March 26, 2002
Animal Model Study Demonstrated
Reovirus as an Effective Treatment for Breast Cancer
Oncolytics Biotech Inc. ('Oncolytics') announces the publication of a
research paper entitled "Reovirus Oncolysis of Human Breast Cancer" by
Norman et. al (Human Gene Therapy, Vol. 13, March 20, 2002), which examined
the use of the reovirus as a treatment for breast cancer in animal models.
Oncolytics is currently developing a formulation of the human reovirus
REOLYSIN(R), as a potential therapeutic against Ras-activated cancers.
The study examined two animal models of breast cancer to demonstrate the
effectiveness of the reovirus in causing tumour regression. In the first
model, human breast cancer cells were implanted over the mammary fat pad of
the SCID/NOD mice. After a tumour had been established, a single injection
of the reovirus caused a continuous regression of the tumour during a
thirty-day observation period. In the second animal model, independent
tumours were established on both flanks of the mice (bilateral model). After
the tumours had been established, a single injection of the reovirus into
only one tumour resulted in complete regression of both the injected and
non-injected tumours over thirty-two days.
The research group also examined the ability of the reovirus to infect and
to kill breast cancer cell lines. Widespread cell killing was seen in all
five established breast cancer cell lines and in one surgical specimen. No
cell killing was observed in two cell lines established from normal breast
"The reovirus clearly demonstrated effectiveness in this study," said Dr.
Matt Coffey, Vice President, Product Development and one of the co-authors
of the study. "In the bilateral animal model, the reovirus levels were
approximately the same in the injected and non-injected tumours over the
last half of the study, and reovirus was detectable in the blood throughout
the investigation. These results support our plans to start human trials in
which REOLYSIN(R) will be administered systemically."
Breast cancer is the most common cancer in women, accounting for about 31%
of new cases. The American Cancer Society estimates that there will be
203,500 new cases of breast cancer diagnosed and 39,600 deaths in 2002 in
the United States. While the five-year relative survival rate for local
breast cancer is 96%, the survival rate for metastatic disease is only 21%.
About Oncolytics Biotech Inc.
Oncolytics is a Calgary-based biotechnology company focused on the
development of the human reovirus (REOLYSIN(R)), as a potential cancer
therapeutic. Oncolytics' researchers have demonstrated that the reovirus is
able to selectively kill human cancer cells in vitro that are derived from
many types of cancer, including breast, prostate, pancreatic and brain
tumours, and have also demonstrated successful cancer treatment results in a
number of animal models. Phase I clinical trial results have indicated that
there were no toxicology-related issues with the administration of the
reovirus, and that the reovirus demonstrated activity in tumours injected
with REOLYSIN(R). Oncolytics has filed a Clinical Trial Application (CTA)
with Health Canada and with the FDA for a Phase I/II trial investigating the
treatment of recurrent malignant glioma patients.