels of a therapeutic protein can
be controlled as needed by administration of
the regulating drug in pill form.
Applications
of the GeneSwitch® technology
include viral and plasmid-based gene
therapy, as well as functional genomic
studies using transgenic animals. VALENTIS'
patents on the GeneSwitch®
technology, which also include previously
issued US Patent Nos. 5,364,791 and
5,874,534, cover gene regulation using
steroid hormone receptors in any gene
delivery system and specifically include the
regulation of therapeutic genes in the body.
"The
strong proprietary position and solid
preclinical performance characteristics of
the GeneSwitch® make it a
valuable part of the technology VALENTIS
uses to develop gene therapy products,"
stated Benjamin F. McGraw, Chairman,
President and Chief Executive Officer of
VALENTIS. "Certain gene therapies
require control over the level and duration
of expression of the therapeutic proteins
they produce. GeneSwitch® gives
us the capability to turn the activity of
the gene on or off as needed, enhancing the
control of gene therapy products."
The
functionality of the GeneSwitch®
technology to regulate long-term gene
expression using a plasmid-based system was
published in the June 10, 1999 issue of the
journal, Human Gene Therapy by VALENTIS
scientists. The paper showed induction of
high levels of gene expression in the muscle
and secretion of protein in bloodstream
after administration of very low doses of an
antiprogestin drug. Repetitive regulation of
gene expression was achieved for several
weeks after a single dose of the GeneSwitch®
plasmid.
The
patent was issued to Baylor College of
Medicine of Houston, TX
("Baylor"), to which Valentis has
an exclusive license. The GeneSwitch®
technology was originally developed in the
laboratory of Dr. Bert W. OíMalley, M.D.,
Chairman of the department of Cell Biology
at Baylor, and a member the VALENTIS Board
of Directors. The full text of the patent
can be found on the Internet at: >www.uspto.gov.
VALENTIS,
formed in March 1999 by the merger of
GeneMedicine, Inc. and Megabios Corp., is
focused on the development of products
incorporating its proprietary biologics
delivery systems. The Company uses its
expertise in gene delivery and expression to
create gene medicines that are intended to
provide a new approach to the treatment of
diseases with high unmet need or where
current therapies are inadequate. The
Company's initial focus has been on the
development of gene medicines for treating
certain cancers, cardiovascular diseases,
neuromuscular disorders, and pulmonary
diseases, as well as the development of
genetic vaccines for the treatment or
prevention of infectious diseases. Gene
medicines deliver instructions to targeted
cells in the body to produce therapeutic
proteins. The Company has established
corporate partnerships with Hoffman-La
Roche, Eli Lilly and Company, Glaxo Wellcome
plc and a manufacturing partnership with DSM
Biologics and Qiagen N.V.
Statements
in this news release that are not strictly
historical are "forward-looking"
statements as defined in the Private
Securities Litigation Reform Act of 1995.
There can be no assurance that VALENTIS will
be able to develop or market a commercially
viable gene medicine, that any clinical
trials will be successful or that necessary
regulatory approvals will be obtained. The
actual results may differ from those
projected in forward-looking statements due
to risks and uncertainties that exist in the
Company's operations and business
environment. These are more fully described
in the Megabios and GeneMedicine Combined
Proxy Statement dated
February 12, 1999 and the Megabios
and GeneMedicine annual reports on Form 10-K
for the periods ended
June 30, 1998 and
December 31, 1997, respectively,
filed with the SEC.
