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Protox reports efficacy data of prostate cancer drug in animals
Wednesday, April 20th, 2005 - Vancouver, British Columbia - Protox
Therapeutics Inc. announces completion of a set of animal studies that provide
further evidence of the efficacy of its lead product, which is being developed for the
treatment of localized prostate cancer. The product is a genetically engineered form
of the naturally occurring protein Aerolysin, which kills cells by forming holes in
them.
The studies were conducted at Johns Hopkins Kimmel Cancer Center under the
direction of Sam Denmeade, M.D., and will be presented on Wednesday, April 20 at
the 96th Meeting of the American Association of Cancer Research (AACR) held in
Anaheim, California. Simon Williams, Ph.D., who was awarded the AARC-AFLAC
Scholar in Training Award for this research, will present the paper entitled
Tumoricidal effects of a PSA-activated pore forming toxin. Protox' Chief Scientific
Officer, Tom Buckley, Ph.D., is a co-author of the paper. A brief summary of the
results are as follows:
- Preliminary studies with cell lines confirmed that engineered proaerolysin
preferentially killed prostate cancer cells.
- An in vivo study showed that a series of intratumoural injections of
engineered proaerolysin into human prostate tumours growing in mice
resulted in large reduction in tumour volume and the mice showed no signs of
toxicity.
- Decrease in prostate specific antigen (PSA) levels is one of the key markers
now used to determine response of prostate cancer to therapy. The effect of
intratumoural injection on blood PSA levels was studied in human prostate
tumour-bearing mice by injecting microgram doses of engineered protein into
the tumours every 72 hours. The results showed complete cessation of
tumour growth and a substantial decrease in blood PSA levels.
These studies establish for the first time the potential to use a modified pore-forming
toxin for prostate cancer therapy. They demonstrate the efficacy of the Company's
lead product with cell lines and human prostate tumours growing in mice, and
provide considerable preclinical support for its use in the treatment of localized
prostate cancer.
"We are very pleased with the pace of the company's pre-clinical development
program", said Dr. Fahar Merchant, President and CEO of Protox. He adds, "These
data validate the strength of our platform technology. The results are particularly
satisfying when taken together with the safety data we are getting from our pilot and
GLP animal studies."
Protox expects to file an Investigational New Drug Application (IND) application with
the United States Food and Drug Administration (FDA) this summer for its first
product designed for the treatment of localized prostate cancer. Subject to FDA
approval, the Company intends to proceed with Phase I clinical trials.
A copy of the abstract can be obtained by visiting the Protox website
www.protoxtherapeutics.com under the Publications section.
ABOUT PROTOX: Protox Therapeutics Inc. is developing novel cancer therapeutics
by engineering the naturally occurring bacterial toxin Aerolysin, which kills cells by
forming pores in them. The Company believes that its engineering approach will
produce targeted cancer therapeutics that have greater efficacy and fewer side
effects than existing cancer treatments.
For more information, contact:
Terry Vanderkruyk
Director, Investor Relations, Protox Therapeutics Inc.
Tel: 604-688-4376
Cell: 604-789-0844
Fax: 604-688-0173
tvanderkruyk@protoxtherapeutics.com
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