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CONTACTS:
LORUS THERAPEUTICS INC. CANADIAN MEDIA CONTACT: US MEDIA CONTACT
Corporate Communications Hugh Mansfield Jennifer Taylor
Grace Tse Mansfield Communications Inc. Mansfield Communications Inc.
Tel: (416) 798-1200 ext. 380 Tel: (416) 599-0024 Tel: (212) 370-5045
Email: ir@lorusthera.com Email: hugh@mcipr.com Email:jennifer@mcipr.com
LORUS THERAPEUTICS PUBLISHES RESULTS OF NOVEL GENE THERAPY
APPROACH FOR COLON CANCER
- Tumor suppression of colon cancer in pre-clinical tests -
TSX: LOR
OTC BB: LORFF
TORONTO, CANADA, OCTOBER 1, 2003 - Scientists at Lorus Therapeutics Inc.
("Lorus") have published the results of experimental studies aimed at developing
an anti-cancer gene therapy based on over-expression of a novel tumor suppressor
gene in colon cancer cells. The results appear in an article entitled,
"Adenovirus-mediated Ribonucleotide Reductase R1 Gene Therapy of Human Colon
Adenocarcinoma" in the October 1 issue (Volume 9, issue 12, page 4553-4561) of
Clinical Cancer Research.
The publication presents the results from studies demonstrating that the large
subunit of ribonucleotide reductase (RNR), R1, acts as a novel tumor suppressor
that, as a gene therapy, has the potential to treat colon cancer.
A virally encoded human R1 gene was delivered into tumor cells by infection
resulting in high expression levels of the R1 protein. Over-expression of R1
decreased tumor cell growth in a number of colon cancer cell lines in culture.
Furthermore, pre-treatment of colon cancer cells with a recombinant virus
encoding R1 resulted in decreased growth of tumors after implantation of the
treated cells into mice.
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Most importantly, a dramatic and sustained decrease in tumor growth resulted
when human colon tumors implanted into mice were directly injected once a day
for a total of five times, with a recombinant virus encoding R1, suggesting the
treatment is clinically feasible. The anti-tumor activity was specific to
expression of the R1 gene as evidenced by the superior efficacy over the same
virus encoding a gene other than R1.
"The expansion of Lorus' research to include development of a viral-based gene
therapy demonstrates our commitment to the discovery of novel cancer therapies.
Publication in a highly regarded scientific journal, such as Clinical Cancer
Research, adds confidence to both our scientific capabilities and to our
approach to drug discovery and development," said Dr. Jim Wright, CEO of Lorus.
Dr. Yun Yen from the Department of Medical Oncology & Therapeutics Research at
the City of Hope National Medical Center is a leading researcher on RNR
involvement in tumorigenesis and metastasis and provides a commentary on the
Lorus discovery in the "The Biology Behind" section of the same issue of
Clinical Cancer Research (page 4304-4308), entitled, "Ribonucleotide Reductase
Subunit 1 as Gene Therapy Target."
Dr. Yen summarizes the current understanding of how R1 functions in cell
proliferation and DNA damage repair. Moreover, he outlines the implications of
the results of the Lorus study to our understanding of the mechanisms by which
R1 contributes to the above processes and the potential application of R1 gene
therapy in cancer treatment.
About Lorus
Lorus is a biopharmaceutical company focused on the research and development of
cancer therapies. Lorus' goal is to capitalize on its research, pre-clinical,
clinical and regulatory expertise by developing new drug candidates that can be
used, either alone, or in combination, to successfully manage cancer. Through
its own discovery efforts and an active acquisition and in-licensing program,
Lorus is building a portfolio of promising anti-cancer drugs. Late-stage
clinical developments and marketing will be done in cooperation with strategic
pharmaceutical partners. Founded in 1986, Lorus Therapeutics Inc. is a public
company listed on the Toronto Stock Exchange under the symbol LOR, and on the
OTC BB exchange under the symbol LORFF.
Except for historical information, this press release contains forward-looking
statements, which reflect the Company's current expectation regarding future
events. These forward-looking statements involve risks and uncertainties, which
may cause actual results to differ materially from those statements. Those risks
and uncertainties include, but are not limited to, changing market conditions,
the successful and timely completion of clinical studies, the establishment of
corporate alliances, the impact of competitive products and pricing, new product
development, uncertainties related to the regulatory approval process, and other
risks detailed from time-to-time in the Company's ongoing quarterly filings,
annual information form, annual reports and 20-F filings.
Lorus Therapeutics Inc.'s press releases are available through the Company's
Internet site: http://www.lorusthera.com.
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